Boondocking/off-grid full time questions - Anyone used a solar generator?

[SkiSmuggs]

There is no reason that solar can't be done a little at a time. Looking at $4-8K scares a lot a folks away from it when a few hundred can be a good start to extending your off-grid capability, especially if you are not full timing in the Arizona desert. Lithium or AGM batteries, monitoring systems, panels, controller upgrades can all be added later.
I started with GC2 batteries, then a 100 watt portable, then 200w on the roof and found the 300w so far meets my occasional boon docking needs.

[okmunky]

IMHO Renology is over priced and according to Handy Bob you don’t need an MMPT charge controller for 500 watts or less. He also told me that Mono vs poly is insignificant unless you have a huge array.

I recently added a extra 100 watt poly panel to my existing 272 watts. I have a 20 amp charge controller. I bought the panel on eBay for $95 shipped and a really nice aluminum tilt mount on Amazon for $40. If you don’t go very far north, tilt isn’t as important, but make sure NOTHING on your roof can cast a shadow on any of the panels. Costco’s have 207 amp hours, Trojans 235

The kit in the link is lacking some parts. You'll probably need a combiner box and cabling from the charge controller to the batteries. Adding a shut off to the panels is a good safety move unless you plan to work on the system indoors or after sunset.

One of the most important parts of a solar system is the battery meter. Trimetric makes the best one - their 2030 model. Backwoods Solar sells a kit that includes everything you need for $230.

You haven’t mentioned your batteries. You'll need ~ 1 amp hour of battery capacity for every watt of solar panels. Most of us use 6 volt golf cart batteries connected in pairs. Costco and Sam's Club sell them for about $85 each, or Trojan T-105RE batteries if you're wanting something better.

Have fun!

[coastalsqrl]

Okmunky, My current batteries are : Coach: Everstart Deep Cycling, 845 Marine Cranking Amps, 122 Amp Hours @ 1 Amp. I just purchased these. Chassis: Interstate High Cycling. I'm getting differing opinions here. Some say to move the new Everstart to the chassis batteries since they're a hybrid, and put two 6 volt golf cart batteries in the coach, and that would be sufficient for a 400w system. Others say that I need a separate battery bank specifically for the solar system. Any input there? Also, for the 1 amp hour per watt, does that only include the coach batteries if I do it that way, or 400 amp hours for the whole bank?

Also you're right about the mppt controller. The issue is if you think you might want to add panels in the future. Spend the extra $$ for the controller now and have it installed, or wait and see if you need more power, but then have to purchase and reinstall the new controller.

SkiSmuggs, I agree that to start small and you can always grow. I think the 400w would be a good starting point since I'm waiting to be full time. There's just a million different options, configurations and opinions that makes pulling the trigger on a final set a bit tough. Can afford a few thousand dollar mistakes...

[Searching_Ut]

It used to be common for the battery manufactures to provide data sheets showing the bench performance of their batteries when it came to cycle depth vs life expectancy. Those charts are hard to find for most batteries now. That said, most hybrid flooded batteries will have lost 20 percent of their storage capacity in somewhere between 250 to 350 cycles down to 50 percent. 6 volt Golf cart batteries which are deep cycle can often be expected to last 750 to 1200 cycles down to 50 percent. Of course this varies with actual depth of cycle, temperature, how long batteries are in a less than fully charged condition etc. Hybrid batteries on the other hand sacrifice deep cycle ability in order to maintain a higher voltage and current demands for shorter duration high loads which may or may not be of importance to you. (IE. Starting an engine) This difference is why Deep cycle batteries are generally considered the better choice by RVers, as the lower current but long duration demand is what we put batteries under most of the time.

As for how big a system you need, most of the general rule of thumb stuff is good for a system that will have an unobstructed view of the sky during summer months. I ended up doubling that after my first year with a system that varied from 400 to 600 watts, flat mounted panels. I now have 1000 watts on the roof to support 460ah of batteries in a bank of 4 Golf cart batteries. Overkill under good conditions most of the year, but we more often than not find ourselves with shade some or most of the day, afternoon thundershowers etc. After a season, with a little over 6 weeks of dry camping, the 1kw system seems about right for us. Cost wise, I've got approximately $2500 dollars into it, including 10 100 watt panels, trimetric, 2 bogart SC 2030 controllers, 4 Golf cart batteries, 2000 watt pure sine inverter, wiring, home made mounting brackets and combiner box, fuses, switch etc. Being able to do everything myself helped a great deal. I wired my system through a transfer switch to power the whole rig, with a cutout relay to shutoff the DC converter when I switch on the inverter. Other high drain items we have to manually switch off

I run my CPAP through the night, we watch a fair bit of satellite TV, few minutes of microwave use quite often. Depending on conditions we use the drip filter coffee maker, and the wife uses a hair dryer most mornings (Smaller 1200watt unit) We even find we can often use the slow cooker for most of the day when we're in a good sun setup and still get a full battery charge by the end of the day. When solar harvest is looking less promising, we use the percolator, wife possibly forgoes the hair dryer, and we don't of course use the slow cooker. By being a little flexible we rarely have to use the generator.

[okmunky]

Chassis batteries do not have anything to do with your solar system except if you have a solar battery maintainer. While there may be a way to wire your chassis battery such that it gets power from the solar system, for the most part it needs to be separate. A chassis battery needs cranking power. Solar batteries need storage capacity, those are your house batteries that run the 12 volt systems in your RV. I agree you need 2 golf cart batteries wired in series to make 12 volts. That's what I have. Mixing battery types is a bad idea.

How many batteries can you put in your RV? If you only have room for 2 then don’t plan on more than 400-500 watts of panels.

My brother just got into RVing in a BIG way - 39’ toy hauler fifth wheel and a HUGE pickup. Until a family emergency caused him to have to leave, he and I were planing his solar system.

Step 1 - install a Trimetric 2030 battery monitor. He bought a kit from Backwoods Solar, cost - $230. It allowed him to see how much power he is using and see what is happening with his house battery system. This might be a good place for you to start as well.

I have a favor to ask. PLEASE put the information about your RV in your signature space. To do that click on User CP in the upper left of every page. From the left column select "edit signature". Add your detailed info then scroll to the bottom and click on "save changes".

For us to help you properly we need easy access to the details about your rig. Also, from some of your questions I don’t think you are reading enough about how solar works in an RV and how to do it properly. To do solar right you need more education. Even if you have someone else install it you need to know how it should be done. There are a lot of people sellling solar systems that don’t work like they should.

https://handybobsolar.wordpress.com

[coastalsqrl]

okmunky,
You are correct in that I don't know completely how the systems work yet. I've been taking this whole adventure one step at a time and just got to solar a couple weeks ago. Before that, I knew nothing about it. I've been researching, but will be using the links provided and watching some videos I found also to try to understand how everything works together. A couple more weeks I'll be fine but until it all clicks I'm sure I'll sound like an idiot. The ideal goal would be to get everything installed and working by the end of the month.

As for the favor, I added my details to my signature and vehicle details. Hopefully it will show up!

I'll check back in in a few days and see where I'm at. Enjoy your weekend.

edit: I screwed up on the sig and put too many lines. Should be fixed for next post. Until then,

1994 Coachmen Destiny 38', C8.3 Cummins Diesel
6spd Allison Trans, 7.5kw Onan/Cummins Diesel Gen
https://www.instagram.com/coastalsquirrel/

[keymastr]

Start small. A fairly simple 3 or 400 watt system may be plenty for your uses. You can always add more and if you get a small generator you can top off the batteries with it to make up the difference. I bought a 1000 watt generator for just running the charger. It is the size of a bowling ball bag, weighs just 18 pounds, is quiet and will run 5 hours on about a pint of fuel. Cost $200 with shipping. Cheap insurance if the solar is not quite enough.

[okmunky]

Bravo! That helps a lot. Now we don’t have to scroll back to be reminded of your details. You can get more lines to your sig if you become an IRV2 supporter. I figured the $15.02/year was a small price to pay for all the benefits.

My apologies for the late night grumpiness. Solar is a complicated issue and this is where you'll get honest answers. Sad to say, but I've heard sales people tell outright lies just to make a commission. Please make sure to read this section of Bob's blog if you can’t get to it all yet.

https://handybobsolar.wordpress.com/2016-the-good-guys/

I'll send you the list of products we put together for my brother's RV in a private message. It's just our opinion of what is needed, but it's backed up by LOTS of research and my 6 years of living on solar.

If you are planning to have someone else install your solar I would suggest you research them as well. Planning to have solar installed within 3 weeks is an ambitious goal.

[harryn]

There are times when I really wonder about the monitoring kits.

Back when panels were costing $1K / each and we were all rationing power like a people living off of dew in the dessert, of course they were a high priority.

Now that panels are fairly inexpensive, if a person puts that $250 - 400 into another panel or battery vs a monitoring system, I wonder which one is really the better investment?

Of course watching dials is fun, but still, you have to wonder.

[MrMom]

Originally Posted by okmunky

IMHO Renology is over priced and according to Handy Bob you don’t need an MMPT charge controller....

After bench testing actual outputs of several solar panels in real world conditions, I will now only purchase Renology Mono panels. They are worth the few extra bucks.

For a 12 volt system, I agree, PWM is fine. MPPT comes out ahead in the higher voltage systems.

I did not want to spend the $$$$ on commercial energy management monitors so I designed my own system for $40.00 using various off the shelf circuits.

[Off Road]

Don’t shoot the messenger, but think hard about solar. I get the impression you are located in Florida or somewhere down in the south. You cannot power air conditioning with solar power. If you need to park in the sun for your panels to work your RV is going to get awfully warm in the south. On the other hand you could get a small inverter generator for battery charging for less than $1000, park in the shade and only run your big generator when you want to run the AC. A couple of Zamp portable panels can keep your batteries pretty close to full and let you park in the shade. Mine have yet to grow legs. Replace light bulbs with led bulbs and stay off the 120 volt usage and you will use very minimal electricity in the summertime. My little Yamaha inverter generator uses about 5 gallons of gas a week when I am running it about 6 hours a day during cold weather as my furnace uses lots of electrical power. In the summertime it gets used maybe once a week for a couple hours. Uses less than a gallon of gas a week. Hardly worth the expense of a complex solar system especially if I have to park in the hot sun. My suggestion would be to try boondocking for a month with your current setup and see how long your batteries last, do you even like boondocking with its navy showers etc. conservation is the key to successful boondocking.

[weredoingit]

Renogy 400 watt 4 6v golf cart battery's 2000 watt inverter total with the battery's about $2200, the best thing I've ever added

[cruzbill]

Your new Boondocker is NOT an INVERTER, its a CONVERTER. Sorry for shouting, but important difference. An inverter makes 120vac from your batteries (12vdc). Usually so you can have an outlet or two for small loads. A converter works when you are plugged into shore power (120vac) and makes 12vdc to charge your batteries and run your fridge and lights.

You MUST use a solar charge controller, either MPPT or PWM. It MUST be wired so the solar panels connect on the input side and new wires go from the output side of your charge controller to your batteries. You cannot connect solar panels directly to your batteries.

Time to get some professional help, as you are going to spend some real money and you don't want to throw good money after a bad idea. Good info here, but maybe a little too much for what you NEED to do (as opposed to what you may think you WANT to do)

[coastalsqrl]

Nice setup weredoingit! Off Road, I appreciate the info and concern. I've been spending winter and spring in South FL at the beach, and coming up to the mountains in NC/VA for summer/fall. I'm not going into this thinking solar is going to fulfill my every need. I always stay right on the beach in FL and usually get a good breeze. Even when I have stayed over the summer in Miami and West Palm I've rarely run the AC, but I also have a 7.5kw diesel gen for when it gets extra hot. I a couple backup battery packs, a couple back up solar battery packs, my 90 gal of diesel to run the gen and 60 gal of propane for fridge and cooking. Also possibly going to Colorado east coast this spring. My main goal in all of this is to make living off grid comfortable, and sustainable, but simple. I figure for $1000-1500, solar should add a good base of consistent energy in addition to my other sources. I also don't use much electricity and am generally outdoors if the sun is out. I went ahead and purchased the system below and hope to install by mid feb. Will update once done. Will it all be enough and work? No idea. But if it fails my new hand crank washing machine will come in handy.

4 100w Mighty Max Poly Panels - $380
TriMetric 2030RV Monitor - $205
SC-2030 PWM Controller w/ Temp Sensor - $143
4 6v golf cart batteries (haven't purchased these yet)

Edit: I did look at the yamaha generator and I do think that may be a good addition for another backup.

Edit: cruzbill, haha yes, I have since learned the difference between an inverter and converter. I have a 60amp converter and a 750w inverter. I may need to purchase a larger one for the 400w system I purchased. I've heard 1500w is plenty... Converter goes in, Inverter comes out... Or something like that.