I went down the path of 4 off slim deep cycles mounted 2 per side over the rear wheel well. They were 100a/hr each. They ultimately all failed from the same condition, which was cell collapse. The batteries I chose were more suited to stationary standby/float condition UPS installations and I believe did not cope with the vibration and thumping around. The cases all developed bulging and failure mode was very quick and all dead within 3 months of each other. The style is shown below, but it was not this brand. The brand shown actually appears to have a more robust construction as its rated for 4WD/camping and has a 5 yr warranty.


https://www.ebay.com.au/itm/KICKASS-...8AAOSw-YZa4SKj