I have 3 lead acid 8 D's
Each of my Cat 3208s has a dedicated starter 8D
1 is house and supposedly "deep cycle"
My charger is 2 Xantrex 40 amp TrueCharge 2's wired to provide 80 amps.
This charger charges all 3.
It's time to replace the house bank.
Question is, if I replace the current house 8D with 2 6V golf cart lead acid batteries in series, would this still be compatible for the charger?
Thanks
AS others have stated, your charger will have no trouble with what you propose.
I have the same boat with the same engines as you. I completely re-engineered my battery bank and charging design earlier this year. I now use 6 205 AH GC batteries for the house bank and one 8D for starting both of my 3208s. I also have one FLA Group 27 for my genset. All are flooded lead acid and were purchased new by the seller a week before I closed on the boat in May 2019 (the old batteries were no good due to a failed 1992 vintage charger).
I ditched the factory battery isolator and in it's place is a Blue Sea Sytems 500 amp ACR between the house and main starting banks so that both are charged whenever either bank is being charged. The ACR also allows me to parallel both banks from the helm if I need to augment my 8D starting battery. That said, my Tolly 44 had a factory "Start Assist" feature that paralleled the house and starting bank from the helm before I by-passed it in favor of the ACR for the same function.
I have a Promariner 1250P 3 bank 50 amp charger that is connected to the main starting battery, the house bank, and the genset battery. My Xantrex Freedom 3012 inverter charger also charges the house bank, but it is throttled to 100 amps to keep the charge current from damaging the house batteries. When the house batteries are in need of bulk charge, I only use the inverter to charge them.
When my FLA batteries are worn out, I intend to replace them with AGMs to allow faster re-charging. With AGMs, I can run the Zantrex at it's full 150 amps and Promariner at 50 amps at the same time, without damaging the batteries. This will dramatically reduce charge time.
I'm in the midst of rebuilding my engine room battery tray right now. It was pretty tired after 30 year. I may try to slide it to starboard a few inches to help with my boat's natural list to port.
If you'd like to discuss any of this, feel free to IM me. I learned a ton while coming up with my new design and I am pleased to say it worked better than anticipated all last year.