I need an electrician!

[Dan]

Ok, I have a strange question. For Christmas I got a small torch, with Alkaline AAA batteries. In the manual it says 'Do not use rechargeable batteries'. Why not.
Dan G

[denishc]

 One of the guys I work with had a small 'flashlight' that took AAA batteries.  One night he came to me and said he couldn't get the batteries out of the flashlight's body.  He said the batteries went in o.k. but during use had some how "swollen" and were stuck fast in the light.  I don't know if these were rechargeable batteries becouse we were never able to get them out of the light!!

 Also, rechargeable batteries must be completely drained before recharging or else they will never recharge to their proper voltage.  This may lead to your 'torch' not being as "bright" as it was when it was new.  

[Hagar]

Dan. I'm no electrician but I've been using rechargeable NiCad batteries for various purposes for a long time. The main difference between the standard alkaline & rechargeable batteries is the voltage. Most rechargeables are 1.2 volts as opposed to 1.5 for the standards. I remember when we first started using them in R/C transmitters this meant using 8 NiCads instead of the usual 7. There are also various different types - available in various capacities.

The latest rechargeables are NiMH. These are more environment-friendly as they contain less cadmium than NiCads & also have slightly different properties. There's no reason why you shouldn't try rechargeables in a torch but they might not give such a bright light or last as long as ordinary alkalines.

I found this site which should tell you all you wish to know about rechargeable batteries. http://greenbatteries.com/
[quote]Can NiMH batteries be substituted for alkaline batteries even though they are only 1.2 volts?

There are a couple of cases where there actual voltage difference may be important to you.

[Dan]

I know what you mean. Where you an R/c pilot Doug? I am almost up to BMFA Electro flight cert. level.
Dan.
The Zagi 400 rules!!!!!

[Hagar]

I know what you mean. Where you an R/c pilot Doug? I am almost up to BMFA Electro flight cert. level.
Dan.
The Zagi 400 rules!!!!!

Hi Dan. I've been flying & instructing on R/C gliders & power models since 1980. Experimented with electric flight back in the early days but didn't like it. Haven't even visited the field for the last 2 years.

[SilverFox441]

The warning may relate to a peculiar characteristic of Ni-Cd batteries...their shorted discharge rate.

Most batteries (or cells) are limited to a short current of about 10 times the amp-hour rating. So a 10 AH battery can provide a 100 Amp surge.

Ni-Cd batteries are somewhat better...100 times the AH rating. That same 10AH battery as a Ni-Cd can pump out a 1000 Amp surge.

1000 Amps, even if only available for a short while can cause fires. Many manufacturers put warnings on to avoid "rechargeable" batteries to avoid liability issues if the product caused injury.