I've got a) one backup set also not charged and b) another set of four that were charged but have been used in Emily's toys since Xmas.

That's the problem with rechargeables.... you've got to actually recharge them. Doh!

So is this more of a fail on your part?

Absolutely

The other being that compared to a Duracell battery, the chrage hardly lasts any length of time at all.

In that case, you either have a device with unusual current requirements or your rechargeables are old and rubbish. Probably the latter. When did you last buy a nice new set of decent ones?

2500mAhr rechargeables will often out last Duracells even when you first take them out the packet without even charging them, especially in high drain applications like cameras and flashes. These days even their self-drain is low so they'll power a clock for about 5 years, giving over a 100 years lifetime.

Absolutely, JJ.

My 2800mAh NimH batteries will go at least 20% longer in my camera than alkalines - especially if I'm abusing the flash.

Duracell 2450mAh and 7DayShop 2500mAh won't work in the Magic Mouse. Eh?

They work in everything else.

Erm.... they're what I'm using in my Magic Mouse.
I might be missing something, I do have a shocking hangover.

...at 7pm

I have heard, from a guy that is often full of [LIFTED], that the peak output voltage of rechargeables won't match that of standard batteries. Maybe that only applies to cheaper ones.

Don't have a clue about this myself though.

It's true. However, that only matters for really badly designed appliances. These appliances usually have a sticker that says "Use Alkaline Batteries Only".

Old nicad cells had a voltage of 1.2v while a zinc cell has a voltage of 1.5v - BUT the voltage present on the terminals of the zinc cell for 90% of it's operating life is far less, because the internal resistance goes up as it runs out. Generally a cell is considered dead when the voltage reaches 0.9v

Because nicads have a very low internal resistance, the voltage does not drop until they pretty much run out totally. This very different discharge characteristic made them very unpopular with people flying radio control planes, btw!

Equipment that fails at a cell voltage of 1.3v will work with Alkaline cells, but not nicads. However, it's a sh!t design because it means you must change the batteries when they're only half empty. The week old Duracels that won't power the sh!t equipment will still power most things for ages.

Modern rechargeables use a very different chemistry to nicads and have characteristics somewhere closer to alkaline, but the peak voltage is still lower I think. I'm out of date so I'd have to research the specifics.

The 1980's. I gave up after that.
You could say new ones are better, but having seen how many we went through during a recent Wii gaming night at a friends house, I think I'll pass.

Did your friend buy his rechargables in the pound shop? They are still selling 500mAh cells that were use-by 1985

You're bang on the money - for NiMH, low-load peak voltage is 1.4V, 1.25V under load at 10% discharge, 1.2V at 80% discharge.

Compare that with an alkaline which has a potential of between 1.1V and 1.3V under load.

I want a multi-function steering wheel for my car. To buy from VW would cost around £450. There are three on ebay.de that would be perfect - one new and two slightly used. But none of them will ship to anywhere outside Germany.

Why are humans such hypocrits?

If an animal is suffering pain and can't be cured, it is inhumane to keep them alive and let them suffer, you have to put them down.

If a human is suffering pain and can't be cured and wants it to end, it is called murder if you put them out of their misery!