Using 4xAA nimh

[jeffy1021]

Besides taking up more space and not being able to charge while playing, is there a con to using 4 x nimh AAs for power? I figure I could add a 5V regulator to feed the power strip. I would save a little space and use less wiring by not using the powerboost and not having to mount an external micro usb.

[johnny-bert]

I am doing so with my build.

4x NiMH with Pololu S7V8F5. Works good at the moment, but didn't pay attention to playing time so far.
Reason was, I'm no electronics specialist so I thought I won't do this LiPo-charging-thingy in my very first build.

[Zero]

I used three nimh aa's in one of my builds and one battery drained a lot faster over the others. If I hadn't been monitoring them I'd have one unrecoverable battery out of the three. You will probably need a circuit to supply current evenly somehow from the batteries if you want maximum life from them. Unless you monitor them constantly. I just ended up using them for an hour, then putting them all on to recharge.

[SidSilver]

I used three nimh aa's in one of my builds and one battery drained a lot faster over the others. If I hadn't been monitoring them I'd have one unrecoverable battery out of the three. You will probably need a circuit to supply current evenly somehow from the batteries if you want maximum life from them. Unless you monitor them constantly. I just ended up using them for an hour, then putting them all on to recharge.

In series or in parallel ?

[Zero]

I used 3 in series to get 4.3-4.5v and used a boost converter to 5.1v. I couldn't boost 1.2v to 5v safely with the boost converters I had, to be able to do it in parallel. Nor the space to use series and parallel batteries together. There are lots of better ways to do it in my case but I like to re-use stuff I already have rather than buying dedicated new parts if I can help it.

[SidSilver]

I used 3 in series to get 4.3-4.5v and used a boost converter to 5.1v. I couldn't boost 1.2v to 5v safely with the boost converters I had, to be able to do it in parallel. Nor the space to use series and parallel batteries together. There are lots of better ways to do it in my case but I like to re-use stuff I already have rather than buying dedicated new parts if I can help it.

Weird that one as discharged faster than the others in series
Theoricaly it should not if the batteries are the same.

[Zero]

Yeah I was surprised too. Perhaps one has older/different chemistry or something, was about the only explanation I could think of. They were all the same batteries, same brand, from same packet. Tried it with another set and had same issue though. It's not the end of the world, but was a bit annoying.

[shenmueman3]

Is there a diy instruction on how this would be accomplished? I like the idea of just replacing the batteries when needed. I got a bunch of the eneloop batteries too.

[iSP]

Is there a diy instruction on how this would be accomplished? I like the idea of just replacing the batteries when needed. I got a bunch of the eneloop batteries too.

I don't know with 4 batteries but I do know with 3 batteries with the Adafruit powerboost 1000c.
You'd need 4/5AA better known as 14430 batteries.
Those are Lipoly (Lithium polymer) with a voltage of 1,20 to 1,25v.

To calculate the total capacity you calculate it like this example with 2550 mAh;
(3 * 2500) = 7500 mAh total, this is rated at 3,6 / 3,75V

However the pi and the rest works at 5v! if you want to calculate the total capacity at 5v do it like this;

(3 * 2500 mAh * 1,2v ) / 5v = 1800 mAh.

With this 5400 mAh you could calculate about how long the battery lasts if you look up the consumption per part in the gameboy zero.


With 4 batteries you'd need another power board, you cannot use the Adafruit Powerboost 1000c.
With 4 batteries a 1,2v / 1,25v @ 2500 mAh you'd do 4*2500 = 10000 mAh total and there's no conversion needed.
You wonder how 4 batteries make 5v? 4x 1,25v would do that .

Also get branded ones like Sanyo/Eneloop/Panasonic etc etc... don't go cheap and get cheap ones from ebay.
Those may be instable or get really warm and cause all kind of problems like certain telephones you read about in the news right now .


Also if I'm correct instead of in series you can also do parallel with 14500 batteries.
Those 14500 batteries are rated at 3,6v and if you use them in parallel they're still rated at 3,6v but you get X * the capacity in mAh from X batteries. You can use either, 3, 4, 5 etc and it can up pretty quickly in capacity.

[Rolen47]

However the pi and the rest works at 5v! if you want to calculate the total capacity at 5v do it like this;

(3 * 2500 mAh * 3,6v ) / 5v = 5400 mAh.

I don't think that's right. It should be:
(3 * 2500 mAh * 1.2v ) / 5v = 1800 mAh.

When batteries are in series their mah does not increase. You can only increase the mah of batteries when you put them in parallel.