LRDG Wireless set up

[Charlie Down]

Yesterday I got Brendan O'Carroll's new LRDG book, 'Fighting with the Long Range Desert Group' (which is excellent) and found a photo of a Wireless Chevrolet WA with panel on the side that could be a charging switch panel. I have now found 2 other WA photos with the same panel fitted. I have grouped a close up of the panel with the panel partially seen on a 1533X truck for comparison.
The panel has at least one knife switch and I assume based on other charging panels it would need 3-4 to make it work (see attached MKV Panel).
Hanno has suggested that the panel could be a main on off switch and posted the image attached. It doesn't match the original photo but has opened up more questions about the set up.
I've been working on the assumption, based on feedback from various wireless forums that the trucks would need a charging switch panel to manage the power and charging of the batteries. There are so far no known charging panels that fit the photo of the 1533X2 panel, so it has been presumed that it would be relatively easy to make one in a base workshop with a few suitable components that would fit onto a truck. I don't know why they didn't use a standard panel, they weren't the only wireless trucks in service in the Desert at that time. And I imagine they would have access to any if they were available. The early British Wireless trucks normally operated with 4 6 Volt batteries, and a separate battery for the vehicle. 2 batteries would provide the necessary 12 volts and the other 2 would be charged, usually by a chore horse or later on, a PTO driven generator. There is no evidence that the LRDG had that many batteries, although the spares could have been stored in a locker or in a box, ( I need to check the battery inventory) which would make sense as the Patrol was really about escorting the Wireless truck to a position to transmit intelligence back to base, and not having back up batteries would seem like a stupid idea, and the LRDG weren't stupid. It was suggested that the 1533X2 panel used knife switches on the charging panel based on the photos, and that they could be commercial not military. The LRDG did have some Chore horses on their inventory, but not it seems enough to equip all the Patrols and they seem to have been retained by HQ. Sorry for the random ramblings and thoughts. Its a serious test of my limited Wireless knowledge. I also need to stop calling the battery on the side step a spare battery, when it was clearly a Wireless battery in series!