12V & 24V diy battery

[pekka8]

I have now a factory made 200Ah 12V battery and Victron 12v inverter charger. My plan is to replace now the battery with diy JK 200A & 8x Eve battery cells and later replace Victron with 24V version. I will install cells in one row. So i have two questions
- is it possible to reconfigure the row of cells from 12v to 24V by just replacing the positions of busbars?
- does a JK BMS support both 12V and 24V? Couldn't find the info on their website

Thanks!

 

[LakeHouse]

- is it possible to reconfigure the row of cells from 12v to 24V by just replacing the positions of busbars?

For your factory-made battery, probably not. For a DIY battery, yes. You can make those 8 cells into two 12V batteries (two sets of 4 in series, 4s2p), OR one 12V battery with twice the Ah (2p4s), OR one 24V battery (8s). It's just different arrangements of bus bars and BMS's.

- does a JK BMS support both 12V and 24V? Couldn't find the info on their website

Yes, JK makes BMSs that can work in either 12V or 24V configuration. JK-B2A8S20P, for example. But anything they make with an 8S designation should work.

 

[pekka8]

For your factory-made battery, probably not. For a DIY battery, yes. You can make those 8 cells into two 12V batteries (two sets of 4 in series, 4s2p), OR one 12V battery with twice the Ah (2p4s), OR one 24V battery (8s). It's just different arrangements of bus bars and BMS's.

Yes, JK makes BMSs that can work in either 12V or 24V configuration. JK-B2A8S20P, for example. But anything they make with an 8S designation should work.

JK's website seems to be listing only 16 cell models so 16S works also? Where do you find this information on the web site?

 

[LakeHouse]

JK's website seems to be listing only 16 cell models so 16S works also? Where do you find this information on the web site?

No, the JK's for 16s batteries (20S, 24S, etc. models) won't work for 4s or 8s. The voltage isn't high enough. JK's website isn't great for finding spec sheets. You're better off looking for a spec sheet from whoever is selling you the BMS, or just searching the web.
Here's one: JK-B2A8S20P Manual

 

[pekka8]

No, the JK's for 16s batteries (20S, 24S, etc. models) won't work for 4s or 8s. The voltage isn't high enough. JK's website isn't great for finding spec sheets. You're better off looking for a spec sheet from whoever is selling you the BMS, or just searching the web.
Here's one: JK-B2A8S20P Manual

Thanks, lots of useful info, but I don't see the voltage anywhere. Maybe I'm just blind...

 

[LakeHouse]

Thanks, lots of useful info, but I don't see the voltage anywhere. Maybe I'm just blind...

What voltage were you hoping to see? 4s is 12.8V, 8s is 25.6V. It'll work for anything in that range.

 

[pekka8]

View attachment 246709

What voltage were you hoping to see? 4s is 12.8V, 8s is 25.6V. It'll work for anything in that range.

Ah okay now got it. So busbars have to be configured for either 4 or 8 strings. And string is always 3.2V. Just learning the stuff.