WARM on charger: Tigerlight, Magcharger, Stinger

Is it OK for these and other lights to get warm on their regular (not fast) chargers? Is this normal and should I be concerned? If so, any suggestions welcome.

Brightnorm

Re: WARM on charger: Tigerlight, Magcharger, Stin

brightnorm,

It is normal for trickle chargers (i.e. "regular") to heat up the flashlight when charging a full battery pack. There is a chemical/electrical mechanism which turns the energy comming into the battery pack into heat.

The light should only be mildly warm to the touch. Certainly nothing as hot as hot bathwater. In any case if you're still getting the full runtime and brightness from these lights, don't worry. The best thing to do is to take a current measurement to see what the charger is putting out. The current should be .1C or less. The TL should be 185 mA. I don't know about the others.

But in any case, yes, my TL's get mildly warm when they are fully charged and still on the craddle.

Re: WARM on charger: Tigerlight, Magcharger, Stin

Jim,

So it's OK to leave them on the cradle for long periods?

Thanks
BN

Re: WARM on charger: Tigerlight, Magcharger, Stin

For extended periods of time it generally is not a good idea to leave the light on the charger because ultimately the batteries are being "overcharged". Granted, the charge rates provided by most "slow" chargers (usually 1/10 C or so) are touted by their manufacturers to be low enough to leave the flashlight connected indefintely, but there is some loss of battery life if the light is left charging for months at a time. You've probably seen it happen with your cordless phone that sits on the cradle more than not - the battery pack needs to be replaced every couple years or so. Well, at least my cordless phones have done it to me.

Now, if you use your light each night, even for brief periods, then I think slightly less damage occurs to the pack even if the light is left in the charger for the rest of the time. Plus the light is fully ready to go at a moment's notice, which may be more important than long battery life.

The general rule that I follow for my rechargeable lights (at least the ones which I do not use very much) is to (slow) charge the light overnight and then remove it from the charger for 1-2 months. Repeat.

I guess it depends on how much you use the light vs time on charger. And it also depends on battery chemistry. NiMH packs should probably be charged more often than once a month if you want to keep the light "at the ready" since NiMH cells discharge faster per unit time (day/week/month) than NiCd cells.

Ultimately it's your choice based on your own requirements.

Re: WARM on charger: Tigerlight, Magcharger, Stin

And to follow up my own post, I'd really like to find a good automatic timer that can turn on for 30 minutes a week and stay off for the rest of the time. Then I can hook up all my chargers to the timer and keep every light charged and ready to go without damage to the battery pack. Anyone do this?

Re: WARM on charger: Tigerlight, Magcharger, Stin

brightnorm,

bmsmith nailed it. In short, NO do not leave the lights on the chargers all the time. I leave mine on for a full charge cycle until I am sure that they are charged, then remove them. Either that or I use a peak detect fast charger. HiTec CG-340, to be exact.

The self-discharge of NiMH batteries is bad compared to Li recahrgeables, yes, but as long as you charge your lights every month, you're all set. Even after a month of sitting around a NiMH battery will have well over 50 percent charge left. For example SilverFox left one of his TL's sitting for a month, and then did a runtime test and got 45 minutes (vs. 66 on a full charge).

If you let NiMH batteries sit for long enough without giving them a charge, you risk them going bad. At a minimum, charge your battery packs every 6 months.

Anyway, hope that helped.

Re: WARM on charger: Tigerlight, Magcharger, Stin

Jim and bmsmith

Thanks, very helpful.
BN