Li ion Battery charger

[Cranky]

I have a couple of decent flashlights that use the 3.7 v battery. One light seems to last a bit longer than the other. My charger has an output of 3.7v/450mA with an end of charge voltage of 4.2 +- 1%. The batteries are 3.7v 6800 mAh. Is the charger not matched very well or just the flashlight having a big draw. They are pretty bright but don't have any info on that or do I need flashlights that use bigger batteries with higher voltage and mAh?

 

[OH71RRunner]

The lithium ion batteries won't hold charge after many charging cycles. I use them in my RC cars and trucks. They typically use a slower/ lower charging rate to even out the charge. Over time, the batteries loose their holding ability and don't last as long as when new. Cheaper batteries have an even less time frame.

The mah on the batteries is the discharge rate. I don't know the actual technical stuff, but your batteries are rated at 6800 mah, which is 6800 milli amps per hour.

 

[Slap Stick]

All batteries pretty much won't hold a charge after x number of cycles.
And there are a few types of lithium ion batteries.
They use a three stage charge cycle. First, the current based charge, then a balancing charge and then a voltage based charge.
As for the OPs flashlights you need to know the current draw of the flashlight. If it is lower than the battery capacity you have the proper battery. Current draw higher than the battery capacity you have the wrong battery.

 

[Cranky]

I have two flashlights that share the same size batteries except the other battery is a 2400 mAh but it's heavier and a different brand. Thing is, the discharge rate is about the same no matter if I swap the batteries. So the lower mAh battery discharges slower than the 6800? No paperwork came with the flashlights....bought them at a gun show and they were just out on the table and not in boxes. Btw, haven't had these all that long and the lights stay charged up about the same as they did last summer.

 

[OH71RRunner]

It's all about how much power the flashlights want to pull from the battery. I'm pretty sure the discharge rate is the maximum the battery allows.

The 2 batteries could be different ages or have different internals. I've got batteries that are identical but the charges last different amounts. Then I have name brand batteries that are smaller mah that lasts longer than the generics with a larger mah.

If they work well, use em till they don't work anymore. Lol