[Wavery]

I lived on my yacht for 14 years and depended on 3 banks of batteries and have used every configuration known to man (including series of industrial 2V batteries @ 200# each).

I agree that gel-cell batteries are the way to go for RV use. I have had extensive experience (4 years @ 365 days a year usage) with gel-cells and found them far superior in charging, discharging and ease of maintenance. However, like anything else, there is a down side as the OP poster alluded too.

Gel-cells do not have the cooling capability of "Water" type batteries. Water dissipates heat much better. Therefore, it is critical that a gel-cell battery never sees anything over 14.4V (thus the special charger). If it does see over 14.4V the case of the battery will literally melt and the sides will cave in. I used to see this all the time on charter fishing boats that change over to gel-cells and run their engines all day long, putting out 14.8V.

Most automotive alternators have a maximum voltage adjustment screw on the alternator case somewhere. Just find out where yours is, and turn the max V down to about 14.5 or 14.6. Your trailer batteries will never see over 14.4.

The next time I buy batteries for our TM, it will be 2 - 4D gel cells. They're pretty heavy but they can be mounted standing on end, if I want.