Battery Extenders

[xamindar]

I am looking for a battery extender that I can plug into my 3100. The one laan posted is almost perfect but I want one that takes (rechargeable) AA batteries so I can always replace them when they stop charging. Anyone know of such a device? Maybe it would be easy to just build my own. 8 rechargeable AA batteries (4 in parallel to 4 more should be 4.8v i think) in a pack plugged into the Z. Any ideas?

Maybe something like this would work? http://www.bixnet.com/usbbaboxc4aa.html

[koan]

I've been using a Sanyo Eneloop KBC-L2 for some time now. Charge by USB or AC adaptor and has 2xUSB output. It's rated at 5000 mAh, with a full charge I can recharge my 750 more than 3 times. I take it on any long journeys and use it to recharge my MP3 player too. I think it's an excellent product.

Take a look at the KBC-E1S on the same page, I think it may be what you are looking for.

[xamindar]

Thanks for the recommendations. I didn't know Sanyo made some of these things. I love their batteries. I don't think a two AA battery one will have enough juice though. I see a lot of 2 battery boosters out there, I wounder why.

I ended up buying the following one:
http://www.amazon.com/gp/product/B0014KLX9C/ref=oss_product
I will post a followup when I get it and have tested it. Hopefully it will be enough.

[xamindar]

Well, got it. It works but gets really hot. It ended up melting so I had to order a replacement. The replacement still gets hot but hasn't melted yet. It gets really hot when charging the zaurus or my sony ericsson phone so it's not the zaurus' fault. I think it is to do with fresh batteries. After the batteries go down a little it doesn't get hot anymore. But for the short first 10 or 15 minutes I use it with freshly charged batteries it gets really hot. Do voltage regulators get hot when limiting voltage?

Two main reasons I got it work though.
-charge the zaurus while it is off
-be able to swap zaurus batteries without having to powerdown the zaurus (avoid very long bootup time). Still have to turn zaurus off though or sometimes it does die as there is not enough juice from this pack to power zaurus/lcd/wifi card all at the same time.

It is also supposed to charge the batteries as well but I have not been able to get it to do that. So far it just blinks the light which means the batteries are not rechargeable. I'll try when they are completely dead.

This item looked promising, but with it melting I will always have to be watching it. I wish there were other things out there that worked well for this purpose.

[koan]

Well, got it. It works but gets really hot. It ended up melting so I had to order a replacement. The replacement still gets hot but hasn't melted yet. It gets really hot when charging the zaurus or my sony ericsson phone so it's not the zaurus' fault. I think it is to do with fresh batteries. After the batteries go down a little it doesn't get hot anymore. But for the short first 10 or 15 minutes I use it with freshly charged batteries it gets really hot. Do voltage regulators get hot when limiting voltage?

Yes voltage regulators do get hot, see http://en.wikipedia.org/wiki/Voltage_regul...age_stabilizers - the metal bit in the picture is for attaching a heat sink.

But it sounds to me like the design is not good if the case gets so hot that it melts. Only using it with used batteries doesn't sound like a good solution to me. Batteries can get hot when they run down but not usually when they are fresh. My Sanyo unit doesn't get hot when I use it.