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Q & A: batteries for halogen flashlight

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Most recent answer: 02/22/2015
Q:
igot this p.o.s. flashlight on promo that was suposed to have a 35 watt halogen bulb that would put out 'a million candlepower beam'on a rechareheable lead acid batrery with a built in charger adapter labeled as converting US house current ddown to 6 volts. i took it apart when it failed to charge. the halogen bulb lights when touched to a good 9 volt battery. it shines brighter when i touch the red and black wires to two 9 v batteries in parallel. so now i'm thinking, how many 9 volt batteries could i line up in parallel inside this thing and connect the red , then the black, to a rocker switch on the outside of the case? screw the recharge feature at this point. i just want the stupid thing to put out the most light it possibly can,with the halogen bulb that's in it already, and i'll just put new 9 volt battwries in it when the used ones wear down. this thing was atrociously designed and pointless to try to make it work as it was purported to. no WONDER it was on sale at such a giveaway price-! but i get a $5 rebate if i succeed in getting it to work for me. can't return it, now that i've jacked it apart...:(..how many 9 v batteries connected in parallel can i put thru that bulb before i'd burn it out? and what gauge wire betwesn terminals? usng 9 v batteries? and not rechargeables....
- janet (age 62)
albuquwrque,NM, USA
A:

Two 9V batteries in parallel still are at 9V, unless so much current is being drawn from them that they can't keep up. In that case they will wear down very quickly. That two 9V batteries in parallel made more light than one tells you that you're in exactly that situatuion.  A 35 W bulb would be drawing around 6A from a 6V battery. Little 9V batteries aren't designed to put out nearly that much current.

So my advice would be to cut your losses and ditch the p.o.s. flashlight, recycling the lead-acid battery or saving it for some other use. You can get a nice new LED flashlight that's much more efficient and convenient. You can get these with rechargeable batteries and chargers. It may end up being cheaper than constantly replacing 9V batteries.

Mike W.


(published on 02/22/2015)

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