Page 1 of When not to use rechargeable batteries ?

Not that I really care :) but generally , I mostly post on the Bargain Forum and very rarely ask a really stupid question , so I thought it was time ;)
I have just put some batteries in a small hand held fan for my daughter and on the packaging (amongst many other dire warnings of death and destruction) , it says

`Do Not Use Rechargeable Batteries`

Why NOT ???

This is printed on the packaging of so much battery operated stuff that the cynic in me might think it is a conspiracy by Duracell / Ever Ready to ensure that we keep using their disposable batteries. I can understand that many rechargeables will not give optimum operation on some high drain electricals (boom boxes and the like for example) , but why can`t you use them for the small stuff. For the record , I have never actually taken any notice of these warnings but I was wondering does anyone know if there are any valid safety (or other) reasons.

Silly Question Mode Off - Back To Bargain Hunting

:)

I read one of Richard P. Fenymans` autobiogs a few years back that had an interesting little story about asking "stupid questions". I use that story when explaining the "apprentices" where I work so as to encourage them to ask what they think might be a stupid question.
Anyway, back to the question, I`ve never thought about it before really, but I suspect that it may have something to do with what the battery is doing, i.e. powering a small electric motor. The characteristics of the motor possibly make it look like a low resistance across the battery when switched on and one of the properties of a rechargable battery is that they will supply higher currents than a normal zinc or Alkaline battery. So if rechargeables are used, the batteries will supply too much current and damage the motor (burn it out).
I hope that it makes sense (I also hope that I`m not barking out of my bottom! :o ).

LB2

PS Richard P. Fenymans` autobiogs are worth a read.

Rechargeable batteries 1.2v or 8.4v

Alkaline batteries 1.5v or 9v

T woudnt put them in a smoke alarm.

This item was edited on Monday, 12th June 2006, 13:47

Rechargeable batteries can quickly lose their charge over time, so are not well suited to certain applications.

So as a general rule of thumb, low current usage, long term power applications, such as remote controls, smoke alarms, emergency torches, stick with Alkaline batteries.

Anything that gets used frequently, uses a significant amount of current, such as portable music systems, torches used daily, hand held consoles, use rechargables.

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Quote:
small hand held fan for my daughter

hehe....we believe you ;)

i use rechargables for everything except the smoke alarms, because as said earlier, they do not hold a charge as well as alkaline batteries do "long term" but i`ve had my old 300mah AAA recharables in pretty much all my remotes & i very very very rarely need to change them, i also use them in my mouse & keyboard without probs (AA) but they are v-high powered 2600mah.

totaly agree about the smoke alarms tho, it`s simply not worth the risk, alkaline batteries run dry slowly & evenly, rechargables simply drop. so you might not be in when the smoke alarm starts warning you the batteries low, & by the time you get back from work etc etc, they could have gone, whereas alkalines will carry on giving you that low batt "beep" for days.

EDIT= tho i should also mention that my 900mah AAA`s last twices as long as duracell`s in my spare mp3 player. dunno why. but it takes a single battery, & an alkaline lasts around 3hrs, but one 900mah rechargable last, me all day.

This item was edited on Wednesday, 14th June 2006, 00:38

The other reason is that older style rechargable batteries voltage level would drop continuously as you use them, they start at 1.2 and immediatly start dropping down to 0 when they are completely flat.

An Alkaline battery stays at 1.5v or there abouts constantly until all it`s charge is gone. A fan would need a constant voltage otherwise the motor would turn slowly.

Newer NiMh batteries can hold a steady voltage now, that`s why you see them in laptops and mobile phones.

All the best

Gerald.

Quote:
`Do Not Use Rechargeable Batteries`

Why NOT ???

I think it`s because the manufacturers haven`t tested it with rechargables, and they`re just covering themselves.

Damn I thougt this was going to one of those threads I shouldn`t read...



I really don`t care what you did last summer Part45

This item was edited on Wednesday, 14th June 2006, 17:13

Sue, why whatever do you mean?

Well, I suppose if you`re bored with the world cup...... ;)