My light is shutting down after a minute. Help!!

woodsman · Jan 10, 2004

I am running a 12 volt 100 watt osram H3 Headlight bulb, it is being driven by a 14.4 volt rechargeable battery that reads 16 to 17 volts fresh off of the charger. After about a minute it shuts down like it's tripping some type of fuse.
The battery seems warm but not scorching hot. I know batteries have thermal fuses, but do some of them also have fuses that will shut them down if they are being drained too fast?
Thanks in advance for any help or suggestions.
Thanks, Jeff

StevieRay · Jan 10, 2004

What is the amp/hr. rating of the battery. Seems like your pulling over 8 amps!

woodsman · Jan 11, 2004

It's only 4.2 ah.

Doug S · Jan 11, 2004

Though you don't tell us, I am going to make a not so wild guess that you are using a Li-ion battery pack. If so, I would think that you have a 3X4 configuration of 18650 cells. At the current you are drawing, 1 minute seems about right to trip the PTC overcurrent devices in the cells.

drs2000 · Jan 11, 2004

Like he said. If you're using a made-up pack from a laptop, they're definitely limited. And that's too much current for an Li-ion pack at that size. You'd do better with a hi-current SLA or a stack of Nimh C size or so. More weight, tho.

Good luck! drs the crazed.

snakebite · Jan 12, 2004

there is a thermal switch in many packs that open if the pack is too hot or overloaded/shorted.
some have a polyswitch for the same reason.
i would get a 17ah sla for that one.

My light is shutting down after a minute. Help!!

woodsman

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