Not in a GPSr, because to date I've used only a car GPSr and a smartphone ... well, come to think of it, that means I've never used NON rechargeable batteries because they have those built in, but that's not very useful information...

I've used them in other devices. The newest ones come precharged and will hold a charge for months unlike earlier rechargeables which would lose charge in a few weeks. I've been fairly happy with them (I've bought Sanyo Eleloops and a La Crosse Technology charger). The one problem is that rechargeables have a maximum voltage that's lower than nonrechargeables, about 1.2 V vs. 1.5 V, and for some devices that's a problem. I have a camera I bought for $5 at a garage sale, and it's easily gone through $50 in nonrechargeable batteries because it insists the batteries are dead if they're even a little bit below full charge. I take the "dead" batteries out and use them in flashlights or even other electronic devices that are perfectly happy with them. On a whim I tried sticking rechargeables in the camera; it didn't even turn on let alone complain about low charge. I hate that camera...

Some devices you can bring up a menu to select what kind of battery you're using, so it'll expect lower voltages if you say rechargeables.

Thanks for the input, I'm going to try some. I figure it makes more sense to have something that's reusable and save $ too.

My garmin came with a pair of rechargeables and they last for about 16hours, give or take, but since I seem to always forget to look when they are getting low a keep a spare set of lithium ion batteries as back up until I use them up then i switch back to the rechargeables.... I have used other rechargeables in my older GPS and they work great the only problem was the charger required 4AA batteries in order for it to charge them. Since my GPS only took 2 I had to have like 4 sets which gets confusing and kinda expensive...