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G8MNY > TECH 15.09.05 18:18l 65 Lines 2918 Bytes #999 (0) @ WW
BID : 62309_GB7CIP
Read: GUEST DL1LCA OE7FMI
Subj: Lead Acid Batteries
Path: DB0FHN<DB0RGB<DB0MRW<DB0WUE<DK0WUE<7M3TJZ<ON4HU<GB7YFS<GB7CIP
Sent: 050915/0733Z @:GB7CIP.#32.GBR.EU #:62309 [Caterham] $:62309_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EU
To : TECH@WW
By G8MNY (Updated Jun 05)
BATTERY 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.
FLAT STATE
+ Plate Electrolyte - Plate
Pb PbSO4 H20 PbSO4 Pb
Grey/White Low SG=1.0 Grey/White
CHARGED STATE
+ Plate Electrolyte - Plate
Pb PbO2 H20+H2SO4 Pb Pb
Brown SG > 1.25 Grey
There is 2 type of lead (PbSO4) sulphate that is formed on flat batteries, the
first type is conductive & allows normal recharging, the 2nd type that
crystilizes over a long time is hard white 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 FIT 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!
WET TYPE DRY TYPE
Top up Hidden
Plug Internal Plug
ÚÄÄÂ==ÂÄÄ¿_ Connections_ÚÄÄÂ--ÂÄÄ¿
ÃÛÄÙ ÀÄÛ³ ÃÛÄÙ""ÀÄÛ³
³Û------Û³--Acid Level--³ÛÜÜÜÜÜÜÛ³
³ÛÛÛÛÛÛÛÛ³ ³ÛÛÛÛÛÛÛÛ³ Acid totally
³ÛPLATESÛ³ ³ÛPLATESÛ³ Absorbed in
³ÛÛÛÛÛÛÛÛ³ ³ÛÛÛÛÛÛÛÛ³ seperators.
³ßßßßßßßß³Deposit ³ÛÛÛÛÛÛÛÛ³
ÀÄÄÄÄÄÄÄÄÙSpace ÀÄÄÄÄÄÄÄÄÙ
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?
73 De John, G8MNY @ GB7CIP
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