Surprising rechargeable cell life

[Jeff Layman]

Clearing out the shed I came across my old 4.8v Challenge Extreme powered screwdriver, which I hadn't seen for at least 6 years (I use my Hitachi drill/driver instead). When I opened the box and took out the screwdriver I accidently touched the trigger and was amazed when the motor turned. I though it might be the dregs of a charge in the cells, but I tried again and it turned. In fact, it was not possible to stop it turning by gripping the shaft.

I have no idea what brand NiMH cells were used in this cheap screwdriver (Argos), but for the four of them to retain a good charge for 6 years seems very unusual to me.

[The Natural Philosopher]

Probably Nicd then

[Brian Gaff (Sofa 2)]

Not sure, Nicads don't last if stored either. However, the non self discharging cells have been around for a good decade now as far as I know. What annoys me is the naff batteries they put into shavers these days. If you get 18 months out of one then you are doing well, and in the old ones you could remove the old ones as a pack, and get a new set, most nowadays seem to suggest you break the shaver to remove the batteries to recycle then buy a new Shaver, you listening Remington? Brian

[polygonum_on_google]

I recently found my very old iPad - generation 1. Flat, yes. But charged it up and it appeared to retain charge very well, and worked as well as ever. (Except the ancient version of IOS hits numerous issues if you actually want to do anything with it.) Even leaving it lying around for a few weeks, charge hardly dropped.

[Harry Bloomfield, Esq.]

I have a 12 year old Philishave and a 3 year old Lidl shaver, both used only very occasionally, Philishave in the house, Lidl in the caravan. Each has a charge remaining display and both will still show 100% if unused for many months.

[Jeff Layman]

They are. Nothing on the device itself, but I dug out the instructions and they say they are NiCd. The instructions are dated 4/2006. I guess I bought it within a year or two of that date; I'm surprised that NiCds were still around them, but I guess they were still using them on low-end products.

Sites vary in what they state is the self-discharge rate of a NiCd cell. The best is 10%/month, but the most common is 15 - 20%. Not in my experience - it's around 1.5% if those cells were last recharged about 6 years ago! :-)

[Adrian Caspersz]

Best electric shave I've ever had was from a mains only Remington shaver with a proper 240v motor, cutters moved violently side to side at

50Hz.

These whizzy electric motors and cams (or whatever) don't have the force (mass * acceleration) to undo my cave man look.

[Graham.]

Can you still get mains only Philishaves, or is my current one going to be my last?

[Brian Reay]

I?d have said NiMH. I find NiMH cells / batteries not only hold a charge for a long time but NiCds don?t. I?ve some cheapish NiMH cells I made into batteries around 2001 /2 which are still good. I check them perhaps every couple of months or so, sometimes top them up ( they are for amateur radio transceivers), and they seem fine.

Conversely, when I used to use NiCads, they died if you stored them and didn?t charge them before they ?reversed? themselves- sometimes within a month.

[Andy Burns]

Doesn't seem to be much choice

They'd rather sell you a cordless Qi recharging, submersible one that applies lotion as it goes, and probably pleasures your wife, but costs

10x as much

[The Natural Philosopher]

no. NiMh are the 10% a month

NiCd seems a bit better

[The Natural Philosopher]

The reverse is actually true.

I?ve some cheapish NiMH cells I made into

Bad cells.

[Brian Gaff (Sofa 2)]

Well that has not been my experience. I cannot see charge remaining displays, but my Remmington has one I know in the shape of a cell. It now refuses to charge or run from its mains supply, even though it used to. Modern ones have such a weedy mains unit that you can only charge, not run the shaver from them. Bah Humbug. Brian

[Brian Gaff (Sofa 2)]

That is a whole other issue of course. There is no reason why rotary shavers based on modern direct drive motors, small versions of those used in drones and dvd players, cannot be set up to work well. Its just penny pinching and crap batteries and power supplies. Brian

[Brian Gaff (Sofa 2)]

Yes and most won't run and charge at the same time. Brian

[Brian Reay]

I don't observe that even with cheap 'unbranded' cell bought from CPC in about 2001/2. I built several battery packs for Icom handhelds plus a special for an IC202S (another transceiver) - 7 or 8 cells in each pack and 10 in the special. When I check them every couple of months or so, they show hardly any sign of discharge. I sometimes miss a check- especially if we are away- and even then they show little signs of discharge when I get around to checking them. I sometimes give them a discharge cycle and a charge, others just as brief top up.

Conversely, when I used to use NiCads, I bought (supposedly) quality ones and treated them like cherished offspring. They were still unreliable.

I've observed the same with commercial, ready built, NiCD and NiMH packs for another handheld bought around 2005 or 6.

I have had NiMH cells fail, including ones which have a good name, but only rarely. I'm currently trying some Ikea ones which have a good reputation and, so far, seem reasonable but I've only had them a year or so. The Ikea 'wall charger' which not only charges them but keeps them 'topped up' until needed seems pretty good.