I know that RV battery's receive their charge from the tow vehicles charging system while being towing which keeps them fully charged what I was wondering was what happens when your parked and the battery's are not fully charged, will plugging into the RV parks power supply fully charge the battery's up or does the charging only take place when under tow?.

Yes they will be charged when plugged in to 110volt

I dont think you get much more than a trickle charge while towing.

Actually I think it's the other way around. I think you get a larger charge while towing and only a trickle charge while hooked up in a park.

The fuses on the tow vehicle are usually 20 amp, which means up to 20 amps of current are available to the batteries.

All I know is that the salesman told me to make sure and give the batterys a good charge when I got it home because the truck only trickle charges it.Sooo,that tells me you are proably the one who is correct.

AS long as your RV has a battery charger in it, it will charge better then your truck when plugged in.

Actually I think it's the other way around. I think you get a larger charge while towing and only a trickle charge while hooked up in a park.

The fuses on the tow vehicle are usually 20 amp, which means up to 20 amps of current are available to the batteries.

I am pretty sure mine is 40 amp, but it is too cold to go out and check right now...lol

If you have a new R.V., they come with a pretty good system for maintaining your batteries...Mine knows how drained the batteries are and will boost the amps, then go to a trickle charge when they are full, this keeps the water from boiling out of my batteries...Was gone a month last summer and didn't have to add any water to my wet cells. Now I think when it is plugged into your truck, the trucks charging system takes over and does the same thing, using the alternator voltage regulator, I have noticed more volts (over 14) on the dash gauge when first leaving when batteries are low and after a few hours it is back into the normal 12-volt range.
Hope this helps answer your questions.

I am no electrician, but there are a number of variables that effect how little/much charging takes place while towing. IMHO charging wire size and length are the most important. As the wire length increases so does the voltage drop (resistance). I had a '91 F250 pulling a '91 25' Excel 5ver. From the factory the charge wire in the trailer tow package was only 14 gage. While under no load I had a solid 14v at the truck end of the plug, when I hooked up the trailer I was barely getting 13v (about .5 volt higher than battery) at the fully charged trailer batteries. I worked around this by wiring an 8 gage wire direct from the aftermarket Powermaster 145A alternator to the trailer plug in the bed of the truck. IIRC this increased the voltage at the trailer battery to virtually alternator voltage when the batteries were fully charged. I had an inline ammeter and never showed more than 10 amps going into 4 T105 batteries. I also had 2 100 watt roof mounted solar panels that contributed to keeping the trailer batteries fully charged when we weren't using it. When hooked up to shore power (120v), the 2000 watt inverter had a 3 stage battery charge system that did an excellant job of recharging. BTW, when I installed the inverter I disconnected the "battery charger" that was part of the trailer converter. It was only a trickle charger by design so that batteries would over charge when hooked up to shore power for extended periods of time.

With the '03 GMC I still use the factory charge wiring, but the new '5ver has larger solar panels and only 2 T105s, now. What I'd really like to do is replace the batteries with 4 Lifeline 6v AGM batteries ($$$), then I'd probably rewire the truck trailer charging wire.

Sorry for the long post, hope my experiences help.

Mike

I am no electrician, but there are a number of variables that effect how little/much charging takes place while towing. IMHO charging wire size and length are the most important. As the wire length increases so does the voltage drop (resistance). I had a '91 F250 pulling a '91 25' Excel 5ver. From the factory the charge wire in the trailer tow package was only 14 gage. While under no load I had a solid 14v at the truck end of the plug, when I hooked up the trailer I was barely getting 13v (about .5 volt higher than battery) at the fully charged trailer batteries. I worked around this by wiring an 8 gage wire direct from the aftermarket Powermaster 145A alternator to the trailer plug in the bed of the truck. IIRC this increased the voltage at the trailer battery to virtually alternator voltage when the batteries were fully charged. I had an inline ammeter and never showed more than 10 amps going into 4 T105 batteries. I also had 2 100 watt roof mounted solar panels that contributed to keeping the trailer batteries fully charged when we weren't using it. When hooked up to shore power (120v), the 2000 watt inverter had a 3 stage battery charge system that did an excellant job of recharging. BTW, when I installed the inverter I disconnected the "battery charger" that was part of the trailer converter. It was only a trickle charger by design so that batteries would over charge when hooked up to shore power for extended periods of time.

With the '03 GMC I still use the factory charge wiring, but the new '5ver has larger solar panels and only 2 T105s, now. What I'd really like to do is replace the batteries with 4 Lifeline 6v AGM batteries ($$$), then I'd probably rewire the truck trailer charging wire.

Sorry for the long post, hope my experiences help.

Mike

You sound like a pretty good electrician to me...By the way, where did you get your solar panels?? I do a LOT of Boondocking in Colorado's San Juan mountains and running a generator all day every 3 days to charge up all of my batteries kind of messes with the tranquility of the mountains.
Do your solar panels keep your batteries up pretty good? Can you run your microwave from battery/inverter power? Do you think it is a cost effective alternative to say a "honda" 2000 generator? I am using the honda 2000 now and it will run anything on my 5'er, but not all at once, like if my Wife needs the microwave I have to flip the breakers on the battery charger from the converter because they both won't run at the same time, same thing with the A/C (which dosn't get used too much in Colorado)...Sorry for the long post, I think I should have started a new thread, and think I just might...lol

My toy hauler has a 55 amp charger converter. while plugged into shore power, or running the genny, my batteries are being charged, unless i throw the battery switch.

While towing, your batteries do get charged, but unless you are towing like 10+ hours, you will need to make sure your batteries are charged before you boondock

to quickly charge my batteries while running the generator, i carry a 12v car charger, that i hook up to 110v and then charge the batteries, takes less than halft the time than by the converter/charger alone.

if you really want the most power out of your batteries, ditch the 12v, and go with 2 6 vlt golf cart batteries, like the kind at costco, or the trojan t105's----more amp-hours, and overall longer-lasting. you have to run them in series

I went to two 6 Volt in series to replace my 12 volts, and couldn't believe how much longer they last. Nearly twice as long and most of my camping is dry camping (no power hookup). I also use a 40 Amp fuse on my vehicle charging system to give the trailer batteries a charge when I am towing, and it charges them up pretty fast. I also have a Honda 2000 generator, but did notice that it took a long time to charge the batteries when I had the trailer plug in attached to the generator. Thats because I was routing the charge through the trailer box which reduced it down to about 2 amps before getting to the batteries. Now I have a DC charge setup that connects the generators DC output directly to the RV batteries and that gives about 8 amps directly to the RV batteries. But if I need the fastest charge I hook the 7 prong electrical connector to the truck and start the engine.

honda 2000 + http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=46944 = 40A charging with the Microwave, 100A by itself..