Batteries and desulfators - I needs ta know!!

[Chaz]

Hey folks,
Back to the age old issues with batteries...... MAN, these things drive me nuts!! And it seems I am always having to buy new ones. (well, I do have a lot ) I just had to put a new gell cell in my daily driver -'56 Chevy. (love that car!  )
Anyway, I really want to know if desulfators work - which I "believe" they do - but, I just don't know. And, if in fact they do, I have also heard that they are not all created equal. Which one(s) the best as far as your personal experience or proven knowledge goes?
My issue now is my start batteries. They don't seem to hold a charge. I replaced them a couple years ago. I had DD's and went to 31's. Now, I did commit the cardinal sin of letting them discharge all the way (a couple times  ) because for some reason the high dollar equalizer switching device (Heart Interface Pathmaker, 200 amp) seems to not be "all that and a bag of chips"!!! I know I have a small drain on the starts (I would love, love, LOVE to have the wires stripped out completely and only the absolute nessecary ones left. Oh well....... one can dream...) but thought I could live with that by putting on the Pathmaker and just deal with it. My bad.
So anyway, I'd love to hear what you guys know about those little "wonder box's".
Thanx a bunch!!!!

Chaz

[Jeremy]

In normal circumstances (ie. in a regularly-used vehicle), start batteries don't die because of sulphation - in fact the duty-cycle of a start battery (high current draw, immediately followed by a high charging rate), is a very good way of avoiding sulphation, and perhaps even re-dissolving any sulphate that has formed.

But if the bus has stood for lengthy periods with the start batteries flat, then, yes, a desulphator might help. I do have one myself, and believe in the principle, but don't have enough practical experience of their effectiveness to give advice. I have also read that controlled over-charging (ie. boiling) is as effective a way as any to desulphate a battery, and perhaps a better approach than leaving a proprietary device connected to it for days or weeks.

Jeremy

[Lin]

I recently bought two and have them on my 8D's now.  After that, I will put them on my house bank.  Since the manufacturer said it would take about 4 weeks to do the job, I will let you know if I can detect a change in a month or so.  My house bank is 3 AGM batteries that used to sit at around 13v.  They now sit at about 12.6 or 12.7.  My thought is that if the sitting voltage can be raised, the desulfators did something good.  Unfortunately, this is just my speculation.

[boogiethecat]

I researched desulphators for a long time and finally settled on three different brands... bought them, tried them and decided that they were all a total waste of money.
They didn't do squat to the batteries but they did put some of my hard earned bucks into someone elses' pockets for nothing!

I did find a process that actually works and works well, as mentioned above by Jeremy... basically you acquire a power supply usually used in the electronics industry that can put out a constant current instead of a voltage, and use it to "overcharge" your battery on purpose.  The power supply is set up to deliver 5 amps to the battery regardless of it's voltage, and once it appears to be fully charged, you continue the process for another 24 to 48 hours.

This results in a battery that will get hot, bubble like mad, eat water constantly, and be very dangerous during that time because it is not only emitting a lot of hydrogen; it is emitting exactly the correct ratio of hydrogen and oxygen that likes to explode with very little provocation.

The results: one set of three Trojan J-185's that were totally dead and sulphated came back to life as if they were almost new.

The second set didn't fare so well- they came bcak to life perfectly as did the first set, but at the very end, about an hour before I was going to turn the process off, something made a spark... the explosions, the fire, and the photos below were the unhappy result...$1000 of batteries totally destroyed and an awesome toxic mess to clean up....




Bottom line: If you're set up safely (Fortunately I did this in a non-flammable concrete block area with a tapered floor that I made specifically for this kind of accident) it works.  But it's not a process for the timid.

A MUCH better option is to use a charger that takes good care of your batteries, keep them watered, and you'll have amazing results for a long time.  I routinely get 6-8 years out of a set of T-105's because I use a good charger that has three stages and an automatic equalization function (my favorite brand is intelipower), and I keep them watered....

EVEN BETTER is to just dump the wet batteries altogether and go AGM.  I finally did this after babying T-105's for all those years, and the whole issue of battery maintainance instantly became invisible to me.
Installing the bank of AGM's eliminated ALL issues, I never think about them ever, and they just work....

[Jeremy]

... basically you acquire a power supply usually used in the electronics industry that can put out a constant current instead of a voltage, and use it to "overcharge" your battery on purpose.  The power supply is set up to deliver 5 amps to the battery regardless of it's voltage....

Interesting - I'd always assumed a basic old-style battery charger would be all that was required; with a dumb transformer-type charger, once the battery was fully charged the voltage, and therefore current, would be more-or-less constant wouldn't it? Or is there more to it than that?

This isn't just an academic interest as I have a matched set of three nicely-sulphated batteries waiting to be dealt with. The safely advice is well received - performing the operation outdoors and preferably with an airflow blowing across the batteries would seem a minimum precaution?

Jeremy

[Mex-Busnut]

Chaz:

In case you missed it, here is my thread about this subject.

http://www.busconversions.com/bbs/index.php?topic=22462.msg246862#msg246862

Also, consider investing in a battery switch that totally disconnects your batteries from the bus when your vehicle is stored. I purchased the large battery cutoff switch at the local Camping World. (I think it was around $23.00.) Buses are famous for coming up with "phantom loads" that will kill your battery, even when you think everything is off.  

Camping World has two versions of this switch: One says "House battery" and the other is "Chassis battery". The house battery one says "Continuous rating 275 amps; Intermittent rating 455 amps; Cranking rating 1,250 amps". It is rated at 48 Volts, and can be wired with cables as thick as 1/0.

I have added a second one to cut off the engine batteries.

[Mex-Busnut]

The safely advice is well received - performing the operation outdoors and preferably with an airflow blowing across the batteries would seem a minimum precaution?

Jeremy

Usually, they recommend leaving the charged battery on a trickle charge, of 1-2 amps.

Also, if you have air going across the charging batteries, you do NOT want the air to take the explosive fumes towards the charger or another possible flame ignition source.

[Jeremy]

Usually, they recommend leaving the charged battery on a trickle charge, of 1-2 amps.

Also, if you have air going across the charging batteries, you do NOT want the air to take the explosive fumes towards the charger or another possible flame ignition source.

I understand what you're saying...but I think the danger very rapidly diminishes as the explosive gases disperse. I don't rightly know how big the 'danger area' is, but my instinct is that it would be quite small, and I'd be doing this in my garden where I could be quite confident that there were no ignition sources for at least 50 feet in all directions.

I'm not quite sure what you were meaning with the trickle charge comment.

Jeremy

[boogiethecat]

Jeremy... "dumb" chargers do put out a constant current, but they are also fixed in the maximum output voltage that they can produce, which usually factory adjusted to somewhere aroung the float voltage of the battery they are charging... the result is that as the battery comes up to charge and it's voltage nears that of the charger's maximum output voltage, the current tapers off eventually to zero or near that.  A constant current lab supply can be set for a max voltage that is much higher than a battery could ever attain, effectively continuing to overcharge it quite aggressively until you turn it off manually...

[boogiethecat]

Also, if you have air going across the charging batteries, you do NOT want the air to take the explosive fumes towards the charger or another possible flame ignition source.

I disagree. Totally.
A good air flow away from the batteries is ESSENTIAL to carry away and dilute the gasses so they can't detonate.  If there is no flow, just like Fukushima but without all the radiation, it will take  very little to make a BIG boom!!!

[Jeremy]

Jeremy... "dumb" chargers do put out a constant current, but they are also fixed in the maximum output voltage that they can produce, which usually factory adjusted to somewhere aroung the float voltage of the battery they are charging... the result is that as the battery comes up to charge and it's voltage nears that of the charger's maximum output voltage, the current tapers off eventually to zero or near that.  A constant current lab supply can be set for a max voltage that is much higher than a battery could ever attain, effectively continuing to overcharge it quite aggressively until you turn it off manually...

Thanks, thats educational. So I guess I'm hitting Ebay for a laboratory-type variable power supply.

Jeremy

[christopher]

i used a black and decker desulphator and it did not work. I was told by a bettery builder that the led comes off the plates making the battery useless.
Chris
mci5c

[RoyJ]

I too, have a little desulfator, and like other, found it to be pretty much ineffective. Over-charging with a dumb charger seem to work much better with mild sulfates.

The constant current supplies maybe a bit too harsh though, as shown by boogiethecat's results... I have 6 amp dumb charger that puts out 16.5volts open circuit. You only see 6 amps at max voltage delta (dead battery). When the batt is full, it floats around 15.5 volts putting out just under 2 amp.

This keeps my 2 8Ds at a nice mild bubble, without too much gas venting. I do this overnight once a year or so, otherwise the bus is always plugged in maintained at 13V.

[boogiethecat]

Ebay, search "bench supply"
Get one that outputs at least 10 volts over your battery voltage, and one that will do 5 amps. You don't want to go much over 5 amps

For example item # 320699271028 is probably a nice choice...

[luvrbus]

If you know how to do it a dc welder works good for a desulfators I have been doing it for years with a welding machine and never blew a battery up yet knock on wood lol

good luck