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No more paralleling JBD BMS allowed - what now?

thedodgersonline

thedodgersonline

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Joined
Nov 19, 2019
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204
Hi
Up until recently I have been happily building batteries (sporadically) and had standardised on the JBD BMS. When I went to order some more gear to build 2 new 12V batteries I noticed - in the spec sheet - these these were no longer allowed to be paralleled. This amazes me because I cannot understand why. It has never been a problem so why create a problem where none existed.
So now lookung for a new BMS to use (don't like Daly at all) and the JK BMS looks pretty solid. Thinking of buying the latest version B2A8S30P. However even with this you need an additional parallel module. Anyone know why this is so and how it is implemented?
Any other suggestions regarding BMS to use. Looking at 12V battery at about 300 amps

THanks and Regards
 
Where does it say it cannot be paralleled?
And what is this parallel kit for the JK, I have never heard of it?
 
SparkyJJO said:
Where does it say it cannot be paralleled?
And what is this parallel kit for the JK, I have never heard of it?
Click to expand...
Hi
In the technical specs I will post a screen shot below
No idea what the 'kit' is. According to the vendors it is an 'option'?? At this stage she stopped talking to me

1709699390683.png
Will see what else I can dig out.

According to the manual Parallel connections are allowed?? Confusion reigns

1709699812660.png

REgards
 
Last edited:
That is weird. A lot of folks here have JK and JBD BMSes put in parallel without anything special. Now if using comms I could see some issues or extra stuff needed. But not if running open loop.
 
interesting. been using DALY for the last three years with no issues after the initial (painful) setup. I was interested in the JK and the JBD but if you cannot parallel them then they are worthless to me.
 
I wonder if that has anything to do with my two batteries on my camper going massively out of balance with each other, even though all the wires are exactly the same length. Like 54% and 32% ... 🤔

I hate to go to Daly's, I'll never waste money on a JK again. I just wish Daly didn't require me to press the button to connect the bluetooth every time.
 
Rednecktek said:
I wonder if that has anything to do with my two batteries on my camper going massively out of balance with each other, even though all the wires are exactly the same length. Like 54% and 32% ... 🤔

I hate to go to Daly's, I'll never waste money on a JK again. I just wish Daly didn't require me to press the button to connect the bluetooth every time.
Click to expand...
are they (JK) that bad? or is it a misunderstanding of the unit?

the DALY will allow the packs to charge differently, of my three packs 27.5 kWh, and two packs that are 21.75kWh charge differently.

Even when I ran four 10kWh packs they would slip in relation to each other. part of that is that the DALY ignore low inputs and low outputs below 2 amps unless you program it with a PC (which i have not done, BT and phone only). but also the health of the various packs come into play. with the four 10kWh packs it ends up they were not all 10kWh due to health of some of the cells. once I rearranged the cells the balance issues still existed but not nearly as large of an imbalance.
 
Hi
Just reading this mega thread about this exact subject. Highly recommended as ther is a lot of input from JK (Nami)

diysolarforum.com

JK 4S 200A BMS

This is a sample, which will be sent to the off grid garage test soon. It supports heating and 4S 5S 6S 7S 8s, support 200A discharge/charge current with active balance 1A/2A support RS485... will be soon................
diysolarforum.com diysolarforum.com
 
Daddy Tanuki said:
are they (JK) that bad? or is it a misunderstanding of the unit?
Click to expand...
I had two in a critical battery build. The first one died in a little over a week, the second only lasted a few days. It's a sad thing that I've had better luck with Daly's than any of my JK's


The only reason I didn't use a JBD on it was finding 150a 8s JBD's is pretty impossible. So I gave JK a shot and they both failed quickly. The Daly was the only 150a 8s that I could get quickly out to eastern Washington.
 
mine are al in a 16s setups and are 200 discharge/100 charge. other than the one pack of older smaller cells gets out of balance with the new winston packs they seem to be fine and dandy.
Maybe I am not pushing my setup as hard as others. :unsure: the highest discharge rate i have seen to date was about 60 amps/3 packs so 20 amps per. charge wise I have seen 150 amps/3 packs so roughly 50amps each.
 
SparkyJJO said:
Where does it say it cannot be paralleled?
And what is this parallel kit for the JK, I have never heard of it?
Click to expand...
Hi
Been dealing directly with the JKBMS Factory and it has taken all day but I finally got hold of some one who has some technical ability.
So the latest model B2A8S30P (4S 300 amp ) can be connected in parallel but you need a parallel module. Trying to find out more about it and where to wire it etc. Pic is attached but just a black box with wires coming out of it.

Regards
 

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Daddy Tanuki said:
interesting. been using DALY for the last three years with no issues after the initial (painful) setup. I was interested in the JK and the JBD but if you cannot parallel them then they are worthless to me.
Click to expand...
Hi
Just confirmed with the JKBMS factory that the latest version can be connected in parallel - but you need the parallel module?
See Pic below
 

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thedodgersonline said:
Hi
Just confirmed with the JKBMS factory that the latest version can be connected in parallel - but you need the parallel module?
See Pic below
Click to expand...
from what i was reading in another post about these it appears they were trying to make a diode pack to prevent cross feed between battery packs. wonder if that's what they were referring to?
 
Daddy Tanuki said:
from what i was reading in another post about these it appears they were trying to make a diode pack to prevent cross feed between battery packs. wonder if that's what they were referring to?
Click to expand...
Hi

This is the wiring of the parallel module - when mine arrives I will open it up and have a look.

Regards
 

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It's really not an issue to parallel these - just make sure you appropriately fuse each pack. I even told JK about this and they added my diagram on their product page at some point. Read the couple of posts on this linked here:

diysolarforum.com

JK 4S 200A BMS

If parallel battery packs are required, the same voltage can reduce the chance of failure, But it's hard to achieve, Or add a discharge diode in each battery pack, which is the way we are currently considering How is the same voltage hard to achieve? 90% of the charge curve is at the same...
diysolarforum.com diysolarforum.com
 
upnorthandpersonal said:
It's really not an issue to parallel these - just make sure you appropriately fuse each pack. I even told JK about this and they added my diagram on their product page at some point. Read the couple of posts on this linked here:

diysolarforum.com

JK 4S 200A BMS

If parallel battery packs are required, the same voltage can reduce the chance of failure, But it's hard to achieve, Or add a discharge diode in each battery pack, which is the way we are currently considering How is the same voltage hard to achieve? 90% of the charge curve is at the same...
diysolarforum.com diysolarforum.com
Click to expand...
That's how mine are wired, I thought this was standard?
What is "not paralleling" then?
 
upnorthandpersonal said:
Yeah, it's standard, but there were some liability concerns in the past (when operated without fuse, due to potential inrush current, especially with non-LFP packs). Therefor, they said not to use them in parallel in general.
Click to expand...
I see, I have breaker & fuses at that position for each of them before the bus bar.
Seems like the only way to do it. Otherwise you could only have 1 battery pack..
 
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