1. Home
  2. ⏣ General Metalworking
  3. battery question

battery question

I ask this question here because between everyone we have the sum of human knowledge ............

I bought some nimh rechargeable batteries and a charger for my camera. They are AA 1.5 v. size.

When I need to test batteries, I use a pretty good Craftsman tester. On alkaline batteries, when new, they test up to 1.6 volts. I had some of these nimh batteries on charge for a good while on an automatic charger. The indicator light had gone out, indicating a full charge.

I wanted to see how much they read. They read from 1.42 to 1.45 volts. Is this normal? Do they just last longer, but don't charge up as much? I know they last a LOT longer in my GPS, and have saved me money already in batteries. In my radios, the nimh runs circles around alkalines or nicd for lasting.

Just curious.

Steve

Reply to
SteveB
Loading thread data ...

This is normal. NiMH and NiCd batteries are really 1.2 volts. They might be dimmer in a flashlight, but for high drain items like digital cameras, and apparently your GPS, they can and do last longer. Their capacity and voltage are lower but they last longer because they have a much lower internal resistance and are far more efficient than alkaline batteries for higher current loads.

Reply to
Cydrome Leader

IIRC the nominal voltage for a AA NiMH is 1.2V so your figure was probably obtained from a cell direct from the charger and off load.

NiMH batteries are better suited to high discharge applications (digital cameras are a prime example) where they significantly out perform alkalines. The discharge curve is also 'flatter' than NiCAD or alkaline which means they provide max power for longer but then suddenly go 'flat'. NiMH batteries (like NiCADs) are prone to self discharging and a fully charged battery will discharge while sitting even if it is not in any equipment. A very useful source for battery information can be found at the following link.....

formatting link
HTH

Reply to
Larry Green

(Should read: Just, Curious Steve...sounds better) Normal! I bought 4 AA and a charger from WalleyWorld for $9.99! Beat that!

Reply to
Tom Gardner

It's impressive to see the energy storage improvement in Ni-MH batteries. A few years ago the best AA Ni-MH batteries I could find stored 1500 maH, now they're up to 2500 maH.

Duracell has a pretty good tech section pdf about Ni-MH batteries at:

formatting link
Jeff

Reply to
Jeff Wisnia

You answered one question that I just happened to want to know when your post showed up, but you missed the other one. What's the discharge curve for a lithium ion battery? Is it flat also? I didn't find the answer on the website you mentioned.

Wayne D.

Reply to
Wayne

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.