Battery Tester?

[StorminN]

aviken,

Those golf cart batteries of yours look pretty new. If they were not abused... ie., overcharged, shorted, swelled, etc. then you can probably recover them. What is their standing voltage right now?

I would second what leitmotif says, especially about not overfilling the cells... they just need enough liquid to cover the tops of the plates, no more... once they are charged, the level will come up. If you're going to add anything, just add distilled water, no acid! I would also add that if they were my batteries, I would charge them slowly... like 2A max and monitor their temperature. I don't agree with the popular auto parts store / service garage notion of "put 50A to completely dead batteries" to "wake them up". Yes, that boils the electrolyte and helps eliminate stratification, but IMHO, that's a good way to murder batteries.

Lead acid batteries left uncharged will self-discharge and develop lead sulfate on the plates, which diminishes the batteries' capacity. You can try wiring them in 12V pairs and charging them, and like Dan said, see how they react. If you're lucky, they will take a charge and you're OK... but what you probably really need is a desulfator... Google "desulfator" and check out the Yahoo groups and such that discuss them.

Desulfators are basically a little electronic box that you connect to your batteries. The theory is, the box has a circuit that generates pulses that resonate within the battery and "break up" the lead sulfate on the plates. Like anything else, there are good pulsers and bad ones. Some commercial models are complete scam rip-offs, just a box with a circuit that makes a light flash, put a 'scope on them, and you'll see that they don't even output a pulse. Other commercial ones do pulse, but don't put out much power, so they might be OK for maintenance of good batteries, but they're not much good for recovering sulfated batteries.

The simple home-made pulsers (desulfators) are usually based around a 555 timer circuit, you can find plans for these online, or buy a kit for about $60, or a completed unit for about $120. They are usually 1W in power and will recover about 2lbs of lead a day... so, for example... if your golf cart batteries are 60lbs each and you wire two in series (for 12V) for pulsing, that's 120lbs of lead, at ~2lbs a day, that's about 60 days to recover two completely dead batteries (less for batteries not so bad off to begin with)

A step up from the 555 pulsers are the pulsers based around a STAMP circuit... these are about 2W in power, and can include other circuits like dedendriting circuits and such. Last time I checked, the STAMP pulsers cost about $250 complete and will recover about 4lbs of lead a day... so 30 days for two of your golf cart batteries wired in series.

The cream of the crop of pulsers are the CIP pulsers (which are 120VAC powered), they are expensive and powerful... like $850 complete, and 50W in power and they will recover 20+lbs of lead per day, so two of your golf cart batteries would take maybe six days.

Both the 555 pulsers and STAMP pulsers are usually powered by the DC of the batteries themselves... so they require that you have a small, 1A or 2A NON AUTOMATIC trickle charger connected to the batteries while they are being pulsed. The trouble is, finding a NON automatic charger these days. Yard sales and eBay seem to be the best bet... find the old, metal case motorcycle battery chargers, and they will work. If you have really dead or big batteries (like the L-16's I had that read 0.2V) even the newer small, non-automatic chargers will trip off on an internal circuit breaker. The old chargers work better. The new AUTOMATIC chargers don't work at all, they get fooled by the pulsing and turn off or error out.

Finally, there are plenty of people that don't understand how these pulsers can work and therefore don't believe that they work. When you encounter this, ask them if they've actually tried one... I  assure you they haven't, they're just guessing... and most of these people have a vested interest... like they SELL batteries... of course they don't want pulsers to work, because you'll never buy batteries from them again. I'm here to tell you they work. I have a home-made STAMP pulser I bought... I've recovered 12V car batteries, big Trojan L-16's, and I recently loaned my pulser to a friend that has an EV with fifteen Trojan 8V batteries (T-890's?) in it. Those batteries have 5,000 miles on them and three of the batteries were getting down on voltage, weaker than the rest of the pack. My friend has since pulsed them individually, a weekend at a time with the STAMP pulser, and those three batteries now consistently show higher voltages than the rest of the pack.

P.S. - None of the pulsers will do any good with a battery that has a truly bad cell... an internal short, something where the battery has been physically abused... overheated, swelled, etc. Of course the pulsers work better (and quicker) on marginal batteries... those with a standing voltage of 10.5V or better for a 12V battery (or 5.25V or better for a 6V battery), than they do on really dead batteries.

P.S.2 - I've wired a few of those Trace inverters and charge controllers (I have a SW5548 and a C40 in my basement), if you need some help, let me know...

I hope this helps,
-Norm.