The last time I removed the battery pack there was a split in a weld at the rear of the battery pack. I decided to quickly stick weld it up but due to the unlucky position of the insulation there was a gap and one cell got a hole in it. I had to remove the whole pack then cut the battery out and weld the battery case up with a glue gun (my favorite tool).

When working on the battery pack I really must remember to keep the vent pipes on the vacuum pump otherwise a Hydrogen explosion is going to happen.

The batteries are constantly producing Hydrogen and Oxygen gas, especially after a water refill. This is because when the water level is raised the acid connects two regions of lead in the battery in different states of charge. (the top of the cell is at lower voltage than the bottom) This produces current from top to bottom of the plates and makes a lot of gas. I discovered this last time when I switched off the vacuum pump while waving a blowtorch around. It ignited the gas and blasted the tops off 18 cells! I had to use the glue gun for about 3 hours that evening to get the van running for the next morning.

In fact I am looking for a vacuum pump that can run continuously to clear the gas.

It has to be able to cope with acid vapour.This video is of an early method of filling the batteries with demin water. I have switched to an Edwards EDM12 with a vacuum regulator.

In between servicing the battery pack every 3 months driving the van is very enjoyable.

The main problem is time. I use the van every week day for commuting to work so the servicing has to be completed in a weekend. This is not easy because you normally find problems when the battery pack is removed. Whatever I discover I have to deal with in a few hours. This is much harder in winter because of the dark short days cold and rain.

Getting the whole battery pack out has only been possible since summer 2007 because I was designing a rail system to carry the 1000kg of battery. What I came up with I am quite pleased with because it allows easy re alignment with the three mountings. And was cheap to make.

This is the usual procedure.

0)Remove the rear wheel

1)Disconnect the battery wires and vent pipes

2)Position the U rails 1m apart parallel under the battery.

3)Using 4 trolley jacks raise the battery

4)Remove the holding pins

5)Lower the battery onto the rails

6)Slowly pull the battery out with a pulley and rope

7)Connect the vacuum pump to one vent hose

8)Put the other vent hose in demin water barrel

9)Allow 18 batteries (1/2 pack) to fill until water flows into the glass jar.

10)Fill the other 18 batteries in the same way.

11)Clean the battery tops of dirt oil mud and acid

12)Fix any problems found

13)Push the battery back under the van using your foot

14)Using the jacks raise the battery

15)Refit the locating pins

16)Remove the jacks and rail system

17)Reconnect the battery cables and hoses

18)Do a test run round the block