Field test: PV Modules

A real world comparison between Mono, Poly, PERC and Dual PV Modules.

Total solar yield: --
Total solar yield: --
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Total solar yield: --
Installation date: 09-03-2020

* This is a field test and the results are specific for this installation on this location please research which is the best solution for your own situation as the results can be different based on environmental influences.

Total solar yield as of 27/03/2023 when the results were reset:
Mono: 9158 kWh
Split-cell: 9511 kWh
Poly: 9113 kWh
Perc: 9471 kWh
Perc-east: 1970 kWh
Perc-west: 1730 kWh

RV enables pedal adventures

Couple dream, design and build cycling base-camp

This week let’s hear from Nebraska, USA based cyclists Russel and Kim Hilliard who turned their dream camper into a reality allowing them to take their hobby further-afield and also to relax at each day’s end in their ideal mobile environment. Over to Russell…

Outdoor adventures

My wife Kim and I are avid road cyclists.  We usually get in about 2500 outside miles per year most of it in Nebraska where we live and also Colorado. We decided a couple of years ago that it would be nice to have some type of a camper to use to be able to extend our bicycle trips beyond day trips.

We began looking into campers but we didn’t like how cheaply they were made. Also we didn’t have a vehicle to tow the camper and so that would mean buying an expensive truck. We looked at a school bus conversion but ultimately decided on an ambulance conversion. After all we are both in the medical field and know the quality of these vehicles and liked the fact that they are usually well-maintained.

We spent about 4 months looking for just the right vehicle and ultimately purchased a Freightliner medium-duty ambulance from the fire department in Chambersburg Pennsylvania. This is the mother of all ambulances. It was a 2014 model and had just 78,000 miles on it.

I was discussing this project with one of my patients who agreed to fly out and drive it back to us here in Nebraska.

The Freightliner today

First moves…

Our first order of business was replacing all 6 tires, balancing the wheels and checking alignment. We also had the brakes inspected. Next was a trip to Cummins to have the engine serviced. We had Cummins increase both the horse power and torque using software and without invalidating warranties. They also removed the electronic speed governor of 75mph. The Allison transmission on this vehicle was a 5 speed but it has a 6th gear that was locked out. There is a company that reprograms the transmission control module making the 6th gear available improving fuel consumption.

When it came to the electrical system we scoured the internet and found that many people were using equipment from a Dutch company called Victron Energy.

A quick internet search and we discovered that there was a Victron Energy ambassador by the name of Marc Stevens whose company Off-Grid Solutions is located in Chadron, Nebraska – virtually at our back door! We set up the first of multiple Zoom meetings with Marc to discuss our goals for the vehicle which included:

  1. A cohesive electrical system where all the components play well with each other
  2. A means of harnessing the energy from the 320 amp alternator that comes with the ambulance.
  3. Energy efficient heating and cooling of the vehicle. We didn’t want to use any of the rooftop traditional units found on most RVs.
  4. As much solar on top of the vehicle as possible.
  5. Battery storage to allow us to camp barefoot for a couple of days even if cloudy.
  6. Robust high speed internet access even when camping remotely.
  7. Remote access to the electrical system from computer or phone.


Bringing it all together

Marc and I worked for about 3 months on the design of the system. We would have Zoom meetings and then swap email schematics and design ideas back and forth. Here’s the final design.

Once the design was completed Marc placed the order for the equipment and I drove to his place in the ambulance to pick it all up. You can put a lot of stuff in an ambulance! I have a background in electrical engineering and am a ham radio enthusiast. I’m also pretty good at using AutoCAD. While waiting on the equipment to come in I mocked up the electrical cabinet and battery compartment for the ambulance and produced an AutoCAD rendering of what it would look like.

Next I started installing the devices and making the connections. Everything worked as planned with the exception of the Buck/Boost which had some sort of a fault from the factory. Marc replaced this and we were good to go.

What’s on board?

The Freightliner installation consists of:
· 10 kWh of Lithium Battery Smart at 24V
·  Lynx Smart BMS This is a Battery Management System especially for Victron Lithium
· Lynx Distributor  DC busbar distribution and termination with monitored fuses
· 900W of PV Modules
·  150/60 MPPT SmartSolar MPPT Charge Controller Maximises and manages Solar Energy harvest
· 5kVA Quattro Inverter/Charger 24V supplies AC power to domestic equipment
· 100A Buck Boost for Alternator Charging
· 24V to 12V Orion DC-DC Converter  allows 12V devices to run straight from the 24V battery storage
· Blue Smart IP67 12V Chassis Battery Charger rugged environment battery charging from gird.
· 1000A Smart Shunt keeps account of power in/power out to provide State of Charge (and so much more…)
· BatteryProtect 65A Ensures that the starter battery will never be accidentally depleted by domestic power use

We next shipped the ambulance off to Colorado Adventure Vans in Golden Colorado. John and his staff worked closely with Kim and I to design the interior of our dreams including:

  1. Isotherm marine fridge/freezer
  2. Queen-sized fold-out bed.
  3. Stand up shower which also has access from the outside.
  4. Wrappon Green toilet, we didn’t want to hassle with black water tanks
  5. Diesel water heater that also heats the ambulance
  6. Pioneer mini-split for heating and cooling
  7. Induction cooker for heating soups, etc.
  8. Installation of Star Link router
  9. Corian counter tops

This is a 3 season camper. 2023 was our first full season with it. We spent 24 days camping and really enjoyed it.

A few other items to note. We replaced the front seats with new units. We also replaced the front center console with one that was custom made by Colorado Adventure Vans with the same Corian that was used in the back.

We left that majority of the ambulance wiring intact.  Lights, sirens, PA system all work. We have 2 One Up bicycle racks mounted vertically on the back.

I designed and built an 80/20 aluminum extrusion roof rack for the ambulance. This holds our solar panels, awning and Star Link antenna.

What next?

Victron Ambassador Marc Stevens told me separately how impressed he was with Russell’s wire management and the placement of the equipment – which figures as in addition to Russell’s health career he has a Bachelors degree in electrical engineering! Rusty and his family loved the Victron system so much that we are working on another design for their home which includes two EV chargers as part of the load!
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