The two books
you referenced are excellent sources.
A couple of notes on your other recommendations.
1. AGMs are great for SOME but not all marine
applications. They are the absolute WORST choice for many boaters, expecially those without adequate charging
sources to bring them to FULL CHARGE frequently;
2. You can't just use "any fuse" to connect to these batteries. You can only use one of three types: AGM, MRBF, or Class-T. Other common fuses don't have adequate Ampere Interrupt Capacity (AIC) for direct connection to house batteries.
3. Fuses should be installed very close to the batteries....ABYC specifies "within 7 inches" unless protected by conduits or special sheathing, in which case the fuses can be located up to 40 inches from the batteries.
4. AGM batteries at 40% discharge or even at 60% discharge will have voltage much higher than you mentioned. If you see 11.0VDC the batteries are very nearly DEAD and should never be this deeply discharged.
The attached graph shows the voltages and State of Charge (SOC) for AGMs and Gel batteries (red line) vs. Flooded batteries (green line).
With 860AH capacity, you'll very likely get more than that because of Peukert's effect. The capacity is established at the 20-hour discharge rate which would be an average discharge of 43 amps, or 1032AH usage per 24 hours. Very few cruising boats draw anywhere near this much amperage, more like a quarter of that or even less. Thus the effective
AH capacity is a lot more than 860AH.
The lifeline AGMs you mentioned are excellent batteries. A couple of years ago I did some longitudinal research on this specific battery
, together with Concorde -- the manufacturer -- and with two other colleagues. Just be sure you charge them with AT LEAST the recommended voltages and that you bring them to FULL CHARGE frequently. This takes many hours, no matter the size of your charging
The attached graph shows the approximate percentage of capacity accepted by the AGM batteries with three different sizes of charger. The blue line shows what a 190% capacity charger would do (in your case, a charger capable of putting out over 1,600 amps!!). The red line shows what happens when the charging source is about 25% of the battery capacity, or 215 amps in your case. Few boats have this much charging capacity.
Notice that no matter the size of the charger, battery acceptance during charging drops considerably after an hour or two, and it takes several hours to get anywhere near 100% full charge.