Bulb discharger info

[crazyjr]

I'm thinking about making a bulb discharger and need some info.

First: Do I need the single or dual element bulbs

second: I heard each bulb is good for 2 amps draw, Is this true?

Thanks for any info you can contribute. I know there are better methods for discharging, but my batteries are old and don't need a disgharge board till i get better batteries. Besides i'm always up for a new project and i've never made a discharger before so its my next project to learn from

thanks again

[HotnCold]

Dual element bulbs - ( 1157 automotive i believe ) are the ones to use - and one bulb is equal to 2 amps - so if you assemble 10 of these bulbs you have a 20 amp discharger - if you do this and you discharge your packs this way and you are not using a voltage cutoff device in line - then be sure to remove the battery when all the lights dim - not go out completely.. Hope this helps..

[coolhandcountry]

Here is the article to help. http://www.rccaraction.com/rc/articl...scharger_1.asp

[crazyjr]

Thanks for the info guysI had to settle for single element bulbs caues i was in a hurry and could only stop at one autoparts store but i got it together in about ten minutes and works good. I'm glad i couldn't find the 1157(dual element)bulbs 20 amps might be too much for these old cells. When i get better batteries i'll get a tekin discharge board

Deans makes a real good bulb discharger
you put it together yourself

[MetalMan]

FYI, each bulb will not pull exactly 2amps, unless you run it at a very specific voltage. The amp draw is determined by the resistance of the bulbs, so the more cells you put on it, the greater the amp draw. The same would also be true for cheap vs. good cells. The opposite is true for lower cell counts.

[BrianG]

Originally Posted by MetalMan

FYI, each bulb will not pull exactly 2amps, unless you run it at a very specific voltage. The amp draw is determined by the resistance of the bulbs, so the more cells you put on it, the greater the amp draw. The same would also be true for cheap vs. good cells. The opposite is true for lower cell counts.

True. I also want to add that light bulbs don't pull their rated current all the time. When the filament is cold the resistance is VERY low. So, this creates a surge current (which incidentally is why bulbs almost always blow as they are turned on). As they heat and light up from the current, their resistance increases until they reach their rated current, which, as MetalMan pointed out, is for a specific voltage.

At some point during the discharge cycle, the battery voltage will start dropping which will reduce the power to the light. Since the bulbs aren't heating as much, their resistance will start to go down again and more current will try to flow (but there isn't enough voltage and current anymore to light the bulbs), and the batteries will drain more quickly. Sort of a runaway effect. This is why you want to stop before the bulbs get too dim to get to that point.

[squeeforever]

i have the deans and love it. its great although a little pricey.

[crazyjr]

Yeah i made mine for $15.00. Thanks for the info everybody

my dad got the deans for his oval car it works great for him and it also makes a good stand for his car but it wouldnt hold up a mt