I really dunno which one to buy and based off their websites .....who can tell?

[davecason]

Greetings Folks,

I'm at a quandary I need to get a new BMS but I'm stuck ...... and it really boils down to who's? OVERKILL / KJ / DALY

If I go to Overkills site - its a normal experience - look! Products clearly labeled with what it is, and what its for, and what it cost. Who knew? (grin)

If I go to JK BMS because Andy told me too, I can again see products but on the entire site I don't actually see a 4S unit there at all, maybe its hidden on the site or I'm just blind and dumb (well OK I know I'm dumd) but I don't see one ! Do they make a 12vdc 4S 100 - 200a BMS w/active balance?

Lastly DALY I can go to their site and navagate to what seems to be the right family of prodcuts under their website heading of: Smart Lifepo4 BMS but again which one and then if I can find the right model number for the one I want where's the bast place to buy it from and all the bits I want.

I do want all the bells and whistles each BMS will have for monitoring that brand of BMS and it's I/O of the BMS, like temp probes, CAN BUS, 485, UART, Bluetooth, remote switch, remote displays, etc .......

SO - based on the website alone, the easiest choice seems to be overkill, get the unit, with the cables and the USB module because that's all they have and I can get it to me landed in Alberta for $279 CDN but that is up there IMHO.

It's for a 1 panel system with a EPEver charge con, and 4 Baesun 272ah 3.24 v Lifepo4 cells - so nothing fancy.

You guys are the experts, what are your thoughts?

Cheers'
Dave

 

[alcook62]

If you don't need active balancing the Overkill BMS is a rock-solid unit. I've had two of the JBD-based units for a couple of years. Can't beat the warranty. Overkill is US-based and quick to respond if needed.

 

[davecason]

Hi, Thanks for the reply .....so the Overkill brand of BMS's don't have any balancing capacity at all ?

Cheers'
Dave

 

[davecason]

Does anyone have an opinion on the JK-B2A8S20P BMS's ...... have you used one? Are you happy with it?

 

[BobR]

Hi, Thanks for the reply .....so the Overkill brand of BMS's don't have any balancing capacity at all ?

Cheers'
Dave

They have balancing but not active balancing (passive)

 

[OffGridForGood]

Does anyone have an opinion on the JK-B2A8S20P BMS's ...... have you used one? Are you happy with it?

I don't have any overkill BMS's, they are well regarded by many on this forum.
I started with Daly BMS's for E-bikes, and have about 12 of these. They work, generally, and for high Amperage output (150-200A) there are few other options.
In my ESS I like the JK's. They work, and have been reliable. There was some recent chat about the JK's changing back to default settings unexpectedly however seems from the forum comments this was corrected with update to the firmware.

The issue about active vs passive balance seems to come down to charge settings & the quality of the cells, ie how well matched.
I bought several active balancers that have just taken up space on my spare parts shelf, since they are not needed, the JK's have kept all my main packs balanced from a starting point of careful top balance using just the passive balance.

You don't say what kind of loads you are planning for the 4s pack, and I am not sure how well matched your four cells may be. If I were you, I would get the JK BMS, carefully top balance the four cells and run the pack. Monitor how it does over a period of weeks, months. A sep active balancer can be added if required later.
Be sure to set up the charging profile to ensure the cells reach high enough voltage long enough for the passive balance to have time to adjust any delta that may develop.

hope this helps.

 

[Rednecktek]

Does anyone have an opinion on the JK-B2A8S20P BMS's ...... have you used one? Are you happy with it?

I've thrown 2 of those in the trash and I'll never buy JK again. For me my best luck has been JBD or Daly. The only issue I've had with the Daly is that it seems I have to hit the button on the BT dongle to talk to it every time which makes the JBD better in my estimation. The JBD's don't have a lot of balancing power (2a instead of 5 or 10a) but it still balances just fine.

That was the second JK I installed in that battery build for my camp 8 hours away. Never again.

 

[OffGridForGood]

Yikes!
did you figure out what the base problem was ?
the vid sounds like shorting out somewhere, but why ?
I don't have any of the high balancing power units, mine are running 0.6A for balance.
As I noted above, a careful initial cell top balance has resulted in not needing high power active balancer on my stationary set up. The delta on each JK pack stays pretty well balanced in that 6-20mV range. I doubt any of my cells are better than 'grade B' either, cause I am too cheap to pay for those automotive grade cells.