"$180 worth of motorcycle batteries"
" I feel confident that the SLA batteries won't be a problem"
Depends very much on the battery, the failure mode on cheap batteries can be not very pretty. SLA are not supposed to leak, but if overheated with a large load they can, and a common failure mode is to stop working halfway into a dive. Don't know what you can get for $180 where you live, but a lot of places it won't get much. Many motorcycle batteries are "sealed" (maintenance free), but not sealed lead acid or deep cycle.
" I feel confident that the SLA batteries won't be a problem"
Depends very much on the battery, the failure mode on cheap batteries can be not very pretty. SLA are not supposed to leak, but if overheated with a large load they can, and a common failure mode is to stop working halfway into a dive. Don't know what you can get for $180 where you live, but a lot of places it won't get much. Many motorcycle batteries are "sealed" (maintenance free), but not sealed lead acid or deep cycle.