This content details the process of selecting and configuring a Battery Management System (BMS) and an onboard charger for a 50 kWh LFP (Lithium Iron Phosphate) battery pack in an electric vehicle, emphasizing the critical role of data sheets and fundamental calculations.
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Yes. [snorts]
Now in yesterday's session we tried the
calculation to do with the
NMC pack. There was one factor which we
had I hope everyone I think we gave
approximately around 30 minutes for this
calculation. Did everyone get the answer
for this one? It is similar to the NMC
but we did with this calculation with the
data sheet the data sheet which was said
Yes. Now if you have got the answers, if
you have got the answers uh the in the
end of the session there will be a link
posted. So with that link you can upload
that answer in that one. Right. Once you
upload that answer we'll see how many of
you have got the answer for that one.
Now shall we solve this or we will move
to the further topics. You want this to
be solved. Hope if you have everyone has
solved well and good. If you have not
got we will solve this and we will move
forward. Let me know we will solve this
Okay. So hope there are mistakes that
you have done in the calculations. So we
will quickly start solving the
question which is given here. For this one,
calculating with the data sheet which we
have got the data sheet. Hope everyone
is having the data sheet. Now with the
data sheet itself we'll solve okay we'll
solve the data sheet
>> Yes. Now the first thing we it's a very
simple question. Let us understand the
question. Question [clears throat]
[clears throat]
LFP battery pack. We have a car. We have
we have our car which is having a high
voltage battery pack. Okay. High voltage
battery pack. We know that the voltage
is 300. 300 volts is the architecture of the
high voltage cut right. So next we have
our per cell was given as our 100h and
what was the back kilowatt it is 50 kow.
So we had this data and we had our LFP.
Now the question asked was simple to
find out the BMS and find out the
charger for onboard charger for the
for this 50 KOW LFB battery pack of a
car. The question is
50 50 kow high voltage car for a for a
50 kow high voltage car we wanted to
select a BMS and the charger. For
selecting the BMS and the charger
what basically we need we need our yes
we need our P we need our charging C we
need our discharging C right with all
these factors itself we can
we can find out BMS and charger with
this one we had now find out yes what is
the number of yes in this one
what is the number of yes in this Yes.
94. Yes. Because obviously we know 300
volt is the
it is this is
This is
pack voltage divided by nominal voltage
gives you number of years. Right? We got
that and even P number of P we got it as
166 is the answer which we got but 166
we cannot do that. So the next
upgradation which you have done is 200H
we have taken as 2p this one everyone
understand till here right. So everyone
understand till here. Now the next thing
is the C rating the charging C rating
and the discharging C and the selection
of VMS or spending which in our previous
now we wanted our discharge C. We have
selected our discharge. The fourth one
we will see with our discharge C. With
our data sheet in the data sheet it
mentioned was maximum discharge which we
can get it was around 300 W hour. 300 W
hour is the maximum discharge we which
we could take out from the battery pack.
Right? Now in if it says 300 W hour,
what is the maximum current that we can
take it out?
Most of you I think we have already
solved this uh when we are reading the
data sheet. We have already solved this
one. Let me know the answers. What is
the maximum current? If it says 300 W hour
what is the maximum current that we can
take out?
what we need we need our I here what is
I? It is basically P / V we'll get our I
right P divided by I we'll get our P
divided by V we'll get our I now what
300 divided by 3.2 to the nominal voltage
discharge pack of one thing which we
have to see is we have to see the entire
battery pack each age also this one this
data sheet is 300 W hour we have got it
for individual cell remember this is for
individual one cell now we are
calculating it for the entire big
battery pack right now is now one
individual cell but battery pack
for 50 thing. So the total age which we
Basically this is
what is the answer for this?
94 amps. What about the C rating?
Whating we were actually checking for
the C rate. We have got the thing is per
our cell we can maximumly take 94 amps.
It is obviously 0
94. Right? Now we in this entire thing
in the previous calculation which we in
the slides when we were doing the
calculations we had seen we had
calculated for the entire uh charging
and discharging everything we had
discharging c rate we we had got around
1.9 9 C and charging C rating we had got around
600 W right so in this one read
carefully the data sheet everyone is
having the data sheet
see here we have done a mistake
here we have done a mistake what is the mistake
mistake
rated charge
maximum charge power. Right? What is the
maximum charge power here? Maximum
charge power is 300 W. Maximum charge
power itself is 300 W but we are
calculating it for our discharging
right. We are calculating it for
discharge but what calculation we have
done is for
charging 300 W right the data sheet that
is the point where I was stressing for
you to read the data sheet carefully
this calculation which we are doing is
completely wrong because we need to
right? Charging is the parameter. Just
open the data sheet and check once. What
what does this says? The sixth one.
Sixth one says that the maximum charge
power is 300 W.
where we have done the mistake we have
to do the charging calculation. Now
charging calculation we have got to know
that it we'll get at around 0.4 4 C
which we'll be rounding at as 1 C right
read the data sheet carefully from
yesterday we are trying to solve this
and no one has noticed this one the
charging and the discharging factors
right the charging when it comes for C
rating 1 C is the discharging what now
1 C is the discharging sorry charging
The charging thing we have got our
answer as 1 C. Wait 1 C. I can charge my
battery pack. If it says 1C, what is the
Now we got to know the individual
battery pack C rating. We have 200H. The
C rating of the battery pack is 1 C.
Now, now if we have 1 C, what is the
maximum current which we can charge the
battery pack with?
How to calculate this maximum charging
current? Basically it is
C into
A H right. See we have our 1 C into AH
200
amps. Right? What is the maximum
We can take it up to
200 amps. What does this say?
This is the maximum current which I can
charge my battery pack. Right? Maximum
charging current. I got it. Now I can
charge it with 40 amps also, 50 amps
also. Right? This is this calculation
which we have got. This says that we can
charge this at maximum 200 amps. But
even though if I want to charge with 10
amps also I can charge my battery pack.
If I want to charge my battery pack at
100 amps also I can charge but I cannot
charge more than 200 amps. What is this
C rating data sheet which tells us that
is the exact thing what this data sheet
charging C. Now let us see with our
discharging C. Right? Now we got our
discharge C rating. Now, what does this
discharging say? Everyone open the data
sheet. Data sheet. Check with the data
sheet. See, I'll just open the data sheet.
seventh one.
Maximum discharge power 600 W. Maximum
discharge power is 600 W. 600 W is the
take it out. Right? 600 W. Now we have
the maximum discharge W given as 600 W.
Let us quickly calculate. Again if I
want my I have to divide my P by V which is
is
again 600 divided by 3.2.
What is the answer? What is the maximum
discharge power? I can take maximum
187.5
187.5
which we will be rounding it off to 188.
188.
Right? This is the answer. 188 is the
180 is the maximum discharge current
which I can take out discharging. See
maximum current we can take it out as
188 amps. Next, what do we have?
Now, we have our BMS to be selected.
Now, we need to select our BMS. Charging
current, we got it. Discharging current
Maintain discharging current. We got it.
It is 1.88 C.
C.
This is
188 divided by 100.
100.
We'll be getting it as in the C rating.
Right? So we will I can round it off up
to maximum as 2 C also or let us
consider this as 1.9 C which is then
1.9 C
from the cell I can take out maximum 188
amps. Now that I have my 1.9C, what is
the maximum current that I can take out
from my battery pack? Now that we have
calculated individual discharging
capability, now in this 50 KOW battery
pack in this one right 200 ah pack in
this one which we'll be having around 200
200
is the
current and what is the formula it is C into
into
the pack ah right see what is the C
rating which we have got we have got 1
Right? What is the maximum discharging
current which we can take is 380 amps is
Right. Now that we have our charging and
discharging both 380 amps and even this
the answer what is the answer for this
it is 1
9 C
is the discharging current which we can
take out from the according to the data
sheet right next what is the calculation
parameter which we want we have to
select our BMS TMS and charger and
cells. These three parameters have left
out. I think till now it is very simple.
Again it is the only division
multiplication which we are doing right.
This is the entire basic very basic
fundamentals. Now the selection of BMS.
Now comes the selection of BMS. See for
this one you need to do you need to do
multiple depth calculation but all those
calculations are very basics you need to
know how to this how this yes came how
this P came with all the if you have
attended all the classes from the day
one it is a piece of cake just just
finding out the number of yes doing the
multiplication and division it is a very
simple concept right now we'll start
BMS for a
with what are the ratings. Till now we
have got we have got the rating as the
the
charging C as
as
1 C and
discharging C as
and yes is
number of yes is 94
and number of P is
what is the number of P it is two for
this parameters now we have to select
Right. For the selection of BMS what we
need BMS. Again we need our seven
criterias. The seven basic criterias.
What was the first criteria?
What was the first criteria? That the
first one is cell voltage should not cross.
cross.
should not be
more than
3.6 six right now just imagine now I'm
verbally writing on the board because
this is how we'll be feeding the data to
the microcontroller right now if I want
to select design a BMS this is how we'll
feed the data for that one that when
you're operating you have to make sure
for the BM for the microcontroller what
are we saying for the microcontroller we
are saying that see if any of the cell
it goes above 3.6 Six you should make
sure that the battery gets cut down.
Right? So according to the data sheet
what is the full charge voltage? Again
What is the data sheet which says the
first one charge voltage in the sense it
is the maximum wtage. What is the
maximum wtage? It is 3.65 65 charge voltage
charge voltage is 3 65 3.65 is the
charge voltage according to when we are
designing it according to the charge
voltage we'll do it it according to the
data sheet itself right the maximum cell
wtage should not cross more than 3.65 65
is the
thing for the
BMS according to the data sheet. Right
should not go below.
Check the data sheet and let me know.
Yes, it is 2.5. It says the eighth one.
Eighth one in the data sheet 81 it says
discharge cutff. What is the discharge
cutff? It is 2.5 volt. 2.5 volt is the
2.5 volt. Next
the third one. What was the third condition?
condition?
you you should have all those screen uh
thing and we'll be sharing that soon.
What is the max next one the maximum
Pack voltage should not
go above
it should not go above how much old that
we have to calculate. How to calculate
that one? Basically, it is yes into
full charge voltage, right? Number of
series into full charge voltage.
Number of series into full charge
voltage is the maximum
voltage. What is the number of yes we
have? We have 94. Yes. And what is the
maximum voltage of a cell? Cell voltage
should not cross more than 3
3
65 which we have. What will be the answer
94 into 3.65 which gives us 343.1.
So we will round it off as 343 itself
which we will be rounding it off as 343
everyone everyone understood pack voltage should not cross more than
Now which was the next condition for our BMS?
BMS? Pack voltage
should not drop below pack voltage should not drop below how
pack voltage should not drop below how much old.
It is the same calculation number of series into but the thing is what should
series into but the thing is what should I select?
I select? You should select the
minimum cell voltage or the cutff voltage. Z what do we call it as? What
voltage. Z what do we call it as? What is the short form? We call it as cutff
is the short form? We call it as cutff voltage.
Right? Cell voltage should not go below cutff voltage. Cut off voltage. Now what
cutff voltage. Cut off voltage. Now what is yes here? Number of series remains
is yes here? Number of series remains the same 94 and it is multiplied by what
the same 94 and it is multiplied by what is the cell minimum wtage? It is 2
5 volt which gives us around what is the answer.
Yes, 235 exactly. There's no need of round off. 235 is the direct answers
round off. 235 is the direct answers which we are getting.
If you remember what was our fifth condition.
We have got the maximum pack wtage should not go more than 343. Pack wtage
should not go more than 343. Pack wtage should not go below 2.3 uh 235 volt that
should not go below 2.3 uh 235 volt that we have got it. Now
we have got it. Now we'll see this discharge between cell
we'll see this discharge between cell voltage should not be more than 0.009.
voltage should not be more than 0.009. The difference the cell balancing
The difference the cell balancing capability right this is universal for
capability right this is universal for everything. This is the universal point.
everything. This is the universal point. Point number five difference between
Point number five difference between cell voltage must be lesser than 0.03.
cell voltage must be lesser than 0.03. It is universally common for all the
It is universally common for all the battery packs which we design. Right? It
battery packs which we design. Right? It is the most common thing for all the
is the most common thing for all the battery packs. Now the difference now
battery packs. Now the difference now basically difference we represent it
basically difference we represent it with delta. Right? The representation of
with delta. Right? The representation of difference is represented with delta.
This is the difference wtage. Right? If we have seen in the previous sessions,
we have seen in the previous sessions, this is the difference wtage which we
this is the difference wtage which we consider. So difference wtage basically
consider. So difference wtage basically we call this as delta. the difference
we call this as delta. the difference between so
between so delta what we will do is we'll consider
delta what we will do is we'll consider as
should not be more than 0 0
0 Thank you.
Right. Delta should not cross more than 0.009.
That is the fifth one. And what is the sixth condition?
We'll add this in the next thing for here. We'll do the calculation must be
here. We'll do the calculation must be under operating temperature. Temperature
under operating temperature. Temperature must be under 0 to degree.
Just open the data sheet and now check
and now check recommended operating temperature. Even
recommended operating temperature. Even this one when we are selecting it
recommended storage temperature operating temperature right this is the
operating temperature right this is the operating temperature what is the
operating temperature what is the maximum operating temperature operating
maximum operating temperature operating temperature charging it must be 0 to 45°
temperature charging it must be 0 to 45° and while discharging minus 20° to 60°
and while discharging minus 20° to 60° everyone open the data sheet
While we design or program a BMS, we need to feed all these data, right? How
need to feed all these data, right? How we'll get to know that which data has to
we'll get to know that which data has to be feeded? If we know the entire basics,
be feeded? If we know the entire basics, then only we can feed the data to the
then only we can feed the data to the microcontroller. Yes, that these data
microcontroller. Yes, that these data has to be feeded.
Right. What is the operating temperature?
Everyone just check the point number nine.
the point number nine. What is the point number nine? Which is
What is the point number nine? Which is which it says point number 9 which says
which it says point number 9 which says operating temperature
operating temperature charging I can charge it from 0° to 45°
charging I can charge it from 0° to 45° discharging from -20° to 60°
operating temperature. So based on when we are designing with based on the data
we are designing with based on the data sheet based on this data sheet itself we
sheet based on this data sheet itself we will design it right. This is what we
will design it right. This is what we will do.
the temperature must be and now the temperature we'll be we have to program
temperature we'll be we have to program the BMS in such a way that temperature
the BMS in such a way that temperature has to be in two combinations one is why
has to be in two combinations one is why which are the two combinations which I
which are the two combinations which I have to do for this battery pack now for
have to do for this battery pack now for this uh BMS now which are the two
this uh BMS now which are the two condition that I have to declare for
condition that I have to declare for this
this which are the two conditions which I
which are the two conditions which I have to tell this BMS charge Charging
have to tell this BMS charge Charging and discharging. Yes, exactly. Charging
discharging. Charging what is the temperature and discharging what is the
temperature and discharging what is the temperature according to the data sheet.
temperature according to the data sheet. It is nothing but we just mentioning
It is nothing but we just mentioning whatever in inside the data sheet is
whatever in inside the data sheet is there. That data we are feeding it to
there. That data we are feeding it to the BMS. It's very simple. charging it
the BMS. It's very simple. charging it is 0° to 45°.
0° to 45°
right 0° to 45°C. Next at discharging it is -20°
60° discharging. Charging and discharging. Right now we have got the
discharging. Right now we have got the charging and discharging also which is
charging and discharging also which is the next
the next thing
thing overurren protection.
Right? Next thing is overurren protection. Now how to know that the max
protection. Now how to know that the max overurren how it has to be declared?
overurren how it has to be declared? over current.
over current. Maximum over current is
Maximum over current is what is the maximum over current? Again
what is the maximum over current? Again I have to declare it at two conditions
I have to declare it at two conditions right
right two condition mention over current
two condition mention over current protection. Now we have done with the
protection. Now we have done with the six parameters declaring
six parameters declaring we have declared the six parameters. Now
we have declared the six parameters. Now we have to declare the overurren also.
we have to declare the overurren also. Now if I select
overcurren protection. Now again it has to be done with
Now that we have finished how many conditions of the BMS?
conditions of the BMS? We have finished six condition. The
We have finished six condition. The seventh one we will be noting it down.
right? Which is the seventh? It is.
Again in over current we have to bifategate with with two condition. Why
bifategate with with two condition. Why two condition? Again it is the same
two condition? Again it is the same discharge and
discharge and charge two conditions. Why that this
why this two condition came again charge and discharging.
and discharging. Why these two condition came again
Why these two condition came again charge and discharging in the
charge and discharging in the temperature also while discharging also
temperature also while discharging also because both the discharging parameters
because both the discharging parameters are different right both the discharging
are different right both the discharging conditions are different
if an example I'll give you an example now maximum charging current is what is
now maximum charging current is what is the maximum charging current which we
the maximum charging current which we have got according to our previous
have got according to our previous calculations what is the maximum Here
things. What is the maximum charging current we have? We have our maximum
current we have? We have our maximum charging current which says
charging current which says it is 200 amps maximum. It is a 200 amps
it is 200 amps maximum. It is a 200 amps maximum charging capability. But when it
maximum charging capability. But when it comes for discharging I can take it up
comes for discharging I can take it up to 380 amps. 380 amps is the discharging
to 380 amps. 380 amps is the discharging maximum current and charging current. If
maximum current and charging current. If I set my
I set my BMS maximum uh discharging current to
BMS maximum uh discharging current to 380 amps, obviously when if anything
380 amps, obviously when if anything happens while charging, while charging,
happens while charging, while charging, if the current goes above 200 also will
if the current goes above 200 also will my BMS protect the battery pack. If my
my BMS protect the battery pack. If my data which is feeded for the
data which is feeded for the microcontroller that you have to become
microcontroller that you have to become an open circuit, you have to protect the
an open circuit, you have to protect the battery pack. When the current over
battery pack. When the current over current production goes more than 380
current production goes more than 380 amps, will the battery pack protect my
amps, will the battery pack protect my battery while charging if the charging
battery while charging if the charging current goes more than 200 amps.
Obviously the BMS will not protect. Very simple.
So we want two different categories. One is for LFP sorry one is for charging and
is for LFP sorry one is for charging and one is for discharging. Again we have to
one is for discharging. Again we have to set the data for this BMS. While
set the data for this BMS. While charging you have to set the current.
charging you have to set the current. While charging what is the maximum
See in over current we have again two categorization
discharge condition and charge condition.
Charge and discharging condition. What is the maximum charging condition?
is the maximum charging condition? Charging current we have already
Charging current we have already calculated it. Maximum discharging
calculated it. Maximum discharging current will go up to 180 amps, right?
current will go up to 180 amps, right? This is of what is the maximum charging
This is of what is the maximum charging current which we had selected.
Okay. Correct. While charging we can maximumly put up to 200 amps.
200 amps and while discharging maximum output I can take out from the battery
output I can take out from the battery pack is 380 amps. Now which is the next
pack is 380 amps. Now which is the next condition?
Seventh is also done. The eighth condition.
It is short circuit. Now what basically short circuit? Now how can I declare the
short circuit? Now how can I declare the data? How can I BMS sense that it has
data? How can I BMS sense that it has become short circuit?
How can I how can my BMS sense that it has become short circuit? See it is very
has become short circuit? See it is very simple fundamental.
simple fundamental. Now everyone knows that what is V?
Zero voltage and infinite current. Right? So basically what happens is what
Right? So basically what happens is what is how to find out V I want answers. How
is how to find out V I want answers. How to find out V
many answers I'm getting I into R I by R which is correct it is I by R R or I
which is correct it is I by R R or I into R
what is the exact answer I I divided by R or I into All right.
I into R. How to find out V?
It is basically it is not I by R. It is always I into R. Right?
I into R. Now for example, we have our battery pack here.
battery pack here. This is already discussed. We have our
This is already discussed. We have our battery pack here.
In this one, both over current production and short short circuit
production and short short circuit production will act at the same time.
production will act at the same time. But which will act instantly that we
But which will act instantly that we have to
have to there's
there's crying in the corner.
Right now we have our battery pack. Now we got we know that we have our positive
we got we know that we have our positive and we have our negative. For the
and we have our negative. For the negative our BMS will be connected in
negative our BMS will be connected in series. This will be the output. This
series. This will be the output. This will be our load.
will be our load. Right? This will be the negative. This
Right? This will be the negative. This will be the positive. Right? This is our
will be the positive. Right? This is our BMS.
Now what this BMS will do? this BMS if anything for example there is a short in
anything for example there is a short in this one. Now this load is here. Now
this one. Now this load is here. Now this BMS is now able to read the voltage
this BMS is now able to read the voltage between now this BMS will be having this
between now this BMS will be having this BMS is now capable of measuring all the
BMS is now capable of measuring all the data from the battery pack. Right? One
data from the battery pack. Right? One wire from the positive will also be
wire from the positive will also be connected.
One wire from the positive is connected to the BMS and the negative is also
to the BMS and the negative is also connected to the BMS there. Right? Now
connected to the BMS there. Right? Now what this BMS can do is now it is now
what this BMS can do is now it is now able to read the D voltage here. Now in
able to read the D voltage here. Now in case if there is everyone in the
case if there is everyone in the previous session we got to know that
previous session we got to know that what is voltage. Basically voltage is
what is voltage. Basically voltage is potential between potential difference
potential between potential difference between two point. Now we have two
between two point. Now we have two points. What is the potential in between
points. What is the potential in between these two points? What should be the
these two points? What should be the potential difference? The force the
potential difference? The force the potential difference is called as
potential difference is called as voltage. We got to know about that one.
voltage. We got to know about that one. Now, if there is no two point according
Now, if there is no two point according to the statement,
to the statement, we have point number
we have point number one here and point number two. Our BMS is able to read the
number two. Our BMS is able to read the voltage. Now in case what they'll do is
voltage. Now in case what they'll do is for in case by mistake the load got
for in case by mistake the load got short circuited.
short circuited. What happens is now the load which was
What happens is now the load which was there it has got shorted here.
there it has got shorted here. So is there any two point here? It is
So is there any two point here? It is only one point here. Right? Even though
only one point here. Right? Even though if I measure it here, if I measure it
if I measure it here, if I measure it here, it is the same point. Now there is
here, it is the same point. Now there is no voltage here. If the voltage becomes
no voltage here. If the voltage becomes zero basically short circuit protection
zero basically short circuit protection how we are
how we are design defining for the BMS here when
design defining for the BMS here when the voltage when this voltage becomes
the voltage when this voltage becomes zero you have to become a open circuit
zero you have to become a open circuit it's a very simple thing when the
it's a very simple thing when the open circuit voltage becomes zero
open circuit voltage becomes zero open circuit becomes uh open circuit
open circuit becomes uh open circuit voltage becomes zero you have to become
voltage becomes zero you have to become open circuit I cannot BMS the
open circuit I cannot BMS the microcontroller put does it know what is
microcontroller put does it know what is short circuit it doesn't know what is
short circuit it doesn't know what is short circuit only we engineers know
short circuit only we engineers know that what is short circuit short circuit
that what is short circuit short circuit in the sense infinite current will flow
in the sense infinite current will flow voltage will become zero infinite
voltage will become zero infinite current will flow that is what we know
current will flow that is what we know but does the BMS know what is short
but does the BMS know what is short circuit if I tell that if the battery
circuit if I tell that if the battery pack become short circuit you have to
pack become short circuit you have to become an open circuit can that execute
become an open circuit can that execute it as execute
it cannot execute. So that for that purpose what we'll do is we will declare
purpose what we'll do is we will declare the data
the data microcontroller
microcontroller in case
in case opencircuit
opencircuit very simple microcontroller
very simple microcontroller it is like a slave. It is like a worker.
pack everyone accept this one. Yes. Now that we have declared all our
Yes. Now that we have declared all our eight parameters, now we have declared
eight parameters, now we have declared our all eight parameters. Now our BMS is
our all eight parameters. Now our BMS is ready.
right now this entire thing is done the selection
this entire thing is done the selection of the BMS. Now BMS selection
with the data sheet because data sheet maximum current
because data sheet maximum current maximum charge battery pack
maximum charge battery pack everything we got it this short circuit
everything we got it this short circuit production it is common for all the
production it is common for all the battery pack whichever we do which are
battery pack whichever we do which are the two common factors which we got
the two common factors which we got without the data sheet if I want to
without the data sheet if I want to declare
declare without the data sheet If I want to
without the data sheet If I want to declare the conditions of a BMS which
declare the conditions of a BMS which are those two one is the difference
are those two one is the difference voltage the difference voltage should
voltage the difference voltage should not cross more than 0.9
not cross more than 0.9 that is the first condition
that is the first condition and which is the second condition
the short circuit protection difference and the short circuit and the first two
and the short circuit and the first two can also be declared the minimum wtage
can also be declared the minimum wtage of a cell and maximum wtage of a cell
of a cell and maximum wtage of a cell Given though that we need the data sheet
Given though that we need the data sheet whether we are selecting it for an NMC
whether we are selecting it for an NMC or LFP pack right now with this single
or LFP pack right now with this single parameter I hope everyone you understood
parameter I hope everyone you understood with the BMS parameters now what we want
with the BMS parameters now what we want is if you're really interested if you're
is if you're really interested if you're really interested to learn about this in
really interested to learn about this in if you're really interested to learn
if you're really interested to learn about this entire parameters we want you
about this entire parameters we want you to practice more right this practice
to practice more right this practice even though this might be a small
even though this might be a small calculation it is only a parameters of
calculation it is only a parameters of multiplication addition but
multiplication addition but it takes
it takes lot of things to be remembered right it
lot of things to be remembered right it takes lot of things to be remembered
takes lot of things to be remembered now the first thing the yes combination
now the first thing the yes combination the charging current discharging current
the charging current discharging current BMS charging onboard charger offboard
BMS charging onboard charger offboard charger
charger Right. The maximum charging current, the
Right. The maximum charging current, the maximum discharging current, then the
maximum discharging current, then the BMS. For the BMS, we wanted our
eight parameters. The eight parameters of our BMS, right?
The eight parameters of our BMS, right? You want to practice more the so that
You want to practice more the so that see 50 K 3.7 all from one past one week
see 50 K 3.7 all from one past one week for this. What is the full charge
for this. What is the full charge voltage of the LFP? 3.6. Now everyone it
voltage of the LFP? 3.6. Now everyone it is in your tip of your mouth full charge
is in your tip of your mouth full charge everyone will say that 3.6 is the full
everyone will say that 3.6 is the full charge voltage and if I ask that if what
charge voltage and if I ask that if what is the full charge voltage of an NMC
is the full charge voltage of an NMC everyone will tell that it is 4.2 into
everyone will tell that it is 4.2 into that is how even though if this
that is how even though if this practicing makes thing you should be
practicing makes thing you should be able to perfectly answer the questions
able to perfectly answer the questions if you're really interested this is a
if you're really interested this is a very big industry the BMS whatever we
very big industry the BMS whatever we have studied whatever we have seen this
have studied whatever we have seen this is only a 1% in the entire BMS design
is only a 1% in the entire BMS design which we have learned right with this
which we have learned right with this basic fundamentals of feeding the data
basic fundamentals of feeding the data now what we have done is
Next entire thing is additional important
entire thing is additional important parameters. There are still much four
parameters. There are still much four factors. For example,
immediately battery it is a safety feature. It is a safety
it is a safety feature. It is a safety feature. Now for that safety feature
feature. Now for that safety feature also there are sensors installed in the
also there are sensors installed in the vehicle sensor sense that the vehicle
vehicle sensor sense that the vehicle has fallen down or the the vehicle the
has fallen down or the the vehicle the car has met with an accident.
car has met with an accident. Immediately what it will do based on the
Immediately what it will do based on the input
input this BMS will become a open circuit.
See microcontrollers used in most it is not one of the common
used in most it is not one of the common thing each application each thing
thing each application each thing differs right every time when you select
differs right every time when you select the microcontroller it is not it will
the microcontroller it is not it will not come for one particular thing each
not come for one particular thing each type for BMS you can select a minor
type for BMS you can select a minor microcontroller which can control or
microcontroller which can control or operate up to 32 or some basics thing
operate up to 32 or some basics thing which can operate it up to but if you
which can operate it up to but if you want the higher application when it
want the higher application when it comes for VCU
comes for VCU VU VCU
should control the entire BMS, vehicle, motor,
control the entire BMS, vehicle, motor, everything is there that you want a
everything is there that you want a microcontroller which can operate at
microcontroller which can operate at higher rates, right? That
higher rates, right? That microcontroller you want for an ECU for
microcontroller you want for an ECU for a BMS it is a very simple thing for each
a BMS it is a very simple thing for each and everything. Even for when you go it
and everything. Even for when you go it when you select it for the MCU also.
when you select it for the MCU also. Even in MCU we saw that we want a
Even in MCU we saw that we want a microcontroller to switch the MOSET.
microcontroller to switch the MOSET. Even in BMS we need a microcontroller to
Even in BMS we need a microcontroller to basically command program do things.
basically command program do things. Even in VCU we need
of obviously there will be multiple microcontrollers. One microcontroller it
microcontrollers. One microcontroller it cannot control the entire thing. Now
cannot control the entire thing. Now which is the last factor? Number of
which is the last factor? Number of cells. I tell the number of cells. All
cells. I tell the number of cells. All the data is mentioned on the
the data is mentioned on the board here. Tell the number of cells.
board here. Tell the number of cells. Maximum number of cells.
Just a minute. We'll just open the board. What is the total number of
board. What is the total number of cells? It is basically P into S. What is
cells? It is basically P into S. What is the number of P which we had got?
188 cells, right? 188 cells is the exact answer.
Number of cells is even we have not selected the charger rate. Even charger
selected the charger rate. Even charger is pending right. When it comes for the
is pending right. When it comes for the cell, what is the total number of cell?
cell, what is the total number of cell? It is S into P.
Basically it is 94 into 2
charger we have already calculated. Just see where we have calculated it.
Now we will quickly finalize the charger also.
charger. What should be the full charge voltage?
voltage? Now for the selection of charger
Now for the selection of charger for the charger, the full charge voltage
for the charger, the full charge voltage of the battery pack. What is the full
of the battery pack. What is the full charge voltage of a battery pack and the
charge voltage of a battery pack and the maximum current
maximum current?
What is the full charge voltage? Not of a cell, of the entire battery pack. What
a cell, of the entire battery pack. What is the full charge voltage?
Simultaneously you want to solve this on the book so that it will be helpful for
the book so that it will be helpful for you guys.
What is the maximum back voltage? It is 343.
343. So full charge voltage should be 340
Maximum charging current we had got approximately
right? 200 amps which we had got. 200 amps is the maximum current. But
amps is the maximum current. But 200 amps if I every day charge my
200 amps if I every day charge my battery pack with the maximum
battery pack with the maximum charge itself obviously my battery life
charge itself obviously my battery life will come down right maximum charging
will come down right maximum charging current to keep my battery packs in a
current to keep my battery packs in a safer limit. Let us not charge that
safer limit. Let us not charge that entire battery pack with 200 amps. So we
entire battery pack with 200 amps. So we will consider this as
3 C itself. See this is the maximum charging current which I can charge
charging current which I can charge maximum charging current. But obviously
maximum charging current. But obviously when I max use this maximum charging
when I max use this maximum charging current daily if I use daily now imagine
current daily if I use daily now imagine if I if we use our energy if we use our
if I if we use our energy if we use our energy up to maximum thing one of the
energy up to maximum thing one of the day we will become sick right that is
day we will become sick right that is what will happen for even the battery
what will happen for even the battery pack if we utilize the maximum energy
pack if we utilize the maximum energy daily then obviously the total overall
daily then obviously the total overall battery pack health will be reduced. So
battery pack health will be reduced. So for that consideration even in the
for that consideration even in the practical application for that
practical application for that consideration we will be using 0
consideration we will be using 0 2 C itself for the charging for that two
2 C itself for the charging for that two this is a
this is a OBC what is OBC onboard charger
charger This is a onboard charger
This is a onboard charger right what for 0.2C 2C what is the
right what for 0.2C 2C what is the maximum current which I can take
maximum current which I can take obviously our battery pack is of 200 ah
into 0 2 C which gives us what is the onboard
2 C which gives us what is the onboard charging Right.
40 amps, right? 40 amps is the
40 amps is for onboard
onboard charger. Recommended
charger. Recommended onboard charger.
onboard charger. Now data sheet charger we are also
Now data sheet charger we are also recommended. Till now we were using the
recommended. Till now we were using the recommended product. Now we were in a
recommended product. Now we were in a stage where we will recommend that uh
stage where we will recommend that uh this is the recommendation. 40 amps is
this is the recommendation. 40 amps is the maximum charge.
the maximum charge. 40 we are declaring it right
40 we are declaring it right now that we have got it for the onboard
now that we have got it for the onboard charger. Now what about offboard charger
OFBC offboard charger I can maximumly charge it up to 200 amps right 200
charge it up to 200 amps right 200 charge right so recommended
charge right so recommended maximum
maximum charger battery suggest smart though.
charger battery suggest smart though. Now for example if we have a Mahindra
Now for example if we have a Mahindra XCV9
XCV9 imagine I think everyone have seen about
imagine I think everyone have seen about this Mahindra XCV9 Mahindra B69 or XCV9
this Mahindra XCV9 Mahindra B69 or XCV9 electric car. Now that battery pack has
electric car. Now that battery pack has 50 kilowatt battery pack. The rating of
50 kilowatt battery pack. The rating of that battery is 50 kow that can be
that battery is 50 kow that can be charged at what maximum kilowatt charger
charged at what maximum kilowatt charger what is the maximum charging capability
what is the maximum charging capability that it supports for that example that
that it supports for that example that we will be seeing here. Right? 200 amps,
we will be seeing here. Right? 200 amps, right? It is basically
right? It is basically 200 into
200 into rating. We will take the rating, then we
rating. We will take the rating, then we will consider the maximum. Always
will consider the maximum. Always remember
remember to go with the rated not with the
to go with the rated not with the maximum. First we will go with the rated
maximum. First we will go with the rated then the maximum. 200 amps is the
then the maximum. 200 amps is the maximum current but with the rated
maximum current but with the rated voltage. Right? Rated voltage. Current
voltage. Right? Rated voltage. Current will be the same thing. Maximum current
will be the same thing. Maximum current by nominal voltage. What is the nominal
by nominal voltage. What is the nominal wtage?
wtage? 300 volt. Right? What is the answer? 300
300 volt. Right? What is the answer? 300 into 200.
into 200. 300 amps is the maximum.
300 amps is the maximum. 300 volt is the nominal voltage into
300 volt is the nominal voltage into maximum current is
maximum current is 200. So it gives us 60 kilowatt. It
200. So it gives us 60 kilowatt. It gives us
300 we got around
60,000 VT right so I can consider this as
VT right so I can consider this as 60 kilowatt
right 60,000 W is nothing but 60 kilowatt
kilowatt 60 KOW is what we have considered 60 KOW
60 KOW is what we have considered 60 KOW the battery pack is of 60 KOW this is
the battery pack is of 60 KOW this is the I can recommend for my battery pack
the I can recommend for my battery pack of 50 KOW 60 KOW rated thing now what is
of 50 KOW 60 KOW rated thing now what is the maximum charging wattage I can
the maximum charging wattage I can suggest now that I have recommended for
suggest now that I have recommended for 60 KOW for the charging thing. What is
60 KOW for the charging thing. What is the maximum recommended thing?
the maximum recommended thing? Maximum current.
again 200 amps into
into what is the full charge voltage?
what is the full charge voltage? What is the full charge voltage?
in BMS we have written it right 343
343. Yes. Answer
What is the answer? 343 is the full charge voltage
and maximum current is 200 amps. 68,600.
67 kilowatt is the 69 kilowatt is the maximum of charging which is
maximum of charging which is recommended.
kilowatt thing. Have we calculated everything?
We have done the entire calculations. Just let us verify that.
calculations. Just let us verify that. Yes.
Yes. Charging
Charging discharging
discharging sele
now we are all able to feed the data now.
So these will be the things in the weekend session I'll be sharing you the
weekend session I'll be sharing you the notes right in that notes BMS data again
notes right in that notes BMS data again the presentation that entire thing will
the presentation that entire thing will be one complete notes right in one
be one complete notes right in one particular notes
particular notes once you just go through that notes
once you just go through that notes you'll understand and remember
you'll understand and remember everything whatever you have learned
everything whatever you have learned here so now basically what is happening
here so now basically what is happening series you'll have all the formulas even
series you'll have all the formulas even though the formulas are very basic
though the formulas are very basic simple formulas you'll be having how to
simple formulas you'll be having how to find out yes how to find out P the C
find out yes how to find out P the C rating the discharging C how to select
rating the discharging C how to select the BMS BMS select factors
the BMS BMS select factors that will be you'll be having that note
that will be you'll be having that note so if you forget about this also with
so if you forget about this also with basics of that notes you will be able to
basics of that notes you will be able to entirely again do the selection right so
entirely again do the selection right so now you guys try because egon freeinda.
now you guys try because egon freeinda. You can try designing different types of
You can try designing different types of now 50 kilowatt do it for 100 kilowatt
now 50 kilowatt do it for 100 kilowatt do it for 10 kilowatt do it for 50
do it for 10 kilowatt do it for 50 kilowatt
kilowatt different practicing different data
different practicing different data sheets Google time try doing with with
sheets Google time try doing with with different data sheets now we have done
different data sheets now we have done with LFP and NMC try it with sodium ion
with LFP and NMC try it with sodium ion lacid it basically cannot we'll not use
lacid it basically cannot we'll not use it in cars and all so try selecting and
it in cars and all so try selecting and doing different types of calculation. So
doing different types of calculation. So just
we will just be solving this but we want you to learn the concepts and you should
you to learn the concepts and you should be able to if I just tell
be able to if I just tell 20 kow battery pack
20 kow battery pack you should consider all these factors
you should consider all these factors and you should be able to give me a 20
and you should be able to give me a 20 kow battery pack. This is the design
kow battery pack. This is the design series parist total cells be we have
series parist total cells be we have considered this cell because your
considered this cell because your application is for electric vehicle or
application is for electric vehicle or inverter
inverter that is how you we want you to be
that is how you we want you to be complete basics. So e basics.
complete basics. So e basics. Next program.
we will see right thank you everyone sorry for yesterday's session I was not
sorry for yesterday's session I was not well so I could not take that
well so I could not take that yesterday's session even today's morning
yesterday's session even today's morning session uh it was bit late uh evening
session uh it was bit late uh evening session we'll start it and we will try
session we'll start it and we will try with other parameters also and we will
with other parameters also and we will try the basics we'll try to touch the
try the basics we'll try to touch the basics of embedded system how this input
basics of embedded system how this input and output data will be fed right Thank
and output data will be fed right Thank you everyone. Hope you have learned
you everyone. Hope you have learned about all the calculations. I want you
about all the calculations. I want you to do with different calculations,
to do with different calculations, right? Thank you everyone. Bye-bye.
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