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

I just saw this thread from a week ago.

So the real answer is that any battery is just an chemical/electrical device, which, like a tire, does not have an infinite life. If abused, the useable life of a battery can be as little as one year.

Recharge your batteries to 100% every day to maximize life.

Use a passive desulfator ($25) on each battery to maximize life. Equalizing (controlled over charge) every month will desulfate also but with shorter battery life.

Reset your charge voltage set points after 5 months of desulfation (for an 8D battery) to 0.2 volts higher. The accept voltage for my Gel is 14.4 volts (manufacturer says 14.2 volt), for my AGMs is 14.6 volts (manufacturer says 14.4). For flooded batteries reset accept to 14.9 volts.

I bought 225 amp hour gell cell batteries.  They are 476 a battery now but you also get about 100 bucks a battery for the old ones.  So now it is 376 a battery. They are the same batteries you can get at A & D for 700.

After doing some thinking, asking questions, and reading tech docs, I now have a plan for my own boondocking.

The plan is to get my trimetric 2020 connected, install about 270 watts of solar, and run my generator each morning until the charge current begins to drop from it's 103 Amp bulk. This should bring my new AGMs up to 75% full charge. Then, hopefully, the solar charging all day will bring them up to 100%.

If  that isn't enough solar to reach 100%, my options are to add more solar or run the generator until the charge rate drops to 50A.

What I learned with my week at Quartzite is that my usage without solar required 3-4 hours of generator charging at mostly 100A to keep the batteries in the 50%-75% charge range, and I need to reach 100% occasionally for battery health.

My refrigerator is propane, so battery usage is minimal.

My main power hog was running both propane furnaces, but that was unavoidable.

Quartzite this year was a worst case test. I usually wouldn't have so much furnace run time.

My refrigerator is propane, so battery usage is minimal.

My main power hog was running both propane furnaces, but that was unavoidable.

Quartzite this year was a worst case test. I usually wouldn't have so much furnace run time.

In Quartzsite, we got a chance to test our solar setup in real world conditions. With 1140 watt potential, the panels installed flat and a low winter sun, we saw a maximum of 580 watts peak. Never had to start the generator and the batteries were "full" by noon with the controller switching to "float". Days that were cloudy took longer to reach float.

Caflashbob:
I recommend passive low power desulfators on each battery with leads as short as possible. The reasons are the price and the minimum interference caused for your 12 volt appliances. A desulfator generates a 1 kilohertz signal, a thousand 50 volt 6 amp spikes per second of very short duration. This spike forces sulfate back into solution and off the plates. Low power and short wires means little of this spike reaches the sensitive 12 volt items like fridge controller, AM/FM sterio. High power desulfators are available at much higher cost which will desulfate an entire battery bank, however, the power line to your 12 volt panel must be filtered so the 1 kilohertz signal does not interfere with your 12 volt items.

Do not reset your accept charge voltage until your batteries have been desulfated for several weeks. The safest way to do this is to disconnect a battery and let it sit overnight when it is fully charged. Measure the voltage in the morning to determine how much the desulfation has raised the fully charged voltage, then increase the accept voltage (for charger, alternator, solar controller) by this measured voltage increase.

With only 130 watts of solar, the maximum amps available is 8 and the number of amps you will actually see will be 2amp to about 5 or 6 amps. You could safely connect this to a 600 amphour battery bank without a controller.

The reason that 14.2 volts is too low for a desulfated Gel battery is that the fully charged voltage of a desulfated Gel is 13.0 or 13.1 volts when the manufacturer expects his battery to have a fully charged voltage of 12.8 volts. Charge voltage of 14.2 with fully charged voltage of 12.8 means the charge voltage is 1.4 volts higher then the fully charged voltage. Increasing the charge voltage to 14.4 maintains this 1.4 volt difference.


The solar panels controller SAYS  7.5 during the peak time.  small wires although from the panel to the refer where for a simple installation my mechanic tapped into the 12 volt there. And the controller panel is after that installed below the refer.

I straddled the three MK 8g8d's with a passive desulfator when I installed the new batteries.  Two months ago?  So I should remove the cabling and seperate the three batteries and let them rest overnight then check the individual voltage?

If they are at 13.0 to 13.1 then I can turn up the alternator and the charger to the 14.4?

There are people who say they know and then a few who do know and have tested their knowledge. 

Thanks for the help.

What capacity and brand of solar and controller should I look at to replace my 130 watt system?

Overnight use in high 40's overnight temps using the aqua hot never exceeds 120 amp hours. 

Have three old inverters I came across and unfortunately all three at modified wave.

A 2022 "458" 2000 watt.  A heart freedom 25 like my current unit and a trace 3012 with a rare remote panel.

They are are the inverter "doctor" a local guy in Costa Mesa, ca that had racks of refurbished ones and an scope to check them.

Not sure of the full wave added efficiency being worth replacing a functioning modified wave? 

The relays in mine were not used as Foretravel used an external ATS that my buddy wired around to use the hearts internal one instead. So mechanically its good.

Not a lot of TV use.

Bob












 

I just saw this thread from a week ago.

So the real answer is that any battery is just an chemical/electrical device, which, like a tire, does not have an infinite life. If abused, the useable life of a battery can be as little as one year.