I need to get rechargable batteries for the gps which seems eat AA's any thoughts on brand or constrution?
I like the Rayovac Platinum batteries. I use them in my cameras and flash.
Problem I have always had with rechargeables is that they are usually 1.25v and regular batteries are 1.5v. Our old hand held cb walkie talkies came with 2 dummy batteries and would use 8 AA if we used regular batteries, but took 10 if we used the rechargeables. Needless to say, the rechargeables didnt last as long either. I used to put 10 regular batteries in mine, didnt help with transmitting that I could tell, but it didnt die as fast either.
Does the GPS have an optional Lithium battery pack you can use or get? I know on my larger GPS, which is a Windows Mobile 5 device, it uses lithium for the main power, which lasts 8 hrs. It also has a backup battery, that keeps unsaved data from being lost until the main battery is recharged. My Cobra CB had a power cord, which doubles as a charger cord. I keep am inverter in the car in case the battery goes flat. Hardly ever use the CB, but better than nothing in the bush. All the log trucks require CB's when hauling wood of company and crown forest roads. Cell, has no coverage away from the river valley or settlements. Pretty much useless. Some rechargables last longer, you need to look at the mAh rating. But I think any I've seen are 1.2V as well. My CB takes 9 AA batteries.
I'm a fan of Sanyo Eneloops (1.2 volt 2,000 mAh). They come pre-charged and hold a charge better than any other rechargeable battery that I have used. I currently have Sony, Panasonic, Ikea, Kodak, and a couple of off brands of NiMH batteries. I no longer use NiCads. The Eneloops work the best. I use them in the camera, kid's toys, remotes, and flashlights.
I have read that it is important to recharge batteries slowly on a good charger. I use a LaCrosse Technology BC-9009 on it's slowest setting.
Duracell makes a 2450 mAh rechargeable. Has to be charged slow for 16 hrs @ 245 mA, or 6 hr fast for shorter life.
I've also read that batteries need to be drained before recharge to make them last longer (more charges).
The "fully discharge and charge" thing was more relevant to the older Ni-Cad technology. Lithium-Ions seem to like to be charged, although over charging or excessively fast charging tends to "cook" them and they die. But worst thing you can do is to let a Li-I battery run flat, then leave it. It often wont change again.
With my cell phones I tend to put them on charge every night, even if it's only down to 80%. Never had to replace a battery in one yet. They've been dropped, washed, gone out of date before the battery died. :-\
Ian
Was referring to NiMH batteries. I do agree about the Li batteries being able to take recharging when not flat though. I have done it with my GPS for 7 years. It sits in the cradle for days. In the winter time though I unhook the power to the cradle unless I need it the day before, then I make sure it's charged. There is an App in it I can tell how much charge it has left, for both batteries.