Rechargeable Batteries

[Dave Plowman (News)]

But a Ni-Cad gives an extremely stable output until near flat so the situation you describe is OK. What does harm them is to run them *totally* flat as many feel inclined to do.

[Chris Hodges]

Or use "-band" "-tribute" etc in the standard search.

[Chris Hodges]

LiIons on laptops which are normally plugged in often suffer - my Compaq now has about 20 minutes life from a nominal 2 hour battery. Toshibas don't seem so bad though. This isn't technically memory effect, but it might as well be to most users.

Chris

[Chris Hodges]

I don't put stupidly cheap batteries in expensive kit in case they leak. You can often get panansonics cheap and I've never had one leak on me, Ikea's are Varta and again I've never had one leak. The "powercell" pack I got aren't worth putting in anything but a cheap torch.

When the GPS or our previous digital camera had finished with a set of alkalines there was a good month or so of life left for my cordless mouse and they're pretty bright in a torch, so it's worth hanging on to them.

btw some digital compacts, while they will work on NiMH/NiCad aren't as good - slower recycle time especially (but not just) when using flash, hardly any use per charge etc. Hopefully this shouldn't be as bad if the camera has its own rechargeable and a charger though.

Chris

[Guy King]

The message from Chris Hodges contains these words:

I've got a dozen of them and despite abuse by the kids none have leaked in the year or two I've had 'em.

[Dave Plowman (News)]

I'm not overly impressed with the life of LiIon under some conditions, although this may be down to the charger. They have their uses where the small size/high capacity is vital, but don't like deep discharge as a regular thing.

[The Natural Philosopher]

Yes. Or rather, no they certainly don't.

Failing capacity is a sure sign of interior damage.

I have to say that they seem to be getting better though.

[lairdy]

In my (limited) experience, the key words in the PP's post are "normally plugged in". I know someone who always used their laptop on mains power. When they came to use it on battery after about a year, it was next to useless. The Lithium polymer battery in my mobile phone seems to be going quite well after 3 years plus, and it's only ever on charge when it needs to be.

Probably best to exercise batteries as they were intended to be used. Attempts to extend their life by leaving them on permanent charge seem to be counter productive.

[The Natural Philosopher]

Again, I think its down to the age, and quality of the cells and the charge regulation circuitry.

Lithium cell actually are best stored at half charge, but they vary markedly in terms of self discharge, internal resistance and peak power delivery.

The good news is that its an area of rapid devlopment.

[tinnews]

But won't be helped by a full discharge. It's just basic "worn out battery" effect.

[John Laird]

Well, that covers all bases ! Not that I would disagree.

Indeed - apparently Toshiba have some super new technology that permits

1-minute recharge times, although I suspect it may never arrive in the initially announced form.

[The Natural Philosopher]

yeah..I wouldn't say that that particular cell is either more than vapourware, or actually any use apart from possible automotive applications. BEVs need to get down to about 3-5 minute recharge times - of at least 70-80% capacity anyway - without sever loss of efficiency and damage.

But of the 7 or 8 lithium packs I have that fly my model planes, the very worst one on power delivery.. it gets hot and loses power if used a high power (20A on a 2000mAh pack) continuously..is the very best on charge retention.

Some of the high discharge ones are a lot worse..and don't seem to be lasting well either.

So it would seem that there are many micro adjustments to cell construction and chemistry that can optimise in different directions, but not ALL directions.

But anyway they are streets ahead of nickel cells in every respect except the ability to go flat and survive, the recharge times and the cost.

[Guy King]

The message from Chris Hodges contains these words:

Are we still talking NiMHs here, or primary cells? I'd not use cheapie primary cells for anything.

[Chris Hodges]

I've had some leak in the packaging and some leak in a torch - 2 different pound shop packs.

Chris

[Dave Fawthrop]

|The message |from Chris Hodges contains these words: | |> >>>Since you can get 4xAA for ?2 from Aldi (and they're OK - I've had loads |> >>>and never a dud or low-capacity) why bother? |> >>>

|> >>

|> >>I don't put stupidly cheap batteries in expensive kit in case they leak. |> > |> > |> > I've got a dozen of them and despite abuse by the kids none have leaked |> > in the year or two I've had 'em. |> > |> I've had some leak in the packaging and some leak in a torch - 2 |> different pound shop packs. | |Are we still talking NiMHs here, or primary cells? I'd not use cheapie |primary cells for anything.

I use cheapie Lidl Alkaline cells for low current uses where I expect them to last for months or even years. Smoke detectors, IR TV hoofadoofas and the like, also cheapie Lidl torches which I leave around and expect them to work when picked up after years sitting unused. NiMHs self discharge much faster and need recharging regularly. NiMhs are fine for regularly used torches cameras, GPSs and other high current uses.

[Peter Parry]

They don't, and in domestic batteries never have. What they do develop is voltage depression which is caused not by failing to discharge them fully, that is irrelevant, but simply by consistently overcharging them.

[Dave Fawthrop]

|Dave Fawthrop wrote: |> NiMhs are fine for regularly |> used torches cameras, GPSs and other high current uses. |Funny you should say that, my Garmin doesn't like even freshly charged |NiMHs - you get ~3 hours life compared to a quoted 22 from alkalines. 1 |walk instead of quite a few.

I never believe quoted figures, only what I find on test.

I get two thirds of knack all from alkalines, a full days walk from NiMH with another pair as backup. All I need :-)

[Chris Hodges]

Primaries - at least I was, and assuming that was what you meant about Aldi. Might have to go there if they've got NiMH that cheap.

Chris

[Chris Hodges]

Funny you should say that, my Garmin doesn't like even freshly charged NiMHs - you get ~3 hours life compared to a quoted 22 from alkalines. 1 walk instead of quite a few.

[Guy King]

The message from Chris Hodges contains these words:

Ah, no, I was talking about NiMHs, and yes, both Aldi and next week Lidl have AAs at 4/£2. Lidl's are 2.1Ah.