Choosing a BMS for 8S (24V) prismatic LiFePO4 cells

[aybabtme]

Hi there,
I've been scratching my head trying to decide on which BMS I should get. I'm working with an 8S battery bank and would like to control up to 250A (750A peak), to feed a 6000W inverter. I've been looking at:

- Batrium
- 123 Smart BMS
- Orion Jr BMS
- REC Q BMS

They are a bit different from each other and I find it confusing to compare them. Has anyone had any experience with them?

[Q Xopa]

Originally Posted by aybabtme

Hi there,
I've been scratching my head trying to decide on which BMS I should get. I'm working with an 8S battery bank and would like to control up to 250A (750A peak), to feed a 6000W inverter. I've been looking at:

- Batrium
- 123 Smart BMS
- Orion Jr BMS
- REC Q BMS

They are a bit different from each other and I find it confusing to compare them. Has anyone had any experience with them?

Yes agreed. I have been mulling over the same question myself for some time.

Sorry I dont have the answer for you either. But I am also looking around the same size as you are talking about with 8S 24V, looking 400-600 AH range. So Im interested in what comes of your question.

IMNSHO its the 'trickiest' question as there just doesnt yet seem to be any clear proven winners.

The chargers are pretty straight forward, although still questions get asked these are relatively minor details. I have gone with Sterling Prochargers, Victron MPPTs and Open source Alt regs. I also have a BS ACR and Sterling B2B to charge my 12V Start batt. I also have a Victron BP220 'LVC'.

Ive got and setup these components in preparation for my LFP upgrade with my existing 'tired' FLA setup. So far it's all working quite well and I'm happy with the way it works. Of course its taken some time and effort to get to this point, and Im still not there yet.

Cells, always some discussion, but to me Sinopoly or CALB seem a reasonable bet with prices getting quite reasonable these days.

I have been leaning mostly towards the 'Smart BMS'. But I have to say the Batrium also looks quite compelling. Its newer on the scene. Although I have heard some possible user 'issues'? It remains to be seen how this will shake out. I guess this has contributed to delaying my decision.

Like you Im keen to hear some real world experience feed back.

[aybabtme]

I attempted to get more information from Batrium, but their support person refused to provide any substantive information, pointing me to their paid consultation instead. I followed up and asked how they would compare their products to competitors, and support basically told me to do my own research. Which obviously I'm doing, but how am I supposed to take seriously a company who basically refuses to explain how they differentiate from their competitors. In my book, and since Batrium comes a bit off putting with their 3D printed setup, that leaves them out of the loop. The interaction was unpleasant and I wouldn't want to deal with that attitude if I have an urgent need.

[tanglewood]

Originally Posted by aybabtme

I attempted to get more information from Batrium, but their support person refused to provide any substantive information, pointing me to their paid consultation instead. I followed up and asked how they would compare their products to competitors, and support basically told me to do my own research. Which obviously I'm doing, but how am I supposed to take seriously a company who basically refuses to explain how they differentiate from their competitors. In my book, and since Batrium comes a bit off putting with their 3D printed setup, that leaves them out of the loop. The interaction was unpleasant and I wouldn't want to deal with that attitude if I have an urgent need.

Wow, yes, that would take them off my list too.

[Q Xopa]

Originally Posted by aybabtme

I attempted to get more information from Batrium, but their support person refused to provide any substantive information, pointing me to their paid consultation instead. I followed up and asked how they would compare their products to competitors, and support basically told me to do my own research. Which obviously I'm doing, but how am I supposed to take seriously a company who basically refuses to explain how they differentiate from their competitors. In my book, and since Batrium comes a bit off putting with their 3D printed setup, that leaves them out of the loop. The interaction was unpleasant and I wouldn't want to deal with that attitude if I have an urgent need.

Yes disappointing to hear.

[aybabtme]

On the other hand my discussion with REC has been fruitful. Still waiting to hear from Orion.

[MikeFergie]

I decided to try out a simple BMS that works on temp, HVC disconnect and LVC disconnect and do the cell balancing separately.

BMS - Deligreen Common Port 4S 250A High Current Lifepo4 12v with programmed 120 amp max charger input. It’s a waterproof unit.

Cell balancers - High tech Active lifepo4 cell Balancer for Lifepo4 . I have one for each cell so 12 in a battery pack

My cells are CALB CA100 cells in 3P4S configuration so 12 cells in one battery giving me 300amp hours or 4140 watt hours. I have built 2 batteries and will be putting them in my boat at the end of the year after running them in my house to check all is in order.

I need to reprogram my victron MPT controllers and my multiplus 3000/12/120 as well. I have also imported the Balmar 614s and combiner to deal with my alternators.




Rgards
MikeF

[MikeFergie]

My build so far.

Is there an advantage/ disadvantage ( must be some I suspect) of connecting all 3 batteries in the parallel group versus only the opposite end or as I’ve seen the 2 end batteries but leaving the centre out in the battery make up.

Rgards
MikeF

[aybabtme]

Sorry I just saw this. Yes there's an advantage: if the cells aren't connected parallel-first, there's nothing preventing them from becoming disbalanced. In theory, you'd need 1 BMS for each series-string, along with all the disconnect protection circuitry. A lot of waste.

[Steve_C]

Has anyone found a good source for the REC BMS here in the US? I really like their hardware, but I can only find it in Europe and Australia. I have emailed them but have not yet heard back.

[ronstory]

Originally Posted by Steve_C

Has anyone found a good source for the REC BMS here in the US? I really like their hardware, but I can only find it in Europe and Australia. I have emailed them but have not yet heard back.

I have the REC-Active, the 12V only version. I just contacted them via email and they replied in a day or so and suggested I just order direct from them. they answer all my questions and I place the order. The price was very reasonable and I got the BMS is right around a week from when I ordered.

[aybabtme]

I looked at REC but with the Orion Jr being a similar price, up to 16 cells and more supported by stores in the US, I think it's a better buy if you're in the US (local electric internet shops sell Orion but nit REC). I don't think the active vs passive balancing is worth getting excited about, it's not like new, quality LFP cells need much balancing anyways.

Also the Orion Jr integrates with Victron's GX devices over CANBUS (like REC).

[ronstory]

In my case the REC came out a lot cheaper for all the options than the Orion. The Orion folks were more in to electric cars... and the canbus option a better deal on the REC IMO.

My money, my choice. Your money, your choice.

[ronstory]

Just checked my invoice. The REC-Active (12V only) was 250 Euros with harness, the PC link was 55 euros and canbus cable 13 euros. Shipping was $40 for 1 week delivery.

[aybabtme]

Yeah I think the REC is probably a great buy! Don't get me wrong!