Sunday, 21 November 2010
I have the power
It seems like it was an age away now but back in the summer I bought the battery from an electric fork lift truck.
It was 48volt, made up from 24, 2 volt cells wired in series like this one
The steel box they were in was split and rusted and the first job I had was to cut the copper links joining them together and lift them out. Easier said than done as they weigh 28kg each and were packed in like sardines. When they were first installed in the box, they were dry, then the water was added. That weight of that water causes the casings to spread and makes it almost impossible to pull them out. Once out, they spread and the water level drops inside causing the lead plates to be exposed, so they cant be left in that state. I made a plywood box in the new sixe and shape needed to fit the space in the engine compartment where they will need to go.
So, I made up temporary handles from insulated wire, twisted round the two poles and lifted them very carefully using an electric hoist. They stand 28'' high and I couldnt lift them manually over the sides of the steel box. I cut off the remainder of the copper links, removed the auto top up tubes and drilled down into the top of each post to accept a threaded insert which has a 6mm thread inside.
For almost 4 months they have been patiently waiting for a new home, not quite dormant, occasionally belching and bubbling hydrogen gas as they slowly discharge. Getting them installed in the new configuration and back on charge has been the priority goal but ive had to delay untill the engine room was weatherproof.
By last monday, things were finally ready and I took them out of the ply box, took the box apart so I could fit it through the wheelhouse floor framework and put it back together. Then I started the painful task of carrying them out of the shed, into the wheelhouse and lowering them into the box.
Its bad enough having to do it once as they weigh almost three quarters of a ton, but once they were all in, I noticed the base of the box was sagging and there was nothing for it but to take them all out, strengthen it and replace them again.
It was an all day job and when it was done, so was I.
It agrevated an old back injury and I needed two days off to recover.
I bought a length of copper bar, 5mm x 19mm, measured the distances between the poles, drilled holes and cut to length to make the links which go between the cells so I can make up 4 strings of 12v batteries comprising of 6 cells each.
Today ive bolted all the links up and sealed round the tops of all the cells to prevent overspill of water from the cell tops. This is what caused all the corrosion and mess in the old steel box, and I certainly dont want acid swilling around the engine room bilges.
Nest step is to get them on charge.