Charge Batteries by Idling Tow Vehicle?
This may be a dumb question, but since every tow vehicle has a generator which is connected to the batteries and they charge while driving, how about hooking up and charging at the campsite while idli...
Forum Discussion
Flatfive wrote:
Okay. Got it. That's what I thought. We have switched to LED lights. We'll probably get a portable solar set-up soon.
What is WyoTraveler talking about: " a diode and 10 ft of wire"?
If you have a motorhome, and tow a car, sometimes the towed car battery can go dead while towing it. So running some wire to the towed car will charge it's battery while towing. Really has nothing to do with your situation, and will not keep your car battery full while you are towing a trailer with a pickup
LED lights are great. However your RV will still consume 35 AH daily to run the CO and propane detectors, refrigerator. The lights, furnace and things like a inverter to run a TV or laptop will consume even more power.
The water pump is actually insignificant, it will pump 2 GPM for 1 hour while consuming 7 amp hours, and empty a 120 gallon tank for 7 AH.
What you really need if you like dry camping is a 140 watt solar panel - it will replace around 45 AH daily per panel. This place had them for $229 a few weeks ago, with aluminum frame, and 12 volt nominal output (actually about 22 volts open circuit, but considered 14 volts under load). Add a PWM controller rated at about 20 amps, and you are set.
Some grey UV rated wire from Home Depot and 4 each 6" long 2" angle aluminum brackets to mount each panel to the roof, some rubber roof sealant to seal all the screw holes, you are set.
Run the wire down the back of the refrigerator, through the roof vent into that space, to the controller, then to the battery. I am using #10 wire for a pair of 120 watt panels, and another run of #10 wire for a pair of 45 watt and a single 75 watt panel.
While #10 wire is rated at 30 amps maximum in house use, the 15 amps that I am running through my run is considered a high load for this small of wire when run in DC applications, and larger wire might be recommended, but still I am charged by 3 pm, so I don't care to much about voltage drop, as it is working fine for me, full timing over 4 years.. .
SUnElec.com
If I where to run the truck engine while charging the RV battery, I would first hook up jumper cables from the truck to the RV battery and let it charge for say 15 minutes. Then start the engine, and let it idle for say 15 minutes and then shut it off for another 15 minutes - cables still hooked up. It will suck come more amps from the truck batteries, but not enough to draw them down to far. After 15 minutes, then idle the truck again for 15 minutes, and after shutting it off, disconnect the jumper cables within 10 minutes, so the battery in the truck stay full.
As stated above, if the alternator is rated at 160 amps, once warmed up, the output will go way down. His ability to charge at 86 amps indicated he was running very large wire, and it looks like he was using a forklift battery connector - those are rated for a maximum of about 350 amps, with very large and low voltage drop terminals inside it.
It is 'bad' on a engine to sit idle. There is not enough oil flow to the heads, and the pushrods will not get enough lubrication. At over 1,000 RPM, then the engine will see many quarts of oil going to the heads, and pushrods will lube fine. Also carbon will build up in a diesel engine. 10 - 15 minutes will not be to bad, but still if you get a flat cam, it is normally due to someone who sits in the truck with the engine idling to keep the A/C on while they do paperwork, or on a van with a lift attached to it, that is left running to run the crane lift hydraulic motor.
Good luck with your system.
Fred.
