Hilux 4x4 Forum

Hi guys, I have a badly sulphated battery that won't even accept 0.5A charge rate. The thing is that the battery was bought new just a little over a year ago but was left standing after the last use at about the same time (my bad, It's the bike battery in the TW and I use the bike to move from one area of a farm to another when hunting).

Anyway, after doing a fair amount of on line research, I have come to the conclusion that the most effective way to restore the battery is to use a pulse charger, preferably one that makes use of a high pulse frequency without excessive voltage but a decent amperage.

I've looked around and can't find anything that really appeals to me IRO of what I have researched. Perhaps my research wasn't comprehensive enough or not sufficiently in line with industry norms. So I'm at an impasse .......

I could just replace the battery, not overly expensive, but I have a number of vehicles and can only use one at a time so they tend to be under used and those batteries are facing the same problem. An investment in a decent intelligent charger with pulse capability would therefore seem prudent. (I have other chargers, but not 'intelligent' and not 'pulse'.)

What are your experiences with de-sulphation and are pulse chargers like the Benton BX2 and C-Tek effective?

Thanks.

Andy my Hi-lux staan 90% van die tyd. Ek ry bitter min rond met hom. Ek het permanent n Benton BX2 laaier op hom en die battery hou al 6 jaar sonder enige probleme.

^^ Ditto.

As per our telephonic discussion last night, the intelligent or pulse chargers can only do so much and if the battery has built up a resistance to charging through sulphation, it is likely to only be useful as a doorstop.

As it is a small battery (you do not state amperage) then I would suggest to leave it on a charger, even at >0.5A for 24-36 hours or so and see what happens. As stated, the BX-2 might be an overkill for a bike battery but it is designed to operate on batteries of capacity ratings from 14 - 240A.


-F_D

Thanks guys. Will try the Benton.

Andy... I've read that you can restore the battery by pouring out all the acid and replacing it with a Water and Epson Salt solution (not sure of ratios) and then hooking it up to a constant charge.

Okay seems you will need baking soda as well
https://www.youtube.com/watch?v=AcE7ErS-Pl8

Another good one to check https://www.youtube.com/watch?v=Br5Wd5w7jI0

I built a battery desulphator some time ago. The problem with the suplhated battery is that the internal resistance is very high and normal commercial chargers cannot overcome that. This charger works with a very very low current but quite a high voltage. Actually the voltage will increase until the internal resistance is overcome and then the theory is that the pulses cause the lead sulphate crystals to break down. I have had some great successes with batteries similar to what you have described. I once completely recovered a 105 A/h deep cycle battery for a colleague that he left uncharged from new. He was very impressed. I have found that on some batteries the crystals breaking down can actually cause a short circuit between the plates in which case it is all over. This is more often the case with older batteries. It is quite a simple circuit to build but you need to make your own field coil which comprises of three field coils "interwoven" and the other problem is the transformer wire is the cost of a new battery.

Thanks Cassie, I haven't read your links yet (will do so later) but I saw the epsom salt thing and I think it does very little IRO desulphating the battery. I think it's so called success is more about stepping up the conductivity of the electrolyte. Emptying the battery and flushing after letting it stand for a while with baking soda might help to break down the sulphation but I have to wonder what it does to the plates .... might end up doing more harm than good.

Marnus, thanks for the input, yes I have read about what you speak of and there are some guys that appear to have a reasonable rate of success with capacitors, bridge rectifiers and high voltage. The capacitors (if connected on the AC side before the rectifier) will release as much as the conductivity of the battery can handle and diminish as the resistance improves, but it can be a dangerous exercise if you touch the live clamps without the battery connected. Those capacitors might kick you into next week if not into oblivion - that's heart stopping electrocution right there.

I think I'll get the Benton in any event and give it a try - if it doesn't work I'll still be using it on the other vehicles anyway, so it won't be an exercise in wastage.

I have built those with the capacitors and the rectifier but they are limited to 50hz. Then there is also the issue regarding the safety as you have correctly mentioned. The one I built runs off 9 volts DC and is completely safe. Basically you send an opposing current between two field coils. The opposing magnetic fields start oscillating and the resultant voltage spike caused by the breakdown/collapse of the magnetic fields is inducted into the third coil. This ac voltage from the third coil is then rectified using high voltage diodes (600v if I remember correctly) and provides a high voltage but very low current dc pulse which is connected to the battery. The desulfation process takes very long with this charger but it can and does work.

Here are some pictures of the coil and the "winding machine" I built.

Mars wrote: ↑Thu Jun 15, 2017 7:28 am I have built those with the capacitors and the rectifier but they are limited to 50hz.

Purely out of interest, correct me if I'm wrong, but household AC is 60 Hz and then doesn't the bridge rectifier double that on the DC side, ... i.e. 120 Hz?

No Andy.Our electrical supply is at 50 htz.

Supply in SA is meant to be 50Hz

Frequency is not really doubled, the latter half of the sine wave (180 - 360 deg) is just inverted, the period from 0 -360 is still 0.02 sec.
In essence it is then not AC anymore, rather a pulsating DC as the current is in one direction.

or something to that effect

OK, 50Hz AC then. But still, isn't the DC pulse in effect doubled ....... i.e AC = 1 forward and one reverse 'pulse' (0 - 360°) which becomes two forward pulses DC rectified (0 - 360° + 0 - 360°) ? ........

Just to update on the battery ..... I got the BX2 and connected it after checking the electrolyte levels - they were all still fine but one cell showed an area of whitish discolouration on the cell wall (it's a white opaque battery casing) - wonder if that's sulphation or lead oxide deposit.

Anyway, when connecting the BX2, three of the red lights started to pulse (indicating state of charge, low / half / full) ... the fourth marked (!) didn't light. The pulses were fairly rapid and short, but within a ½ hr they were a lot less rapid and longer. So it seems there might be some hope to recover the battery.

So how are things going with the battery?

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It would seem that the Benton was unable to recover it. It kept pulsing for 4 days without improvement in the state of charge. Could well be that the sulphation has bridged plates in the battery in which case it's FUBAR.

At the end of it all I'm gonna toss the battery and thought I'd try the epsom salt trick - nothing to lose anyway. It didn't help at all even though I put it on the Benton for 36 hrs. In fact I think it became worse - after the initial 4 day charge the battery read 12.10 volts and after the epsom salt and charge it read 11.58V. Forget the epsom salt "trick", it doesn't work to recover a buggered battery.

Im sorry it did not help. Thank you for the experiment info tho.

It seems to be a great charger tho.

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