Lithium problems

Millstone Grit

Full Member

Messages
45
My 100ah lithium battery state of charge indicator sya that the battery is fully charged as does the app. However, the display at the van master switches indicates that there are only 11v. So does the app. I've plugged into the mains but this doesn't seem to shift the voltage. I've attached pictures of the app etc. Anyone got any ideas?? Cheers David Screenshot_20210913-151653_Poweroad.jpgScreenshot_20210913-151659_Poweroad.jpgScreenshot_20210913-151713_Poweroad.jpg20210913_151912.jpg
 

wildebus

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3,697
Well, the Battery Info is from a Poweroad Infinity BMS (or something that uses an identical BMS I guess?)

I have found that the Battery Voltage that is quoted on those is pretty accurate. I just checked and my Infinity is saying 13.54V and the Victron BMV for the battery is 13.62V.

It is strange that it should show 100% though for sure with that voltage.
 

Okta

Full Member

Messages
584
I am not familiar with this battery. However with the BMS showing a full charge whilst also registering a voltage that clearly contradicts this I would be suspicious that the BMS needs resetting. It also looks like the cells are out of balance. Might be a good idea to talk to the manufacturer or supplier.
 

wildebus

Full Member

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3,697
I am not familiar with this battery. However with the BMS showing a full charge whilst also registering a voltage that clearly contradicts this I would be suspicious that the BMS needs resetting. It also looks like the cells are out of balance. Might be a good idea to talk to the manufacturer or supplier.
I find the cells are out of balance a bit after a significant load or charge. The BMS then internally does the cell balancing over a time (they can only transfer small currents so take time to even out).
These two did a recharge from 40% SOC this afternoon. By the morning, due to no load and only float charge levels, all the cells with be within a few 100ths/V of each other
1631566815035.png1631566838211.png
 

Millstone Grit

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Messages
45
I've just directly wired the charger to the battery instead if going through the knot of the wiring loom which was produced by the van converters. I assume that they did it this way to fuse the ctek 250SA. I've now got a Victron for the lithium which has its own fuse. The Victron now shows bulk charge at 15 amps so maybe it was the wiring that is awry. I will strip the whole lot down and check. Ooooo me aching back. Thanks to all you contributors.
 

wildebus

Full Member

Messages
3,697
Bit off topic, but to finish my observation from last night and this may be of interest to the OP as he has the same battery I believe?

I find the cells are out of balance a bit after a significant load or charge. The BMS then internally does the cell balancing over a time (they can only transfer small currents so take time to even out).
These two did a recharge from 40% SOC this afternoon. By the morning, due to no load and only float charge levels, all the cells with be within a few 100ths/V of each other
1631605619237.png1631605634791.png

So just after some extended charging (where, I believe, Cells within a Lithium Battery always are out of balance to a degree due to the fact that no cell is identical to another, even though the manufacturers try to match as closely as possible the various cells in each battery),
Battery 1 (4 cycles) has a range of 0.065V and Battery 2 (52 cycles) has a range of 0.08V between the highest and lowest values.
After the BMS has done its stuff while the batteries are under little load or charge the cells are pretty well matched up
Battery 1 (4 cycles) has a range of 0.003V and Battery 2 (52 cycles) has a range of 0.03V between the highest and lowest values.
The second battery is a little more unbalanced as it is currently more active in terms of charging, but will balance out more when it is more 'at rest' (even though these are in parallel, just like with Lead Batteries, there is a difference between them. It is only when you have individual cell or battery monitoring you actually see this. a standard battery monitoring setup like a BMV on a whole bank doesn't reveal this detail).
1631605675279.png1631605695968.png
 
Last edited:

Millstone Grit

Full Member

Messages
45
Bit off topic, but to finish my observation from last night and this may be of interest to the OP as he has the same battery I believe?



So just after some extended charging (where, I believe, Cells within a Lithium Battery always are out of balance to a degree due to the fact that no cell is identical to another, even though the manufacturers try to match as closely as possible the various cells in each battery),
Battery 1 (4 cycles) has a range of 0.065V and Battery 2 (52 cycles) has a range of 0.08V between the highest and lowest values.
After the BMS has done its stuff while the batteries are under little load or charge the cells are pretty well matched up
Battery 1 (4 cycles) has a range of 0.003V and Battery 2 (52 cycles) has a range of 0.03V between the highest and lowest values.
The second battery is a little more unbalanced as it is currently more active in terms of charging, but will balance out more when it is more 'at rest' (even though these are in parallel, just like with Lead Batteries, there is a difference between them. It is only when you have individual cell or battery monitoring you actually see this. a standard battery monitoring setup like a BMV on a whole bank doesn't reveal this detail).
View attachment 61035View attachment 61036
👍👌
 

Millstone Grit

Full Member

Messages
45
Bit off topic, but to finish my observation from last night and this may be of interest to the OP as he has the same battery I believe?



So just after some extended charging (where, I believe, Cells within a Lithium Battery always are out of balance to a degree due to the fact that no cell is identical to another, even though the manufacturers try to match as closely as possible the various cells in each battery),
Battery 1 (4 cycles) has a range of 0.065V and Battery 2 (52 cycles) has a range of 0.08V between the highest and lowest values.
After the BMS has done its stuff while the batteries are under little load or charge the cells are pretty well matched up
Battery 1 (4 cycles) has a range of 0.003V and Battery 2 (52 cycles) has a range of 0.03V between the highest and lowest values.
The second battery is a little more unbalanced as it is currently more active in terms of charging, but will balance out more when it is more 'at rest' (even though these are in parallel, just like with Lead Batteries, there is a difference between them. It is only when you have individual cell or battery monitoring you actually see this. a standard battery monitoring setup like a BMV on a whole bank doesn't reveal this detail).
View attachment 61035View attachment 61036
It's a poweroad infinity
 

Okta

Full Member

Messages
584
I believe, Cells within a Lithium Battery always are out of balance to a degree
Some manufacturers use matched cells. This is what Relion say.
“Tests show that the cells are so precisely matched, batched together with high conformity and passive assembly design that the balancing function will remain innactive for most of the battery life.”
 

wildebus

Full Member

Messages
3,697
Some manufacturers use matched cells. This is what Relion say.
“Tests show that the cells are so precisely matched, batched together with high conformity and passive assembly design that the balancing function will remain innactive for most of the battery life.”
All manufacturers do.
On the Poweroads, the QC process matches the cells up to go into the batteries, and the batteries themselves are also batched together also so if you have multiple units, the supplier can match the batteries up as well for optimum balancing (as long as you buy multiples at the same time). The Poweroads can also have interlink cables to do BMS balancing between batteries. I have not got around to fitting that cable.

Of course, if you have no way of checking the individual cells, you have no way of validating or confirming the manufacturers claims. I don't think there are any indicators that tell you if a BMS is active or inative ;)
When they say "most of the battery life", it implies (to me anyway) that they seem to be claiming the BMS is only active when the battery starts to age. I think what they are really saying if you dig down is that is inactive for "most of the time" - a very different thing.

I am wary of marketing claims personally and if I wanted info would speak to the tech guys and not the sales/marketing people.
 
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