14s BMS recommendation

[Oliver90owner]

As per the title, what make/supplier please. Or any to avoid.

[Marcus]

I must admit I was a little hoping that somone would suggested something as i looking to buy one myself. Possibly it's the 14s bit that's the issue as the lifepo poeple would likely be wanting 15 or 16s; but the manufacturers generally produce the same bms's in a choce of cell numbers.

For myself i was trying to choose between jk, seplos, daly and heltec.

Probably one that includes active balancing at >1A as otherwise a separate balance unit must also be wired in.

And probably either smart or with a display - the reason for this is that my existing (not smart) 24v 7s heltec bms works well enough, but if i want to just check that the battery is ballanced as it should be, i have to get the voltmeter out, open up the case and probe the cells individually - not a big deal but enough of a faf to make me put it off.

Also would be nice to be able to set min and max cell voltages to maximise cycle life, although the inverter settings ought to cover that.

Edit to add:
It would be nice - for future proofing - if it could communicate with the inverter by emulating one or more of the popular commercial battery comms.

[Tinbum]

I'd go with the JK-BMS https://www.aliexpress.com/item/1005006349311630.html does all you ask.

[AlBargey]

I didn't originally say anything as there isn't enough information on the system or BMS requirements from Oliver to suggest anything, depends what is wanted or needed.

But, if affordability and functionality are key then the JK BMS's all with active balancers built in are one of the best, if easy communication with an inverter is needed via CAN, then go for the 'Inverter JK BMS' series starting with a PB. Other close options for good communications are the Pace P16 series BMS or Gobel RN150 - made by Pace. I'm not sure if they can also do 14S quite possibly though. - They will need a separate balancer though.

I have the 8S 'old' style JK B2A8S20P, which has a Bluetooth phone app, can also communicate with Victron using the TTL serial connection or Bluetooth with an extra driver, but that's not a simple process, Dali, Heltec and quite a few others can also use the Victron driver, but there's no point buying anything other than the JK, unless you want a separate balancer deliberately as they don't have decent ones built in unlike the JK.

If affordability isn't a concern then look at Orion or REC.

There's at two 'Official' JK BMS stores on Aliexpress and also Hankzor BMS Store has been used by quite a few on the other DIY forum.

[AlBargey]

heltec bms works well enough, but if i want to just check that the battery is ballanced as it should be, i have to get the voltmeter out, open up the case and probe the cells individually - not a big deal but enough of a faf to make me put it off.

Also would be nice to be able to set min and max cell voltages to maximise cycle life, although the inverter settings ought to cover that.

Does your Heltec have bluetooth to use one of the apps? Or can you add a bluetooth dongle if it doesn't so you can then use the app to check and adjust settings?

[Marcus]

Ooh, Thanks! Apologies if this is a silly question:- but how do i find an official jk bms store on aliexpress? Is it called "the official jk store"? tinbums linky seems to be a different store - is there a risk to going to an unoffical store?

heltec bms works well enough, but if i want to just check that the battery is ballanced as it should be, i have to get the voltmeter out, open up the case and probe the cells individually - not a big deal but enough of a faf to make me put it off.

Also would be nice to be able to set min and max cell voltages to maximise cycle life, although the inverter settings ought to cover that.

Does your Heltec have bluetooth to use one of the apps? Or can you add a bluetooth dongle if it doesn't so you can then use the app to check and adjust settings?

No it's a dumb cheap bms without any comms, and built in voltage settings - but I've decided my next battery/system will be 48v, and once that system is up and running i will change the 24v 7s6p to 14s3p and merge it with the new battery.

But the new battery is going to be quite a bit bigger and more expensive, so worth spending a bit more on the bms.

[Oliver90owner]

Thanks. At last I’ve got something to get me started. It is for a 14S
(as far as I have thought, at this stage) for a ~2kWh set of pouch cells. I’m expecting (hoping) to charge from solar, then use via an off-grid inverter for the discharge side. There may/will be up to 6 or 7 of these in parallel - not yet sure of the final 50V battery size. It is a dismantled hybrid EV battery.

Any further suggestions are appreciated.

[Tinbum]

Ooh, Thanks! Apologies if this is a silly question:- but how do i find an official jk bms store on aliexpress? Is it called "the official jk store"? tinbums linky seems to be a different store - is there a risk to going to an unoffical store?

I've placed 4 orders for a total of 6 BMS's from the store I linked to with no problems. (They don't seem to let you order more than 1 at a time now though). What I've paid on aliexpress has been it- no duty or anything else. It's always been cheaper than the official stores.

[AlBargey]

Ooh, Thanks! Apologies if this is a silly question:- but how do i find an official jk bms store on aliexpress? Is it called "the official jk store"? tinbums linky seems to be a different store - is there a risk to going to an unoffical store?

Originally Hankzor was the first Aliexpress store to stock the all the JK BMS's and accessories, and they helped make the first English language manual, I'm not sure which is the official JK BMS store, but it's quite likely they could all be official.. or not!? having a look there are many of them, most suppliers seem to confusingly have two different stores on the Ali sites.

This is the Hankzor store though: https://hankzor.aliexpress.com/store/911303103?spm=a2g0o.detail.0.0.426c508dkYVKFh

I think this is official JK store: https://www.aliexpress.com/store/1103059734?spm=a2g0o.detail.0.0.6bf97c09bOEwOJ

Make sure the models of any BMS will be able to take the charge and discharge currents as they vary on the models, I found the 2A active balancers work well for my 340ah cells, for 100Ah and smaller the 1A balancer is probably enough but it can't hurt to balance more quickly with the 2A models.

Don't forget for warranty and UK stock there's also Fogstar, but you pay for it.

There's also the Seplos BMS's, new video from Andy on the latest firmware upgrade, I think they were a bit lacking in operation before, maybe ok with firmware upgrades though:

https://youtu.be/Lvrrog1W57I?si=4WzM9PC2RoLJucdC

@Oliver are you thinking of 6-7 BMS's? I would, but some don't - assuming it's a single 14s7p parallel bank then a single BMS can sense the average of all cells in that parallel group, but if one cell is a problem it can be hard to find or worse case the others cells could discharge into it with sparks. If just using one then maybe the cheaper JK's are enough and run them 'dumb' (no inverter coms), as it will add up quickly with the smart inverter JK's or CAN Pace, Gobel, Seplos, but inverter coms would be another useful safety factor.

[AlBargey]

Ooh, Thanks! Apologies if this is a silly question:- but how do i find an official jk bms store on aliexpress? Is it called "the official jk store"? tinbums linky seems to be a different store - is there a risk to going to an unoffical store?

I've placed 4 orders for a total of 6 BMS's from the store I linked to with no problems. (They don't seem to let you order more than 1 at a time now though). What I've paid on aliexpress has been it- no duty or anything else. It's always been cheaper than the official stores.

Yeah, Aliexpress is generally more pricey from the official stores and compared to Alibaba for the more expensive larger items.

As a side note for others, I ordered my BMS's from my battery box supplier on Alibaba, https://szluyuan.en.alibaba.com/?spm=a2700.shop_co.88.14 and they were £51ea vs £68ea for the cheapest on Aliexpress, so if buying cells or boxes on Alibaba (don't buy cells on Aliexpress - too many scammers!) then ask for BMS's at the same time to save on shipping, but Aliepress is generally more geared for smaller sales and quicker delivery.

Maybe another option is to ask Colin on the forum for prices on BMS's