Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 10, 2025 ...

The batteries are two years old.

That is not a good thing either.  The next step is to charge them up, move your coach into storage is disconnect the ground lead from those batteries.  I use plural because I'm assuming that you have two or four T 105 batteries powering your house.  It's really only one ground  wire.  If, after 24 hours the batteries have lost their charge you need to have a talk with Trojan.

Randall, there are two main types of lead acid battery construction.  The more common battery is a Starting Lighting and Ignition battery, one meant to deliver electricity on big torrents for a short period of time.  The less common Deep Discharge battery can deliver lower amounts of current to a deeper state of discharge without sustaining damage.  Your Trojan T-105 batteries of true deep discharge batteries with solid lead plates and a space underneath the plates for the material shed during normal operation to accumulate without reaching the bottom of the plates.

If after 24 hours you find your disconnected batteries in a low state of charge, well, sorry?

Understood. I plan to move inside tomorrow, whereupon I can charge the batteries by shore power. I will then disconnect ground and see what happens. I have six Trojan T-105s for house and two Interstate for chassis.

Again, many thanks for the help and insights.

I had been so focused on replacing my current pair of 4D batteries with a pair of Interstate 8D I never considered doing the math for 6 T-105s. 
The latest change in plans has been the addition of an oxygen concentrator and Bi-Pap machine.  So time to re-think power storage needs.

With wet cell or AGM's, you can use about 30% of the Ah capacity before needing to recharge, to maximize battery life.  With Lithiums, you can use about 80% before needing to recharge.  So a 100Ah lithium has 80Ah of usable juice, where you'd need a 260Ah lead acid battery to have the same 80Ah usable.  Lithiums are more expensive as well.

AGM vs wet cell - you don't have to worry about AGM's cooking off the electrolyte like you do with wet cells on a constant charge.

That's what I've gathered so far anyway.