BMS capacity vs Load


HUGE range of batteries & accessories at www.batteryhookup.com 5% coupon "POWERWALLS"

507PowerWall

Member
Joined
Jun 6, 2020
Messages
103
Hi All,

I have a question related to BMS amps capacity.

Im building a 14s18p powerwall , lets say that I can draw 5am per P = 90amps (idealy)

But I know that the max charge capacity from the Charge Controller is 30 amps

And the Load will not exceed 20 becuase I will use a 1k GTILv2

Im planing to buy a 50amp BMS since I will not exceed 30amps and I know these chinnesse BMS 50amps is max short burst, but constant 30 to 40amps

50amp BMS is ok for a battery that probably will have 70 to 90 amps capacity ?


Thanks in advance
CG
 

OffGridInTheCity

Active member
Joined
Dec 15, 2018
Messages
2,032
507PowerWall said:
Hi All,

I have a question related to BMS amps capacity.

Im building a 14s18p powerwall , lets say that I can draw 5am per P = 90amps (idealy)

But I know that the max charge capacity from the Charge Controller is 30 amps

And the Load will not exceed 20 becuase I will use a 1k GTILv2

Im planing to buy a 50amp BMS since I will not exceed 30amps and I know these chinnesse BMS 50amps is max short burst, but constant 30 to 40amps

50amp BMS is ok for a battery that probably will have 70 to 90 amps capacity ?


Thanks in advance
CG
Yes sir - its not about capacity, its about how many amps flow thru the BMS. My battery can do 1000a but I have a 400a shunt-trip because of $ and wire size andbecause that's most I want to draw for the forseeablefuture.. If you buy a smaller BMS now its fine, but if you think that ater you will want more current flow - then you have to weigh the cost of replacing the smaller one with a bigger one vs putting in a bigger one now.
 

507PowerWall

Member
Joined
Jun 6, 2020
Messages
103
OffGridInTheCity said:
507PowerWall said:
Hi All,

I have a question related to BMS amps capacity.

Im building a 14s18p powerwall , lets say that I can draw 5am per P = 90amps (idealy)

But I know that the max charge capacity from the Charge Controller is 30 amps

And the Load will not exceed 20 becuase I will use a 1k GTILv2

Im planing to buy a 50amp BMS since I will not exceed 30amps and I know these chinnesse BMS 50amps is max short burst, but constant 30 to 40amps

50amp BMS is ok for a battery that probably will have 70 to 90 amps capacity ?


Thanks in advance
CG
Yes sir - its not about capacity, its about how many amps flow thru the BMS. My battery can do 1000a but I have a 400a shunt-trip because of $ and wire size andbecause that's most I want to draw for the forseeablefuture.. If you buy a smaller BMS now its fine, but if you think that ater you will want more current flow - then you have to weigh the cost of replacing the smaller one with a bigger one vs putting in a bigger one now.
 

507PowerWall

Member
Joined
Jun 6, 2020
Messages
103
OffGridInTheCity said:
507PowerWall said:
Hi All,
Thanks in advance
CG
Yes sir - its not about capacity, its about how many amps flow thru the BMS. My battery can do 1000a but I have a 400a shunt-trip because of $ and wire size andbecause that's most I want to draw for the forseeablefuture.. If you buy a smaller BMS now its fine, but if you think that ater you will want more current flow - then you have to weigh the cost of replacing the smaller one with a bigger one vs putting in a bigger one now.

Thanks good advse
 
Top