Solar Van Man® — 2015 Fleetwood Discovery 42' Diesel Pusher
2015 Fleetwood Discovery 42' at Solar Van Man®.
A 42-foot diesel pusher gives you a lot of roof. It also gives you a lot of electrical load.
This 2015 Fleetwood Discovery came to Solar Van Man® with a factory residential refrigerator and a conventional six-battery flooded-lead-acid house bank. The objective wasn't to rebuild the entire coach around lithium batteries. It was more focused: use that enormous roof to reduce the time the generator has to run just to keep everyday electrical loads alive.
We installed six Rich Solar 250-watt, 24V-class panels for 1,500 watts of permanent rooftop solar.
Six 250W panels put 1,500W of permanent solar on the Discovery roof.
On a coach this size, simply adding wattage isn't enough. You also have to think about how you're going to move that power from one end of a 42-foot motorhome to the other.
That's why this array is wired 3S2P: three panels in series per string, with two strings in parallel.
The series configuration raises the PV voltage and keeps the current coming off the roof remarkably low for a 1,500-watt array.
At maximum-power voltage, each three-panel string is roughly 111 volts. Two strings in parallel produce only about 13.6 amps on the PV side.
That's the important part.
Trying to move 1,500 watts around a large coach at low voltage means monster amperage, heavier conductors and greater voltage-drop concerns. Instead, we move the energy at higher voltage and relatively low current until it reaches the solar charge controller.
Then the big blue box goes to work.
The heart of the system is a Victron SmartSolar MPPT 250/85 VE.Can charge controller.
Victron SmartSolar MPPT 250/85 VE.Can, installed in the coach.
The controller takes that high-voltage, relatively low-current solar input and converts it into the voltage the Discovery's 12V house battery bank needs.
And this is where the numbers get interesting.
The array may be delivering only around 14 amps from the roof, but the MPPT can deliver as much as 85 amps of charging current to the battery bank.
In one very good hour of full sun, that's roughly 85 amp-hours of battery charging if the batteries are sufficiently discharged to accept it.
That is what an MPPT is supposed to do: let us design the solar array around efficient power transmission while delivering serious charging current where it actually matters.
The installation also included the new PV downlead, combining and connection hardware, appropriately sized cabling, and battery-side protection.
The PV array can be electrically isolated with a two-pole DC breaker, disconnecting both PV conductors at once.
None of that is glamorous equipment. It is also the difference between simply putting solar panels on an RV and building a solar charging system.
Solar wasn't the only thing this Discovery needed.
Once you're working across this much roof, the existing sealant condition becomes impossible to ignore. The coach needed substantial roof-sealing work, so we cleaned the affected areas and resealed them as part of the project.
Roof sealing work addressed the Discovery's existing roof condition while the coach was in the shop.
A solar installation should leave the roof better protected, not simply add another collection of penetrations that somebody will have to worry about later.
The Discovery also left with a replacement driver's-side window. The original window was badly fogged and the owners planned to replace the window in the future. However, when we ran the autolevling down before running the slides out to work on minor interior issues, the already-failed window cracked. We sourced the replacement directly from @RevGroup Fleetwood; the clients picked it up, got it to Illinois, and we installed it before the coach went home.
The Discovery is ready to return to service after the solar, roof, and window work.
This system isn't meant to make a 42-foot diesel pusher pretend it's a tiny off-grid camper.
The Discovery already has a generator. It already has a substantial conventional house electrical system. And we're not replacing perfectly serviceable equipment simply to produce a more fashionable equipment list.
The goal is simpler.
That factory residential refrigerator needs electricity every hour of every day. So do the inverter and the coach's background electrical loads. Every watt we can harvest from the roof is a watt that doesn't have to come from shore power, the generator or stored battery energy.
With 1,500 watts overhead and up to 85 amps of solar charging available at the batteries, a sunny parking spot becomes a meaningful energy source rather than decoration.
The finished Discovery: 1,500W overhead feeding up to 85A of solar charging into the 12V house system.
That's the advantage of having 42 feet of roof.
We decided to put it to work.
Solar Van Man®
RV, van, camper, trailer, mobile-energy systems
(224)310-9847