dnmun
1 PW
post up your pictures in your thread. use VGA setting on the camera to make them the right size.
take a picture of the BMS close up.
take a picture of the BMS close up.
A2b battery dead how to reverse charge?
- Thread starter Cambridgebiker
- Start date
Cambridgebiker
10 mW
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- Aug 30, 2015
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Ok thanks. So tonight I'll try to open up that bms part. I didn't know if that is where I should be measuring or go somewhere else to measure. I'll open that up take some pictures and poke around and try to take some measurements this evening. Here are some pictures of it all hope they come into the forum ok. Thanks!
dnmun
1 PW
set your camera to VGA and post up your pictures here in your thread. the BMS is where the sense wires come from.
Cambridgebiker
10 mW
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Hi all I tried the black and red wires in the middle with multimeter nothing. Opened the bms pics on this dropbox link.
https://www.dropbox.com/sh/bu6415rjjbpi38g/AACpYvPcpH5MIY1Hu8Dqgi0oa?dl=0
Ill try ti post images in forum next post not seeming to work right from iphone6 will try on laptop in a sec.
I tried to test some wires with mutlimeter but got nothing. If I dont hear back I think the next step is to take this board off and look at the other side there might be wires there.. Thanks all; in the meantime from all this my other bike seems like rear hub died going real slow and stuttering a bit, so I gotta figure out how to fix that now too
https://www.dropbox.com/sh/bu6415rjjbpi38g/AACpYvPcpH5MIY1Hu8Dqgi0oa?dl=0
Ill try ti post images in forum next post not seeming to work right from iphone6 will try on laptop in a sec.
I tried to test some wires with mutlimeter but got nothing. If I dont hear back I think the next step is to take this board off and look at the other side there might be wires there.. Thanks all; in the meantime from all this my other bike seems like rear hub died going real slow and stuttering a bit, so I gotta figure out how to fix that now too
dnmun
1 PW
post up your pictures in your thread.
If you look to the right of your last photo, you can see a line of 10 holes with pads around them. The multipin connector is underneath, but you don't need to remove anything because you can pick up the cell voltages from those pads.
dnmun
1 PW
yep the first cell is between that top line and the B- the measure each of the next 9 by measuring the voltage from one hole there to the next.
where do those paired lines go. the blue blbue, red black and yellow and orange brown. i assume the red and black with the spade clips in back go to the charger?
where do those paired lines go. the blue blbue, red black and yellow and orange brown. i assume the red and black with the spade clips in back go to the charger?
999zip999
100 TW
Good work. If you could list the cell voltage starting at the neg end as number 1 like.
1. 3.85
2. 3.65
3. 2.88
11. Xxx volt
1. 3.85
2. 3.65
3. 2.88
11. Xxx volt
Cambridgebiker
10 mW
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Hi all so some good and bad news good news is one cell read .8v and maybe one other read close to that, all others zero. Thanks for the b- I never would have known that thanks! At first i put it on b+ and same cell went up to .8. I added pictures to the same dropbox link here showing needle etc. https://www.dropbox.com/sh/bu6415rjjbpi38g/AACpYvPcpH5MIY1Hu8Dqgi0oa?dl=0 I am going to try again tomorrow with a digital multimeter just to be certain. If say this is the case, the cells are close to zero, is there a way to trickle charge each cell to bring back to life? If so any suggestions on chargers and correct voltage? Thanks again everyone if there is a way I can mail you all a brew I would 
You haven't measured correctly. They should be about 4v each. To check that we're on the right track, put one probe in the end hole and the other in the one next to it. Then measure 8 more times keeping your first probe in the same place and move the other one to the next hole for each measurement. It should go 4v, 8v, 12v.. etc, but we need the exact values. It doesn't matter which end you start.
Cambridgebiker
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Hey so I tried again with my digital multi and got some strange results. One of them was saying 1.1 it was farthest on the end. But a lot of the others were saying 0 or -.3 or #.3 +.6 etc. it literally looks like the batteries were taken down to zero. I put the black multi meter in the b- and the red on the pins I took a picture of my multimeter setup to see if I have it right. i already tried a few combinations but thought I would post here to see if Im doing it right. New pics up on dropbox link here is link again. https://www.dropbox.com/sh/bu6415rjjbpi38g/AACpYvPcpH5MIY1Hu8Dqgi0oa?dl=0
It doesn't look good, but I'm still a bit suspicious of your results because it's not easy to get the cells down to that voltage.
When you run the red probe along the 10 pads with your black on B-, the voltage should only increase, so lowest at one end and highet at the other because pad 1 is cell 1, pad 2 is cell1 + cell2, pad 3 is cell1 + cell2 + cell3, etc.
Did you verify your meter by measuring something of known voltage, like a working AA cell?
One last test before condemning your battery: See if you can find the positive from the cell-pack, which should go to a pad marked B+. Measure the voltage between the two. Also, peel off a bit of insulation from the cells so that you can get at both ends of one cell, then measure it directly.
When you run the red probe along the 10 pads with your black on B-, the voltage should only increase, so lowest at one end and highet at the other because pad 1 is cell 1, pad 2 is cell1 + cell2, pad 3 is cell1 + cell2 + cell3, etc.
Did you verify your meter by measuring something of known voltage, like a working AA cell?
One last test before condemning your battery: See if you can find the positive from the cell-pack, which should go to a pad marked B+. Measure the voltage between the two. Also, peel off a bit of insulation from the cells so that you can get at both ends of one cell, then measure it directly.
Cambridgebiker
10 mW
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Thanks! So last night I tested on a few batteries that are similar to AA and got the right voltage (1.4). I do see how the voltage increases (at the end it almost got up to 2 or something) but it seems like a couple pads in the middle are dead. I tried to open insulation and test the wires there, I got 1.4v which was similar to what I was seeing on the test pins. I broke open the plastic that holds the cells together and tried to pull one cell out, it is glued in there pretty good, and feel sketched out really messing around in there. I saw where it connected to and put my meter on the top pin and on the bottom and read 0. I think it might be time to call this thing dead.
Do you have any suggestions on a next step? Maybe replace the individual cells in the pack? I have also been looking at this pack but unsure if I can wire it up directly to my A or B input (which ever is in the back) http://www.ebay.com/itm/NEW-48v-10ah-LiFePO4-Battery-3A-Charger-BMS-Rechargeable-Powerful-For-500W-700W-/141771486017?hash=item21023d3341 I figure I can use the connector from my pack and get it connected in the back somehow. If I can't use 48v I'll just go 36. I'll look around if I need to add a resistor or anything to preserve the battery life led guage or anything else to protect other stuff.
Any other suggestions would be appreciated.
Thanks everyone!
Do you have any suggestions on a next step? Maybe replace the individual cells in the pack? I have also been looking at this pack but unsure if I can wire it up directly to my A or B input (which ever is in the back) http://www.ebay.com/itm/NEW-48v-10ah-LiFePO4-Battery-3A-Charger-BMS-Rechargeable-Powerful-For-500W-700W-/141771486017?hash=item21023d3341 I figure I can use the connector from my pack and get it connected in the back somehow. If I can't use 48v I'll just go 36. I'll look around if I need to add a resistor or anything to preserve the battery life led guage or anything else to protect other stuff.
Any other suggestions would be appreciated.
Thanks everyone!
Yes, it sounds like it's dead then. Unless you have a spotwelder, it won't be easy to re-cell it. AFAIK, there's nothing special about it, so you can replace it with any battery of the same voltage that can supply at least 20 amps.
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