Bms suggestion for homemade 48v battery

[Chill3dMilk]

I'm getting 16- 3.2v 105amp Eve LiFePo4 cells from 18650 battery store. I would love to wait for Overkill Solar's upcoming Pathfinder bms, but time is prohibitive.

Reviews for the Daly seem hit and miss for quality control and customer service.

I'm leaning towards the Jk smart bms.

It's going to be used with an eco worthy 48v 5k watt hybrid controller/inverter 80amp PV output.

What I'm really asking is what model is suggested for this kind of set up so I'm not under or over buying.

I'm thinking the 8-24 string 100amp 0.6a is right for this application.

Any suggestions are appreciated in advance.

 

[doctron]

Jk bms if its compatible with your inverter.

 

[Chill3dMilk]

I'm set on that now, just trying to figure out what specs I need for my system.
Understanding the spec sheet is confusing first time.
If my
Inverter max draw is 5K watt/ 48v= 105 amp,
Controller PV output is 80amp
Cells are configured for 48v 105amp 1C

Does this mean I need a 16S 48v 150amp 1A BMS? Not the specs I mentioned originally.
As far as I get it, the 150 amp is the maximum surge draw before the overcurrent protection is activated.
The 1A is the 1C rating for charging the batteries?

 

[E. Cho]

Is your inverter rated for 5,000 watts continuous or short term peak?

Are you planning on connecting the inverter to the BMS for communication? That is not always needed. Many here do without the communication. With communication, it is a JK Inverter BMS and has a different model #

The .6, 1A, 2A has nothing to do with the charging C Rate but in the JKBMS, it signifies the Active Balancing max Amps that the BMS may use at the user set Balancing cell voltage, eg: user set triggers to on at 3.40v to 3.45v per cell. They will all do the cell balancing job but the .6A BMS will take longer than the 2A BMS. Some like it slower, some faster, not sure if there is a correct balancing current. Faster equals more $$.

 

[Chill3dMilk]

Is your inverter rated for 5,000 watts continuous or short term peak?

5000 watt continuous 10k peak watt
10,000/48=208.33
So a 200 amp charger would fit or a 250 amp for the extra capacity before over draw shutdown on the bms side?

The .6, 1A, 2A has nothing to do with the charging C Rate but in the JKBMS, it signifies the Active Balancing max Amps that the BMS may use at the user set Balancing cell voltage, eg: user set triggers to on at 3.40v to 3.45v per cell. They will all do the cell balancing job but the .6A BMS will take longer than the 2A BMS. Some like it slower, some faster, not sure if there is a correct balancing current. Faster equals more $$.

Thanks for the clarification

 

[Rednecktek]

So a 200 amp charger would fit or a 250 amp for the extra capacity before over draw shutdown on the bms side?

Yes... BUT... that's a 2C + draw which is really painful on your cells.

Personally, I'd go JBD. I have 9 operational JBD's, 2 operational Daly's and 2 JK's that were only good for range targets.

And no, the .30 caliber holes didn't make any difference in performance.

 

[Chill3dMilk]

Yes... BUT... that's a 2C + draw which is really painful on your cells.

Gotcha, I wasn't worried about the fastest results but longevity. Thank you for that note

Personally, I'd go JBD. I have 9 operational JBD's, 2 operational Daly's and 2 JK's that were only good for range targets.

I've heard good things about JBD, the original web vendors I visited were all out of stock.

I think I found their direct site, does this look like a good model for my current specs?(the headline of that link isn't correct, clicking on it takes you to the right store page)

JBD Smart BMS 6S 7S 8S 9S 10S 36V 20A 30A 40A 50A Li-ion Lithium Battery PCB for Freeshipping - Jiabaida BMS

Jiabaida BMS JBD Smart BMS 6S 7S 8S 9S 10S 36V 20A 30A 40A 50A Li-ion Lithium Battery PCB With Uart Rs485. High quality better service and favorable price with free shipping. Battery Management System for NMC/Li-ion Lifepo4 battery

jiabaida-bms.com

 

[Chill3dMilk]

2 JK's that were only good for range targets.

And no, the .30 caliber holes didn't make any difference in performance.

Thanks for the warning. I'm trying to avoid fueling my expensive paperweight addiction. Ammo costs to much as it is!!

 

[E. Cho]

I have 2 x 200 amp 2A active balancing non inverter JKBMS and have had no problems, along with others in the forums. I would not use them for target practice and some could argue they are better than JBDs.

The JK inverter versions can work well too in non inverter connected mode. JKs do have issues for SoC drifting in communication use and a couple of other issues that JK is trying to fix. Long thread about this to read and learn from. I use a Victron shunt anyway as my main SoC calculator and that works well.

From my reading here, all the BMS have pros and cons and quirks, so pick what works for your tolerance for compromises, because none are perfect and not for all systems. Some also have pretty horrid user guides, especially for new DIY learners.

 

[Chill3dMilk]

Thank you guys I think my questions got answered here... for now.
I'm going to pull the trigger on the JBD for now, it's a little more budget friendly.
I'll grab a JK for the next pack I build, looks like the savings really come in with bigger amp hour cells.

 

[Kornbread]

Had one jk bms stop communicating via bluetooth. It kept doing it's job, just stopped communicating. Otherwise, no issues with the older non-inverter jk bms. I like to use the ess grade cells, and for that prefer the 2amp active balancing of the jk.