Spent Batteries Are Still Good?

[medoug]

Once my batteries get weak enough that they no longer work in my eTrex Legend, I had been throwing them away. One day I tried one of the used batteries in a toy and found that although they no longer had their full charge, they worked just fine in the toy. When my clock had a dead battery, I replaced it with one of the partially-spent batteries from my Legend and it seems to work fine now. (I wonder how long it will keep running on this battery that I would have pitched in the past.)

 

Could there be something wrong with my Legend that its battery power threshhold is higher than normal, or is this typical? If it is typical, I'll have lots of half-used AA's ready for use in other devices.

 

medoug.

Edited August 31, 2005 by medoug

[marty621]

Save your half used batteries for use in TV remote, they work until the batteries are nearly completely dead. Also LCD clocks. Why not use NiMH batteries?

[+Thrak]

Make sure that your battery type is properly set on your GPSr. There is a setting for different types of batteries and I think it is pretty much just for tracking the "juice" left in the battery and differs according to the set type. If it is set wrong it may well show the battery as being low on power when it really isn't.

[medoug]

No, it can't be the setting alone since that just sets the battery power indicator level. These half-spent batteries are due to the low battery warning popping up on the screen and then followed by the Legend becoming completely inoperable (blank screen/automatically shuts off).

 

medoug.

[+Bob Blaylock]

  Some devices are much more demanding on batteries than other devices.  Got a digital camera?  Try putting the “dead” batteries from that in your GPS.

[+Elracs]

As batteries die they lose voltage. The amplifier that the GPS uses to amplify the signal from the satellites would need a voltage over a certain amount. This is probably much higher then what you would need for a remote or whatever. (That is mostly a guess, but I do know that analog amplifiers need a bit of voltage)

 

-Elrac

[Major Catastrophe]

Or you could purchase some NiMH batteries and charger. Typically, you can buy a charger that comes with anywhere from 6 to 10 batteries, and costs about 2-3X what you'd pay for the same number of alkalines. This seems a better investment than lottery tickets.

[+Miragee]

I agree. I bought a 15-minute Energizer battery charger with four Energizer NiMH batteries for around $25.00.

 

I've used rechargeable batteries for many years. In my GPSrs, I did learn that the off-brand batteries do not last as long as name-brand batteries.

[goodweather]

As Elracs says, some devices need a certain voltage to work and when the voltage delivered by the batteries goes under this limit, the device stops working. It only depends on this limit, which is lower for remote or a clock than for a GPSr or a digital camera.

 

Also, the main difference between alkaline and NiMH batteries is that when discharging, the alkaline battery will progressively drop voltage as NiHM batteries will keep a constant voltage and drop to 0V suddenly. See for example:Energizer Web Site.

 

That's why you have to "tell" your GPSr what type of batteries you are using so it can correctly predict how much charge is left. Example: Let's say that the battery life of your GPSr is 20 hours. If you set your GPSr to Alkaline and you actually put NiMH batteries in the unit, after 17 hours, it will still measure about 1.3V per battery and it will assume that the batteries are almost fresh. Then the unit will suddenly turn off without any notice.

[+Greymane]

  Some devices are much more demanding on batteries than other devices.  Got a digital camera?  Try putting the “dead” batteries from that in your GPS.

Absolutely right. You can "cascade" your batteries to save money. Digital camera to GPS (still about 50% life), then to remote (or other low power consumption item) for many more hours of use.

[goodweather]

That's an interesting idea.

The problem is that after a month of "cascading", you'll have 10 spare batteries for you GPS and 20 spare batteries for your remote...

[+Where are we]

I use the the oldies in my analogue clocks (the ones with hands) around the house and get about 6 months out of them.