I noticed an important error in my post above. It concerns the capacitors.
I erroneously stated I use "three large (1,000mFd) capacitors."
The error is I meant 10,000mFd. A desulphator with only a few thousand mFds will work and is ideal for perhaps small batteries. I have made desulphators with three or four thousand mFds. But the only ones I use now have a minimum of 20,000mFds and my favourite one(s) use over 30,000.
* And I findthe trannsistor blocks from old air conditioners perfect to deliver the pulses. The ones I use are a block of 6 X 20A. And it's not difficult to blow them!!! Must be a couple of hundred amps pulsing when I crank it up a bit ... The lights in the room will flicker a lot when the desulphator is set at high power, and too much and of course the transistor block will fail - usually in a dead short, so be careful!
Statistics: Posted by mael — Mon Oct 03, 2011 1:14 am
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it going and going and going...
Yes, you've discovered the secret - intense pulses
with sharp leading edges.
And you're correct about each battery having its
own unique characteristics and problems - one size
does not fit all!
My test circuit which pulses batteries at about one
pulse per second (160 Volts DC/4000 microFarads) by
means of a voltage triggered heavy duty SCR is still
plunking along and has brought quite a few batteries
back to life over the past several years. I've had to
replace the capacitors twice as the heavy current
pulses will eventually degrade them but, otherwise,
I'm pleasantly surprised by the durability of the circuit.
I suppose it's long overdue for fabrication into a more
permanent hookup as a full-fledged desulfator which
has survived experimentalism.
It's very good to see that you're still at it and that
you're having good success.
You're right about some batteries being poorly made
to have very short lifetimes.
Statistics: Posted by SeaMonkey — Sun Oct 02, 2011 5:28 pm
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I haven't posted here for a while, and the reason for this is that I seem to have reached a kind of limit and have nothing really to add.
Of course there are secrets I haven't discovered, but I know how to get new life out of batteries.
I can tell you that the death of a lead/acid battery is the degradation of the positive plates. They eventually become soft and basically rot.
The spongy mess of rotten positive plates does supply a lot of power. The positive plates rot from the bottom up and the final gasp of life for a battery is when the lead lines leading to the rail above loses integrity.
Thus - old batteries being put through a load test which are low on electrolyte are capable of sparking internally and exploding. I never had a battery explode - but that's not due to my carefulness ... I was lucky.
Another problem battery which I found extremely rare - two batteries out of perhaps two hundred had an intermittant open circuit which wasn't noticable at low amperages but when used to near-cranking amperages the inter-cell connection(s) seemed to fail.
And of course those shorted cells! I'd say quite honestly not to attempt to repair a battery. Taking the cells apart is more of a hobby than something practical. If it is necessary to take the cells out of the case then the plates are certainly crumbling and cannot be repaired. The cells can be replaced - if you can order new plates from the manufacturer or you could even conceivably try to make your own plates by pressing globs of lead oxide into plat plates - and good luck to you if you try that! It'll not work for a starting battery methinks - too thin anyway.
*
Here's what I think:-
Sharp-edged pulses between 1 & 100 pp/s will fix your battery in terms of the sulphation. Thus you can get the longest possible service life from a battery by keeping the plates clean so it can charge properly and discharge enough to crank something.
I have never had any decent measuring equipment, but I find a power source with a hefty transformer which has an open voltage after being rectified of over 20 V and less than 40. 40 volts stored in a few tens of thousands of mFds is of course something which requires continuous observation because quite frankly when that is being pulsed in a hundredth of a second it is an enormous jolt.
I vary the duration of the pulse and the length of the pulses depending on the battery I happen to be working on. I do not think there is a one-size-fits-all pulser, and I think such a system requires careful observing during operation.
The store-bought ones are crap. Their problems are the frequency of the pulses is too fast and the pulses too piss-weak. Batteries like to take things slow ... they like lots of foreplay.
What I usually do these days is to bring the battery up to between fifteen and sixteen volts and keep it there by occasionally adjusting. It takes no longer than three days to desulphate a battery, and often takes only one day to get the electrolyte back into the green after being so weak the balls in the hygrometer wouldn't float at all.
If you want to fix batteries then the process is by no means guaranteed to work every time. What you can be certain of is that after desulphating your battery will be in the best condition it can possibly be for its age and life-history.
If a battery doesn't like going above 15 volts then suspect a slow short. And if you determine it has a short then use it as a doorstop or a ten-volt battery ... don't waste time trying to fix a cheaply made starting battery.
Use a 400W transformer which can produce a rectified voltage of 40 V, Use lots of caps - I get them from discarded air conditioners... I get three large (1000mFd) caps from ech circuit board from them. - Actually I get one 1000mFd and probably the other two are a bit less - but mixing them on your pulser looks cool!
I use an astable multivibrator to drive a relay and the relay drives transistor block rated at 6 X 15 Amp. - I have blown quite a few of these on very fast pulses at times - so you can imagine there is a heck of a lot of current in the pulses if you set it like that. I make mine variable so I can do small 2 A/h m/cycle batteries as well as 150 A/h marine batteries.
Well - I want to be here to help you guys save money and help you to make a pulser which works.
In a nutshell all you need is an arbitrarily high number of potential amperage delivered into a battery in pulses with a sharp leading edge - nothing's going to give you a sharper edge than a relay.
So ask away if I can help!
I haven't bought a car battery for twenty years. Just last night I pulsed my e/bike's batteries and I'm pleased to say they came round again. Two years ago I did them and hoped I could get another year out of them, and the batteries are approaching twenty years old. They are not as good as new ones, but I can use the bike to get the shopping and my wife uses it to pick up the little'n from the nursery.
Statistics: Posted by mael — Sat Sep 10, 2011 5:09 pm
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