That was my plan, but I too am out of XLR's. As all my batteries are identical I incorporated the diodes into the charger cable, which needed extending anyway. They are mounted on a bit of stripboard encased in a short length of plastic tube, the ends closed with shrink tube. The diodes dissipate about 1/3 of a watt each so I cut some slots in the tube for ventilation.I might make up an intermediate jumper lead incorporating two or three for discharging the 33 cell battery. Got a line socket, but run out of XLR plugs, so another raid on Maplins due!
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Another round tuit dealt with.