I too use a custom LM317 charger. I use a pot to control the rate of charge so I can do a standard quick charge like the controller or do a 5mA 12-16hr trickle charge. I am a tight ass so an intelli peak charger or similar was out of the question. For $1.80 for the LM317 plus a couple more bucks for the other components I have a charger that is pretty much indestructable (chip has thermal cut off). Get yourself a multimeter so you can check which positions on the pot are what rates.
With NiMH batts you should NOT fully discharge them as you should with NiCad batts. It is possible to over discharge a NiMH which does some serious damage. To stop fully discharging the NiMH batt, you need to take it out of the car or put in a switch. The NiMH batts have no major memory effects so you can half charge or fully charge with no side effects. NiCad’s on the other hand do have memory effects, ie if you do a full charge you should only fully charge it from here on, likewise if you do a partial charge you should do the same from now on. You can mix you charge rates around but the performance will change quite a bit.
With the smaller batteries, the longer more gentle (low mA) charges are better in the long run. I don’t like to do a full charge in less than an hour, but as long as the battery doesn’t get hot you can charge it faster.
If you think you batt is stuffed try putting it in the freezer for 24hrs then try it again. May fix your problem. (This works on Mobile phone batts too).
Dave,
I am in the process of making a charger with 4 independently operated bays (for different batt sizes). Will keep you posted.
Cheers
.
