The LDG Z11 PRO II Auto Tuner has solder pads on the PCB so that it can be adapted to be used with internal battery supply which is handy for portable use.

I choose an 8 AA cell holder for the job. Unable to source a flat side by side holder from the likes of Maplin I turned to ebay and imported one from HongKong (ebay seller andrew_lau). Quality item and cheap as chips @ £2.71 delivered to the door within the week.

I used two Velcro pads to secure the holder to the top of the relay banks. There is plenty of height inside the case to accommodate the battery carriage and the lid fits back on and clear of the holder. Soldering is simple as solder sucking the pads to reveal the existing holes, feeding through the battery holders fly leads and soldering.