Re: Idiots guide to battery change

John38 wrote:
On Tue, 18 Jul 2006 16:08:30 +0100, Gibbo <gibbo@xxxxxxxxxxxxxxxx>
wrote:

If you have a decent charger you could try equalising them. Don't fanny around with the gentle approach as recommended by the charger manufacturer. Just bang 16 volts on the batteries for a few days. And keep an eye on the water levels. If anything is going to get rid of the sulphate that will.

Won't very fast charging buckle the plates?

Well, there are a few points here.......

1. Plate buckling happens as a result of *very* heavy charge/discharge currents. The actual voltage is irrelevant. Deep cycle batteries don't suffer from it to such a dgree as engine start batteries. This is *partly* because the internal resistance of deep cycle batteries generally is higher which therefore limits the maximum charge/discharge current to a level which prevents plate buckling.

2. Equalisation should always be done *after* the batteries have been fully charged (or rather charged as high as they will go). So there won't be any high charge current.

3. Putting 16 volts across the batteries bubbles the electrolyte so much that the bulk resistance of the electrolyte becomes very high (as it is full of gas) therefore no high charge current can flow. 16 volts generally produces a much lower charge current than 14.4 volts because of this.

4. The batteries are badly sulphated up. Until this is sorted they won't ever accept a high charge current.

5. They're already knackered. Equalising *may* get them back to life. But if not, nothing has been lost.

--
Gibbo

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