2015 Chevy Colorado won't charge our camper battery!

The ONLY way that this will get accomplished is if the campers battery is Properly tied into the tow vehicles charging system… and I bet that plug wont do it properly…

If one or the other batteries is low…the Alternator will sense this and charge either or both at the same time.

I bet this issue is stemming from not having the camper batt properly and robustly tied into the tow vehicles system. Its pretty simple…


Perhaps if OP went to the dealer with the camper in tow. The service drive should be long enough to accommodate this

It’s a lot easier to brush it off, if the camper and its battery aren’t around

I know from experience it’s always better if you can physically demonstrate/point out the problem to the mechanic and/or service advisor

The ONLY way that this will get accomplished is if the campers battery is Properly tied into the tow vehicles charging system... and I bet that plug wont do it properly....

The 7-way plug is designed to do just that. I have no problem charging my camper battery when towing. It’s a deep-cycle battery so it won’t get killed when it gets completely drained.

The battery charger I linked to in my last post will apply the proper charging voltage and current to the second battery no matter what the vehicles system voltage is doing.


The RV refrigerator draws 14 amps when operating on 12 volts. They would need 3 of those Power stream chargers to supply power to the refrigerator and charge the battery. That would draw nearly 30 amps, likely the limit on that circuit.

The charger referenced by circuitsmith is exactly what I mentioned in my previous response. But I couldn’t find the reference. Thanks.

Re refrig. I’d guess it only draws that current periodically, so you may get by.

The same company makes higher current versions, but much more expensive. There are other brands. The key phrase for google is “DC-DC charger”.

I would get a nice gas generator for camping. If u really expect to sit in the woods and rely on a battery for the fridge, you are being shortsighted. It’s like comparing an all elec car to a hybrid. Battery dies, ur out of luck

People don’t go camping to listen to a generator run. When you reach a camp site the refrigerator should be switched to run on propane. The problem is that on a 6 hour trip the refrigerator will drain the trailer battery if the power supply is insufficient.

I hear you MikeInNH…But methinks they may have a Ground problem or something like a bad connect via that 7-Pin Plug… That thing needs to be checked and verified… because if that camper batt was properly and Robustly connected to the tow vehicle via that plug…you would need to do NOTHING… The system would sense the extra batt or one of those batts lower voltages and simply compensate…

This isnt’t Rocket Science… If they have a Robust and Secure connection thru that plug…that other battery would simply get charged… Perhaps the Camper batt wont accept a charge??


OP should run the refrigerator on propane all the time.

Friend just bought a new toy hauler trailer. No generator or roof air. Sounds like a hard sided tent to me.

A gust of wind will blow the flame out on my refrigerator while using propane. I never tried propane on the highway, I believe I would arrive with warm food and drinks.

The two trailers and one RV I’ve used had no problem with warm food.

My father advised me against storing raw meat in a cabinet in 100F heat.
When I hand my buddy a hot bottle of beer he hands it back.

But seriously, I find it easier to put my food and drinks in a cooler and keep it in the truck until I arrive at my destination. I then load the refrigerator and operate on propane. The refrigerator will only cool to 60F in the 100F heat of the valley. That is probably the easiest way to avoid discharging the battery while on the road.

While on this issue of refrigerators I will mention that yesterday I defrosted the 1949 +/- refrigerator in my shop. When finished I plugged it in and turned it on and once again it is cooling. As a matter of fact I am now enjoying a cold Michelob Ultra from that grand old appliance. Obviously someone thought that I deserved better than the Bud Light and Pabst Blue Ribbon that I usually keep there. I’ll try not to let myself become spoiled.

As for the OP’s problem, I to have found that icing down perishables and beer in a good cooler works well. Even in 90*+ Mississippi heat there is still ice after 3 days. Why ruin a good weekend over the less than satisfactory operation of a battery and charger?

When 'm trailering my pop-up I don’t run the refrigerator. And depending on the campsite determines how I run the frig. If I have electrical hookup, then I run off of that. If not I run propane. But the 12v option is to run when you’re towing…I’ve just never used it.

Wow, you folks are amazing! We appreciate your willingness to share your expertise. Sorry it has taken a while to respond. First off, we must tell you that our Chevy dealership (family owned for over 80 years) has "reached out” to us again. The owner has agreed to contact Chevy on our behalf. They also want us to bring in our truck with the camper (as db4690 suggested we should do) so that they can have a first-hand look at what is going on. The General Motors bulletin will be extremely helpful (thanks Nevade-545) when discussing the problem. Circuitsmith’s link to the DC-DC charger will be especially useful if we need to take the aftermarket route. But cj2 perhaps hit the nail on the head when he states “If tow/haul mode doesn’t provide “charge mode” voltage then it’s faulty period. Easy to verify with a simple volt meter.” We will be asking our dealer to test this again and this time we want to know just how much increase there is in the alternator output when this mode is engaged. My husband (an engineer for 35+ years) and his buddy (an electrical engineer) did not see any noticeable change when they tested this in June. Missileman asked if the truck has a heavy duty alternator and yes, it does. We do keep the battery on a float charger when at home and that is why we can dry camp (no electric plug-in) for the first three nights we’re out, but when depending on the Colorado to charge the battery when driving to the next campsite, we only have electricity for one night at best. When it comes to our refrigerator, we have always towed (prior to the Colorado) with it working off the DC power (camper owner’s manual doesn’t recommend running it on LP because of safety reasons) and we never noticed any adverse impact on the camper battery. When using the Colorado, it might be worth considering now. We really would rather not use a generator, but would consider adding solar power. Most of all, we just want our Colorado to do what the owner’s manual says it should do. I guess we just took for granted what our previous tow vehicles (Toyota Highlander and Nissan Xterra) did so effortlessly.

When your husband measured the charging voltage was it at 12.8 volts in tow mode? In your original post you didn’t mention whether or not you always use tow mode. The voltages shown are for normal mode.

As others and I suspect, the reason why there is no change in charging voltage at the camper battery is due to the wire losses between the two batteries while the camper battery is trying to charge up from a low charge state. Checking the difference between the battery voltages will tell the story. You could easily have around a 1.5 volt voltage drop difference if the wiring is not adequate. One way to prove that would be to move the discharged camper batteries near the front of the truck and connect the batteries directly to the car battery using some good heavy gauge jumper cables. Then check the alternator voltage output.

Nevada_545 - we measured the charging voltage at the 7-pin plug at the back of the Colorado (measuring voltage between the battery charge and ground pin)s. We observed no difference in charging voltage when we engaged and then disengaged Tow/Haul Mode several times. It appears that alternator output is governed solely by the charge level of the Colorado’s battery. If it’s charged up, alternator output is limited to 12.8 volts. When the Colorado’s battery charge level drops, alternator output kicks up to 14.5 volts.

Cougar - we measured wire losses from the Colorado battery posts to the 7-pin plug at the back of the truck, using a strand of heavy gauge wire from the battery posts to the back of the truck so we could use a single multi-meter. Very low resistance was observed (0.006 ohm, I believe). The camper has been used with three tow vehicles other than the Colorado and recharges effectively with each of the other three vehicles. We’ve also recharged the camper battery with two different trickle chargers and via the 30-amp AC cord on the camper itself. We purchased a battery load tester near Rocky Mountain National Park and found camper battery health to be good after trickle charging or using the AC power cord to charge the battery. The morning after our refrigerator quit working, the camper battery showed just under 11 volts and good response to a 10-second load test.