Charging trailer batteries while towing

  #16  
Old 03-22-2019, 09:44 AM
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Our RV residential fridge draws about 7 amps when it is running. We have fully charged batteries after a day of towing. Maybe look up the wattage of your fridge? Divide by 12 to get amperage draw. We have a 90 watt LG fridge. When we are ready to roll, inverter on, fridge running, we have a positive 3 to 4 amps going to our batteries.
 
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Old 03-22-2019, 11:33 AM
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What about the condition of the batteries themselves?
 
  #18  
Old 03-22-2019, 01:54 PM
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Originally Posted by acadianbob
Our RV residential fridge draws about 7 amps when it is running. We have fully charged batteries after a day of towing. Maybe look up the wattage of your fridge? Divide by 12 to get amperage draw. We have a 90 watt LG fridge. When we are ready to roll, inverter on, fridge running, we have a positive 3 to 4 amps going to our batteries.
That math is 120V I think. Through the inverter the DC draw is going to be closer to 70 amps, but it does not run constantly. I looked into running a larger charging wire from the truck into my fifth wheel but decided to go the solar route instead.
 
  #19  
Old 03-22-2019, 06:28 PM
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If it's precooled just turn it off traveling it should hold hours if not being opened.
 
  #20  
Old 03-22-2019, 06:51 PM
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Originally Posted by Edd505
If it's precooled just turn it off traveling it should hold hours if not being opened.
^^^^^^ Simple solution here. When I was moving from ND to AZ, I had just purchased a half beef. I did NOT want toleave it behind, so with that, I plugged in the RV to a 50A service at my house in ND. Then set a chest type freezer in the garage part of the RV (Toy hauler) and plugged that in and got it cold. Once cold I transfered the already frozen beef to that freezer. Once under way, the freezer in the RV had no power, but when done traveling for the day, we would set up in an RV park and plug in again. Just for my own satisfaction, I bought a cheap digital indoor/outdoor thermometer and set the sending unit inside the freezer, and had the readout in the cab of the truck with me so I could monitor the temp in the freezer. I don’t think it varied more that a couple degrees during the whole trip.
 
  #21  
Old 03-23-2019, 08:51 AM
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Originally Posted by ford390gashog
Pin#1 is the ground, make sure it is connected on the trailer side.
The easiest way to check to make sure everything is grounded properly is to back the truck up to your trailer and ONLY hook up the wiring, no chains, pins, ***** etc.
If all of your lights work then your ground is working correctly.
 
  #22  
Old 03-24-2019, 08:56 PM
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Originally Posted by Edd505
If it's precooled just turn it off traveling it should hold hours if not being opened.
We do this all the time during cooler months or on shorter trips. But, an 8-10 hour drive in Texas summer heat is asking too much of the fridge. Actually the fridge doesn't get too warm but the freezer does.

I plan on wiring a new charge cable from the truck battery to the trailer batteries. Think of a set of jumper cables with the Anderson connectors. I'll be able to get all the power I need to run the inverter and not drain the trailer batteries. Also, if I ever get a winch, I can plug it into the connector on the back 😀
 
  #23  
Old 03-24-2019, 08:59 PM
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Originally Posted by Birdhunter1
The easiest way to check to make sure everything is grounded properly is to back the truck up to your trailer and ONLY hook up the wiring, no chains, pins, ***** etc.
If all of your lights work then your ground is working correctly.
All my lights work when plugged in. I think the issue is either too much draw from the fridge or the small gauge charge wire on the 7 way can't keep up.
 
  #24  
Old 03-25-2019, 10:26 AM
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Originally Posted by Magnolia Tom
All my lights work when plugged in. I think the issue is either too much draw from the fridge or the small gauge charge wire on the 7 way can't keep up.
When you hookup without being grounded by the hitch check your battery voltage before and after hooking up with the refrigerator running on the inverter to see if the voltage increases with the truck running, if it doesn't you have a wiring problem either from a weak ground, bad connection or to small of a wiring in the trailer going to the battery. It should be #10 both for the ground and 12V supply wire. I say the trailer because Ford supplies heavy enough wire to the plug, I run both a freezer and dorm refrigerator off my inverter going down the road with stops running off the batteries only within problems. To find where the problem is you will need a meter and check to see where the voltage drops starting at the 7 pin plug all the way to the battery.

Denny
 
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Old 03-25-2019, 11:07 AM
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Originally Posted by rvpuller
When you hookup without being grounded by the hitch check your battery voltage before and after hooking up with the refrigerator running on the inverter to see if the voltage increases with the truck running, if it doesn't you have a wiring problem either from a weak ground, bad connection or to small of a wiring in the trailer going to the battery. It should be #10 both for the ground and 12V supply wire. I say the trailer because Ford supplies heavy enough wire to the plug, I run both a freezer and dorm refrigerator off my inverter going down the road with stops running off the batteries only within problems. To find where the problem is you will need a meter and check to see where the voltage drops starting at the 7 pin plug all the way to the battery.

Denny
Also if he's pulling too much current for the wire size, it will cause a voltage drop and the wire should be getting warm if not hot.
 
  #26  
Old 03-25-2019, 11:55 AM
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The biggest thing is to put the system under a real load not just lighting load to find s voltage drop or bad connection.

Denny
 
  #27  
Old 03-25-2019, 11:02 PM
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It's a combination of the resi. refrigerator and the inverter, which is inherently inefficient. It's not my intention to give offense, but I personally think resi. refrigerators are one of the dumbest things the RV industry has adopted. I suppose if you spend your time in parks it's fine, but my wife and I Iike to camp in more remote areas. Yes we have a pair of inverter generators, but I'd rather not have to run one most of the day. It's kind of a hot-button item for me right now because we're currently shopping for our next 5er and we're having a hard time finding a quality/luxury trailer not hobbled with a resi. fridge. If the trailer isn't built for an RV fridge, you cant just swap one in because they require a ventilated cabinet. But they also don't vent their heat into the interior like a residential model. The only reason they did it was to cut construction costs, because now the fridge location doesn't have to be built into the coach and floor plans can be more easily manipulated on the assy. line.
 
  #28  
Old 03-26-2019, 08:28 AM
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High-efficiency residential fridges are available. Her’s a link to a relevant post I made last year:

https://www.ford-trucks.com/forums/1...l#post17832241

HTH,
Jim / crewzer
 
  #29  
Old 03-27-2019, 08:16 AM
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Originally Posted by P.Bronner
I personally think resi. refrigerators are one of the dumbest things the RV industry has adopted. I suppose if you spend your time in parks it's fine...
Right. So it's only dumb for some people. We love our residential refrigerator and it works very well for how we camp.

Dave.
 
  #30  
Old 03-27-2019, 08:52 AM
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I just want to know what special properties they have. You can get ice makers in RV fridges, so thats not it. The residential unit is nothing more than a way to make manufactuing cheaper/ easier for the builder. It causes the owner to be tethered to a 120VAC source and unnecessarily heats the interior of the coach. If it suits your needs, that's great. A lot of newer owners have been talked into it being told it's just the way the industry's going, and hyped by the sales force as the newest greatest thing. Now they're realizing the limitations. Last weekend we were trailer shopping and had two salespeople at different lots tell me they're now getting a lot of blow-back on the resis and opt out whenever possible. I did discover Keystone is still keeping it optional on the upper end trailers. I was really interested in some if the upper echelon products from Jayco and Heartland, but they have taken a hard line on the issue. I guess we'll stick with Keystone (currently have a Montana).
The RV industry really has me perplexed. My Wife and I have been RV-ing for 25 years, and currently own our fourth 5er. Now shopping for #5. I swear I've never seen an industry try harder to kill itself.
 

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