TCA Rig Gets Important AM Solar Upgrades

The modifications to the Truck Camper Adventure Rig continue at a rapid pace, but this time with a twist. As you know, we normally do all of the work to our camper ourselves, but two weeks ago we had AM Solar in Springfield, Oregon, do the work for us. These upgrades included the installation of a 90 watt monocrystalline solar panel on the roof, installation of an 8 AWG portable solar power plug, and a swap-out the old battery isolator in the camper for a Victron Cyrix-Li-Ct lithium battery switch. Sure, we could’ve done this electrical work ourselves, but we ran out of time before our big summer getaway, and decided that a visit to AM Solar at the beginning of the summer fit well into our schedule. AM Solar has been in business since 2002 and is widely known for providing quality RV solar installations, so it was great to finally meet the team and get the full “AM Solar” treatment.

If you’ve been keeping up with our modifications, you know that we recently installed a pair of Expion360 Viper 120 amp hour Lithium Iron Phosphate (LiFePO4) Batteries and a Go Power 1,500 watt inverter with a built-in transfer switch. Each was an important upgrade that took our rig’s electrical system to a whole, new level. Because lithium batteries offer a usable capacity of 90 percent vice 50 percent for lead-acid batteries, we essentially had doubled the battery capacity in our camper from 220/110 amp hours to 240/216 amp hours. Because of this, we wanted systems that could charge them quickly, and more effectively. Here’s what we had done:

1. New Zamp 90 Watt Long solar panel: Installing an additional solar panel is something we’ve been wanting to do for about a year. This new 90 watt monocrystalline “long panel” not only gives us a total of 330 watts on the roof, but still leaves us with plenty of room topside to perform maintenance on the roof because of the panel’s long and slender size. This additional solar panel gives us a nice boost in amperage (5 amps) and still matches well Vmp-wise with the other two panels. The 240 watts we had on the roof before provided us with a maximum of 13.5 amps in Arizona, but with this additional 90 watt panel, we’re now getting nearly 17 amps and that’s up here in the higher latitudes of Oregon and Washington. Not bad.

The new Zamp 90 watt long panel on the passenger side still offers plenty of room on the roof to perform maintenance, a major consideration for us.

2. New 8 AWG solar charge plug: This is another item we’ve been wanting to add to our camper’s solar power system for several months. In a previous article, we documented a problem we were having supplementing the camper’s main solar power system with a portable solar panel. What was happening is that the charge controllers in the two systems were “dueling” with each other and generating voltages that were tricking the other controller into thinking that the batteries were completely charged. This essentially shut the “losing” system off. The solution, as we saw it, was to remove the crappy charge controller in our Renogy 100 watt portable array and plug that array directly in to the camper’s main charge controller. This new 8 AWG charge plug allows us to do that and gives our solar power system a total of 430 watts when we use the portable array. This portable panel will especially come in handy during the winter months when the sun tracks lower in the southern sky.

The new 8 AWG solar charge plug is mounted underneath on the driver-side wing.

3. New Victron Cyrix lithium battery switch: The third and final mod involved swapping-out the old lead-acid battery isolator used in the camper’s alternator charge circuit for a Victron Cyrix-Li-ct lithium battery switch. As you know, one of the biggest benefits of the lithium battery is that it operates at a higher voltage (usually around 13.0 volts) compared to a lead-acid batteries which puts out a maximum of 12.6 volts. Essentially, what the Cyrix switch does is prevent the lithium batteries in your camper from “back feeding” or charging the lead-acid starting batteries in your truck. It also provides under voltage, over voltage, and over temperature protection for the lithium batteries when driving and charging via the truck’s alternator.

Closeup of the new Cyrix Lithium Battery Isolator Switch

Overall, our time at AM Solar was great. The AM Solar team is comprised of professionals who are very knowledgeable about RV electrical systems and even designed several systems specifically for truck campers. If you need extensive work done to your RV and you’re not comfortable with the level of your knowledge, then I wouldn’t hesitate to give AM Solar a call. In addition, to the work we had done, they also upgraded some of the solar power and alternator circuit wiring and connections done at the Northstar factory. Nothing major, but it’s the little things that sometimes make a big difference in how a system performs.

Sean Wilson did a terrific job during our visit to AM Solar.

In addition to AM Solar’s upgrades, we were able to learn a few valuable things about solar power installations and testing while we were there. One tool that AM Solar uses to calculate solar power efficiency is a hand-held device called a Daystar DS-05A Solar Power Meter The readout of the meter, which measures the amount of natural sunlight present at any one time, is compared with the RV’s solar power output to determine the system’s overall efficiency. Here are the numbers Sean ran for my system:

  • Daystar Meter Readout at 10am: 64 percent
  • The three solar panels on our roof are rated to produce 18.5 amps total
  • 18.5 x .64 = 11.84 amps
  • Our Zamp ZS-30A Controller was showing 11.9 amps at that moment which is exactly what we expected.

As you can see, our upgraded solar power system passed with flying colors!

A Warning

One other thing about our visit to AM Solar. Because the work we had done was somewhat extensive, we had to stay in a hotel room for a couple of nights (yuck!). We ended up staying at a dive called the Village Inn, which is about a mile from AM Solar’s location. With a drive less than five minutes, the hotel’s proximity to AM Solar is a bonus, but I still wouldn’t recommend it. The carpet was filthy and stained and the room stank of cigarette smoke. The rooms are reasonably priced at around $77 with tax, but not if you have a dog like us. If you bring along Fido, you’ll have to pay an extra $25 pet fee per night, which puts you at around $102 a night. Not worth it. Fortunately, Mitchell Boyer, who is one of the owners at AM Solar, just opened an airBNB, which after looking at the photos, is ions better than the dive we stayed at plus Mitchell told us he will be charging less. I wish we known about Mitchell’s airBNB before we booked reservations at the Fleabag Inn.

About Mello Mike 889 Articles
Mello Mike is an Arizona native, author, and the founder of Truck Camper Adventure. He's been RV'ing since 2002, is a certified RVIA Level 1 RV Technician, and has restored several Airstream travel trailers. A communications expert and licensed ham radio operator (KK7TCA), he retired from the U.S. Navy in 2004 as a CWO3 after 24 years, holds a BS degree, and now runs Truck Camper Adventure full-time. He also does some RV consulting, repairs, and inspections on the side. He currently rolls in a 4WD Ram 3500 outfitted with a SherpTek truck bed with a Bundutec Roadrunner mounted on top.


  1. Hi Mike

    I’m thinking of putting in a Victron Cyrix-Li-ct lithium battery switch as you just did.

    Did you keep your Battery Isolation Solenoid (to keep the camper from drawing down the truck battery when the truck engine is off), or does the Cyrix-Li-ct unit protect the truck battery if the camper battery is low and wants to draw on the truck battery?

    I like how it will keep the higher voltage lithium battery from back feeding to the truck battery in addition to other protections. But I’m worried that if my lithium battery gets low there is a chance that the camper might draw down the truck battery without Battery Isolation Solenoid when the engine is off.


    2018 Ram 3500 Cummins diesel long bed 4×4
    2012 Northern Lite 9’6″

    • Hi Steve,
      The Cyrix switch also isolates the truck’s batteries from the camper. There’s no way that low lithium batteries (which would be pretty rare quite honestly) would draw down my truck’s batteries. The lowest I’ve ever seen my lithium batteries is 12.8 volts. 🙂

  2. Mike, I have a question regarding your statement “what the Cyrix switch does is prevent the lithium batteries in your camper from “back feeding” or charging the lead-acid starting batteries in your truck.”
    I am quite new to this game. The 7 pin connector always has voltage to it from the truck even if the ignition is NOT on. So, how do you and your followers keep from discharging the truck batteries while boondocking or away from shore power? I do not like to crawl under my Laredo SC just to unplug while stopped or to replug in when breaking camp. What other options are there besides the disconnect/reconnect routine? I have thought about installing a manual battery disconnect switch in the camper that would isolate the positive side of the truck battery from the camper at the flip of the switch but am wondering if there are better options.
    At the moment I only have one AGM battery in the camper and two solar panels on the roof but apparently my electrical needs are minimum. I do not take a TV or other entertainment items or use the microwave. My refrigerator is one of the three way which I use on battery while driving, propane when boondocked and shorepower when available. I do work from the mobile office using a power hungry laptop needed for the tool and gage design work I do for the machine shop I own. I have used the air conditioner on shore power to knock down the temperature and humidity but usually the nights cool down enough here to keep comfortable with windows open and the vent fan running on low.
    I have used the auto start on the truck from inside the camper to “top off” the batteries but that is another issue as I know eventually I will need to increase my battery capacity.
    I live in Minnesota and it takes a bit juice to start my Duramax diesel in the cold so a discharged battery is NOT an option so any ideas on preventing the truck battery from discharge while away from other power sources.


    • Wayne,
      A battery isolator or in my case, the Cyrix switch, prevents the backfeeding or draining of your camper batteries. No need to disconnect the pigtail.

  3. Mike,

    I like the changes, in particular the workaround to get away from portable panels fighting the rooftops. Your thinking regarding saving room for maintenance on the roof is spot on. Those panels can be a pain to walk around, even when well thought out.

    The founders of A.M. Solar, Greg and Deb Holder were close personal friends as we were on the same talk circuit for several years. Greg did solar and I did everything else electrical. You went where I would go to have solar work done!!

    That 17 amp output rivals what most folks are seeing out of their onboard power converters when tethered to the shoreline. 🙂


    • Good question. Because the Heki Vent is an egress point on the roof. We wanted the space around it free from any obstructions. Not only that, but the front part of the roof is very weak and isn’t what you’d call walk-on capable.

  4. Curious…I haven’t read anything about your “big summer trip”. Where are you going? Another question: Where do you store your portable solar panel? We have a dog that takes up the entire back seat of the truck so no storage room there.

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