First test... Didn't work out quite as planned

ericfx1984

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So I did my first test last night... New build, Eve cells 230ah, 4s, JBD 200a BMS, I built two of these batteries

I hooked up a msw 750w inverter to a heater on low, 671w on the AC side, 853w on the DC side

The first battery pulled full capacity no issues... However I was not able to pull down to low voltage disconnect only about 2.7v per cell (recovered to 3.02v)... At this point the inverter was not happy as we were so close to its maximum wattage anyway.. the inverter shut down due to heat

However the battery pulled more than full capacity and was at full capacity before heading 12 volts

And I went to test the other battery I noticed that the voltage had dropped and was setting around 3.35v per cell. This is confusing because the only thing that was actually hooked up was the BMS

I did test it for about 10 seconds the night before and it wasn't registering any amperage so I checked all my connections everything seemed fine but here we are

Anyway I'm not sure if it's worth it to do a capacity test now or if I should recharge the battery but I'm confused as to why it would self discharge like that? BMS shouldn't really draw anything right?

So I guess my question is should I be concerned about the discharge that I'm seeing on one battery? Or should I just capacity test it and see what it does?

And my other question is should I be concerned that I wasn't able to fully complete the capacity test on the first battery or should I just leave well enough alone since it did test above rated capacity and I did not have to draw the battery fully down to get there?
 

ericfx1984

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If I wasn't actively using my 3000 w inverter I would plug that up and draw down at 1500 watts or so.. but it's actively in use
 

ericfx1984

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Alternatively I do have a DC heater that could be used to draw it down even further it has a 15 amp fuse and was designed to plug into a cigarette lighter so that could be used for the final drawdown I suppose but I really don't see the point at this point right?
 

Samsonite801

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On the second pack, the self-discharge concern, did all cells drop evenly, or were there any particular cells that were dipping lower than another?
 

Browneye

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So you got 'em all going together and everything's peachy?

I also have the Eve LF230's, 4S 12V.
When I tested out my Xantrex inverter at full capacity, with everything else on in the RV that I could turn on, including a second smaller inverter for the TV/Surround tuner, I was pulling 78A @12Vdc. It was recommended I test at full load and check for warm spots in the system. The inverter lead terminals got to 80*F (from 67/68) but the inverter housing went to 102* I think I read the cooling fans run at 103 - they weren't on yet. Nothing else around or on the pack got warm, except one spot on the BMS face near where the leads attach, also got to 80*. I was happy and confident with the results. I still have not drawn my pack all they way down, it would take several hours. But after about 40-50 minutes I shut it down, pack was at about 60%.
 

Samsonite801

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With in 0.001v

Well, if the self-discharge issue happens again, try switching the 2 BMS's around to the adjacent packs, and see if the issue follows to the other pack. Perhaps it's the BMS, or maybe the bluetooth isn't going to sleep on one of them or something... At least a test like that might help narrow down the cause...
 

ericfx1984

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So you got 'em all going together and everything's peachy?

I also have the Eve LF230's, 4S 12V.
When I tested out my Xantrex inverter at full capacity, with everything else on in the RV that I could turn on, including a second smaller inverter for the TV/Surround tuner, I was pulling 78A @12Vdc. It was recommended I test at full load and check for warm spots in the system. The inverter lead terminals got to 80*F (from 67/68) but the inverter housing went to 102* I think I read the cooling fans run at 103 - they weren't on yet. Nothing else around or on the pack got warm, except one spot on the BMS face near where the leads attach, also got to 80*. I was happy and confident with the results. I still have not drawn my pack all they way down, it would take several hours. But after about 40-50 minutes I shut it down, pack was at about 60%.
I got mine down till the test inverter was no longer happy... Around 11.2-11.3
 

Browneye

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On the self-discharge....
Are you sure it wasn't just settling voltage? My pack immediately settles back to about 3.45Vpc as soon as charging is terminated.
What does your BMS say? Does it show amps discharging when at rest? Do you have a BT app? - I couldn't remember.

I have about a half-amp parasitic load, haven't been able to identify it. Some of it was the car-radio, when 12V is switched off and then on it turns on and doesn't turn off - that was about 20mAh. There's a LPG sniffer, supposedly these are just milliamps too, but I haven't tried disconnecting it to see - it's hard to get to. And then all the meters, shunt, etc. If I switch the aux battery cuttoff then it does go to zero, so I quit worrying about it. It would take weeks to discharge the pack to any extent.
 

ericfx1984

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On the self-discharge....
Are you sure it wasn't just settling voltage? My pack immediately settles back to about 3.45Vpc as soon as charging is terminated.
What does your BMS say? Does it show amps discharging when at rest? Do you have a BT app? - I couldn't remember.

I have about a half-amp parasitic load, haven't been able to identify it. Some of it was the car-radio, when 12V is switched off and then on it turns on and doesn't turn off - that was about 20mAh. There's a LPG sniffer, supposedly these are just milliamps too, but I haven't tried disconnecting it to see - it's hard to get to. And then all the meters, shunt, etc. If I switch the aux battery cuttoff then it does go to zero, so I quit worrying about it. It would take weeks to discharge the pack to any extent.
Not sure but it passed a full capacity test with well over the full capacity
 
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