Battery Rescuer
....... or Destroyer. We'll soon find out.
My turbine is churning out amps and my PV panels are churning out amps and the time has come to look deeply at my battery situation.
I have two second-hand golf-cart batteries and two 172ah second-hand Telkom batteries or about half a ton of batteries but effectively I don't have much at all. They charge too quickly and they discharge too quickly.
So I contacted my son who is a mechanical engineer in the USA and he writes technical articles for aero magazines and owns his own aeroplane. He knows the technical writing fraternity and he asked around if anyone had a way to rescue a battery. Well he got a couple of replies most very technical and of no use to me but here's one and I quote :
Subject: Bringing Batteries Back from the (almost) Dead
Found on another list...it works BTW, I`ve tried it. Marc
I didn`t believe this would work but as luck would have it, I had flown
to Reno with the bad battery, visiting family, when a long technical
thread came on line. The trick is to pass a constant charging current of
l to 2 amps thru the battery for many hours. Mine took 3 days before the
specific gravity stopped rising.
Get a 3 AMP x 200 volt or higher diode (Radio Shack $0.75). Cut 1 wire
of an extension cord and connect one cut end to the negative battery
terminal. Connect BAR marked end of the diode to the battery (+)
terminal (the arrow will now point toward the battery). Connect the
other end of the diode to the other cut end of the extension cord.
Plug in lamps to the extension cord. You will get .63 amps per 150 watt
bulb so 2 bulbs are faster. Tape or protect your connections and plug in
to 120 VAC. Wait as long as you can. You cannot overcharge and this will
work from 2 volts to 28 volts since it is current regulated.
[Note that he`s recommending wiring the lamps and the battery in SERIES;
if you put even rectified 110 volts across a lead acid battery, you`ll
soon have a hydrogen explosion combined with sulfuric acid spray. Very,
very bad thing. Paul]
Unquote
The article is a bit disjointed but I've put together a piece of apparatus (see picture) which consists of a fan, a bridge rectifier and eight kettle elements. I intend to rectify the mains current and then put it through a suitable configuration of kettle elements and then charge one golf-cart battery at 1 amp for as long as it takes. I have an SG meter and I'll monitor and record my readings and time as I go along. I'll let you know how I fare.