EDTA

[George]

I have been using some large (500 A/hours) lead acid batteries that were washed out with distilled water, dried thoroughly and sealed in about 1985, for about 6 months now. After refilling with fresh acid they appeared as good as when they were stored during most of this time, but in the last 4-5 weeks they have all (4 X 6v. batteries) lost a great deal of their capacity.

This is very disappointing as I have another 12v. ordinary car battery that has already done about 8 months from the same era and with the same treatment, it seems as good as new still. The 6v ones took about 4 gallons of acid too!

Having used EDTA long ago and having achieved good results, I feel inclined to use this again. However, I cannot find a supplier here in Norwich Norfolk. Everyone says I have to be a business user or I must buy 25 Kgs at least - or 200 pounds cash minimum. Or they say because of these all pervading REGULATIONS, they are not allowed to sell it to me. It's a food additive for heavens sake!!

Does anyone know where I can get a Kilo or so? Please.

Thanks. George.

[HLAH]

"George" wrote

There's an international seller on Ebay who has it.

H

[Stuart Noble]

Anything that doesn't actually kill you will eventually turn up on EBay as a health product.

[meow2222]

Did you use it for long term sulphation or this problem? I would be surprised if your cells are already sulpahted and that were the cause. I assume you've checked the sg of the acid in the cells since theyve gone bad.

NT

[Steve Firth]

Tell them that you want to buy sequestrene, which is a soil treatment.

[Peter Ashby]

If he's selling the powder stay away, that stuff is a bugger to get into solution unless you know what you are doing. Cue memories of standing at the pH meter dropping pellets of NaOH into the flask until the EDTA disolved (around pH8 if anyone's interested).

Peter

[Stuart Noble]

When you see the number of synonyms, it's not surprising common chemicals are difficult to find

[Steve Firth]

Get around that by ordering sodium EDTA which dissolves more rapidly than the acid form.

[meow2222]

that doesnt stop people freaking out when you want to buy it. A chat about the intended app and reasons for it usually works. Just let them know youre not crazy basically.

it looks. Still a minefield tho.

NT

[Steve Firth]

Yeah well, but if you inject it into a vampire it is exploding innit?

[George]

Thanks for that Steve. My local garden centre had some, but it has additional manganese and magnesium added as plant tonic. I rang them and they said they did not sell it pure, but that there was only trace amounts anyway.

Ithink I shall try it after I have made sure the SG is OK. I can't fing my measuring thing. The cells appear to be gassing a bit while on charge.

Regards Gearge

[meow2222]

Will lead acids survive that? They seem to be very sensitive to foreign ions, even tap water is unacceptable.

What exactly is going wrong with these batts? I know the symptoms, but whats causing it?

NT

[meow2222]

NT

[George]

I found the SG measure. All the cells were well over 1.3 SG. the float was out of the acid! I figured that this was because the cells had been dry charged and then filled with acid and then charged a lot, but only enough to bring the level down to about an inch above the plates.

I disconnected the 2 batteries and in so doing noticed that the interconnecting cable had a lot of sulphating round the two common terminals. I tipped out some of the acid and topped up with distilled water. I filed the lead battery lugs and put new greased connectors on where desirable. When I connected them into the inverter it ran on battery only, for some 10 minutes, which was an improvement. (When I first connected then they ran for about 5 hours.) I shall give them a full discharge next time I have time.

Two other of these batteries are connected as a starter battery for an old Fordson Major. As this had exactly the same symptoms, I thought that they had both sucumbed to sulphating because of the long storage. This may not be the case and it may just be poor connections. I have not had time to check out the tractor connections yet. One problem with the batteries is that the pitch round the top has cracked over the years and I have only just got some from a roofing contractor working on our garage. I think the cracks have allowed acid to creep over the top. They are extremely heavy and it is a bit of a job to get them out to work on. Maybe I don"t need ADTA after all!

Thanks for all the comments, sometimes you get an idea and then cannot see the wood for the trees. George.

[Phil Addison]

What's EDTA and what's it for?

Phil The uk.d-i-y FAQ is at

Google uk.d-i-y archive is at NOSPAM from address to email me

[Jim Hatfield]

Ethylene Diamine Tetra-Acetic Acid?

Don't know what it's used for though.

[Guy King]

The message from Jim Hatfield contains these words:

It's a chelating agent - binds to metals (in particular) to prevent their taking part in reactions you don't want them to take part in.

[Steve Firth]

It a chelating agent, it can form a compound with a huge range of metal ions and hence "lock them up" - remove them from a solution. It has a huge range of uses from household detergents to agriculture and in the treatment of waste water to remove heavy metals.