Do not use rechargeable batteries?

[malloc]

Is it possible to harm any normal consumer electronics device that states "do not use rechargeable batteries" by using rechargeable batteries? I know that the voltage may be less, but that it also may depend on load and that rechargeable batteries may have a high self-discharge rate. But I do not know if, or how any device would actually get damaged from this, is it possible? How?

 

[picbits]

I think a lot of it is to cover their own backs if something went wrong internally. A normal AA battery can provide a couple of amps sort circuit while a rechargable can provide many times that.

 

[dr pepper]

Yes theres more risk of a fire with rechargeables, manufacturers worry about the slightest cost increase these days, and its cheaper to make something for dry batteries then rechargeables, as you can use less copper etc.
Some products have a side contact so they can detect if a rechargeable is fitted.

 

[WTP Pepper]

If the circuit has it's own switched mode Boost regulator, then by running at a lower voltage over a long period of time may stress their boost circuit as the current will have to be higher to generate the same output voltage.

With dry batteries, the power will dwindle fast, Nicads can still supply high current on lower voltages - increasing the current into the boost reg.

 

[MrAl]

Hi,

Also, sometimes the voltage is just too low for the device to operate properly.

I had a flashlight with a regular bulb in it a long time ago. It was really made for regular AA batteries, not even alkaline. When i used rechargeable batteries it blew out the bulb. I added a small series resistance so i could use it with rechargeable batteries and alkaline batteries without burning out the bulb. Lucky we have LED flashlights now.

There are also devices that do not allow the use of non rechargeables. They say "do not use alkaline batteries". That's because they automatically charge the batteries and you should not charge alkalines.

 

[crutschow]

I think they state that mostly because NiMH batteries have a lower voltage than alkalines and thus the device may not operate properly. An electronic device is seldom harmed by low voltages (since even regular batteries generate a low voltage when they are mostly discharged) so I think it would be safe to try with the recharageables and, if the device works OK, then you can use them.

If you're concerned about self-discharge, the "pre-charged" type NiMH batteries have a very low self-discharge rate.

 

[dr pepper]

They used to put a side contact on rechargeables and the sleeve over the outside of the battery was a little shorter on the negative end, so that the charge contact connected and charged the battery, non rechargeables having a full length sleeve so that the side contact didnt connect and the device didnt try and recharge a non rechargeable battery.
You dont see them like that anymore, pity as it was a good idea.

 

[alec_t]

It's also possible (says he in cynic-mode) that some equipment manufacturers are in league with the makers of non-rechargeable batteries