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G8MNY > TECH 03.04.05 21:50l 42 Lines 2017 Bytes #999 (0) @ WW
BID : 39629_GB7CIP
Read: GUEST OE7FMI
Subj: Lead Acid Batteries
Path: DB0FHN<DB0THA<DB0ERF<DB0HGW<ON0DXC<IW2OAZ<IZ0AWG<IW8PGT<TU5EX<CX2SA<
GB7YFS<GB7KHW<GB7CIP
Sent: 050403/0950Z @:GB7CIP.#32.GBR.EU #:39629 [Caterham] $:39629_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EU
To : TECH@WW
By G8MNY (Updated Nov 04)
OPEN CIRCUIT.
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
may 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 TYPES??
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.
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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?
73 De John, G8MNY @ GB7CIP
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