Solar + inverter: where to start?

[donkro]

Alexisc, I discovered mine has the "Furrion" plug which means a Furrion solar panel would hook right in, similar to your set up, but different manufacturer, and they too are expensive. But I've discovered there are plug adapters out there that can allow you to hook up different brands, and there's always the option of just replacing the plug (looks pretty simple).

[pmsherman]

Originally Posted by alexisc

Just bought a new Sunseeker 2290 S yesterday. I will be spending a lot of time in National Park campgrounds & boondocking on National Forest land this Summer without a hookup. I do have a Cummins Onan RV QG 4000kw generator, but the campgrounds have limited hours of use in morning and evening, so I do want to have solar and an inverter installed.

For a non-techy person who doesn't understand much about electricity and how all this stuff works, is there a magic calculation somewhere to help me figure out what I need?

I'm thinking I might need 200-300w solar to be safe but not sure on the inverter. I have a lot of gear that needs charging or to run for extended periods - camera batteries, laptop, drone batteries, RAID / hard drives, air purifier, maybe a portable electric heater and fan, etc.

Any guidance (or links to previous posts) would be really helpful.

While I don't have solar power on my rv (yet), I do have a remote controlled, off grid, observatory that's solar powered. All of the issues you face are ones I've already solved.

Inverters make things easy because it's just like having power from the grid. Unfortunately, inverters provide the worst efficiency when looking at battery life. Your RAID device probably has a wall wart that provides 12VDC to power it. You can power it directly from the rig's 12V battery with a replacement plug. You can purchase a DC power supply for your computer that will allow running it directly from a 12V battery.

Devices requiring voltages different than 12V can be powered by DC-DC voltage regulators. Buck regulators create voltages less than 12V, boost regulators create voltages higher than 12V, and buck/boost regulators can provide voltages from a few volts to 35V when hooked up to a 12V battery. I like using buck/boost units for devices that require 12V because the DC voltage in my class A rv varies from below 12V (battery nearly discharged) to over 14V when the converter or alternator is outputting its maximum voltage. A buck regulator set to 5V will supply power for recharging your cell phones, tablets, and many other current consumer electronics devices. My 12V desk lamp has two 5V charging outlets and I can also charge devices from the computer's USB ports.

I installed a tap on one of the rv's lighting circuits that has a 15A fuse and only a 2A load after I changed the fixtures to LEDs. The tap ends in a PowerPole connector that fees a small distribution box with 4 PowerPole connectors in it to power other devices. From this, I can run my computer using its DC power supply, the router, a wifi range extender, and a nice bright 12V desk lamp. I have an additional outlet available because the wifi extender requires 24V which is a separate output from the boost regulator installed in the distribution box.

You can purchase these regulators as prebuilt, sealed, boxes that just require attaching input and output wires to them. My preference is to buy small circuit board regulators that require soldering the connecting wires to them then setting the output voltage using a meter. I can mount these little boards in whatever enclosure I need to use.

Your solar power system should include an MPPT controller. These are much more efficient than the PWM controllers that are less expensive. Solar panel units need to be mounted where NONE of the cells will be shaded because, for most panels, if one cell gets no sunlight, the entire panel produces no output. If you're planning on camping in national parks, you may discover that you hve a shaded site and the solar panel doesn't produce enough power for you.

To determine how much solar power you'll need, you need to check all of your equipment that you'll be using to determine how much power it uses. Don't believe the power ratings on wall warts because they are designed to support the maximum amount of power the device may need, not what it actually uses over an extended period of time. The easiest way to measure a laptop's power consumption is by measuring how long its battery will run it while you're using it and dividing the battery's capacity by the number of hours it runs the laptop. A new 65WH battery that runs a laptop for four hours yields a value of 16W/hour. Your wall wart for that system is probably rated at 55-65W output.

When computing output from solar panels, a good starting point is to use the following formula: Daily power available = rated output power * 10 hours / 2
The divided by 2 accounts for decreased power from the panels not at right angles to the sun all day, losses in the wiring between the panels and the controler, losses in the wire from the controller to the batteries, and the occasional passing cloud. Summer, with its longer days may have more hours of sunlight but you'll discover that the maximum number of hours of sunlight on tilted panels is 12 or less unless you can move them during the day. Flat mounted panels can get more hours of sunlight in the Summer but suffer from higher incident light angle losses than angled panels. A good MPPT controller will support wiring two 12V panels in series, decreasing power losses in the wiring from the panels to the controller.

Don't forget that your furnace, with its heavy duty 12V fan motor will be a significant nighttime drain on the batteries. Most rvs come with 12V marine hybrid batteries that aren't as good as true deep cycle batteries. Two options are to replace these batteries with 6V golf cart batteries wired in series or true deep cycle 12V batteries. Based on my dry camping experiences in my class A, I'd suspect that you'll need at least 300AH of batteries if you're going to be using the furnace at night. If this is true, four golf cart batteries will end up giving you around 440AH, or you could go with three 12V deep cycle batteries giving you 300AH or more, depending on the specific batteries you get.

[Jay2504]

On my 2504s, the "Zamp Solar" plug is on the curb side of the camper. I pulled the panels and reversed the wires to use with a 1.5 amp "charger/maintainer" that I allready had. I also connected the wire under the unit directly to the batteries, by passing the shut off. The wiring is only 14 gauge. From what I have read here, everyone uses at least 10 gauge for their solar setup with most using 6 or 8 gauge to reduce resistance. Thought I would pass on what I found. Jay

[alexisc]

Thanks for all of the comments. So much to take in. I get my unit on Saturday and I had a Samlex 1000W inverter and remote shipped to my dealer this week for them to install. I'll figure out my solar needs after a couple of weekend trips

[nodrawers]

All the auto switching is great but expensive to install. I just installed my 2000W inverter close to the batteries and installed a female plug with a short 10awg extension that plugs directly into the inverter. To use the inverter I just plug the trailer power cord into the female all weather receptacle. then the AC panel is hot and you select the outlets you want. Before turning on the main breaker just make sure all breakers except the outlets are off, especially the converter for charging the batteries. I have 200W solar roof mounted with the Bogart Eng. controller and monitor and two 6V batteries. Also have 200W portable that I can just plug in to up it to 400W solar or use in the winter when the sun stays real low. Did a trip for 27 days last Oct through NM, AZ, UT, Colorado & KS. All boondocking and never had a hook up. Had some cold nights in UT& CO and used furnace no problem. I do use the microwave and a small coffeepot but not at the same time. seldom any TV as There is never any signal where I normally camp. Just got back from 16 days in NM with no hookups & never used the additional 200W portable with no problems. The Bogart controller and monitor are a must in my opinion. Never got below 80% on batteries.

[nodrawers]

As a power saver I also installed 3 double 12V outlets/W usb in bedroom and kitchen area as they are less power hungry than an inverter for charging the usb type items, phones, laptop, notebook etc.

[alexisc]

Originally Posted by pmsherman

While I don't have solar power on my rv (yet), I do have a remote controlled, off grid, observatory that's solar powered. All of the issues you face are ones I've already solved.

Inverters make things easy because it's just like having power from the grid. Unfortunately, inverters provide the worst efficiency when looking at battery life. Your RAID device probably has a wall wart that provides 12VDC to power it. You can power it directly from the rig's 12V battery with a replacement plug. You can purchase a DC power supply for your computer that will allow running it directly from a 12V battery.

Devices requiring voltages different than 12V can be powered by DC-DC voltage regulators. Buck regulators create voltages less than 12V, boost regulators create voltages higher than 12V, and buck/boost regulators can provide voltages from a few volts to 35V when hooked up to a 12V battery. I like using buck/boost units for devices that require 12V because the DC voltage in my class A rv varies from below 12V (battery nearly discharged) to over 14V when the converter or alternator is outputting its maximum voltage. A buck regulator set to 5V will supply power for recharging your cell phones, tablets, and many other current consumer electronics devices. My 12V desk lamp has two 5V charging outlets and I can also charge devices from the computer's USB ports.

I installed a tap on one of the rv's lighting circuits that has a 15A fuse and only a 2A load after I changed the fixtures to LEDs. The tap ends in a PowerPole connector that fees a small distribution box with 4 PowerPole connectors in it to power other devices. From this, I can run my computer using its DC power supply, the router, a wifi range extender, and a nice bright 12V desk lamp. I have an additional outlet available because the wifi extender requires 24V which is a separate output from the boost regulator installed in the distribution box.

You can purchase these regulators as prebuilt, sealed, boxes that just require attaching input and output wires to them. My preference is to buy small circuit board regulators that require soldering the connecting wires to them then setting the output voltage using a meter. I can mount these little boards in whatever enclosure I need to use.

Your solar power system should include an MPPT controller. These are much more efficient than the PWM controllers that are less expensive. Solar panel units need to be mounted where NONE of the cells will be shaded because, for most panels, if one cell gets no sunlight, the entire panel produces no output. If you're planning on camping in national parks, you may discover that you hve a shaded site and the solar panel doesn't produce enough power for you.

To determine how much solar power you'll need, you need to check all of your equipment that you'll be using to determine how much power it uses. Don't believe the power ratings on wall warts because they are designed to support the maximum amount of power the device may need, not what it actually uses over an extended period of time. The easiest way to measure a laptop's power consumption is by measuring how long its battery will run it while you're using it and dividing the battery's capacity by the number of hours it runs the laptop. A new 65WH battery that runs a laptop for four hours yields a value of 16W/hour. Your wall wart for that system is probably rated at 55-65W output.

When computing output from solar panels, a good starting point is to use the following formula: Daily power available = rated output power * 10 hours / 2
The divided by 2 accounts for decreased power from the panels not at right angles to the sun all day, losses in the wiring between the panels and the controler, losses in the wire from the controller to the batteries, and the occasional passing cloud. Summer, with its longer days may have more hours of sunlight but you'll discover that the maximum number of hours of sunlight on tilted panels is 12 or less unless you can move them during the day. Flat mounted panels can get more hours of sunlight in the Summer but suffer from higher incident light angle losses than angled panels. A good MPPT controller will support wiring two 12V panels in series, decreasing power losses in the wiring from the panels to the controller.

Don't forget that your furnace, with its heavy duty 12V fan motor will be a significant nighttime drain on the batteries. Most rvs come with 12V marine hybrid batteries that aren't as good as true deep cycle batteries. Two options are to replace these batteries with 6V golf cart batteries wired in series or true deep cycle 12V batteries. Based on my dry camping experiences in my class A, I'd suspect that you'll need at least 300AH of batteries if you're going to be using the furnace at night. If this is true, four golf cart batteries will end up giving you around 440AH, or you could go with three 12V deep cycle batteries giving you 300AH or more, depending on the specific batteries you get.

This is a lot to think about but thanks for the detailed overview. I have an inverter in. Now I'll be spending a few nights in it to see how much I use.
Does the furnace drain the battery? I thought it was gas?

[alexisc]

Originally Posted by nodrawers

As a power saver I also installed 3 double 12V outlets/W usb in bedroom and kitchen area as they are less power hungry than an inverter for charging the usb type items, phones, laptop, notebook etc.

I have usb outlets in the bedroom and living room - they came with the unit, so that's good for my phone and ipad