Rechargable GPS batteries

[+albsch]

I am using a Magellan 500le that uses AAA batteries. I have tried using the Rayovac 15 minute recharables with no success. I have cycled the batteries 5 times and even when fully charged the meter on the gps ony shows the batteries to be abo0ut 1/3 charged. I also only get about a 20 use with these batteries. I thought I had a bad set so I exchanged them for new ones with the same results. I am open for suggestions. I know Magellan has the lithium battery that can be used, is this worth it?

[+lostnlookin]

I just purchased the 500LE from Costco. There was a cupon for the Magellan rechargable battery for the 500, including the charger for $14.00. This seems like a great deal. check out the Magellan site

[+cache_r_joe]

Is there a setting to tell the GPS what type of batter you have in it. I know mine if I have it set for Alkaline and put Nickle batteries in it the meter will be off. Check that out, might not be anything wrong with the batteries.

 

J

[+Prime Suspect]

I am using a Magellan 500le that uses AAA batteries. I have tried using the Rayovac 15 minute recharables with no success. I have cycled the batteries 5 times and even when fully charged the meter on the gps ony shows the batteries to be abo0ut 1/3 charged. I also only get about a 20 use with these batteries. I thought I had a bad set so I exchanged them for new ones with the same results. I am open for suggestions. I know Magellan has the lithium battery that can be used, is this worth it?

Alkaline and lead-acid batteries put out 1.5v. Almost all rechargeables put out 1.2v to 1.25v.

 

3 alkalines will put out 4.5v. 3 NiMH batteries will put out 3.6v. The unit thinks the batteries are only at 80% capacity. Different battery chemistries also have different discharge profiles. Unless your unit has the ability to set it for different battery types, you're not going to get an accurate power level reading when using rechargeables.

[peter]

Alkaline and lead-acid batteries put out 1.5v. Almost all rechargeables put out 1.2v to 1.25v.

Actually, lead-acid batteries generate about 2.0 V/cell, which is why the 6 cells in your car battery generate a nominal 12 VDC. Not that this has much relevance to most GPS use since they don't generally use lead-acid cells.

[+Prime Suspect]

Alkaline and lead-acid batteries put out 1.5v. Almost all rechargeables put out 1.2v to 1.25v.

Actually, lead-acid batteries generate about 2.0 V/cell, which is why the 6 cells in your car battery generate a nominal 12 VDC. Not that this has much relevance to most GPS use since they don't generally use lead-acid cells.

You're right, I meant to refer to "standard" (zinc-carbon) batteries. But my mistake was doubled, since lead-acid batteries are rechargeable, and I intended to reference a throw-away 1.5v type battery.

[eaparks]

I've been using the "AA" Rayovac 15 min. NiMh rechargeables and haven't had any problems and I like the ability to fully charge in 15 min. I have gone to using them in everything - cameras, flashlight, gps, etc., so when I buy something now it has to use AA batteries. I'm using them in a 60CSx and they'll last a full 1 1/2 days before running down, would probably would last 2 days if I conserved battery use, but I turn it own first thing in the morning and don't turn it off until dark that night, with compass own, and using back light as needed. The 2300 mAh Rayovac are the highest mAh I've found in the 15 min. Rayovacs and are not as easy to find as the 2000 mAh. I believe I read somewhere that all NiMh have a fully charged volt reading of 1.35V and from my measurements with a volt meter after being charged and letting sit for an hour to cool off I usually see readings of 1.35V to 1.37V. As has been said in other posts on this forum, NiMh have a very short shelf life and should be fully charged at least within a few days of when you expect to use them. There are charts that show the actual voltage loss over time which is quite significant and happens within just a couple of days. If I remember correctly after 48 hours they loose about 20% of their output voltage just sitting, someone can correct me if they have more recent information.

 

Most newer GPSs do have a battery setting in the Setup Menu to select the type of batteries that are being used. As others have suggested, check your GPS battery setting so your battery meter will give a more accurate indication.

[+Prime Suspect]

As has been said in other posts on this forum, NiMh have a very short shelf life and should be fully charged at least within a few days of when you expect to use them. There are charts that show the actual voltage loss over time which is quite significant and happens within just a couple of days. If I remember correctly after 48 hours they loose about 20% of their output voltage just sitting, someone can correct me if they have more recent information.

The shelf life is not nearly as short as you're portraying, and your 20% loss after 48 hours is way off.

 

 

As you can see, it takes nearly a month before hitting 80% capacity. The RoT I've always heard is a loss of 1% per day. Cold temps will retard this effect, while hot temps will exacerbate it. The bottom curve shows the capacity when stored at 104F.

[+Goodguys]

Some AAA batteries are worse than others. We've had poor service from Kodak 700mAh NiMH batteries. Life span ranges from several minutes to a couple hours depending on how recently they were charged. Most of what little charge they hold seems to dissipate within days. I'm looking forward to getting some eneloops for our Geko.