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testing the batteries/cells out of an LG Chem RESU-7H system
#11
No burnt wiring or leaky cells, I would have smelled if there were. Probably should have said smell check: check for burnt wiring/leaky cell smells found none.

I had seen 63 Ah in the specs on the LG Chem RESU-7H so I didn't question it. Hope I am wrong.


Hope you can revive your cells

later floyd
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#12
Cool
My DCDC case was dented, but I'm not likely using it. Cells and wiring looked great.

If it goes well, I should have my first pack up to 20 volts this evening. My cells were lower than yours so I have been going with a lower current. 200mA, it takes forever, but it feels safer.
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#13
I probably won't be reusing either of the dc-dc units.

Glad you have managed to get a pack to charge. What are you using to charge it?

I agree it feels safer at a lower mA rate. if no heat or swelling maybe up the mA after you get to 21v? even feels slow at 2A I have been charging one of the better packs for 9 hours@2A the voltage is 25.5 and has put 17.75 AH into the battery.
later floyd
p.s. 23.85v to 25.5v
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#14
Currently, with the cells so low I am using a bench power supply with a chargery BMS hooked up only to monitor cell voltage. The chargery also includes temp sensors, so I thought, might as well throw one on each side of the pack. They are sort of tucked under the blanks where the original temp sensors were not installed.

Once I get to 3 volts/cell I think I will switch it to the x8 and turn up the current to something similar to the 2a your pushing. But, 2a into a what might be 63ah cells? And there are 6 packs. This could take quite a while...
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#15
Finally got enough time to get the first pack up to 3.2v/cell. I just bumped the current to to 2.0a

Cell differential is good, but not as good as your pack. 51mV at roughly 3.3 volts
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#16
very good

later floyd
the first pack charged between 51.293 and 56Ah, I know I need to do a discharge test
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#17
Battery 1 Charged @2A topping off after battery 2
Battery 2 got warm when charged @5A now toping off @4A
Battery 3 57.864Ah 28.66v 6mv done at 4A charge
These Three were around 10v.

The last 3 were around 7v I have charged them to 24v later this week I will do a regenerative discharge from 10v group of batteries into the 7v batteries
later floyd
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#18
Impressive. I like the results, getting 57ah into one pack on the first cycle. I wonder how much more capacity will return after a couple cycles?

How warm at 5a? That is a bit concerning. I was expecting these to handle something like 30a charge and 60a discharge. But, that's a guess. I still haven't come across a spec sheet for these cells.

My first pack is just finishing the first charge up. 4.05v/cell now. Going up to 4.1/cell (28.7) then I will use it to trickle into the next cell group. Your set up seems much more efficient that what I have going on. My first pack has spent nearly 24 hours on the x8 and is just reaching my max (for now)

Also, my cell voltage differential improved quite a lot. Before I switched to the icharger, I had 5mv delta. The x8 has been balancing since connected.
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#19
Warm as in I was being overly cautious probably was 10 degrees above ambient temp and I don't need any more heat than the central valley already has. Smile I suspect that you are right about charge and discharge rate being quite a bit higher.

I was having to do the charge in stages only charge when I am home and awake since I live in the city and I like my neighbors and neighborhood.

I will find out more once do a discharge test.

my cell voltage differential at end of charge has been 5mv rather consistently. both packs I charge till the x8 said done have been 5mv
later floyd
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#20
Good news, on the temps. I'm out in the central valley also and following about the same strategy. Only charge when home and able to check on the pack frequently.

It had about a 5mv cell diff once I got into a more normal cell voltage range. Then I hooked it to x8 to charge, but forgot to turn off balancing. Now it's 1mv!

Starting to charge pack #2
I am tempted to trickle the remaining 4 up to 3.0v/cell. Then parallel them all together and charge as a pack. It would speed things up a bunch.

This is taking for ever! The first pack literally spent 2 entire days on the charger to reach 4.1v (that puts the entire charge time well over 24 hours, possibility closer to 30)
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