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02-01-2016, 10:41 AM | #1 |
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A123 battery back from the dead - what to watch for?
I left the 2500 mAh A123 battery in my current project on for several days. When I tried to charge it in LiFe mode I got a low voltage error (as expected). A little research showed me that I could charge it as a NiCd for several minutes to bring the voltage up, which I did. After ten minutes I tried the LiFe charge again. No low voltage warning, and the battery balance charged to 2488 mAh.
So it looks like I got my battery back. But is there anything in particular I should watch for? |
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02-01-2016, 12:11 PM | #2 |
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Re: A123 battery back from the dead - what to watch for?
I did that to one of my packs. I found that it went out of balance quite easily, but after several cycles it wasn't as much of a problem. I do notice that while it maintained its capacity, I find that it drains down during storage a lot faster with one cell dropping faster than the other which will toss out the warning when charging again.
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02-01-2016, 07:53 PM | #3 |
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Re: A123 battery back from the dead - what to watch for?
From what I've read here and elsewhere it's worth cycling the pack to see how it responds. Unfortunately my charger (Hitec X1) does not have a cycling mode; I will have to run manual charge/discharge cycles which will take a little while.
With a fully charged pack I set it to discharge (1.0A, 4.0V). Unfortunately the 120 minute safety timer cut in with only 1700 mAh discharged. I charged it up again and set the timer to 180 minutes. It's running now - we shall see. I will share the results when I have them. |
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02-03-2016, 10:12 AM | #4 |
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Re: A123 battery back from the dead - what to watch for?
At any time , when that happens, do a few cycles and then a full regular charge. Let sit , say a week and then do a voltage check on each cell and see if there was any drop and how much. Any of the lithium batteries should hold their voltage for that length of time or more.
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02-03-2016, 11:25 AM | #5 | |
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Re: A123 battery back from the dead - what to watch for?
Here's what's happening.
Tried a discharge with the 180 minute timeout and the following settings. When I came back to the charger this is what I found. From the manual: The newer version of the manual states: Quote:
Result: Clearly the storage mode is not taking enough out of the battery to be considered a proper discharge, but the discharge mode encounters an error. Does that low cell mean that the battery is toast*? *This is academic; a new battery has already been ordered. But I would like to know. |
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02-03-2016, 11:43 AM | #6 |
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Re: A123 battery back from the dead - what to watch for?
John : what can happen with multi cell lipos and life batteries if one cell is out by a lot(2.86v..1.33v) the charger may not charge or cycle properly. Some of the more expensive chargers will shut down with an error message of some sort if the voltages are out this much. What I have done and works well for me; is, I made up a separate set of charge leads that I charge, discharge and cycle thought the balance plug to help the "lazy" cells. Will post a picture after I meet with some of the boys for coffee. Sorry not great pics but you get the drift ?
First pic is the two pin pluged into cell number two of the balance lead/ watch polarity....second pic is of the lead with pigtail for the charger. Set the charger for 1S and the function you want to do. What I usually do is charge the weak cell up to a full charge and then discharge down to storage charge and then a full charge for maybe 2-3 times then down to storage. Then go to the good cell and do a storage charge. Check voltages of each cell and then let sit for say a week and check voltages again. They should hold the same voltages... if the weak cell does not come around and hold a storage or full charge then that cell is toast. Max charge I use is about 1 amp as the balance leads may not handle more than that. I use 20-22 gauge for the single cell leads plus the lower charge rate allows the charge to dissipate better in that cell. Last edited by stegl; 02-03-2016 at 02:30 PM. |
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02-06-2016, 09:39 PM | #8 |
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Re: A123 battery back from the dead - what to watch for?
I read this and immediately wanted to recommend that. Good to see.
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