Charging batteries/running fridge while on the road?

[annie]

I'm planning a road/boating holiday this summer and was thinking it would be good if I could keep the batteries topped up while on the road.
I have a good power supply to the front of the trailer for the braking system.
Does anyone do this or know of a way to do this?

 

[Lazy Daze]

It's an interesting idea, but I believe you'd probably end up over taxing the alternator on a smaller-sized tow vehicle. You definitely don't want to take chances pulling power from the trailer's braking system or other vehicle-important things. It might be fine, but it would likely be a good idea to install a heavy-duty, higher output alternator. Basically, you'd be charging your vehicle's battery and at least one of the boat's battery. You'll need some gigantic battery cables (expensive), though!

Will you have access to AC power on your trip to charge the batteries? With two, good batteries in the boat, you could probably go two or three days (at least) without needing a charge.

What about hooking up a good solar charger? Lay it on the deck of the boat so it gets good sun. I would think a decent charger would be less than even the cost of the cables.

 

[annie]

Hey Dennis, thanks for the reply. All good points.
I do have solar but the panels get thrashed to death on the canvas, I could move them to below the windscreen but then I'd have to drive towards the sun which would limit our travels. Lol.
I think your right about over taxing the alt and also the cables needed to charge the batteries... To hard.
Maybe I'll just try to run the fridge @ 3.5 amps.
I could fit a two position switch ( 1: boat batt 2: tow vehicle) by the fridge and run 10 amp cable to the acc plug just inside the tailgate. That's a 10amp plug that only has power when the ignition key is on.
I could then store the cable in the anchor locker and run it out the anchor windlass warp access flap, tie it to the anchor and run a loop straight to the truck. Sorry about the rant but I'm thinking through my fingers.
I was hoping to get to some pretty remote areas without ac. If we got some bad weather we wouldn't then run the batteries flat.
Potential problems:
1- forgetting to disconnect the plug before launching.... Resulting in a plug getting wrenched out of the truck.
2- forgetting to store the cable before dropping the anchor.... Resulting in ripping the fridge out the anchor locker..lol.