In most applications, batteries are installed in an upright position, but in some situations there is a need to tilt them (sometimes at very extreme angles) or lay them completely flat on their backs.
We usually supplies AGM batteries (Maintenance Free type) with separate acid packs that you must fill (and charge) yourself. We do not recommend that this type of battery be installed on it's side, or even an extreme angle, due to possible leakage occuring.