Is it viable to restore a vintage accumulator?

[SurreyNick]

Hi

I have acquired two vintage accumulators. A Magnet BC114 by GEC, which may be a gel-cel, and an Exide DFC (pics attached).

Has anyone restored an old accumulator to working operation? I'm employing a 2v Cyclon for my battery operated set, but was wondering if it is viable to restore an original accumulator to working operation.

Thanks

Nick

[mole42uk]

It is possible, but hazardous and messy.

I restored a large quantity of old PO telephone exchange cells few years ago. These were 2V glass-cased cells, I don't remember the capacity but they were previously used to run a rural telephone exchange during power cuts.

The technique I used was to remove the old acid and dispose of it, then wash out the cell to remove the deposits at the bottom - a very important step. I refilled with new acid, diluted with water to the correct specific gravity and added about half an ounce of EDTA (Ethylenediaminetetraacetic acid) which is used to dissolve excessive sulphate deposits on the lead plates. The cells were then trickle charged for about a week and put into service. They lasted only a year or so in regular service so it probably wasn't worth it in the long run, but I learned a lot about battery chemistry!

[hansomcommon]

Your Exide looks highly saveable, following Richards excellent technique should have it back working for years. The other cell less so.

[Refugee]

Old cells can also be converted to alkaline.
http://blog.hasslberger.com/2007/01/..._acid_bat.html

[G6Tanuki]

Any lead-acid cell that's been left discharged for a long period will have undergone significant chemical-change to the active material on the plates - as well as the usual 'sulphating' the spongy lead that actually does the work can mechanically deteriorate in a way rather similar to the way old foam-rubber crumbles.

It then detaches from the solid-lead support grids/baskets and ends up in the bottom of the cell - if enough of it does this it can short the plates out.

[Even new-but-unused batteries can suffer this: in the early-1970s I acquired a number of 2-volt 16AH cells made by "Pritchett & Gold & EPS Ltd" - they all had original manufacturer's seals on them and came in military-standard packages with production dates from the 1950s. Following the procedure printed on the side of the case I filled them with acid [scrounged from one of the lab-technicians at school, who made sure the s.g. was correct] and charged them again in accordance with the instructions.

They worked just fine - for about six months, after which they rapidly lost capacity. Eventually I washed one out and a good cupful of light-grey powdery sludge came out. Cracking the case showed that around half the active material had separated from the plates and in places you could see right through them!]

I'd suggest washing your cells out and if much in the way of 'sludge' comes out you may be on to a loser. Remember that the sludge may have set in a lump at the bottom of the case and so be un-shiftable without breaking the cell apart.

[mole42uk]

Originally Posted by Refugee

Old cells can also be converted to alkaline.

Snake oil? My detector is receiving some signals.....

[broadgage]

Agree, snake oil.
Firstly if it was that easy everyone would be doing it.
Secondly, I know of no reversible chemical reaction involving lead plates and an alkaline electroylyte that produces 2 volts per cell.

[audion_1908]

I like the Exide cell with the built in charge level indicater, when I was at school I built a lead acid cell that worked well, if you take it apart I would love to see how the charge level indicater works, I know it is some type of hydrometer, I think if an old lead acid cell was stored dry it could be revived. interesting project

[pmmunro]

As lead acid batteries are not as common as they once were, it is probably worth repeating a warning on acid dilution to anyone who gets to this stage.

Mixing sulphuric acid with water evolves a great deal of heat and can cause localised violent boiling with a high risk of splashing onto anyone or anything in the vicinity. For this reason the concentrated acid should always be added to water, not the other way round.

PMM.

[SurreyNick]

Very good advice, and something I shall bear in mind if I do decide to have a go at reviving it. Thanks.

Originally Posted by audion_1908

if you take it apart I would love to see how the charge level indicater works, I know it is some type of hydrometer

If I elect to have a go at reviving it, I'll be sure to let you know
Nick

[TrevorG3VLF]

When diluting acid,
Do as you oughter,
Add the acid to the water.

Lead is nasty stuff, I would not play with mush out of the bottom of a lead/acid cell. How are you going to safely dispose of it?

[Radio_Dave]

I took one of these apart a couple of years ago and it was a useless, crumbling mess. I believe they were originally supplied dry, so it might be worth keeping an eye out for an NOS one?

David

[SurreyNick]

Originally Posted by TrevorG3VLF

How are you going to safely dispose of it?

If I do elect to have a go at restoring it, I will contact SITA and/or the HSE about disposal of any lead contaminated waste that is produced. Thanks for the warning, but I am quite familiar with the safe disposal of hazardous waste

Originally Posted by Radio_Dave

I believe they were originally supplied dry, so it might be worth keeping an eye out for an NOS one

If anyone ever sees one please let me know. I'll have it in a flash
Nick

[audion_1908]

New plates can be easily cast for old glass cells to get them 100% working, just have to be careful with all the hazardous materials!
if any one has a vintage accumulator with an inbuilt charge indicator I would be interested in buying

[AC/HL]

One post moved to a new thread here: https://www.vintage-radio.net/forum/...d.php?t=106442

[broadgage]

Whilst new plates can indeed be cast, the capacity thus achieved is likely to be a very small fraction of that originly available.

Even basic batteries tended to use plates cast in a grid pattern into which the active materials were pressed or pasted.

A home made plate of plain lead would work to an extent but be reliant on the thin film of active material that forms naturaly when first charged.
Each charge/discharge cycle slightly increases the capacity.

The casting of grid patterns is rather innvolved, as is the application of the active materials. Probably beyond what most people would attempt in a home workshop.
If you try it, please take great care as lead compounds are highly toxic. Pure lead is relatively safe, but fine powders of lead compounds are more of a risk. Any gas/vapour/or fumes released from the melting of lead are potentialy dangerous.

[AC/HL]

Originally Posted by audion_1908

if any one has a vintage accumulator with an inbuilt charge indicator I would be interested in buying

I had one, a barn find with a damaged top and a dried-up lump of decomposed plates. When I tried to salvage the indicator, just a hinged pointer which hovered submerged in the acid, it just crumbled. A lifetime in sulphuric acid is not good for early plastic!

[Bob_Moss]

Detailed instructions on how to repair accumulators is given in Odham's wonderful "Radio, Television and Electrical Repairs" page 469 onwards. If you haven't got this book (every home should have one) I'll try to find time to scan the relevant pages tomorrow.

[SurreyNick]

Found a copy on Amazon. Will read with interest. Thanks.
Nick

[audion_1908]

I found a copy on ebay, and will be interested in accumulators repair section, I have not made a lead acid battery since I was at school!

Originally Posted by AC/HL

I had one, a barn find with a damaged top and a dried-up lump of decomposed plates.

shame better luck with the next old!