It's not a link 2000r . We had that but replaced it.... Now we have a link-lite battery monitor and I guess a Link 2000. And these are AGM batteries.
By the way, when the batteries are discharged, the generator (through the freedom), will charge at more than 20 Amps....maybe up to 50 Amp for a while, but it is always less than the engine, and it backs down to a low charge rate much quicker than the alternator does making it take many hours to get a good charge. It makes the generator way too inefficient.