Tuesday, September 22, 2009

Battery Strategy

I am old enough to remember when "rechargeable batteries" meant big square things full of lead & acid that you could just pick up with 2 hands.
Imagine what mobile phones would have been like…

So I was initially impressed with the first Ni-Cad rechargeable cells which were the same size & weight as ordinary torch batteries, but cost a lot less to recharge than the ordinary cells cost to re-buy.
With 4 daughters in the early days of cassette-tape Walkmen (Walkmans?) the economics were striking.
But it gradually became obvious that the Ni-Cads did not age well.
We started to hear about "memory effect" & realized we couldn't recharge then until they were run down.
But if you run them down too much they never recover…
And the number of recharge cycles is limited, so you don't want to recharge if you don't need to.
Then the "leak-down" effect which meant the emergency torch was always useless when you needed it, even though it hadn't been used since recharging.
With further ageing, some of them developed very short lives & of course having one flat battery in a Walkman is like having all flat batteries in a Walkman.
So we got good at sorting & marking the weaker ones, which were OK at home but no good on the bus.
But oh, the arguments when certain daughters cornered all the best batteries!

After that the arrival of the more expensive, but less troublesome, Ni-MH cells came as a great relief.
Of course that meant new chargers as well as new batteries, and being careful not to mix them up.
But, in general, they are pretty satisfactory.
Little or no memory effect, so you can recharge without needing to run them down.
Still some "leak-down" though.
And supposedly a limited number of recharge cycles (but I haven't worn any out yet).
So they would be OK in Walkmen, but that need has long since fizzled out.

My main usage of small rechargeables these days is for my camera, which is old enough to need 4 x L6s.
A freshly-charged set of 2300mAh Ni-MHs (if you see what I mean) will take about 200 shots.
I have a little pouch with 4 spare unused batteries to take over, which I carry on day-trips, and a small charger, which I carry on longer trips.
So that should be OK, right?
Well, no, it isn't.
As often as not, when the set in the camera runs out, I put in the set from the pouch, and – leak-down effect – they are flat too.
So I suppose I need to develop some special strategy for topping up the pouch batteries more often (how often?).
Or make a point of swapping the batteries over more frequently?

Apart from the camera, my other battery bugbear has been cordless drills.
My first one was a Black & Decker.
A puny device, but it worked OK for several years.
Except that when the battery ran down you had to stop work until it was recharged.
It was still in as-new condition when the Ni-Cad battery gave up the ghost.
At that point I discovered that the battery was non-removable & non-replaceable, so the as-new drill was junk!

I replaced it by a bigger Wagner drill with 2 removable Ni-Cads.
So I could recharge one while using the other.
And replace either when it expired.
Except, of course, for the "leak-down" effect, so that the spare battery was usually flat when you needed it.
And that one replacement battery cost more than a new drill with 2 new batteries.

So when both batteries were too far gone for reasonable use, I decided I did not want to go down that path again.
I spent a lot of money on a new Bosch drill with 2 Li-Ion batteries, which are very small & light for their capacity.
And supposedly have little or no memory effect.
And little or no leak-down effect.
So far, the absence of leak-down is astonishing & I am delighted with these batteries.
The spare is always ready & willing when the worker expires, even after several months.

Of course, they might explode, but then, nothing is perfect!

Parting thot: "In the beginning there was nothing. God said, "Let there be light!" And there was light. There was still nothing, but you could see it a whole lot better." - Ellen DeGeneres

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