When traveling I put the fridge on 12 V and several hours later when we arrive at rv park I find that the camper battery is practically dead. I have the power line from the truck battery to the 7 terminal connector and have tested with a voltage meter all the way to the battery on camper and am getting power. I can hook up truck and disconnect camper battery and fridge is working off of truck power. Also with camper positive cable disconnected and truck running I have power all the way to end of camper battery positive cable from the truck. Hooking camper battery back up and also connected to truck why is it not keeping my battery charged while I travel with fridge turned? Fridge works great on A/C or D/C power.

Freddie, the truck wiring is not heavy enough to prevent too large a voltage drop. It will go below the camper battery voltage and then the fridge will draw from the camper battery. I ran a separate 6 gage line direct from the truck battery to a separate connector.
Works great

^^^

What he said! In my truck the 10 gauge wiring to the trailer plug was not able to keep up with the refrigerator's demand either. However, my 300 Watt solar panel installation on the roof of my trailer works constantly when traveling and we arrive at a campsite now with a fully charged battery now.

So, those are two options for you.

- Jack

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Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH, Progressive Dynamics Converter, Fan-Tastic Fan, LiFePO4 battery 12V DC Electrical System, SoftStartRV mounted on A/C
2024 F150 Platinum FX4 3.5L PowerBoost SCrew

I currently have a # 12 wire running from battery. Am going for a #6 wire and see if that helps. If not I may attempt the solar panel if I think I can actually install and wire up one.

I appreciate the answers and will keep on it since my wife really likes to have cold things in the fridge when we set up and I like to have power to raise the camper immediately.

Freddie - I think 6-gauge may be a bit of "overkill". 8-gauge should be enough to carry the needed Amperage. Of course, you can install anything, but 6-gauge is awfully thick and quite difficult to work with. And, I think I misspoke in my previous post. I think the wiring in my vehicle is 12-gauge, not 10. Higher numbers are thinner. My solar wiring is all 10-gauge.

The other consideration is your tow vehicle's alternator. It may not have the capacity to provide the needed additional current. If your vehicle is equipped with a "tow package", it probably does, but you MAY find that to be problematic too, but I suspect the wire size is the main culprit.

- Jack

If you haven't already, you may want to add a second 12-volt battery, that will double your battery power.

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My Great Wife Joyce
2018 Jayco Jay Flight 21QB
Formerly owned 1705T and 2310H
2012 F150 4X4 SuperCrew EcoBoost w/Leer Cap
Reese WD Strait-Line Hitch
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back to dealing with this problem. Bought a heavier and newer truck for towing but same battery problem. Can you actually hookup two 12v batteries in tandum and not mess up the 12v system? There is room for a second battery and a second tie-down in the compartment.

Freddie - Yes, you CAN hook up two 12V batteries in a 12V system and not mess up anything, as long as there is room for both. The key is: you HAVE to connect them in parallel, which means you MUST connect the two positive posts of the batteries together and the two negative posts of the batteries together using short, heavy, "jumper cables". Then you simply attach the positive cable of the trailer to a positive battery terminal and the negative trailer cable to a negative battery terminal. It does not matter which battery is connected to the trailer, because the parallel unit is "seen" by the trailer as ONE bigger battery, at 12V.

The other, WRONG way to connect the batteries would be in "series". This would use only ONE jumper cable, connecting the positive post of one battery to the negative post of the other. Then, the trailer cables would be attached to the two remaining free posts. Again, this is the WRONG way, because the batteries now deliver 24V, which will damage electronics and/or blow fuses.

- Jack

Thank you.........Jack. Am going to give this a try. Was thinking it might could be an alternative.

This is the way I have mine hooked up - second post in this thread: Adding a second battery - Forest River Forums

A quick scan through that thread revealed some other useful information too. I suggest you read it.

- Jack

I replaced old with larger 6 gauge wire on all my trailers. Dedicated + and - wires straight from battery and fused on the positive side, the fuse tucked away in battery box. For example on my PopUp trailer (the most recent one I did) I took some before and after voltage reading. Old wire with fridge off I had 12.65 volts at battery and it was 12.2 volts back at the fridge terminal block. Turned the Fridge on and my battery went to 12.0 volts and back at the fridge was at 10.3. There was only about 15 feet of wire but probably 12-14 gauge. That was a loss of 1.7 volts or .11 volts per foot of circuit.

After changing the wire ( required a new terminal block at the fridge to handle the larger gauge ) I had 12.65 volts at battery and fridge with the fridge off. When I turned it on the battery went to 12.55 volts and at the fridge I had 12.2 volts, a drop of .35 volts.

This was a supply voltage increase at the fridge of 1.9 volts or .127 volts per foot of circuit. A huge improvement.

Thanks for all the info. Made copies for my file folder and will be doing this before next trip on the day following Thanksgiving.

You said you bought a newer truck to tow the Hilo
I did the same I bought a 2017 Chevy Silverado
The problem I have and many trucks made after 2014 they have a variable voltage alternator controlled by the trucks computer at idle it reads good voltage but at freeway speeds if the computer senses good voltage at the start battery it shuts down voltage output from the alternator the save gas which at this point it will not charge the trailer house batteries
With a variable voltage alternator it won’t matter how big of circuit and gauge of wire you use it won’t charge the house batteries while running the refrigerator
The fix : Install the redarc dcbc1240d DC charger
Which will boost charging voltage to charge the house batteries on the Hilo
The dc charger mounts at the house batteries and 4 gauge wires back to the truck start battery and a trigger wire to the ignition circuit used to turn on the dc charger
I will be installing this setup soon and parts run about $ 650
Go to Redarc .com for more info ( I am NOT a seller of this product , just trying to get you more info they also have many YouTube videos)

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Les & Patricia
2006 22ft towlite (replaces 97 21TL)
2006 Toyota tacoma pre-runner 4.0 L V-6 quad cab
w/ 98 chevy Powervision towing mirrors
2017 Chevy Silverado 1500 5.3 v8 (replaces Toyota)
2 Hobie mirage pedal drive kayaks

Here's my remedy, and it works for me. I ran a 10 wire from the positive post of the Batt to a marine grade circuit breaker and from there to the 7 pin plug. The hard part was changing the thin #14 wire to the 10 at the pin. But I eventually got it back together. I could have just installed a new plug and wired it up. Simple. Result was, as the vehicles computer detects a draw in voltage it will compensated by the alternator. When I disconnect from shore power I have 13.7 volts, when I arrive at my site, I usually have about 13.5+ or - a point
Tree

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2703 Tow Lite
2002 Escalade
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Andrews, NC