I've seen this question about mounting lithium batteries on their sides - but I don't know what "Lithium HE" batteries are, though he specifically says they are not the same as the 12.8 LFP range.
If possible put them up right; thats what they've been engineered for. But can be done on their side. Note that this is not for the 12.8V LFP battery ranges. Only the Lithium HE batteries.
How does this relate to this battery (link below) - the 12.8-330Ah Smart battery. No good on their side? It would give me enough space to mount 3 instead of 2, based on the measurements I see, appx. 8.1" wide and 10.4" high (if you don't mind me using American measures instead of mm).
This: (https://www.victronenergy.com/upload/documents/LiFePO4-12,8V-330Ah-Smart.pdf) - I have not found anything about side mounting either for or against, but perhaps I missed it? Is there some official white paper on this topic which explains this? Thanks!