Does this Battery need desulfated?

[Devo]

This is the battery I am using it used to charge up good into the green on the hydrometer but lately it will bareky start to touch the green mostly it stays in the fair range I can charge for days but it gets no higher.

I sent an Email to a web site that sells them but never got a response. It is a 500 amp hour string I have 3 more plus thius battery that was said to be scrap but seems to charge & discharge quite well.

 

Where can I buy a desulfator & how do I know if it is big enough to do these batteries?

Also I am wondering if the batteries are getting weak because I am only charging them with 5 to 25 amps ,sometimes a 30 + spike never the 100 that it used to get at work.

Any thoughts?

Devo

[Devo]

I must have forgot to insert the first pic this is the one that won't fully charge

 

[Kilroy2k1]

  I'm sorry I dont have an answer to your question but I gotta ask.. That first pic is Exactly the same battery I have. You wouldnt happen to have the specs on that one?

 I also picked it up for scrap price and after sitting for 4 years that the guy can account for it still had enough juice to burn the end of a coat hanger off.

 My appoligies for hijacking the thread, any info would be appreciated.

Thanks

Tom.

[Jerry]

Hi Devo.

I have a very simular battery as pictured in the first picture. The wharehouse tossed it because it was old and it wouldn't make it through it normal work piriod (thats what happens when you get old).

I got it free (very good price). It is 36 volts or it was. I cut some jumper bars and rewired it to 12 volt.

I found a few cells with low SG. At that time I was playing with DIY battery desulphators. That topic was very popular for a while here on the board.

My first desulphators were some what complex. They used a 10 amp 30 volt power supply, 2 TO-3 power transistors and a small 555 timer circut using opto photo couplers as trigers for the transistors. It also used a large 120,000 UF/ 50 volt cap.

The 555 circut would turn the input TO-3 on to charge the cap from the 30 volt supply. Then it would be turned off and the output TO-3 would be turned on to domp the 30 volts from the cap onto the battery. Pulse speed was addjustable at the 555 timer curcut. This all worked OK.

However a much simpler circut was presented here on the board and I've been using it ever since.

The circut is simple and works very well. I use this circut daily in several apllications.

1. on my E-car. 1 on my golf cart. 1 on my shop RE system, and 2 or 3 restoreing batteries at home and my store/shop.

Its simple but dangerus. 2 parts are needed. A large value motor run cap and a fullvave bridge rectifier/diode.

 One side of 120 volts gose into the cap the output of the cap gose to one ac conection on the bridge. The other side of the 120 volts ac goes to the other ac conection on the bridge. The dc outputs of the diode go to the battery needing desulphation/pulse charging.

To avoid shock hazard from a direct conection to the ac line I use a suitable large isolation transformer.

I use a few of these chargers/desulphators direct on the ac line ( but I urge don't try this at home or anywhere for that matter).

This system has brought many batteries back to life and good SG for me.

I used it on the battery that looks just like yours and now that battery is the hart of my store RE system.

I'm now building a few of these charger/desulphators fo a few of my freinds.

I found a very cheap islation transformer. There was several things I needed to build these units.

Suitable metal housing, fan to keep the transformers and diodes cool, a heavy power cord and fuseing plus a big isolation transformer.

WALA old microwave ovens. I picked up a pile of used microwave at the used appliance store cheap (nice metal houseings), heavy cords, nice windy fans, 20 amp fuse holder and the best part a 1500 watt transformer.

Big problem with transformer though, primary 120 vac, secondary 2000 volts ac.

Problem solved. Since they were so cheap and plentyfull. I'm using 2 transformers per charger/desulphator. Thats right and it goes like this. 120 volts primary tranformer # 1, 2000 volts secondary of tranformer #1 to the 2000 volt secondary of transformer #2 and the very well isolated 120 volt output is taken from the primary of transformer #2.

These transformers do have some insertion losses so at about 6 amps load I'm see'ing about 100 vac out of this combo. But this is a good amount for charging/desulphation.

This system will work with a singel 2 volt cell all the way up to, well I'm using it to charge my 120 volt battery bank in my daily driver E-car (20 X 6 volt golf cart batteries).

BIG WARNING! Make all conection to battery first befor plugging in the pulse charger even if isolated. Open circut the pulse charger is developing 170 volts (don't touch) Once hooked to the battery it asumes battery voltage.

I use used motor run caps (not motor start). For ever 24 UF of cap 1 amp of charging current is passed. So I wire a group in perelell.

This system works so well for me, I'll keep building more and you gotta love the cheap price, easy to build and to top it off bring junk sulphated batteries back to life.

I even use this charging system on new batteries. I'm on my second year of new batteries in my daily driver E-truck and the SG is as good or better than when I put them in 2 years back.

                       JK TAS Jerry

[Jerry]

I don't remember the specs on mine at the moment accept it weighs 2850 LBs.

                   JK TAS Jerry

[Devo]

The one in the first picture is 36 volt 750 amp hr so 3 tied in 12 volt would be 2250 amp hr.

Devo

[fungus]

Jerry, do you think that circuit could be run off one the AC phases of a reasonably high voltage wind turbine?

[Jerry]

Hi Angus.

I've often thought of doing just that. Many of the motor conversions I've done have turned out to produce hi voltage. That might work for this pulse charging scheem?

I think though at startup the pulse frequency may be to low? I think though a 3 phase arangement may be posable.

Its all on the list of things to try. Problem is its a long list.

                       JK TAS Jerry

[The Crazy Noob]

Jerry, I searched the boards last week and have just finished making your "jerry pulser" yesterday to try and revive some dead batteries. I tought that that would be the best solution.

Now you say that another solution (i presume you are referring to the "watgas.gif" schemetic) is also good.

What would be the best? the 555-pulser circuit or the watgas circuit? And which one is the most efficient one (i guess the latter because it's more simple, less components)?

By the way: Good to see you back!

[Ungrounded Lightning Rod]

If you don't mind me chiming in:

It looks to me like the circuit is using the capacitor as a current-limiting device.  With the input voltage of 120 volts or so it acts much like a constant current source, raising the voltage across the cell as needed to drive current through them, even if it must disassemble sulfate crystals to do it, but limiting the current once it's driven to a level too low to cook the cell.

The "pulsing" from line current AC seems slow enough that it probably doesn't have anything to do with the process (as resonance with something in the crystal structure is alleged to be involved in the semiconductor pulsers.)

Assuming this, and that your genny voltage is also well above the cell voltage, you should be able to do the same using one phase of a genny.  You'll want to scale the capacitor up if you want the same current:  Once for the lower frequency of the genny, again for the lower voltage.

Alternatively you could boost it with a transformer - especially if your genny is going to be left connected to the normal battery bank while being used to desulfate the battery being treated.  (Use the voltage ratio you want, but remember to scale up both the primary and secondary voltages by the ratio of the transformer's rated frequency to the cutin frequency of the genny, to avoid saturation and astronomical primary currents.  You can do this by hooking a number of transformers in series on both sides, with attention to start vs. finish on the windings, if you can't find one with the voltage ratings you want.)

[inode buddha]

There's another way to do it. Use an R-C circuit in series with a small neon lamp. The neon fires and lights up at about 90 volts. So for any value of C, you can vary the R so that the voltage at C increases to 90 volts more or less rapidly. When the lamp fires, it goes into the battery. It makes a kind of "sawtooth" waveform at C.

[Flux]

I really don't believe any of this nonsense about resonance in batteries, most of it seems to have come from bad hf measuring techniques. It is circuit resonance.

If there is any form of crystal resonance I have no idea of its frequency or whether it is possible to excite it.

I have had no luck with the inductive pulsers that sting the battery with an amp or two. They may help prevent sulphate forming if used constantly but do nothing to cure a truly sulphated battery.

Large current pulses do seem to do some good but how much is due to desulphating and how much is due to blowing away dendrite growth I am not sure.

It seems as though discharging a large capacitor charged to several times battery volts is effective but I have never tried doing it on a scientific basis.

I am not sure whether it is rate of rise of pulse or just energy that works.

Most of the things that are claimed to be cured with the inductive pulse things would be cured with a good equalising charge.

Just my controversial thoughts on something that I spent some time playing with, good electronic fun but never cured a battery that was known to be sulphated but otherwise ok.

Flux

[Jerry]

Hi Crazy Noob.

I'm not femileur with the watgas circuit? Is that a scimatic you could post or link to?

I built a few of the 555 pulse circuits but soon abandoned them for the ac line cap diode pulser.

Its brought so many batteries back for me its all I'll use. It works much better then the 555 unit and its way cheaper and easyer.

                     JK TAS Jerry

[zap]

http://www.otherpower.com/images/scimages/231/pulsecrg.GIF

This is the watgas.gif...not sure why it's named pulsecrg.GIF.

[Jerry]

Thanks ZAP.

OK my bad. That is the circuit I use. For safty I add an isolation transformer at the AC input.

2 microwave transformers back to back work very well. This limets amperage but with fans on the tranys they stay cool enough. A 1500 transformer (microwave oven) = 12.5 amps so I figure with insertion losses around 10 amps output should be safe? For a 12 volt battery thats 240 UF of cap.

I use 12 of the 80 UF-440 vac = 960 UF on my E-truck. This is on a 120 VDC battery bank. After my trip to work or back to home the amp metter reads 12.5 amps at initial plug in. just 2 amps at te end of the day. End of day battery bank voltage of 144. I think as the battery bank voltage goes higher more UF in cap is requiered.

It seems to take less cap UF when charging indevidual 2 volt cells.

Its not hard to collect 6 or 8 of the 35 to 40 UF motor run caps dumpster diving at the HVAC shops. They just through them out anyway.

                        JK TAS Jerry

[margusten]

Very interesting desulfator.

Only capacitor and diode bridge. Hard to find this big transformator. We have here in Europe 220V AC available.

I think AC welder can be used as transformer. I have one capable up to 160A. Never measured output AC voltage. It must be 60V range.

Has someone used this AC desulfator in Europe?

 

[fungus]

Could it be used on 240v?

[bahnfeldt]

hi flux

i have done a bit of mucking about with desulphaters and woundered the same thing

makes me wounder what these battery reconditioner companys do to they batteries they claim they recondition

have heard of a theory that a very high say 1000amp pluse for a very short burst predeeding convertional battery charging , not sure how this achieved have you heard of this before

how many farad cap would you say for a 800amp hr 24volt string

arny

off the grid and still using the toaster