Need to build a Thor X battery pack?

[KPrime]

My dad gave me an old Thor 10Mcp that has a dead battery.

I know they under drive the 100w bulb that is in them, so I am looking at making my own battery pack and upping the voltage.

I have found a few Thor mods here, but most are to convert it to HID or use crazy 400W bulbs and such.

I don't have a real need for a searchlight the size and weight of a large watermelon, but it would be cool to have it working again, and brighter than before. Therefor, I don't want to spend a bundle on making it work again.

I was looking at these: http://batteryjunction.com/tpeh-tsc3000b.html
I figured I would built a pack with 16 of them in series, giving me 19.2v

From what I understand there is about a 30% loss with the thor wiring, switches, battery connections, cell loss, my (poor) soldering skills.
So that should drive the lamp at about 12.6v which should not cause any heat or instaflash problems.

I read somewhere (can't find my source right now) that those batteries can handle up to a 10A draw, and I think it would be in the 7A range with this setup, so it should be sufficient? Am I correct on that?

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Finally, is there a better/easier/cheaper/cooler/brighter way to go that I am missing? I really don't want to stick another Lead-Acid in there, and I would love to see what it looks like when driven at or close to its potential. :twothumbs

Thanks!!!

 

[LumenHound]

A 19.2 volt pack will flash the bulb for sure.

Why not start with a 11 cell pack and add in an extra 12th cell via the switches, while the bulb is powered up from the 11 cell pack.

This would allow you to check the voltage at the bulb during operation before you add the extra 1.2 volts (under load) of the 12th cell.

The old Boost yor Thor! 15MCP - > 25MCP thread explains the switching for the "boost" mode.

You may find the third graph in this old post interesting. It shows the lux output of your stock 100 watt Philips bulb at voltages up to 15 volts.

 

[KPrime]

Thanks for the info, and thanks for that old thread, I did a number of searches, but apparently not all the right words to find that one.

I may have been a bit overzealous on my calculation. Since I need a new battery in it's entirety, I think I will build a 15.6v unit, and either build a simple soft-start circuit, or maybe just a Pot?

Thanks

 

[BVH]

The bulb will easily handle 14.5 Volts (under load) for a very long time as they do in automotive use. I was thinking you 30% loss factor estimate was very high. I'd guess around 12 to 15%.