Iíd like to share a little background information about my RV Solar installations with my past RVís and the current one, all of which were completed by Marvin at Precision RV - Specializing in RV Solar Power Systems and Repair
Iíve had solar installations on two previous Airstream trailers and my current Newmar class A. The first was a Flying Cloud 25 which had 600w of panels, 2000 watt Magnum Inverter/Charger and 4 6 volt AGM batteries. A couple of years later, I sold that trailer and bought a new 30 foot Classic. This was updated with 800 watts of solar panels, a Magnum 3000 watt MSH3012 Hybrid inverter and my first set of Lithium batteries, 600 amp hrs total.
I had followed the lithium battery evolution, starting with early installs for the folks from Technomadia (500ah of GBS cells). Shortly after, I had the Airstream Classic updated. Paul and Nina from www.wheelingit.us
upgraded their coach with more panels, Hybrid Inverter and a set of GBS lithiumís from Precision RV as well.
My two Airstreams were built out by Marvin Braun of Precision RV - Specializing in RV Solar Power Systems and Repair
. Paul and Nina used Marvin for both their original solar install and their significant upgrade the second time around. Marvinís work is professional, the installs are immaculate, system works as designed and the attention to installation detail as well as functionality is outstanding.
When I got my 2017 Newmar Dutch Star 4369 I started planning to have a Solar, Hybrid, lithium system installed. I started working with Marvin over several months, with phone discussions and trading many emails on some of the technical design questions. I wanted to install the GBS lithiumís where the current 8 AGM batteries were located. Part of the challenge of that location is that the bay is open to the elements on the top and back. Some work would need to be done to seal up the space.
While I had great service from the BlueSky controllers in the Airstreams, I wanted to explore using the Magnum PT-100 solar controller. This would allow integration with the Magnum remote and the RV already had a magnum auto gen-start. It would also allow for adding a Magnum MagWeb networked monitoring system so that I could monitor the system over the internet.
Lastly, and often not fully understood when thinking of adding Solar, the newer Newmar coaches have a raised roof facia. On the passenger side these contain the Girard awnings. On the driver side they are false facades. They are about 10 inches in height above the roof and narrows the overall width to work with by about 10 inches. Those and the three air conditioners and satellite dishes present a challenge with shading of the solar panels, which can seriously degrade the output of the panels. For a good example of this see the Gone with the Wynnís video of testing they did with both parallel and series panels.
Marvin and I did some research on how best to raise the solar panels up from the roof so that shadowing would be eliminated. Marvin performed a 1960 watt installation previously on a like Newmar, designing and building a custom rack for the panels. You can see that installation here. 2000 Watt 1200 Amp Hour Newmar Motorhome Solar Power System - Precision RV
Marvin was able to position twelve, 180 watt panels on the roof. These were wired in series with four strings of three panels. I had Newmar pre-wire for solar so there was a 6awg cable from the roof to the battery bay. The panels were connected to a combiner box and then down to the battery compartment.
Panels were raised onto a solar rail system so that they are about Ĺ inch below the side rails. The air conditioners are still the high point of the roof, although my KVH in-motion dome (towards the front of the coach) is maybe an inch taller.
In the battery bay, the AGMís and the sliding tray was removed. Marvin built an insulated box for the new batteries. Six 200ah GBS lithium cells were mounted for a total of 1200ah. The high/low voltage relays, battery cutoff, solar panel CB/cutoff switch and the Battery Management computer (brain) were mounted to the side of the box. All of this is sealed with a cover so that the box is completely enclosed.
The 1200ah capacity is regulated to 80% or 960ah. Marvin programs the CPU to 80% DOD to give the customer the best balance between usage and life span for the batteries. Lithiumís can be run down to 10% capacity, but I am setup on the conservative side. I have extensive experience with lithium batteries in large aerial drones and always used them down to the 20% safety level. It extended their useful life.
I added further sealing to the space on the door and door edge. This compartment does not have the rubber bulb sealing around the edge that Newmar has installed on the other compartments. It wasnít needed since the space was for batteries and opened at the top. This gives me a bit more sealing against the elements.
Installed on the battery compartment wall in the first narrow bay aft of the battery box is the Magnum PT-100 solar controller. This is integrated in the Magnum network so that it can be controlled and monitored by the Magnum ME-ARC50 remote control. The box to the left of the PT-100 is a breaker for the solar input feed from the panels.
I will be monitoring the temperature in the space since GBS lithiumís temperature operating ranges are -20C to 65C for discharging and 0C to 65C for charging. The Magnum BMK helps with this monitoring. I also have the video output of the BMS computer displaying on the front coach television, set through the video input on the tv (giant monitor), which shows the battery temperature of the GBS cells down to the individual cell level.
This photo shows the batteries and box but without the final cover which installs to seal up the entire area. Marvin designed it so that in the off chance I need to do other maintenance it is easy to remove pieces from the box for access.
There was also a Magnum BMK installed for monitoring. This allows for using the MagWeb system, and fully interfaces to the Magnum AGS for automatic starting of the generator. In the photo below you can see the battery shunt, battery cutoff switch, BMS CPU on the left. On the right are the main fuse, solar panel cutoff/CB and a switch for jump starting the CPU if needed after a power disconnect situation if needed.
The Magnum MSH-3012 Hybrid Inverter/Charger was a swap for the standard MS2812. The MSH Hybrid is 3000 watts and allows for the mixing of AC power and Inverter Batteries. This would be a benefit in a place where you had only a 15 amp circuit for shore power or even 30 amp. The MSH would use 15 or 30 (or whatever I set it to all the way down to 5 amps) shore power and supplement that with Battery Inverter power as required.
One of the biggest parts of the job was completely rewiring the AC electrical panel and installing a new 50A sub-panel. Marvin works closely with each of his customers to make sure all the electrical items that a customer wants on the Inverter circuit is understood,along with any limitations. The standard Newmar CB panel from Precision Circuits was maintained, but the breakers in that panel that were for connecting to the original Magnum inverter/charger were functionally moved to the new sub panel. The Precision Circuits monitor still functions as it did originally.
My setup has the middle air conditioner wired to the MSH. On the new subpanel the CBís that are installed allow me to use the middle air conditioner, floor heat for the bath/BR, mid-floor, front floor, microwave, cooktop, P/S outlets, DS outlets and refrigerator.
I asked Marvin to install a MicroAir Soft Start module. This reduces the startup load on the Penquin AC significantly. It also reduces the load when the AC restarts. It does this with a combination of a longer startup time between cycles and doing its magic of load reduction. The AC pulls about 15-17 AC amps or an average of 150-170 DC amps or 150 to 170 AH when running. I also wanted the electric floor heat and the Induction cooktop. The big culprit in an RV like this is the Digital touch pads and the residential fridge. This greatly increases the base load over a 24-hr period. There is a good article on Marvinís web site, PrecisionRV.com here: A new trend in Motorhomes - Residential Refrigerators - Precision RV
This is where a good energy audit becomes important and the BMK plays the key role. I created a spreadsheet by recording the DC amp load for each of the DC circuits in the coach and then again on the AC side. My coach, while in storage, pulls 4.5ah with spikes to about 8ah every 5 to 6 hours. The spikes are when the BIRD relay kicks on to charge the chassis batteries. (Marvin also installed a bypass switch if I wanted to disconnect the BIRD operation).
The load increases to 12.8ah simply by turning on the inverter. This is the base load for me. It includes having the AV cabinet items in standby or turned on, Travelír dish on, and any items like phone/computer chargers operating, etc. Adding the fridge takes the overall DC load to about 14-15ah at fridge idle and up to about 24ah when the compressor is running. Generally, overnight I will see a total consumption of 200-250ah.
Most of the light switches are in the .4 to 3ah range, main ceiling lights being the highest. Each ceiling fan is 1.4, 2 and 3ah based on speed 1, 2 or 3. The floor heat circuit that has the bed/bath and mid controllers pulls 71.5ah when on. Floor heat levels low, med and high are settings that vary the amount of time on and off for the heat panels. TVís donít take much power. Front and Living room TVs take 3.6ah and the smaller one in the bedroom, 1.6ah.
For two weeks the only time I plugged in was to check the overall system while on a 50amp connection and to record charging times and current.
And finally, the MagWeb. It monitors everything except the PT-100. Magnum told us that they have either firmware upgrade or replacement in development. Probably a bit overdue since the interface firmware shows a date of 2011. The MagWeb is connected into the same phone cable that goes to the ME-ARC50 remote. Besides the main screen below, there is a screen to show the current setups and complete data sets for each day that can downloaded in either a text or CSV format if you want to do additional review or charting in Excel.
The MagWeb needs to connect via ethernet cable to a router in the coach that in turn is connected to the internet. When I had my coach built, I added a special order to run conduit from the Ĺ bath to the basement. It was easy to pull a CAT-6 cable from the MagWeb, mounted close to the PT-100 to the Ĺ bath where it connects to my WiFi Ranger. That, in turn is connected to my AT&T wifi/cell puck allowing the data to flow to the Magnum servers. Magnum says that this ďalways-onĒ connection will consume about 2.5mb of data per day.
My first foray into the wild after the build was two weeks in Rapid City, SD. Coach was oriented nearly north and south. Maximum sun angle was 49į. Time available when the sun was above 10į was from 7.35am to 6pm. I was seeing peak output of 80-85ah from the panels. This perfectly aligns with a reading taken with a sun irradiance meter which was showing 80%. This easily allowed for full recharge from overnight loads by mid-afternoon.
I have Solar/Lithium because I like boon docking and want the options it provides at any time. I spend most of my time in the western U.S. Having the ability to have more battery storage, use solar as the primary source of charging and have the added benefit that, if needed I can use the generator and recharge very quickly with the Lithiums.
For those that are contemplating a solar or lithium installation, I would suggest installing a battery monitor system, Magnum BMK, Tri-metric or other, so that you can do a real energy audit to determine the amount of energy you are actually using. This information is invaluable for determining system sizing, especially battery capacity. But to be honest, Marvin has a great amount of real world experience and knows his RVís. He takes a great amount of time asking probing questions to get an idea of use or for the customer to think about how and what they want to use in their RV. He can then recommend the battery bank needed to achieve your personal goals.
Installation took 2 weeks. Build out of the system was perfect. Marvin always does a great installation from craftsmanship of the battery box, to enclosing the wiring to spotlessly cleaning up any installation debris.
You can get further information on the Precision RV - Specializing in RV Solar Power Systems and Repair
website. Many examples of his previous installs on a variety of coaches and trailers can be seen. There is also general information about solar, batteries and other information available on the site.
This is my third install with Marvin and I have been extremely satisfied each time. I think one of the things that impresses me most is the attention to customer satisfaction that Marvin exhibits. From the initial conversations, through planning to post install support the focus on the customer makes a difference.