Good advice above. These units started with a dual 12/24v 100a alternator that as folks have mentioned was overloaded trying to maintain the four batteries in 2 in series-24v banks. Over the years they tried several different configurations. I believe the mid 90's units had a polarity unit between the batteries and alternator. Our mid aughts unit replaced the polarity unit with capacitors (LBCD) and remote disconnect relays to protect the 100a alternator.
Adding 4 new AGM's is likely not the best idea for your existing system as
@GeneralDisorder mentioned. Most folks are dropping to 2 AGM's and that is easy to do with the existing wiring.
With our M1078A1 we also hope to do some off road camping so are in the process of 'upgrading' our cab and chassis wiring before adding the habitat systems. Here is a simple schematic of what we have accomplished so far, a
link to the thread here on SS.
View attachment 920420
We are separating the 2-in series 24v banks uses: bank 1 will run the existing cab and chassis plus power windows, door locks, usb charging ports, etcetera; bank 2 will run our 24v cab AC, two way radios, gps, etcetera. Our habitat LiPO4 batteries will be entirely separate, though we may add a special Victron balancer that is designed to manage separate AGM and lithium banks between habitat and chassis.
So far we have replaced the dual 12/24v 100a alternator with a 24v 200a adding a Victron 24/12 70a DC to DC between X1 and X2 at the PDP to provide 12v; and removed our LBCD and disconnect relays.
Welcome to the forum, it is an adventure in learning.
@Ronmar and
@GeneralDisorder know far more than most here.
@MatthewWBailey just replaced his alternator, too, if I recall correctly—