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floyd's powercabinet
#11
looks like I jumped the gun, my supply of used laptop batteries has suddenly turned into nothing, and my good cells aren't as good as when first tested. I have been retesting every cells I have and many are returning low mAh much lower than when i first tested them. guess I will be retesting them again. hope I can get consistent results.

later floyd
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#12
Man, that sux.   Confused   What charger(s) are you using? What settings? And what ever other questions that might need to be answered .....
Proceed with caution. Knowledge is Power! Literally! Cool 
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#13
(11-06-2017, 03:21 AM)floydR Wrote: looks like I jumped the gun, my supply of used laptop batteries has suddenly turned into nothing, and my good cells aren't as good as when first tested. I have been retesting every cells I have and many are returning low mAh much lower than when i first tested them. guess I will be retesting them again. hope  I can get consistent results.

later floyd
Indeed. Let us know what equipment you have, there could be many explanations as to what is going on. Poor cell contact can give very poor test results. It is unusual for cells to loose a lot of capacity between one test an the next.
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#14
2 Opus BT-C3400 V3.1 Battery Charger Analyzer Tester for testing
I charge all the batteries to 4.2 v let them sit for a week check voltages
use The charge test which charges to 4.2 volts then discharges to 2.8 volts (mAh results) then charges it back to 4.2 volts
I have a Foxnovo-F-4S-4-Slots-LCD-Battery-Charger I use for charging.
a Foxnovo F08 8-Slots Li-ion Battery Charger which I no longer use. it charged to 4.35
various single 18650 cell chargers no longer used going to use them as cell holder for the TP4056's thanks Korishan
it is the cells under 1800 mAh that are testing lower. they may have been weak in the first place
I have 137 cells @2000 mAh plus probably 20 @ 1900 mAh plus 20@1800 mAh plus 100-150 @>1800 mAh

later floyd
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#15
(11-06-2017, 04:53 AM)floydR Wrote: 2 Opus BT-C3400 V3.1 Battery Charger Analyzer Tester for testing
I charge all the batteries to 4.2 v let them sit for a week check voltages
use The charge test  which charges to 4.2 volts then discharges to 2.8 volts (mAh results) then charges it back to 4.2 volts
I have a  Foxnovo-F-4S-4-Slots-LCD-Battery-Charger I use for charging.
a Foxnovo F08 8-Slots Li-ion Battery Charger which I no longer use. it  charged to 4.35
various single 18650 cell chargers  no longer used going to use them as cell holder for  the TP4056's thanks Korishan
it is the cells under 1800 mAh that are testing lower. they may have been weak in the first place
I have 137 cells @2000 mAh plus probably 20 @ 1900 mAh plus 20@1800 mAh plus 100-150 @>1800 mAh

later floyd

If cells seem to have lost capacity - clean the contacts on the Opus. There is also often some variation between tests.

How much capacity do your cells appear to have lost?

Also are you testing a the same discharge current. If you discharge cells at a different rate you will definitely get different results.
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#16
(11-06-2017, 05:01 AM)Geek Wrote:
(11-06-2017, 04:53 AM)floydR Wrote: 2 Opus BT-C3400 V3.1 Battery Charger Analyzer Tester for testing
I charge all the batteries to 4.2 v let them sit for a week check voltages
use The charge test  which charges to 4.2 volts then discharges to 2.8 volts (mAh results) then charges it back to 4.2 volts
I have a  Foxnovo-F-4S-4-Slots-LCD-Battery-Charger I use for charging.
a Foxnovo F08 8-Slots Li-ion Battery Charger which I no longer use. it  charged to 4.35
various single 18650 cell chargers  no longer used going to use them as cell holder for  the TP4056's thanks Korishan
it is the cells under 1800 mAh that are testing lower. they may have been weak in the first place
I have 137 cells @2000 mAh plus probably 20 @ 1900 mAh plus 20@1800 mAh plus 100-150 @>1800 mAh

later floyd

If cells seem to have lost capacity - clean the contacts on the Opus. There is also often some variation between tests.

How much capacity do your cells appear to have lost?

Also are you testing a the same discharge current. If you discharge cells at a different rate you will definitely get different results.

will clean the contacts.
300-400 mAh
I thought all my tests were at 1000 ma. and all discharge results.
I think by rearranging the cells  I could use the 1800-1900 cells  to complete a 7s20 pack only need 3 cells.
Might be that i am tired and got sloppy with how i was testing. The buttons need to be fixed Mike or Daniel has a video on fixing ithe buttons

later floyd
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#17
That is a huge difference. Odd indeed. If you are short of cells I would use the <1800mah cells. A lot of my cells are 1500-2000mah. Anything less is torch battery.
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#18
(11-06-2017, 05:47 AM)Geek Wrote: That is a huge difference. Odd indeed. If you are short of cells I would use the <1800mah cells. A lot of my cells are 1500-2000mah. Anything less is torch battery.

Man, that's a lot of torches! :-P
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#19
I blame tiredness and finding I had fewer good cells than I thought. kinda disheartening  to realize you haven't met your goals. On the plus side a coworker gave me two laptop batteries today. First laptop batteries I have had to harvest in the past couple weeks.

 Later floyd
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#20
(11-07-2017, 02:28 AM)floydR Wrote: I blame tiredness and finding I had fewer good cells than I thought. kinda disheartening  to realize you haven't met your goals. On the plus side a coworker gave me two laptop batteries today. First laptop batteries I have had to harvest in the past couple weeks.

 Later floyd

Onwards and upwards, one reclaimed laptop battery at a time.

It sounds very easy from the onset but as soon as you get into it and start planning things for real you soon realise that you  need _a_lot_ of 18650's and getting those tested and sorted is a long process. And there's a lot of work going into this too, I certainly didn't expect it to be that much so that needs to be taken into account too.

I am leaning more and more towards simply buying new cells and use those if this works out as I want it to, that way I can test the concept out and then if / when I decide to go for a big system I will most likely use new cells for the new packs. 

I'm trying to work out a pack layout that I can make so that I can reconfigure the packs easily into different configurations and something that fit my wished for form-factor but I haven't made that decision yet.

I still got a crapton of cells to test and sort so will decide on a layout when I know how many cells I have and of what capacities.
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