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I want to be ecologically responsible and was hoping to get a GPS unit that has the capability to use rechargeable batteries. Is this option available with ALL GPS units??? Thanks.

Yes, absolutely. I have been doing it for years with no problems at all. One thing though - rechargeable batteries are susceptible to "memory", meaning they need to be fully discharged at least a few times and not left charging for long periods. This is expecially true for the cheaper brands so it's something to be aware of. When using a solar charger you really need to let it achieve a full charge before loading it back into the device, whenever possible, for best results. This takes some time depending on the power of the panels, etc.

As an aside: I've found that the Duracell Ni-MH rechargeable batteries seem less susceptible to this effect and tend to last longer, as well.

Some of the more expensive chargers will discharge the batteries first and then charge only to capacity and shut off. I seem to remember having a charger like this some years ago, but I couldn't even guess at the brand.

matt gilbert wrote:Some of the more expensive chargers will discharge the batteries first and then charge only to capacity and shut off. I seem to remember having a charger like this some years ago, but I couldn't even guess at the brand.

Oh, that's cool! I wonder if the portable solar stuff can do that now...might be time for an upgrade

I don't think any of the solar chargers do. We sell some at the store, and they're pretty basic (and pretty expensive...) but give it some time and they'll have it all figured out.

NiCad batteries used to exhibit the greatest "memory" effect. Older/Cheap batteries may still have this problem, but I believe most of your newer NiCads and NiMH batteries don't have too much of a memory effect anymore.

Something to keep in mind is that I've found rechargables have a slightly lower voltage than AA/AAAs, about .2-.4V less. Haven't run into a device that has problems yet, although sometimes it seems that a few gadgets think the batteries are dead sooner than they really are because of this.

Be careful buying rechargables, look at the capacity. I've seen some gimmicks where they try to sell 0.7AH AA rechargables for a dime less than the 2.5AH ones, buyer beware!

Also remember to change your GPS settings to recognize the batteries you are using (a lot of them have this feature now). The discharge rates of varying batteries differ and if the GPS is set to the correct battery type it will have less problems "thinking" the batteries are going dead when they are not.

nonot wrote:NiCad batteries used to exhibit the greatest "memory" effect. Older/Cheap batteries may still have this problem, but I believe most of your newer NiCads and NiMH batteries don't have too much of a memory effect anymore.

Something to keep in mind is that I've found rechargables have a slightly lower voltage than AA/AAAs, about .2-.4V less. Haven't run into a device that has problems yet, although sometimes it seems that a few gadgets think the batteries are dead sooner than they really are because of this.

Be careful buying rechargables, look at the capacity. I've seen some gimmicks where they try to sell 0.7AH AA rechargables for a dime less than the 2.5AH ones, buyer beware!

Memory is still a huge problem. Just ask FEMA, who were sold a bill of goods about new battery recharge technology only to find out at the worst possible time that all of the flashlights and radios they wanted to hand out were dead and couldn't be charged...

Thank you all for your continued help and tips... :thanx:

You want to store NiCads discharged. With NiCads, storing them charged can be a terminal condition if left for too long.
This is different than the memory effect.

You generally store NiMH's charged and want to recharge them once a month (all batteries drain on their own.)

NiMHs have very little memory effect.

The lesson is: buy NiMH batteries for general use.

nonot wrote:The lesson is: buy NiMH batteries for general use.

Steve, so you recommend buying NiMH (rechargeables) for our handheld GPS use?

nonot wrote:You want to store NiCads discharged. With NiCads, storing them charged can be a terminal condition if left for too long.
This is different than the memory effect.

You generally store NiMH's charged and want to recharge them once a month (all batteries drain on their own.)

NiMHs have very little memory effect.

The lesson is: buy NiMH batteries for general use.

I'm not going to squabble but you made my point: they have to have routine maintenance. Even this does not guarantee they will last if they are not subjected to load. There are plenty of studies and field reports that beat this argument to death available via Google so I'll leave it at that.

Grasshopper: NiMH is all I use, personally...

Grasshopper, I'm currently using some 2500 mAH AA NIMHs for my GPS and so far so good. They're usually in the camera section of the store. You'll need a charger too if you don't have one, look for one that can do both AA and AAAs, pay the extra 80 cents for it

NiCads are made for high power applications and aren't worth the trouble in my opinion.

I used regular AA's at first but after burning through about 6 of them in less than a month of hiking I realized rechargables are better in the long run.

Keep in mind that if you like sub freezing weather no battery will work very well for you.

nonot wrote:You want to store NiCads discharged. With NiCads, storing them charged can be a terminal condition if left for too long.

Terminal condition...sounds scary. Will stay away.

Terminal condition? Whats real scary is you leave from a "terminal" on all commercial airline flights!

A bit off -topic here.

I just tried some of the Lithium batteries in my GPS. A new set went three days and the battery indicator is still showing a full charge (4 bars). Regular copper tops were good for maybe two days per set.

The charge indicator in my Garmin GPSMap 60CS is not accurate when I use Lithium batteries. The batteries do last quite a bit longer than alkalines, but the indicator stays pegged at four bars until a few hours before total depletion. The charge indicator must be based on voltage, which doesn't tail off as quickly for lithium as for alkaline as the charge depletes.

I've had some luck with a solar charger hooked up through the USB port on my Garmin...more info later...

Big_load is correct. The power level indicator will show full to near full then empty without notice. Nevertheless I use them for half the year. I've found they out perform rechargeables to one extreme. I forget if it's hot or cold as I haven't had the opportunity to hike much since last year. Which ever it is then the other half of the year the rechargaebles are the way to go.

I want to say lithium in the summer and rechargeables in the winter. However google isn't backing this up.

Among non-rechargeables, lithium does better in cold than alkalines. I don't know how lithium-ion recharchables fare vs. temperature.