using multiple 4s/12v BMS in series for 48V battery

Just John

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QUESTION: Anyone know/try if the ubiquitous 4s/12v BMS (from JiaBaiDa brand, xiaoxiang, china mfg, etc) can handle being placed (4x) SERIES to 48V battery bank?

Check the advertising that specifically states their 150 amp model supports 4 in series for 48v. They have told me when asked that the 120 amp model does as well.

Post in thread 'JBD / Overkill BMS 120A 4S Lifepo4 in series / parallel' https://diysolarforum.com/threads/j...-lifepo4-in-series-parallel.19228/post-357531
 

sparklehunt

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Just John

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Just checked it, but the mosfets listed in the bom you posted from JBD only shows 30V max Vds. See their fet HY4903B
Then don't. I personally don't read Chinese, and thus can't find every data sheet. They tell me the 100, 120, and 150 amp are rated for 80v. I believe them.

The BOM is from the 200 amp that I have not asked about. Maybe you should?
 

pauluk

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Feb 5, 2021
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QUESTION: Anyone know/try if the ubiquitous 4s/12v BMS (from JiaBaiDa brand, xiaoxiang, china mfg, etc) can handle being placed (4x) SERIES to 48V battery bank?

MORE INFO:
I would be using (3x) VICTRON BATTERY BALANCER ($65 ea) to go in between each pair of 12V batteries I make.

+ lead ---- 12V batt w/ 4s BMS --victron-- 12V batt w/ 4s BMS --victron-- 12V batt w/ 4s BMS --victron-- 12V batt w/ 4s BMS ---- minus lead

POSTULATION: it works

POTENTIAL ISSUE: when any bms DISCONNECT triggers (last failsafe, the charger and loads will have limits configured within the BMS limits), it would see a full VOLTAGE of 48V across it's mosfet/whatever method of disconnecting it utilizes (by the way is this really true? does the voltage travel through the load when the current stops). Please note this is similar to putting all-in-one/drop-in 12V packs (like BattleBorn) in series which is COMMONLY done and even suggested by them. Of course they use the BATTERY BALANCER too.

PRIOR / RELATED THREADS

WHY? My THOUGHT PROCESS....
Sourcing good, affordable 16S BMS is hard; either expensive, bad reviews, or OOS/sketch ordering.
Overkill Solar backordered
REC/Orion/Batrium/ $500+ minimum.
Affordable Chargery/Daly/Ant are from China (I get anxious about shipping from China). Chargery has threads about their issues like accurate SoC, etc a couple months ago, not sure if fixed. Daly has threads about smoking when not approaching their limits.

For the 4s bms though, seems WIDELY AVAILABLE and RELIABLE (bigger market perhaps?). Also they are PROGRAMMABLE. Oh and I forgot AFFORDABLE. and many youtube vids prove they function as advertised. For example Battery Hookup says theirs are in medical equipment and COSTS $40 in their package. So I THOUGHT: how can I use this BMS for my purposes. Btw COST wise is 4*$40 (4s bms) + 3*$65 (battery balancer) = $340 vs $500+.

Also this is my FIRST battery bank, it would be ADVANTAGEOUS to be able to RECONFIGURE with 12V and 24V system if I want. Of course I will balance them before reconstructing.

EXTRA QUESTIONS if you are feeling generous
what BMS does Battleborn use? In Will Prowse's teardown, the bms looks very similar. Could it possibly come from same manufacturer?


thank you for your assistance in advance.

edit: updated some links and grammar
According to the Jiabaida engineer at the company, SP04S028A is the only model that can be parallel. 4s4p, no more than 4p. Hope this helps.
 
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