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testing the batteries/cells out of an LG Chem RESU-7H system
#21
That is great news
I found where I saw 63Ah https://static1.squarespace.com/static/5...Global.pdf


Later floyd

While charging just before it switched from CC to CV all my packs the cell differential has got down to 1mv-2mv then rose to 5mv as the charge ended.
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#22
How's progress going? Have you cycles the packs and done any capacity testing?
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#23
I haven't cycled the cells, trying to build fire resistant boxes for capacity testing and charging. The first couple I built weren't to my satisfaction. They will work just not my best work. Also hard to do a capacity test inside (don't feel safe) so outside it is. I couldn't move fast enough if the cells started to go thermal. Easy to toss an 18650 into a bucket of sand not so easy to move a 7s large format lipo battery to bucket.
I will be doing a regenerative discharge as soon as I can. Don't do well in the heat anymore 90f is about my limit and there doesn't seem to be enough hours in the day.

Later floyd
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#24
Good point, have you considered using the factory aluminum case? You have two cases? Maybe isolate the once pack being cycled with the remaining good packs in a separate case.

I'm doing mine open air. The only thing near by is the shade sail covering the work area. Worst case, I can't see the nylon rope spreading fire 10ft to the house.

I have been slowly recovering the 7s packs one at a time to 3.0v/cell. Then using the already charged packs in parallel to bring the newest pack up to 4.1v/cell.
Just finished getting the 4th pack to 4.1, the 5th is nearly at 3.0.
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#25
That is a thought about using the cases to do the capacity tests, will move one of the cases to the back yard where the other case is. Thank you

later floyd
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#26
I cycled my first 7s pack a few times yesterday morning. At 30a charge and discharge the pack was 5 degrees warmer than an unload pack right next to it. So, I think that's a good sign.

I don't have a spec sheet, so I have no idea what I should use for the min/max cell voltage. Any thoughts?

I used 3.5-4.1v
The first cycle was roughly 41ah, third was cut short by the heat (forecast of 110f as you probably know), at 3.6v it had discharged 48ah
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#27
I don't know the specs either but that is right around where I was going to use on the discharge test.
I was planning on 4.1v-3.43v (28.7v-24v) not sure what energy is left in the .7 volt from 3.5v to 3.43v but will see what the x8 says. I might end the discharge sooner.
Now I just have to have some cooler weather and free time to discharge test the batteries.
Later floyd
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#28
400bird I found this with a search but didn't post it cause I am not 100% sure it is for the right LGX cell
High Capacity 3C / 5C 3.7V 60Ah Polymer Lithium Li Ion Cells combine to 12V 24V 48V 72V 60Ah battery pack

Specifications

Type : HR37145100300
Material system :Multivariate composite lithium (remark-Multivariate composite cathode material)
Nominal Capacity :60Ah
Minimum Capacity :60Ah
Nominal Voltage :3.7V (Mean Operation Voltage)
Delivery voltage :3.50~3.60V (Within 10 days from Factory)
Charge Voltage :4.20V±0.03V (By standard charge method)
Standard charging method:1.0C constant current,4.20V constant voltage charge to 4.20V,continue charging till current deadline to ≤0.05C (25±3℃)
Standard discharging method :1.0C constant current discharge to 2.75V,
Cell Internal Impedance :≤1.0mΩ (Internal resistance measured at AC 1KHZ after 50% charge )
Weight :0.88±0.02Kg
CC Charge :CC charge 1.0C/60A、cutoff voltage 4.20V,Capacity>60Ah 1.0C
High-Rate Discharge Big GrinC discharge 3.0C/180A、cutoff voltage 3.0V,Capacity>60Ah
Operation Temperature and relative humidity Range:Charge 60±25%R.H.
0~10℃:0.2C
11~20℃:0.5C
21~45℃:1.0C
Discharge 60±25%R.H. -20~60℃
Storage temperature for a long time:-20~25℃≤Six months
-20~45℃≤one month
Size:14.5*100*300mm
https://s.click.aliexpress.com/e/_dVSfDO4
near the bottom of page there is a cell with lgx XXX couldn't read the last part of it.
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#29
Thanks, good find!

I feel like those last two pictures say something like LGY E49 or similar.
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#30
And on further reading https://www.s-power.cz/wp-content/upload...asheet.pdf it appears the units were the RESU 10H as the RESU 7H didn't come with can communications my units' dc-dc converter has a can label, Plus the 6 7s modules 1.6317 KWh x 6= 9.790 kWh is equal to the total power in the RESU 10H

later floyd
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