Battery charging when towing

[Bob K4TAX]

Our 2011 Silverado has a tow mode which keeps the voltage higher when activated. More voltage means more amps since R is constant.

In monitoring the voltage in our TT when connected to the truck, idling, and in tow mode, I see 14.2 volts. That will certainly add a nice charge to the battery.

Bob

[FrankG]

The surveyor trailer line-up with the Norcold 12V refrigerator combined with the provided 80W solar package and a good battery will survive a all day trip 12+ hours. Then it needs shore power to get it through the night and be fresh in the morning to start another day on the road. We do this all the time. We have even unhooked using the power jack and ran the slide out before plugging in.

We NEVER boondock, no idea on how to accomplish it other than powering up a generator.

The 80W solar keeps the Battery full up when in storage. Two happy travelers here.

[Dirthawg_]

OP, I have a 2021 Surveyor with the 12V Only Norcold Fridge (love this fridge by the way, its a huge improvement over the absorption fridge my last trailer had in it). I have the standard single Marine/RV Battery that the dealers install with the standard 80W solar panel on the roof.

I tow with a 2016 F250. I've towed up to 4hrs with available sunlight for the solar to help recharge the house battery and the lowest I've seen the house battery upon arrival at camp is 12.6V on the solar charge controller. I always have the trailer plugged in at home for a few days prior to leaving so everything inside the fridge is already cold and battery is fully charged before leaving on a trip.

I regularly tow in 95+ degree weather and travel 2 hours from home and still arrive with 12.6V or better on the house battery. Earlier this spring I towed for 10hrs+ in cold weather and the fridge was fine running off that single battery, solar and whatever the truck adds.

If you are trying to boondock with this 12V only fridge you will deplete the factory battery in just a few hours without a genset or AC power.

Here is the amperage draw these Norcolds draw from the tag located inside the fridge. Prior to purchasing this trailer I considered installing a pair of Trojan T-105 6V batteries in series on the tongue because I was concerned the fridge would not make the trip to camp. I have not needed to do so for my usage of the trailer.

[tomkatb]

I own a highly educational recording battery monitor.

It is a voltmeter only. However it keeps a history of voltage if the disconnect is on which ours always is while traveling. Study that graph and you will learn a lot. Mine also has alarms when we are getting low. $40 on Amazon.

On a fifth wheel often the #14 wire is 30’ long. It is two wires. So you have to look at a 60’ for resistance.

A trailer is likely 50’. A motor home, very little. So you will see differences. .

On mine, a 16 Ram diesel with I think 160amp alternator rarely over 13 volts in the rv.

Doodly squat, to be technically correct. Trickle at best.

The problem is the wire. Bigger is better. DC/DC converter. Bigger batteries. Maybe. Changing the voltage to a higher number is not usually good for the batteries. Too much boils them.

Be careful switching to lithium and inverters. Not so easy! Get help.

[MontanaWill]

Use a clamp on amp meter to determine charging by the TV. Usually only a trickle charge. Do not rely on that. Use Propane on the fridge to run normally unless you can see that the TV will run the fridge.

[Mandog]

I had to remove a dummy fuse and replace with a 40 amp fuse in My 2005 2500HD Silverado. The picture may be rotated but in my truck the fuse was while standing at the drivers fender on the top left.
Also if you fashion a way to install 2-6volt golf cart batteries your refrigerator will run over night on them. My truck keeps the batteries charged to 12.45 volts when traveling. I have an Everchill 12v only fridge that we love. I have 2-12v interstate batteries and once they go bad I’m going to the golf cart 6v dual batteries. I hope this helps.
Good luck.

[bikendan]

Originally Posted by MontanaWill

Use a clamp on amp meter to determine charging by the TV. Usually only a trickle charge. Do not rely on that. Use Propane on the fridge to run normally unless you can see that the TV will run the fridge.

The OP has a 12v only fridge so no propane.

[Tom48]

Originally Posted by BHolmes

2021 Surveyor only comes with 12v/110v fridge

That whole electric frig thing seems to take the camping out of campers. Truth to be told I wonder how much the RV manufacturers are saving on their costs.

My first one years ago had an ice box and we got by on a block of ice. At least we were not dependent HOW TO CHARGE THE BATTERY. LOL.

[Dirthawg_]

Originally Posted by Tom48

That whole electric frig thing seems to take the camping out of campers. Truth to be told I wonder how much the RV manufacturers are saving on their costs.

My first one years ago had an ice box and we got by on a block of ice. At least we were not dependent HOW TO CHARGE THE BATTERY. LOL.

Why does it matter if the manufacture is saving money on installing a 12V only fridge? They install a 12v compressor fridge that will out perform an absorption fridge any day of the week at the same time also installs a 80w+ solar array on the roof that will counter the cost of the absorption fridge. The compressor fridge out performs the absorption fridge hands down. How many new RV buyers are only interested in boondocking? I bet 90 percent are going to a site that has a 30 or 50 amp electrical pedestal. If you want to park your camper in a site that has no electric or water connection then a cold refrigerator should be the last thing on your agenda. Hell, go purchase some dry ice and put it in a cooler and you have cold food for a few days.

I spent 20 years primitive camping in a tent with two very large coolers and didn't give a damn if my site had any amenities other than fresh water somewhere available. I purchased a travel trailer to have the amenities I enjoy at home and expect to have a site that has electric and water to keep my food and beer cold and take a cold shower on a hot summer day.

If I want to camp on a sandy beach without any power then I would expect to come prepared with the necessary equipment to keep my food cold.

Why should every RV owner be restricted to only using an absorption fridge that frequently breaks down and provides less than stellar results compared to a compressor fridge?

I'm not the only one that thinks this way.

https://www.youtube.com/watch?v=HNCnwXOh1ng

[tomkatb]

I would guess an absorption fridge costs almost $3000 installed vs $500 for a 12 volt compressor roughly the same size.

Our 12.3 cu ft gas electric fridge was properly installed. Another issue. Many are not!

It allows us to go Harvest Hosting as we please. You cannot do that with a compressor fridge in many situations.

We went to Moab in mid October. Used the Honda every other day to charge the batteries. The DW used the convection oven and I used the tv.

Compressor fridges cool faster, cost less, and eat batteries like mad.

Works well,for those who plug in daily. We are sort of starting to lean the other way. Slept at a horse farm. Brewery. Parking lot. Art museum in Roswell. A volcano in New Mexico. In the Moab desert. Several places in Nevada. .

$2000 worth of batteries helps a compressor fridge a lot!

[Jcape]

Originally Posted by hack522

Another possibility is use propane while driving. I do that sometimes.

Sent from my IN2015 using Forest River Forums mobile app

You can't use propane on a new 12 volt refrigerator, they run on 12 volt only, and I would be careful running down the road with the refer running on propane. I did that for over 40 years, but it finally caught up with me this year. Refrigerator caught on fire and nearly lost the whole rig.

[Jcape]

Originally Posted by Bob K4TAX

Our 2011 Silverado has a tow mode which keeps the voltage higher when activated. More voltage means more amps since R is constant.

In monitoring the voltage in our TT when connected to the truck, idling, and in tow mode, I see 14.2 volts. That will certainly add a nice charge to the battery.

Bob

Tow/haul mode does not change charging to the trailer. And you get more than a trickle charge from the 12 volt line in the 7 pin plug, it is a 40 amp fuse protected circuit.

https://www.worktruckonline.com/3164...g-easier-safer

[Jcape]

Originally Posted by tomkatb

I would guess an absorption fridge costs almost $3000 installed vs $500 for a 12 volt compressor roughly the same size.

Our 12.3 cu ft gas electric fridge was properly installed. Another issue. Many are not!

It allows us to go Harvest Hosting as we please. You cannot do that with a compressor fridge in many situations.

We went to Moab in mid October. Used the Honda every other day to charge the batteries. The DW used the convection oven and I used the tv.

Compressor fridges cool faster, cost less, and eat batteries like mad.

Works well, for those who plug in daily. We are sort of starting to lean the other way. Slept at a horse farm. Brewery. Parking lot. Art museum in Roswell. A volcano in New Mexico. In the Moab desert. Several places in Nevada. .

$2000 worth of batteries helps a compressor fridge a lot!

You will not find a 12 volt compressor fridge for $500. I just bought a Norcold DE 105 3.5 cf frig to replace my Dometic gas/electric and the frig cost $1300 without installation.

[Jcape]

Originally Posted by Oaklevel

I know this is not a great answer, the tow vehicle can trickle charge the batteries. A lot depends on the tow vehicle.

What is your tow vehicle ?

The 12 volt feed through your 7 pin plug is fused at 40 amps, that's more than a trickle charge.

[aeblank]

Originally Posted by Jcape

Tow/haul mode does not change charging to the trailer. And you get more than a trickle charge from the 12 volt line in the 7 pin plug, it is a 40 amp fuse protected circuit.



https://www.worktruckonline.com/3164...g-easier-safer

I thought that too, but I read somewhere (reputable) that tow/haul or turning the lights on changes the alternator output voltage (by a volt or two), which would increase the amperage the batteries see. This being on a "modern" GMC/Chevy, anyway. I haven't tried to verify this for myself, however.

I've seen like 15A from my 2014 LML. Battery voltage would have to be pretty low to see 40A...

[Jcape]

Originally Posted by tomkatb

Technically yes. Actually, no.

There is terrible line loss on dc wiring.

Your truck likely sends 15 amps per hour back there. However, line loss dramatically cuts that.

We have a blutooth battery monitor. My monitor says the voltage back there in the rv is 13.0. Barely a trickle. Your fridge and parasitic loads likely often needs closer to 10 amps. Therefore the tv does not supply enough.

You need a 200-400 watt solar panel. A dc/dc charger gizmo, Or double or triple the battery capacity. I think you have only 40 dc amps available.

My guess is the rv has the DOT minimum battery designed only to power the trailer brakes. Not a properly sized rv battery. Pretty normal today. Your rv needs to be plugged in daily.

Installing a battery monitor is a good idea. Batteries are now, and have always been, the weak link.

A fully charged 12 volt battery has 13.5 volts. The tow vehicle puts out 40 amps to the trailer, the refrigerator draws 5.2 amps. All of the lights, pumps, furnace, radio and any other 12 volt appliances in the trailer wouldn't pull 40 amps, if your trailer is like most, your 12 volt main fuse is 30 amps.

https://norcold.com/product/norcold-...-refrigerator/

[Dirthawg_]

Originally Posted by Jcape

You will not find a 12 volt compressor fridge for $500. I just bought a Norcold DE 105 3.5 cf frig to replace my Dometic gas/electric and the frig cost $1300 without installation.

Agreed, and from these two links both refrigerators are similar in cost.

https://www.recpro.com/rv-refrigerat...ainless-steel/

https://www.recpro.com/rv-refrigerat...-and-electric/

[Bricklayer123]

Pretty sure the wires to your 7 pin plug on your truck and the wires on your trailer hookup are not rated for 40 amps.
Unless you have upgraded them.

[Bricklayer123]

To put 40 amps from your alternator/battery to your 7 pin connector it would require minimum 6 gauge wire even 4 to be really safe
30 amps would require 8 gauge minimum 6 to be safe.

Then add on another 4-5’ or more from TV to trailer and your Probley in the 25’ length of wire from battery/ alternator to connection point on TV. So you’d want the larger size wire with that length.
Don’t think the manufacturers install this thick of gauge wire for the 7 pin connector from the factory.

[acadianbob]

We have two 12 volt AGM Group 27 batteries in our 5er. We also have a residential refrigerator that runs off of an inverter. We have a Victron battery monitor so that we know with some certainty our state of charge. We left camp with our battery bank at 80% charge. Refrigerator on of course. Started the truck and read a 7 amp charge on the Victron (engine at idle). Batteries were fully charged when we arrived at our next site.

Pretty awesome "trickle charger" wouldn't you say?