Generator vs Battery/Inverter/Solar
We have just purchased our first truck camper - a used 2007 Lance 845 and have a couple questions that I hope you can help us out with. The camper is still at the dealer and we're considering having a...
Forum Discussion
HMS Beagle wrote:
With a separate alternator and remote voltage sense, you would not need the large cable. #6 AWG will carry 100 amps safely, but there will be a voltage drop. Remote sense is a separate small wire (#18) running from the battery terminal to the regulator sense input, the regulator increases the voltage output of the alternator until the battery terminal is at the required set point regardless of voltage drop in the charge cable. That system would also regulate the house battery according to its needs exclusively. Equalizing the state of charge between house and start batteries in not really ideal - you do not want to bring the start battery down to the same SOC as a discharged house battery.
How far to go to finesse the system is debatable. People have been camping with a simple #10 wire in their 7 pin harness doing the charging for decades. But there are much better ways available.
I am quite familiar with remote sensing, having used it on my Sterling Alternator to Alternator charger and using it on my solar controller.
You are correct. Assuming the right gear, you can raise the origin voltage to compensate for losses in the circuit. Sterling, CTEK, and others do this all the time. In the end, all still require large cables to deliver large amperages. In my tests with the Sterling, the two 125A alternators on the truck were providing 190A at the batteries - and the 1/0 AWG cable was getting very hot.
Obviously, with a separate, dedicated alternator, you can play with the voltages and amperages as much as your heart or pocketbook allows. I'm not sure that any commercially available gear will get you enough voltage boost to push 100A DC through 20 feet of 6 AWG, but I could be wrong.
Equalizing the SOC between the camper and starter battery is exactly what you want; you want them both at 100%. This is what you will achieve with a decently sized intelligent relay and properly sized wiring. You can, indeed, accomplish this with smaller wire, but it will take much, much longer. A battery will charge as long as the charge source is higher than the voltage of the battery.
As a practical matter, your Ford probably has at least a 200A alternator - heavier wiring will get you a much better charge rate than you will get though a classic 7-pin setup.
In my case, cooking electrically and running heat or air conditioning, I want the fastest charge I can get. Lifeline specs up to a 5C charger. With a 600Ah battery bank, I am not going to find a 3000A charger, but the difference between being able to deliver 150A+ at a proper 14.4v and, say, 25A at 13.5v is considerable.
As always, YMMV. My numbers are based on two years of field use and a lot of logging. Call me in eight years to see if I make a full ten years on the batteries!
To return to the original question:
-- Can you live without a generator? Yes, many high end campers (e.g. Earthroamer, Earthcruiser, some Tigers) do exactly that.
-- Is it enough to simply add a few more batteries? Probably not. You will need to be able to charge them and your inverter may not be large enough.
-- Is it worth it for YOU? Only you can answer. I hope that the information that I have offered is correct and helpful.
;)
