Regaining Battery life..... [Archive]

michel-2000

12-29-2004, 01:09 AM

Ok, here's the deal:
My brother in law bought a used Evader BX, that came with 5 batteries, from 1500 to 3300, with a regular charger (no discharger).
The problem is that 4 of them don't keep the charge !!!!!!..... :cry:

Is there a way to 'reboost' the defective one ?
Is there a way or someone that can check them and regive them their 'life' ???
I don't really mind having to ship them somewhere (would rather like to ship them in Canada), he would love to get them working again ??????????

Thanks

Michel

highroller

12-29-2004, 04:18 AM

Once the cells start to really go bad, there is no possible way of bringing them back. However a couple of things may have happened that is causing them not to charge properly. If you notice a discoloration to the shrink wrap then cells may be no good from the start or it could be that cells need a couple charges before coming back up to somewhat normal conditions.
1. ensure they are completely discharged - use a string of 5-10 1157 type bulbs plus one single one(the single one helps bring cells down a little more so they charge a little better). Remove the bulbs as soon as they start to dim in both uses.
2. Allow the packs to cool at room temperature or overnight
3. Now charge the packs noting time of start and if possible monitor the voltage of packs either with charger (hopefully it has digital display) if it has only an analog display then use a DVM (digital volt meter) to monitor pack voltage. Couple of things to note that will indicate a possible problem with cells, if pack voltage starts high 9.20+ volts and suddenly drops or causes charger to shut off, one or more of the cells may be bad. These cells will also start to feel much warmer than the rest after 10min or so of charging.
4. For charge rates I'd use 5amps using a .03mv voltage detect with all the cells for the first charge. For NiMh 6cells use .03 to .05 for Nicads .09 is good for recreational use. Good peak voltage should be around 9.38 to 9.58 volts, voltage above 9.60 means cells have built up internal resistance - only thing you notice in racing is pack may not to seem to have as much punch.
5. Also depending on how long the packs were left unused they may not charge consistantly for one or two charges. But after a couple of cycles (charge/discharged, or charged and used) may start charging normally.
6. for storage Nicads discharge after use, discharged to 5.40volts for 6cells or .90volts per cell the same method should be done with NImH however for Panasonics if pack has not been used for 2-3 wks if should be cycled (charge then discharge) for Sanyo and GP they can be stored for a month with .90 volts per cell, then cycle after 30days if they have not been used.
If packs don't charge well the first time, discharge them down to 5.40volts let them rest one day (24hours) and try a second time, with NiMh attach the single bulb (remove the instant it dims) wait 15 min and charge. The reason I suggest discharging lower is cells are more closer in voltage, with NIMh cells and low voltage detect setting if cells are off in voltage this has led to chargers false peaking. It helps eliminate some of the false peaking if cells start out closer to the same voltage levels.