BB. wrote: »
I would guess that most (all?) modern UL/NRTL listed batteries chargers are isolated by transformers from the AC line (Hot/Neutral and grounds).
woodrose wrote: »
When you get one or 2 batteries underperforming out of 16 the better chance is that one way or the other they have been abused. In my case I suspect it was in the original shipping. Another way is if all the batteries weren't shipped from the same lot and some might have set uncharged for a while.
From my experience (bad) only buy a battery set that was shipped direct from the factory.