How much real fire hazard

[alex trent]

Thanks for the comments.

I was in the States and hunted down a hard plastic box that will fit three of my AGM 31 batteries just right. It likely is not the real deal for batteries..more for storage, but is hard plastic not the soft kind. It is transparent so I can see what i going on. 

I am going to vent it passively with 3" PVC near top and some 1" inlet hole about 3" from the bottom . That should take care of and gassing...though supposed to be little with AGMs. Be around when charging. The floor is ceramic tile so I have some backup there on the rare occurrence of a leak cause by cracks.

I like the plastic better than steel because of the acid and this means i will not have to drill my good steel storage box.

I have a small bottle of mixed bicarb in the vicinity and will mix a big one as stand by...outside.

Now, all I have to solve is why my battery is not fully charging...I also have a voltmeter so can trouble shoot better now and not rely on the inverter meter.  Still need to test against a known good battery to see if I could have a bad AGM.