GCP battery life questions

[sonictimm]

I have a 14.4 V Ni-MH battery (my first build, and i didn't know anything about Li-ions when I got it except that they are tiny) anyway, I am not willing to buy another battery due to price but I want to make the most of what I've got. The battery is a 12-cell custom pack and each cell has 3300 mAh. I was wondering whether or not it would be worth it to split it in half and use the two 6-cell packs in series, or if it wouldn't make a difference. I designed a custom circuit that would allow me to charge both halves from on charger, but would I actually get a battery life increase? as it is, I get 1.5 hours using the original GC regulator board. The circuit I'm using is posted http://forums.modretro.com/viewtopic.php?f=7&t=7562&p=133856#p133856
note: I am also using the original DD, no wiikey.

 

[vskid3]

Re: GCP battery life question

Not sure what you mean by splitting it, making 2 6 cell packs and putting them in series would leave you in the same place, and putting them in parallel would only give 7.2v, which the stock regulator won't work with.

 

[sonictimm]

Re: GCP battery life question

I know that the stock regulator wouldn't work with it, but if I can get a longer battery ife by making my own regulator board then I want to do it. I just want to know whether or not that could extend the battery life,even If It means it won't work with the original regulator board.

 

[superben51]

Re: GCP battery life question

Yes.

 

[vskid3]

Re: GCP battery life question

Battery life is better with a custom regulator, and I believe the custom regulator is more efficient at 7.2v than 14.4. However, while you can discharge your NiMHs in parallel, disconnect them from each other and charge them separately (I think that's what your circuit would do). NiMHs don't like to charge in parallel.

 

[sonictimm]

Re: GCP battery life question

Thanks and btw my circuit puts them back in series when the switch is turned off. That way I can charge them both off of one charger.

sadly, I just discovered that my screen won't run off of 7.2 volts, so I need something higher voltage.
Is it possible to put an 8 cell and a 4 cell pack in parallel using diodes to prevent them from shorting each other? and if so, what voltage would it end up with?

also, would I be able to power the GC from a car cigar lighter using the original regulator board?

 

[superben51]

Re: GCP battery life question

you could also just use a step-up regulator. As for powering a GC of a cig lighter, I'm pretty sure you could.

 

[Prog]

Re: GCP battery life question

DO NOT use batteries of different mAh ratings/different no. of cells hooked up to each other. You WILL kill them and/or start a fire.

 

[sonictimm]

Re: GCP battery life question

Thanks superben and Prog. do you know of a good 12V step-up regulator for this? (preferably cheap)
and if I do make a costom regulator, I only have to worry about volts, right? not amps?

 

[Prog]

Re: GCP battery life question

Yup, all you'll have to worry about is volts.
EXCEPT
The 1.9V line requires a regulator that can handle a higher maximum number of amps than the reg that most people use, and obviously you need to know how many amps the GC draws to calculate battery life.

 

[superben51]

Re: GCP battery life question

The GC draw 'bout 1.5 amps and I'd say a screen would pull about 200-300 miliamps. The PTN04050C is a Ti step-up reg that can do up to 18v I think. Plus it's free if you just get a sample.

 

[sonictimm]

Re: GCP battery life question

Cool, but I don't really want to regulate it down then back up, so how about if I use a PTN78000A along with the original A board? would I still get a better battery life than before? Or better yet, what If I use two for the GC and one for the screen so that I have enough amps?