Guru
Joined: 15/07/2006
Location: AustraliaPosts: 676
| Posted: 07:38am 10 Feb 2012 |
Yahoo2, no problem, you can start a thread if you like.
Cell 13 was cell 23. Position 23 is the centre of pack and is always the hottest. This cell showed signs of greater internal resistance. Then appeared to charge higher and discharge lower than the others.
I shifted it (the whole 5 cell block) to position 13 so that it would be able to cool better. As stated in a previous post, I had over charged it by quite a bit. This over charging created a masive internal resistance. I continued using it but under normal discharging (driving) it always sagged to 1.0 -1.5v. As soon as discharge stopped it sat on 3.0v +. It was not empty. It still drove me round trip of 75km each day for a good while.
It has now been removed from the series string. The last couple of trips was driven with it sagged to 0.0v when pulling around 100-150A. It showed normal voltage 3.0v, with no discharge. Then you can see what happens with 15A charge. The resistance in the cell pushes the voltage up. I believe this is only tension, not really what is in the cell. Terminal voltage only if you like.
Then the next day I run the charger for a little while. Pictures are charging at 15A and 31A. You can see it doesn't need much current to give the voltage rise.
I let it charge with both chargers (31A) and near the end of charge the voltage rises quite high. (Originally I had the chargers set to 167v, but currently is set to 156v). 1 charger is set slightly lower voltage to the other and so 3A still coming from the 2nd charger. I disconnected the 2nd charger to show 15A.
I switched off the charger and then switched it back on. See cell 13.
Seperated battery block, shifted cell 13 to the end and then put back together. Clamps hold it together to get the srews back in the stainless stell bands. Back in the Hilux, cell 13 now is cell 45. It just takes up space. It is not connected in the series string. I had to put it at the end so the Battery Monitoring Screen still reads corectly.
I still have been driving my usual round trip of 75km with some capacity spare. The loss of one cell is not noticeable.
Trev @ drivebynature.com