Joined: Aug 2017 Posts: 2,748 Threads: 31
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Location: Auckland, NZ
04-10-2018, 11:44 PM
(This post was last modified: 04-10-2018, 11:47 PM by Bob Culver.)
If the conventional chrger is rectifying and producing 6 or so volts across the battery, charging will likely kick in after a few hours. Protracted charging at a very low rate (say 2%) is recommaned for sulphated batteries. Anything which vaguely indicates amps would be helpful. It may not be too difficult to borrow the meter out of the car.
As always with batteries have to be careful of direct battery short through ammeter , spanner, metal watch band, ring etc....
Joined: Aug 2017 Posts: 425 Threads: 30
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Location: Wellington, NZ
Austin Carr asked the right question with what's the battery voltage. 2 volts on a 6 volt battery probably means the battery is stuffed. In a lead acid battery each cell is just over 2.3 volts per cell when fully charged. What they called fully discharged is about 1.95 volts per cell. So for a 6 volt battery with three cells about 5.85 volts. I would think anything lower means the battery is broken. I've found that with SLA batteries, once you start measuring low voltages on them nothing you do brings them back.
A truly intelligent charger (one measuring the voltage to start with) is probably not even starting to try to charge it.
The battery also acts as a ballast/load to keep the dynamo voltage down. If you run a car without a battery in circuit (or a dead one) then the voltage will shoot up and exploding bulbs may well be the result as noted above!
Simon
