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My first Vruzend Battery not quite right?  

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Simoc
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15/10/2017 9:58 pm  

I finally finished my first Vruzend battery pack using 65 x Samsung 30Q cells in a 13S configuration. But it's stopped charging at 41V. The cells are showing 4.1V each though I haven't checked all. For some reason I'm getting 0.0V off some which can't be right.

It would seem that maybe 3 lines haven't charged at all but all connections seem good. 

What is happening?


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Micah (Vruzend Rep)
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16/10/2017 2:11 am  

Let me make sure I understand you correctly. You are saying that 10 parallel groups of five cells each that are showing 4.1 V, giving a total pack voltage of 41V. That leaves three parallel groups of five cells each that are reading 0 V for the entire parallel group?

Also, are you using a BMS connected to the pack? 


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Simoc
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16/10/2017 7:15 pm  

After checking again I have 11 parallel groups reading 4.1V each and two groups reading 0.0V. I took the BMS I bought off . It started smoking when I put a balance wire out of position so I'm not sure that it's a goer now. The batteries were down to 3.3 so needed charging. I tightened all the connections but maybe I need to find that block of wood again. I just don't see how the cells at row 1 and row 7 can read 0.


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Micah (Vruzend Rep)
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17/10/2017 4:59 am  

Yea, once you let the magic smoke out of the BMS, it's usually a goner. You have to be careful to not put a connection in the wrong place or you'll create a short circuit that can damage the BMS.

Regarding your battery, if it was a loose connection on the caps in that parallel group, you likely wouldn't be able to get any battery ready at all out of your discharge leads, as there would be an open circuit caused by the lack of connection between the battery and the caps. 

When did you smoke your BMS. Is there a chance that a damaged BMS drained a couple of the cell groups?


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Simoc
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18/10/2017 10:55 am  

I measured row 1 after I took the BMS off. I suppose the thing to do is rearrange the rows and see what happens.

Edited: 6 months  ago

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Micah (Vruzend Rep)
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18/10/2017 12:41 pm  

Before you take it apart and rearrange it, can you measure the entire pack voltage from the two end terminals? Are you getting something between 30-54 V still, or getting 0V now from the entire pack?

If you are getting 0V from the entire pack, that's probably a sign of a loose connection. If you're getting nearly full voltage from the pack even with two cell groups reading 0V, that's more likely an indication that those cell groups have died for some reason, perhaps due to a BMS dying and taking them down with it.

Those aren't the only options, but occum's razor says they're probably the cause.


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Simoc
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18/10/2017 10:00 pm  

I started charging at 37.9V total with all cells at 3.2 (after removing the BMS) and ended at 41V with most cells at 4.1 but 10 on zero. It was also the first use of an EMV charger on the high option which I thought would charge each cell to 4.2V.

The BMS had only one black wire connected and smoked when adding the balance wires.

 


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Micah (Vruzend Rep)
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19/10/2017 4:08 am  

So if the charger can actually charge the pack, that sounds like the cells are all connected. If the caps were down far enough, that would also give you a reading of 0 V, but you wouldn't be able to charge the pack because there wouldn't be a complete circuit. So it sounds like theres a problem with those cells that is causing them to read 0 V.


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Simoc
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19/10/2017 6:56 am  

Yes. I decided it was the BMS balance wiring that caused the problem. Nothing else makes sense.I was around half way when it happened. Are 0.00V cells revivable? I was thinking of buying a single cell charger to see.


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Micah (Vruzend Rep)
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20/10/2017 9:05 am  

It's not certain that they're permanently gone, but it's more likely than not. You can try charging them slowly with a single cell charger, but you should do this in a safe place because there is the chance that these cells could be internally damaged and thus smoke or catch on fire. An oven, BBQ grill, or on a driveway or brick surface would all be good options. And don't leave them unattended while charging.


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Simoc
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Street cred = 10 mAh
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08/11/2017 6:18 pm  

So I bought a single charger and the first battery charged up perfectly.  But so far no luck with the nine others. Most won't charge at all but I'm still trying on three of them that indicate they're charging. One green at 0.61 (this one has heat damage to the cover) and another at 0.21 the rest at 0. Now to change my configuration. 


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