Solar Power for the Truck

We have been interested in solar power for a long time. Our second truck had a solar panel on it, but it wasn't quite enough to do what we needed. The board we had was 100 watts. That isn't much power when you think about it. Keeping the batteries charged while off duty was about its limit.

We are on truck number four (T4), and I think we have got it right this time. A little back story, when we started to build T4, we wanted it to be as efficient as we could get it, low idle time and low generator run time while on a layover. We needed to understand how much power we consumed with each appliance, laptop, phone, and anything else that used power, 120V, or 12V. After reading many owner's manuals, we determined it was possible to consume about 3,000 watts. That 3,000 watts is if EVERYTHING electric is on at full power, all at the same time (that should never happen).

We knew that not having a generator wasn't an option, and we needed a backup to the battery bank. An Onan 7500-watt generator is what we ended up installing. We also went with a Zantrex power inverter, so the rooftop A/C could run off of the batteries with solar support. Here we are now, eight Northstar batteries powering the Zantrex inverter that will run everything we need to run, including the rooftop A/C, all appliances, chargers, and lights.

We have three solar panels from Merlin Solar and use a Morning Star charge controller for regulating the power created. Each of the panels are 330 watts, for a total of 990 watts, almost 1 kilowatt, now that's a lot of power, all from a free renewable source. We worked with Toby Tuckley, at Bergstrom Solar Energy Systems, who helped us decide how many panels we would need and helped with the installation.

I traveled to Rockford to meet Toby and install the system at Bergstrom's world headquarters. The system consisted of the Merlin panels, a Morningstar charge controller and monitor, a circuit breaker, wiring and connectors. The panels are self-adhesive so the roof of the cargo body was cleaned with rubbing alcohol to ensure adhesion. Each of the panels is fairly large, approximately 4' X 6', yet very thin, about 6mm. They were placed so that the wiring from each could be connected without crossing any of the panel surfaces. All wiring was then sealed and covered.

I chose to run the wiring inside the box, then through the floor to be connected to the charge controller inside the battery box, two wires, positive and negative, doesn't get much simpler than that. The Morningstar charge controller was preset for our system, so it was an easy install. Mount with three bolts, connect the panels, connect the monitor cable and then connect the batteries with the inline breaker. I did have to make a place for the monitor inside the sleeper, but the monitor is small, and the placement went smoothly.

In all of our past trucks, if the microwave was turned on, even for 30 seconds, we would need to start the generator. Now we can run the microwave, the instant-pot, and the air fryer all at the same time without the generator running. It was a nice sunny day, but that is still a lot of power from the sun. During the day, while sitting, the batteries are maintained at 13.6 volts, which is impressive no matter how much power we are using.

Nowadays, the NorthStar batteries are keeping us powered overnight, rather than the generator starting for low voltage during the night. We are still using the generator to run the roof A/C at night, and for now, during the day, but this spring I will change some wires to run the A/C off of the inverter, that will be the ultimate test of the panels and the inverter. I can't wait to run fuel-free A/C.

The solar panels are mostly maintenance-free. Obviously, they need to be kept clean, but they are coated with a material that is self-cleaning somewhat, rain, and the rinse at the truck wash will keep them working without you getting on top of your truck.

If you own your trailer or are in a straight truck, several panels will keep you powered, but there is an option for a tractor roof panel that will help with smaller loads and maintaining battery loads without idling.

In our history of having a generator on the truck, we have averaged about 350 hours per month. Keeping us cool, batteries charged, and for cooking, the generator would be running. After the solar installation, we cook, charge electronics and keep the batteries charged, during the day, without the generator running. We took delivery of the truck in August 2019; the A/C was used to get us into fall. Beautiful days and nights, no heat needed no A/C needed, no generator required. It is now February 2020, four months with solar on the truck, and the generator still only has 600 hours on it. Before the solar, those four months would have tallied up a thousand hours or more. The lion's share of our 600 hours is for the A/C in August and September. For optimal performance, a cool to sunny day is best. Most of us think that solar works best in a hot climate, but that is false. We have found that parking under a street light will generate small amounts of power.

I sleep better since the generator is not starting and stopping during the night. Linda makes two cups of coffee every morning at 4 AM. I thought the coffee pot consumed lots of power, so I had her start the generator before parking. After we discussed the system and how it was performing, we decided to try not starting the generator. The generator hasn't started for a week, for any reason. The batteries are staying above 12.8v, day and night. The coffee pot drops the voltage to about 12.5v, but it rebounds quickly back to 12.8 or higher. Once the sun starts to rise, the voltage rises quickly to over 13v peaking mid-afternoon towards 13.8v, this will sustain us overnight. My hopes for maintenance-free power may have been fulfilled with the help of Merlin Solar and Bergstrom.

Bergstrom has idle-free options for almost any need, heating, and cooling. You can contact Toby at ttuckley@bergstrominc.com, or his direct line is 815-873-4422. Give him a call to discuss an option that will fit your needs.

Till next time, power-up.