Best 12v BMS

[Visionquest]

Picking a BMS is the last step in my 12v battery project. I will be using 304 aH cells from EVE. From everything I've read getting a high balance current spec (1 - 2 amps) and overall high current spec (200 amps) is my best bet. I also definitely want bluetooth connectivity. I'm trying to compare the following three BMS's and appreciate any insights and help on which is best.

1) https://xiaoxiangbms.com/product/4s-lifepo4-12v-100a-120a-150a-200a-amart-bms/ (looks like just 150mA balancing or "equalization" current?)

2) https://www.alibaba.com/product-det...html?spm=a2700.shop_index.89.8.7db6273e0Ast3U (can't tell if this really supports a 4 cell config since it doesn't show up in the table)

3) https://www.alibaba.com/product-det...a2700.wholesale.you_may_like.3.2d596450Ey0ZQy (this one seems to have everything I need

I've also noted that the Daly BMS has just 35mA balance current so I didn't include that. But I am a bit confused as to why there are so many BMS's with low balance current capability. Do they expect a separate balancer to be used with their BMS?

Thanks for the help!
Bob

 

[MisterSandals]

I have 4x JBDs running right now. The are same as Xiaoxang and Overkill. Their apps are interchangeable and work really well.

I think JK is equivalent but thinking their app is not quite as good but their new communication capabilities in some models, for closed loop systems, will likely become a differentiator when/if their compatibility expands.

Daly is a no go for me (i have 2 small dumb ones that only occasional get use). Their failure rate seems much higher than JK or JBD.

Many many other "best bms" threads...

Search results for query: best bms

diysolarforum.com

 

[Visionquest]

I have 4x JBDs running right now. The are same as Xiaoxang and Overkill. Their apps are interchangeable and work really well.

I think JK is equivalent but thinking their app is not quite as good but their new communication capabilities in some models, for closed loop systems, will likely become a differentiator when/if their compatibility expands.

Daly is a no go for me (i have 2 small dumb ones that only occasional get use). Their failure rate seems much higher than JK or JBD.

Many many other "best bms" threads...

Search results for query: best bms

diysolarforum.com

Thanks. I did find many of those search link but your query has a couple more.

The Overkill BMS documentation is great. The only think I'm concerned about is that it uses passive balancing. The JK uses 1 or 2 amp active balancing which is desireable from what I've read? Can I get your thoughts on the importance of that spec?

 

[Rednecktek]

I've had JBD's, JK's, and Daly's in various packs. Here's my $0.02 worth:

Daly: Simple, cost effective, wires are too small and can't be replaced, have to hit the BT remote button every time I want to talk to it which is annoying. Never had one die yet so that makes them better than JK.

JK: Screw them. Just screw them. The piwer button is a PITA, both of mine died in critical parts, replaced with a Daly bacause it was all I could get in a hurry. Wiring was a PITA because of extra wires.

JBD: Best BMS's I've ever had. BT always works, easy to wire, Overkill app works well. Only down side is their 8s versions are VERY limited in options and I had to use a JK for my camp battery which both died. The heater function I also couldn't ever get to work, and not the greatest documentation out there for them if you get one of their weird 3-24s variable units.

When using the big cells, like the 280's and 304's, any BMS is going to need LOTS of time to balance if you don't top balance during construction. A 5a balancer is cheap enough to throw in a pack and the balancer AND the BMS will work together nicely IME.

 

[time2roll]

Overkill is working great. I have three of them. Although my next BMS will have active balancing.

 

[Brett V]

I only use the Overkill offering. A bit higher price than the Ali offerings but you get a tested unit with a printed report of test results and a lifetime warranty…even if you do something wrong and fry it.

 

[Hans Kroeger]

I bought about 35 units b2a8s20p and had no problems up till now (except for the password problem, which was resolved by an update of the app).
See also:

BMS and Balancer

If you connect several cells in series, you definitely want a BMS. If not for optimisation purposes then for sure for safety and peace of mind. A BMS controls and monitors your whole battery on cel…

off-grid-garage.com

 

[Marinepower]

150 to 200 mili amps of passive balancing should be fine for a 300ah pack if you charge to full on a regular basis....

I have run 280ah, 4S 12v eve for years like this with no trouble. I did top balance initially.

 

[Visionquest]

I've had JBD's, JK's, and Daly's in various packs. Here's my $0.02 worth:

Daly: Simple, cost effective, wires are too small and can't be replaced, have to hit the BT remote button every time I want to talk to it which is annoying. Never had one die yet so that makes them better than JK.

JK: Screw them. Just screw them. The piwer button is a PITA, both of mine died in critical parts, replaced with a Daly bacause it was all I could get in a hurry. Wiring was a PITA because of extra wires.

JBD: Best BMS's I've ever had. BT always works, easy to wire, Overkill app works well. Only down side is their 8s versions are VERY limited in options and I had to use a JK for my camp battery which both died. The heater function I also couldn't ever get to work, and not the greatest documentation out there for them if you get one of their weird 3-24s variable units.

When using the big cells, like the 280's and 304's, any BMS is going to need LOTS of time to balance if you don't top balance during construction. A 5a balancer is cheap enough to throw in a pack and the balancer AND the BMS will work together nicely IME.

At the moment I am leaning towards the JK because Overkill only has up to 120amp and the JK seems to be the only one with adequate active balancing without adding anything.

However, you input is the first I've read about quality concerns with JK. Can you tell me a bit more about the failures?

 

[Visionquest]

I only use the Overkill offering. A bit higher price than the Ali offerings but you get a tested unit with a printed report of test results and a lifetime warranty…even if you do something wrong and fry it.

I am really impressed with Overkill. Just wish they made a 200amp BMS since I want more peak current for confidence in starting my Onan5500. The JK spec's 350amp short term.

 

[Visionquest]

I bought about 35 units b2a8s20p and had no problems up till now (except for the password problem, which was resolved by an update of the app).
See also:

BMS and Balancer

If you connect several cells in series, you definitely want a BMS. If not for optimisation purposes then for sure for safety and peace of mind. A BMS controls and monitors your whole battery on cel…

off-grid-garage.com

Thanks for that link. Great summaries of available gear. Interesting comment about cold weather charging using low currents.

 

[Rednecktek]

However, you input is the first I've read about quality concerns with JK. Can you tell me a bit more about the failures?

That video I posted was my replacement/spare BMS in my cabin's battery. The first one did the same thing after a few days and I filmed the second one when it started acting up after a week or so.