lipo voltage levels

[jamie7]

Hey,


Anyone know if I can use a larger voltage lipo on a lower rated system by placing some resistors across the battery terminals? Will this destroy the battery? I'm a chronic DIYer and a little cheap so I don't want to have to go out and buy a different lipo because of a couple of volts.

In my case I have a 7.5v lipo I want to use on a 6v system. Could I put about 2ohms in front of the battery to make it work?


Thanks for any guidance!

ps I actually got 2 7.5v lipos wired in series inside a plasitc yellow case when I bought a AH Stormlauncher battery pack on sale for $14!(reduced to clear after xmas) I don't have a Stormlauncher but when I saw the cheap price for lipos I couldn't resist. I very carefully forced the yellow plastic open and found the above. Bonus! I desoldered them and now have the two separate batteries with new leads soldered on them ready to go. Don't know if i'll have any use for the charger that came with it but who cares.

best...

[thanhTran]

It depends on the load (read how many amps/milliam) you're going to use to decide the value of the resistor. Also, if the load is not constant, you can't use resistor. The output voltage also changes depending on the battery charged level (8.4v - 6.4v)
You can use series of diodes to lower the voltage down. You can build a low drop regulator to lower the voltage down to 6v which works better I believe.

[jamie7]

Hi TT,

Thanks alot! Good to know it is possible. I'll research that stuff a bit on line and see what I can find (low drop regulator). if you know any links for schematics or parts please post.

best

[MatC]

If you can tolerate 5v you can use a 7805 voltage regulator (good for about an amp as I recall, lower current versions also exist [eg 78M05 I think] ). 7806 will give 6v but might be harder to find. Both are 3 terminal: vin, vout, common. Easy+cheap. If you can't find a 7806 and need 6v, variable regs exist but are slightly more complicated to set up (a few resistors).

[TrappedinNM]

Hi TT,

Thanks alot! Good to know it is possible. I'll research that stuff a bit on line and see what I can find (low drop regulator). if you know any links for schematics or parts please post.

best

http://www.dimensionengineering.com/AnyVoltMini.htm

[mikeythev]

If you need an odd voltage value, you can use a LM317 with a fixed value as your feedback resistor to get 6V. I don't know what value you'd use. I just made a circuit using the 7805 and diode.

The weight savings for me is 22gm in my HLG. That's quite a lot!