There's nothing wrong with running the battery down. There is protection circuitry in there that keeps it from hitting a damagingly-low voltage per cell.

If you want to get the maximum life out of your batteries, you should not run them totally dead every time. But running them totally dead once in a while is totally fine. If you wanted to never run a 4AH battery down load, it wouldn't really be a 4AH battery anymore, would it?

In fact it's probably good for the batteries to run them down once in a while, maybe every 20 cycles or so. Less so with LiIon, but probably still not at all harmful.

What you do NOT want to do is to run the battery dead and then let it sit for months, because then self-discharge WILL run it down below critical voltage and you will damage the cells.

Li-ION batteries shouldn't be too deeply discharged. Also, do not recharge in an unheated area.

From Battery University (http://www.batteryuniversity.com):


-Do not discharge lithium-ion too deeply. Instead, charge it frequently. Lithium-ion does not have memory problems like nickel-cadmium batteries. No deep discharges are needed for conditioning.

-Do not charge lithium-ion at or below freezing temperature. Although accepting charge, an irreversible plating of metallic lithium will occur that compromises the safety of the pack. Not only does a lithium-ion battery live longer with a slower charge rate; moderate discharge rates also help.

The built in protection circuitry will prevent the batteries from being discharged to a damagingly low level. I wouldn't full-cycle them on a regular basis, but it's not really going to hurt them to do it once in a while.

I mean really, what's the point in buying a 4000 mAH pack if you only ever take 2000 mAH out of it? It's like having a 15 gallon gas tank - I never let my tank get below 1/4 full, but if it's not convenient to fill up just then, I'll let it go lower.

also the vendor was saying that a full discharge and specifically a 6 hr charge would reset the circuitry somehow to fix the OP's runtime issue. I wonder if that means leave it plugged in for 6 hrs even if the green charge light comes on sooner ...?

I used to unplug my MS batteries every night, but now I leave them connected 24/7. When I was unplugging them every night, my indicator light would glow red just after a day's use, and giving me a false indication of my battery charge status. For the most part, after leaving my MS lights connected all the time has doubled my run time before the indicator starts glowing red.

I know that although fully discharging the battery doesn't do anything for the actual battery with lith-ion, it does do something to help/reset the electronic battery gauge that tells you how much battery you have left with lith-ion batteries.

Latest development: discovered there is a slight short in the charger cord at the connector end. Touching it slightly changed indicator from red to green or vice versa. No telling how much of a charge I have now. Have written GeoMan, will again post results. FWIW, I am extremely careful with the connectors as I noticed how difficult they are to separate and how snugly they fit together.

Sorry to continue to hog this thread, but this is valuable information.

After draining and recharging the battery on my MS, I left it on high after the charge was complete. It lasted (on high) for three hours and 15 minutes - about that the factory specs indicate. Mind you, I had to wiggle the cord to be sure I was getting juice during the charge cycle. GeoMan got a new charger in the mail to me SAME DAY (well done, sir), and I have offered to send back the iffy unit I have. So far, so good. I never expected more than an hour out of the high beam...

we're interested. so did you get that charge with the new or the old charger? 3 hrs 15 min is perfect

I just charge by time run at max brightness... the mechanism which regulates the low-battery signal is affected by the cold it seems... usually shows green for hour and half or so then goes red and runs for another hour and a half just about. I don't run it down more than 2hrs(20-30%) charge remaining.

Sorry, this was the old charger, but I had to monitor it to be sure the connection was valid.

3:15 is exactly what my MS got when it was new. BTW, be sure to run a fan blowing air on the light when running it on high to test with. It gets pretty hot otherwise.

I'm not actually using my MS anymore now that I have a P7 flashlight and found that medium mode is more than bright enough for my needs.

someone in my neighborhood and I should know his name but I don't stuck his head out of his van window when I was passing in the opposite direction last night and said he liked my light where did I get it. I barely had enough time to say geomangear.com and hear him repeat it correctly before we were out of earshot of each other. so hopefully there's another user coming in my neck of the woods.

Received my new charger in two days - great service. Sadly, the new charger has the same issue. I charged for two hours, and the charger still indicated red. I moved the cord down by the connector, and it flickered between green and red. I unplugged the charger from the wall with the battery still attached, and the green indicator remained on. Plugged it back in, it was red. Seeing as how this problem does not allow me to know how much of a charge I have left, I'm not sure how far I need to go in charging it.

This ain't rocket science - am I doing something wrong?

leave it plugged in until the light turns green. it takes a long time. ok to leave it in all night.

:foo: fun old thread :innocent: