Pulse charging VRLA & SLA batteries.

[mael]

[mael]

I had three batteries pulsed with my homemade pulser. They were pulsed for a total of approximately 20 hours over two sessions.

Initially they were all registering zero on the battery load tester. One would indicate there was 12 V, but when the test button was pressed the needle would drop to zero in a hurry. The others wouldn't register at all.

The long and short of it is that two of the batteries are borderline OK, and one is a write-off. I don't know why one wouldn't respond after 20 hours pulsing.

The other two batteries (3 A/H & 6 A/H) were, as I said, borderline. They fell in the region between 'good' and 'bad.' So they'll work, but they'd be a cause of worry.

I am trying one of those 'borderline' batteries again to see what improvement is possible with my pulser after three goes.

* I have a question:-

If sulphation can be cleared and the sulphur put back into solution - by for example using resonance of the sulphate crystal, would the battery be considered charged? That's a bit obvious I suppose. I ask because I wondered whether using resonance to break the sulphates down and return them to the electrolyte could charge a battery the same way as a normal charge?

I am asking because I wanted to know if it was possible to take a different approach to desulphating batteries and charging them. If the sulphates are returned to the solution in a way other than straight-forward DC charging, and it can be done using much less energy, then wouldn't this be interesting?

[mael]

[AlaskaStar]

[redriderno22]

[mael]

[mael]

[redriderno22]

[AlaskaStar]

[mael]

[mael]

Redriderno22

I just wanted to make something clear about the batteries which may fail.

I meant that batteries I had desulphated and returned to the customer failing.

I wouldn't return a battery as 'good' if it had shorts or if the cells were reacting very slowly or in a strange way. I sort those dodgy batteries out soon after I get them on charge and see how they act after a short and relatively strong charge. (Maybe a quarter of the a/h rating).

* So I mean that it is a worry for me if any of the batteries which I feel are in good condition failing.

Of course at some time one of these will fail... a short can come at any time. I just want to avoid this situation as much as possible. If the customer feels the battery isn't as good as expected then I will assume responsibility and replace it or refund. I don't want people to walk all over me, but I'll be willing to go more than half-way IYSWIM.

[mael]

I suppose what I want feedback on most of all is:-

... It's about my objective of getting the electrolyte into the green zone. ie- getting the electrolyte SG at least up to 1,260.

I think that if a battery has electrolyte which has been pulsede until all the cells are in the green then the battery must be about as good as it can get.

what say you?

* Or am I going to have to tell you the answer when I find out?

[redriderno22]

i agree mael

grt the SG in your batts as high as possible before you turn them over

[mael]

[mael]

It took four more days with the pulser I was using to get all the cells at at least 1,260.

The two cells next to the poles showed the lowest SG level.

The two end cells are at 1,260 or maybe a bit higher and the other four are around 1,300.

I'll take it back and see if it can start the diesel truck it was from.

I feel bad about it. It sure does take time! I am overly optimistic a lot of the time. It is true that some batteries can respond well in a day of pulsing. But it seems more usual for the process to take several days, and in the case of a battery which has been neglected for (?) a long time, it takes a week. The battery which I am returning tomorrow is a 95 a/h.

So on the face of it I don't think I can really grumble about getting such a large battery to such a high SG level.