Pulse charging VRLA & SLA batteries.

[mael]

Sorry for any confusion. I seem to have posted my last post in the wrong thread.

I mentioned I had a battery fail and that I was doing it again for the customer.

My mistake was measuring the SG when the electrolyte was low in the cells.

When I replenished the cells to near the maximum line, the SG went from the green, to half way up the red.

... That's the batt which is now well into the green with the cells at about full. And it took four extra days of pulsing.

The pulser I used was probably averaging a current draw of 2 Amps and the pulse is around 10 - 15 Amps on the setting it is on (Max).

[redriderno22]

can you post any pics of your setup

[mael]

[mael]

[redriderno22]

[mael]

I have recently returned and re-installed the two batteries in an electric wheelchair for a friend.

They were five years old and when I tested them after they had been charged and left for a day the V was 12.5 in one and 12.6 in the other. They were in good condition for their age I think. the lady who owns and uses the wheelchair always charged the batteries via the on-board charger every time she went on a trip.

They could struggle on for a bit longer in that condition, but I wanted to fix them for her, so I pulsed them for about three days. When I returned them the V was around 13 V each. That was after 12 hours of resting. I pulsed them in parallel.

They were rated at 38 A/h, and after I pried-off the lid and got at the cells I poured in around half a litre of distilled water to get the cells just covered. I needed to add a few drops to a few of the cells during pulsing, but at the end the cells were evenly soaked, but not covered. i think this is about right.

I used contact adhesive in this case to re-attach the plastic strip which covers the cell openings.

I wonder how long these will last? I intend to test them again in a year or two. I reckon they must be good for another five years if they are pulsed and maintained with electrolyte. I intend to pulse them for a few days after two years has elapsed.

*

I'm also doing a battery for myself. It belongs in a 500 cc bike I rarely used, but I need to get it running so I can take it to the bike shop to have a worn tyre replaced.

I didn't even bother to try to start it. It has been sitting there since the spriing and before then it was only run once a month or so.

I had charged the battery manually once before. But this was just a straight DC charge.

The V was 12.03 when I got it on the bench. It is rated at 12 A/h, and the top was particularly difficult to remove. But 'coz it's mine I wasn't worried about the apprearance, so I prised the top off and I'll worry about fixing the mis-shapen lid back when I'm done pulsing it.

So - same rigmarole as always with VRLA batts ... fill the cells so that they are just covered and keep an eye open to make ure the cells don't dry out too much during the process of rejuvenation.

My battery was severely sulphated. The cells were all covered with a snowy-white fuzz of crystals.

My m/cycle battery isn't finished its dose of pulsing yet. I'll take it off tomorrow evening. But I wanted to report that after 12 hours of pulsing the cells had begun to be visibly clearer of the sulphation. The plates were becoming distinguishable from each other and the colour of the plates was turning brown.

Now after over 24 hours the plates look 'clean.' The plates are not dark brown and dark grey. - Looks like another winner.

[mael]

*Correction.*

"The plates are not dark brown and dark grey"

I meant that the plates were now dark brown and grey.

[redriderno22]

mael

can you e-mail me

id like to help

redriderno22 @ yahoo.com

bring it all together to make it work

[mael]

That 12 A/h VRLA battery of mine which is about five years old is now 13.05V.

I tested it again after more than 24 hours had elapsed.

That seems like it would even pass the rigorous 'load' test for a new battery.

Hmmm! Three days!

That's 'kin' great!

[mael]

I put the 12 A/h battery back in the bike today and it was fine. As I hadn't used the machine for months it was difficult to start. I cranked the 500 cc engine for over half a minute in total and it would have cranked a lot more.

And I went shopping and decided to check the price of batteries in a cheapo have-everything shop. I was surprised as they are expensive. ie - an 80 A/h SLI was around 18,000 Yen. That's gone up a lot since I last looked a few years ago.

- And I (want to) sell (more) rejuvenated ones for two or three thousand! -

So there ya go kiddies! My battery would have cost me about 20,000 Yen as it is supposed to be special. Rip the tops off and pulse them and save heaps.

* I re-sealed the plastic top by 'stitching' it around the edges with a cheap screwdriver heated by a small propane burner).