The problem is not getting the batteries to last another few years or not. The problem is doing some 50-80s in a row until there is not enough AHs left in the bank to get you through the next night. Could be only five 50-80s to get like that.
Now you must find shore power to "recover" the battery bank to be able to do some more 50-80s. You need a charger that will be able to do a recovery on your night with hook-ups, which the Iota can't do.
For the big trip IMO arm yourself with another charger that can do the recovery job to use when that happens. Use the Iota for normal situations. Now you won't be stuck.