So I got a cool custom super duper LED drop in for my old beat up Patrol SL20x as well as a NiMH 3500mAh battery. I have been using my real RC charger but want to try and keep the light in the wall sleeve constantly so it is ready to use whenever I want it. It trickle charges at about 880mAh so I would get a full charge in about 4 hours, but in the past this constant type charging has killed many a NiCD battery stick.
880mA, not mAH. A charge rate can not be a capacity, and a capacity can not be a charge rate
Have you actually tested 880mA from the charger or is this just what it says on it?
Keep in mind there is power lost to heat, and to fully charge and balance out a Nickel chemistry pack requires that there be some over-charge. 4 hours would not completely charge a 3500mAH pack at 880mA charge rate, it would be closer to 5 hours by my guess...
Would NiMH be more tolerant of this constant trickle charge?
NIMH is less tolerant to baking on a constant charge than NiCD, sorry... you'll be best off trying to address the major drawbacks to that charging system if you intend to have that NIMH pack last....
Technically speaking, a trickle charge rate would be ~350mA for a 3500mAH pack... I'm curious, does the charger included with the SL20X actually just keep on charging at 880mA all the time regardless?
Most dummy style charge setups choose a slow enough charge rate that a NiCD stick can sit on it for years without a problem, an 880mA constant charge on a NiCD stick with the capacity of a SL20X's, would indeed ruin a lot of batteries... (Sales Department puts in a request to engineers to design a rechargeable flashlight:.... "but try not to make those batteries last too long... We need to sell yearly replacements to everyone so we can afford another one of those stellar christmas parties on top of a skyscraper"....)
Would putting the charger on a timer make more sense? 4 hours a week? A day?
I do believe this would be a good cheap quick and easy dirty fix and would probably work fine for awhile... The amount of charging time should be based on how much self-discharge the cells have and how often you use it.... Might be kind of hard to determine exactly the best amount of weekly time on the charger is reasonable, so while this option would certainly be better than letting the cells sit there and cook all the time, it's still not great.. I think I'd be tempted to let it charge like 2 hours a week and see how that works out.
Does anyone know if the OEM charger will discharge/reverse charge if not powered?
I doubt it would do anything like that, shouldn't be a problem
Thanks for any help!
Dennis.
ps. Still getting to know my new drop in but I will post a review after I get some first impressions. Let's just say SUPER FLOODY & SUPER BRIGHT!
If I may... Have you considered gutting the stock charger sleeve, and wiring up a cheap "smart" charger to it... and putting THAT on a timer to kick on and top of the pack say- once a week? IIRC that's a 5 cell pack... I'd be tempted to wire one of these up to it:
http://www.batteryjunction.com/unsmchfornib.html
give it 2 hours a week on that thing, set to 1.8A charge rate, and it will properly top up the cells each week, (it'll probably only charge for about 30 minutes each week before terminating the charge, depending on how much you use it)....
