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-   -   Battery charging (https://www.bikeforums.net/electronics-lighting-gadgets/784882-battery-charging.html)

mtnbud 12-03-11 10:24 AM

Battery charging
 
I bought this light through Amazon. It looks like the type of light you'd buy at DealExtreme or such. It's incredibly bright and the quality of the light looks good. The rest of the system possibly questionable. The battery came charged. There were no instructions in the box.

I'm concerned about any precautions I should take when charging the battery. The website says the battery is a Lithium cell. The sticker on the charger says Li-Poly input:100-240V; 50/60H 0.35A max. Output: 8.4V. Does the battery need to be discharged before charging? Do I need to be careful not to leave the charger plugged in too long? There's a little light on the front of the charger. When I plugged the battery into the charger, it glowed green. If the light is glowing green, does that mean the light is 100% charged?

AndreyT 12-03-11 10:40 AM

Your light looks like a typical MagicShine light with optional head mount. (MJ-808E) If it doesn't say MagicShine on the light itself, then this could be either the same light made by the same OEM manufacturer but sold through a different channel as a no-name light. Or it could be a knock-off of the MagicShine light.

The battery does not need to be discharged before charging. Green light on the charger means that the battery is fully charged. And there is no danger in leaving the charger plugged in with the light green. Of course, all that assumes that the charger is implemented properly, which no one can guarantee with a no-name light.

Basically, with a no-name product sold without support and/or instructions there's always a notable "use at your own risk" element.

a1penguin 12-03-11 06:26 PM

Check out Battery Univeristy. Since getting Li Ion 18650 battery powered flashlights, I don't trust any Li Ion battery charging unattended, including my laptop. Most of the chargers continue to trickle change and can overcharge batteries. I always charge mine on the kitchen counter where I can watch from the couch. I also own a fire extinguisher.

YMMV

seeker333 12-03-11 07:11 PM


Originally Posted by mtnbud (Post 13558535)
Does the battery need to be discharged before charging? Do I need to be careful not to leave the charger plugged in too long? There's a little light on the front of the charger. When I plugged the battery into the charger, it glowed green. If the light is glowing green, does that mean the light is 100% charged?

That's a fair price for a generic XML MS900.

Regarding the charger, it's LED is red when charging, green when not charging. It charges based on battery voltage, so you can't charge it if it's already fully charged. The recharge is an automatic process. It terminates when a high shut-off voltage (~8.4v) is reached. You can leave it plugged in overnight. Yes, green means 100% charged, although it can also mean the circuit to battery is not complete, so that the charger cannot measure voltage to determine it's necessary to begin charging.

I'm curious, where did your light ship from - China? The Amazon link gives no info regarding Crazy Cart's address, and google is not helpful.

mtnbud 12-04-11 10:32 AM

Thanks for the info guys! I thought the price was very good. I also felt safer buying from Amazon than some other website. I'll try to keep an eye on the charger when charging, but I won't worry too much about it with what I know now. My guess is the light was shipped from China, but it came very quickly - about a week. Maybe they have a warehouse located in the states? BeamTech is printed on the box.

Looigi 12-04-11 03:15 PM

A friend of mine's house burnt down when LiPo batteries he was charging in the garage caught fire. Put the batteries in or on a non-flammable surface and well away and from and not under other flammable materials.

AndreyT 12-04-11 06:19 PM

The battery pack in the OPs light is Li-Ion, not Li-Poly.

Consumer Li-Ion batteries accompanied by proper chargers present incomparably lower probability of combustion than "naked" Li-Poly cells used by RC enthusiasts. Otherwise, we'd have to charge our cell phones, photo cameras and laptops in fire-resistant metal boxes.

As I said above, whether this specific setup implements all standard protections - I don't know. If it doesn't, then a better idea would be to stop using it entirely, instead of having to implement some abnormal fire safety precautions every time the pack is charged.


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