Recent content by JimW

Out of the shipping container looks like this. Voltage reads as 3.82 (which is what I expect for these cells). What do you think? Try a charge cycle and see what happens? Try a discharge cycle and see what happens? Try to squeeze the cell to return it to it's original non-puffed state...

Hmmm. Would it be more important to have a pack with the voltages of each cell all the same, or a pack where the watts of power in each cell was the same (regardless of voltage reading). I'm not sure how one would practically determine the total watts in a cell (except by discharging it). If...

"BMS" = "Battery Murdering Systems" LOL :lol: Perhaps I have found a niche in which I can contribute a bit. Thanks, Jim.

Thanks to all who replied. This has been very educational. One point I'm still not perfectly clear on - If you have one really low cell, are the rest of the cells discharged down to the low cell voltage in order to achieve 'balance'? (Can I assume that a balanced charger has some sort of...

Also, the balanced chargers don't do any charging through the balance leads. Right? That would be a manual operation to try to fix a low cell. Thanks, Jim.

Ok. I think I got it. The pack is bulk charged while monitoring each individual cell voltage. Then 'high' cells are discharged to match up the volts of the rest of the cells. If you have a super performing cell, the charging stops, that cell is discharged, and then the operation picks back...

It occurred to me that I really don't know the 'details' of how chargers balance a battery pack. I know that a balanced pack has all the cells within .1 (or better) volt of each other. I know that balance chargers have a discharge circuit. But I don't know how the balance is achieved. Does...

Interesting that you should mention this. I was just testing an HK cell over the weekend. My test objective was to see what kind of performance the cell had at max C discharge. Turnigy 2200 mah 40 C cell - testing at max C Starting voltage was 4.2 (unloaded) Load is 250 watts of .05 ohm...

Ahhhhh... It's really going to depend on what each charger is using for a ground reference. If each charger is just the isolated secondary winding of a transformer, then fine. If the charger has any sort or Regulator on it, then it will depend on what the Regulator is looking at for it's...

?? Perhaps I am misreading this board. C-discharge defines the maximum discharge rate, or how much amperage you can get from the cell without damaging it. C-charge defines the maximum charge rate, or how much amperage you can put in without damaging it. If you exceed either, you are...

Depends on the C of the batteries. Hot off the charger, the voltage will drop like a rock (what, about half a volt guys?) at maximum C discharge and then continue to slowly fall based on the total capacity (Amp hours) of the cell. If, however, you exceed the maximum discharge C, the voltage...

Totally interesting and truly excellent ! Thank you for posting this. Jim.

I have read with interest that there are some post-purchase machining operations performed on motors. I think mostly by those interested in high performance. Anyway, this made me curious. What are these machining operations and what do they do? (are we talking bearing changes, lightening...

I think perhaps my question got lost in the shuffle.. auraslip, Can you tell me the significance of the Red, Yellow and Green on your spreadsheet. I understand that they represent the cell voltage, but what conclusions do you draw from the voltages. Does red indicate a bad cell, or just a low...

auraslip, Can you tell me the significance of the Red, Yellow and Green on your spreadsheet. I understand that they represent the cell voltage, but what conclusions do you draw from the voltages. Does red indicate a bad cell, or just a low voltage one? How low a voltage would you consider to...