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G8MNY > TECH 14.11.04 01:27l 36 Lines 1869 Bytes #999 (0) @ WW
BID : 19950_GB7CIP
Read: GUEST
Subj: Lead Acid Batteries
Path: DB0FHN<DB0RGB<DB0MRW<OK0PPL<DB0RES<ON0BEL<GB7CIP
Sent: 041113/2222Z @:GB7CIP.#32.GBR.EU #:19950 [Caterham] $:19950_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EU
To : TECH@WW
Lead acids. Have you checked to see it they come up with a reverse charge?
This is something that is quite safe to do to a Lead acid (but never a Nicad as
they explode), as this is how the original batteries were made.
There is 2 type of lead (Pb) sulphate that is formed on flat batteries,
the first type is conductive & allows normal recharging, the 2nd type is hard
lead sulphate that just insulates the cell plate & inhibits normal recharging
unless very high voltages (>5V/Cell) are applied. But reverse charging (with a
suitable current limiting lamp in series) will break down the hard sulphate
immediately. A couple of charge/discharge cycles will then bring back a heavily
sulphated battery to near normal capacity.
DRY?? The so called dryfit batteries are actually wet types with a clever
seal. They are just as susceptible to loss of water by over-charging & warm
temperatures as wet batteries are, but your supposed to throw this type away
instead of topping them up! However closer examination of the top of dryfits
will show a glued cover over a set of 6 rubber cup caps that if removed will
let the cells be topped up as normal. Only some success is possible with this
method, as over-charging usually destroys the lead frame in the +ve plate as
well & it falls apart.
Cycle charging up to 14.5V (6 cells), 13.8V standard infinite float charge, but
13.5V MAX on sealed cells.
Tony, G8TBF says there is another way to recover batteries that have gone high
resistance due to being left idle for long periods.
Connect a bridge rectifier across the battery, + to +, and supply this from a
240V AC source in series with a 15W or 40W light bulb. The supply should
preferably be from an isolating transformer..... 73, Tony, G8TBF.
Why Don't U send an interesting bul?
/QSL
73 De John, G8MNY @ GB7CIP
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