Lead acid Positive plates problem

Oh yes. You can solder lead easily.

IIRC batteries are 'burned' rather than soldered, using lead not solder.

Wiki fwiw: 'All intra-cell and inter-cell connections are of the same lead alloy as that used in the grids. This is necessary to prevent galvanic corrosion.'

NT

d out, dried and sealed in the 1980's I shipped about 100 back to UK from the Oil Company in the United Arab Emirates. Some time ago I heard about us ing Alum, - Aluminium Sulfate as the electrolyte and I got about 30 - 40 ce lls working, OK.

out with rain water and some I actually removed from the plastic container s to clean out the sediment that I thought must have stopped a few of them from working. When I got them apart I discovered that some of the positiv e plates had broken off where they were all connected together and where th e fat lead terminal went up to the top of the case. They had all fractured at the same place, although the rest of the plates including the negative ones seemed in very good condition. Only about 6 or 7 have fractured like this and I do not know why. The other question is how do I repair them. I can easily get at the fracture and I have filed the faces back to solid lea d but I wonder what is the best way to repair them, providing a low resista nce joint again.

ing point than pure lead? If so, it will be fairly straight forward. the ot her way might be to drill small holes and clamp the pieces together with st ainless nuts and bolts. The electrolyte is probably not going to effect t he materials. Has anyone any thoughts about this before I start to experim ent. I am going to make up a bank of cells to feed an inverter to provide a no break supply for a house. or to charge up during the day from my solar array, (4Kw)

You need a high tin solder. This reduces the melting point to below lead. And a large soldering iron.

I assume there is no actual sign of the joints corroding or having melted due to current drain or anything like that. It is indeed odd they have broken if neither is the case. Brian

Yes as to lower melting point, depending on the solder. (Though the electrodes may be a lead alloy). Solder comes in many different formulations, so check.

It sounds as if the plates are accessible -- so look at "welding lead". From a glance at some youtube videos, it looks as if it needs a small and hot torch, to heat quickly while limiting the melted pool, and a filler rod. A spare plate would provide filler of exactly the right composition, and avoid any problems of introducing new materials into the plate and the chemistry.

Welding would be easier if some kind of form-fitting dam or backing is possible

-- silicone moulding, possibly?

Or is recasting the plates out of the question? (I ask because I've read of some of your rebuilds, and the seemed comprehensive...)

Thomas Prufer