I need a topic

[bagmaker]

Depending on your charger, Norman, you should be able to rescue the critically injured cell.
You might need to lie to the charger to get it to actually input some power, if it senses the low voltage cell it may alarm out of the charge cycle.
Does your charger have a "Lead Acid" / LA, Lead or other charge options?
As Terry says, whack any sort of current into it below 4v and monitor for a few minutes. Once the dud cell gets moving a bit you can revert to a normal balanced charge cycle

[BruceS]

I recently replaced both of our Toshiba laptop batteries. For fun I pulled one apart with the plan to look at what is involved in replace/rebuild.
The thin strips connecting the cells are resistance welded (spot welder?) to the ends of each cell.
Although there was easily enough room for 6 cells, there were only 3 in it. They looked to be around the same size as "C" sized alkaline ones.
There was minimal info on each individual cell.
Not sure of voltage but Toshiba run on 19v power brick/charger. From memory they were 5200mAh.
I didn't bother doing it ..........

[brett&kat]

As my ban from the CF has been extended for another mth because of my extreme good looks and the REDMEN there are jealous (only reason I can think of at the moment )

And you'd go back there for more punishment because..........

[T1 Terry]

no house battery Terry, these are for radio control airplanes. i have 2 x 11.1 batteries according to the balance charger the middle cell in each is below 3v.. I need to recover them. How to do that without a fire is the problem. some say they are no good, I have heard that more voltage ( 15v) may do the trick?????? These are lipo 11.1 and when fully charged are 12.6v

So these are 3 cell batteries, max cell voltage is 4.2v fully discharged is actually 3.2v per cell or 9.6v, 3.7v is their nominal voltage.
To rebalance the pack you need a DC charger, preferably around the 4.5v mark and 1 amp to avoid heating the cell rapidly. Charge the battery normally while the second 4v charger is also connected to the low voltage cell if the battery has a balancing module attached. If no balancing module then charge the battery till the high cells reach 4.2v, stop charging and attach the 4v charger to the low cell and charge it to 4.2v. Now discharge the battery and recharge while watching the cell voltages, you may need to repeat the boost charge to the low cell a few times before it comes back into balance with the other 2 cells, but if it doesn't by the 3 rd recharge/discharge cycle, that cell is stuffed and needs to be replaced.

T1 Terry

Tricky that one Terry

Not that bad Norman. You can buy replacement cells with the tab spot welded on, carefully peal the tab off the dead cell so you still have the tab connected to the good cell each side. Now solder the tab from the new cell to the tab from the good cell and you have replaced the bad cell and brought the battery back to life.
Bruce's idea of opening old laptop batteries is a great source for good used cells, use the multimeter to determine which cell died, peal the tab off at the cell top and base and fine a good cell from another battery pack, solder the tabs together and away you go. Balance charge the cells till they all come up to 4.2v and the battery is good to go again.
Get one of these little chargers and solder a wire to the terminals each end, you can even use an old not quite dead cell so you can just slot it into the charger, then add small alligator clips to the wires so you can connect to the metal tab each end of the low cell to recharge it.

T1 Terry

[T1 Terry]

As my ban from the CF has been extended for another mth because of my extreme good looks and the REDMEN there are jealous (only reason I can think of at the moment )

And you'd go back there for more punishment because..........

I enjoy teasing them I wouldn't post any technical stuff there again, they have killed that well and truly, but I'd still offer help to anyone who wanted it via the PM facility.... and mention that I am on another RV forum where 12v information isn't seen as the devils work

[brett&kat]

I enjoy teasing them I wouldn't post any technical stuff there again, they have killed that well and truly, but I'd still offer help to anyone who wanted it via the PM facility.... and mention that I am on another RV forum where 12v information isn't seen as the devils work

devils work..... love it

[norman]

Thanks for the info Terry. Will be able to do some tinkering when we get home..Got a few dead ones to practice on.

[dcsingos]

Norman you need a good soldering iron, one that can heat very quickly, the older type Scope ones are great, you only want the heat in the tabs and solder, the other types take to long to heat properly or don't get hot enough then the heat transfers into the cells, you just need the heat to melt the solder between the tabs. I used to build all my own battery packs from nicads and then Lipo. As T1 said you can just test to find dud cell and replace with another cell then rewrap batteries.

[bagmaker]

How come the bubbles in Schweppes drinks are smaller than the bubbles in other drinks?
How can simple CO2 be different in one soda water compared to another.
if the ingredients are Co2, water, thats it??

[dcsingos]

How come the bubbles in Schweppes drinks are smaller than the bubbles in other drinks?
How can simple CO2 be different in one soda water compared to another.
if the ingredients are Co2, water, thats it??

Cause some have more expensive bottles with better lids that seal better and they hold the Co2 better LOL