Electrical system for Boondocking?

[Indiana Rambler]

What is everyone’s thoughts on this unit? Seems like it would be a decent idea to wire everything to this box from the camper. I plan on having running water, lights, two to three 110 outlets, max air fan, USB ports, interior and exterior lights, an ac unit mounted in a built tongue box, and maybe in the future a propane heater. I feel that this generator may be a good fit to make it plug and play. I understand I’d need shore power to run the ac, but everything else in the middle seems this unit would suffice. Or, should I just piece all these parts out myself and build this unit as it’s own entity.

https://www.fuelzero.com/FuelZero-G2-12 ... 2-1280.htm


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[tony.latham]

Or, should I just piece all these parts out myself and build this unit as it’s own entity.

I think that's what you should do for several reasons. First of all, all batteries fail including. So in ten years or so, that box will need an upgrade and you probably can't buy a drop-in battery from them.

Secondly, "25AH 51.2v LIFEPO4 Battery " Are you kidding? 25 amps?. But maybe I'm getting my Ohm's law since it's an odd voltage. But amps is amps. My $200 AGM that should last nearly a decade has 35 usable amps.

Thirdly, that's a monster of a box that I think is designed to be put in the back of a truck bed. It would be a challenge, at least for me, to find a place to put it in a teardrop which would waste a lot of space. It wouldn't be a challenge to find a place for the battery to live and a Progressive Dynamics inverter system to distribute your power.

That's my two-bits.

Tony

[Indiana Rambler]

Or, should I just piece all these parts out myself and build this unit as it’s own entity.

I think that's what you should do for several reasons. First of all, all batteries fail including. So in ten years or so, that box will need an upgrade and you probably can't buy a drop-in battery from them.

Secondly, "25AH 51.2v LIFEPO4 Battery " Are you kidding? 25 amps?. But maybe I'm getting my Ohm's law since it's an odd voltage. But amps is amps. My $200 AGM that should last nearly a decade has 35 usable amps.

Thirdly, that's a monster of a box that I think is designed to be put in the back of a truck bed. It would be a challenge, at least for me, to find a place to put it in a teardrop which would waste a lot of space. It wouldn't be a challenge to find a place for the battery to live and a Progressive Dynamics inverter system to distribute your power.

That's my two-bits.

Tony

Those are kind of my thoughts as well Tony. Electronics are ever changing and something better keeps coming out. I would be “stuck” with this system and to find parts and pieces as they life out or fail could and would be difficult. I was thinking a built system I would be able to replace the parts or pieces as they failed.

As far as the lithium battery goes, there’s always a controversy over them I keep finding. The pros are their power curve (total power output for a charged battery) seems better than AGM, but, they can be a bit finicky with charging, and, they don’t like to be in freezing temperatures. I’m still torn with what type of battery I should go with. Thank you for the info on your AGM battery, that was in my too two choices for batteries.


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[tony.latham]

The pros are their power curve (total power output for a charged battery) seems better than AGM,

You're right. But amps is amps. And 25 is on the short side (And for $2,000). Who knows if it has a low-temperature charging cutoff?

Tony

[Indiana Rambler]

Think I am going this route for my electrical. With the exception of using a Renogy 3000 watt inverter, 200 AH lithium battery, and also using two of the flexible 175 watt solar panels on top of the camper, and adding a briefcase type of solar panel so I can chase the sun with. And thoughts for or against this idea?


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[mtbikernate]

I've read a lot of reports of reduced lifespan of flexible panels mounted on a trailer roof.

I bought 2x 100w rigid panels for mine. For now, I plan to set them both up as portable panels to chase the sun, but I want to mount one of them to the roof, in a sort of quick release fashion, so I can both charge while driving and remove to chase the sun in camp (or get it out of the way to carry more things on my roof rack).

I've also seen recommendations to have at least 200w of solar per 100Ah of battery to start with. Sounds like you're probably on the right track there.

That particular charging diagram looks a lot more complicated than it needs to be. I've omitted the DC-DC charging from mine. I've read plenty from folks who charge their TD from the car battery. everything from not even using a dc-dc charger to running separate charge-specific HEAVY gauge wires straight from the battery to an Anderson powerpole connector at the back of the vehicle, so you have to connect 2 plugs when you hook up your trailer. For the amount of battery drain I'm going to experience while driving, it's not worth it. And this is what solar mounted on the roof is able to address, anyway.

I have also omitted a permanently attached inverter from my system. I have a very small one that I can attach to my battery if I happen to need it, but in 5yrs of owning my trailer, I haven't needed it. My tow vehicle has a small inverter in it, too.

Mine will look a little more like this.



Though my panels will be mounted in parallel. Replace the inverter with the a/c charger (noco). I haven't decided if I'll wire my DC loads as in this diagram from the battery or through the charge controller as I've seen some wiring diagrams indicate. Eventually I'll be adding a shunt/battery monitor so I can more accurately keep track of my power usage, so that might warrant running my DC loads from the battery.

[tony.latham]

And thoughts for or against this idea?

A couple of things. First of all, I believe most flexible panels are junk. They're made using PET plastic and have a short lifespan. I really like my 100-watt Renogy panel that's made from ETFE. I see no physical degradation with it. But perhaps you're looking at Renogy's 175-watt panels?

Secondly, with that much solar, I doubt you'll ever need to charge from your tow vehicle. So you might save some money, for now, leave room for the DC/DC charger, and add it at a later date. My latest-greatest teardrop is facing its fourth season. I installed a switch to turn on charging from the tow vehicle. It's never been on.

And I'm with MtBikeNate on the 120-volt issue. We keep a small plug-in inverter in the tongue box. It's bounced from teardrop to teardrop since 2004 and I can't recall when we used it last. You can pleasurably camp without 120 volts. DC will do everything we need. Something to think about.



Tony

[troubleScottie]

Hopefully your solar panel controller has a second input. Many do. This means towing vehicle (TV) to TD charging only needs the wiring to bring the power back to the TD ( cable, fuses, isolating solenoid, Anderson connectors ). The "standard" power wire on a 7pin connector is not designed to not handle battery charging. The only issue is dealing with solar vs TV assuming you can do solar charging while driving.

Your last diagram covers the bases -- VAC charging, VAC output as needed, solar/DC charging, etc.

Sticking to 12V, possible 24V batteries are the best plan. There are some 24V charging systems, typically in boats, due to some higher need items eg radar. But boats have engines and generators to handle this. However, most of the devices that you might install in a TD are going to be 12V, so no major reason to exceed 12V.

[Indiana Rambler]

I have read that the flexible panels aren’t the greatest either as they degrade, and quite frankly, I’m certain I won’t always be in the sun while camping. I was looking at the Renogy 175 w panels as they seem to be pretty efficient. I do like the idea of installing panels to be able to be removed from the camper if needed, plus it’s a way to store them while traveling. Thank you all for your inputs!


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[TimC]

I agree with Tony. You could save your money up front and see if 200 watts of panels will cover your needs. Two 100 w Renogy panels mounted "permenantly" on the roof cover my needs. I am not in a real sunny location here on the WI/MI border. Running a 35L fridge, lights, case fans and charging some electronics I have had very good success recharging my batteries each day. I am careful by conserving energy. I don't charge phones and such until afternoon when possible.

You can always add an inverter later if you just have to have it. Boondocking in my mind means simplicity. Different strokes for different folks though!

Cosmo might be a good resource for real world flex solar panel longevity. I know in one of his older videos he had already lost one flex panel that was maybe a year old.

How do I know what my approximate state of charge on my battery is? I have two Bayite ammeters showing me solar production and consumption. I know Bayite ammeters are not popular with some folks here as there are ammeters on the market that do the math for you (at a considerable markup), however, it's very simple to interpret the readouts. I reset both to zero watt hours before a trip when the batteries are fully charged (either by solar or house current. I just watch the watt hour readouts and without doing any math I can tell if I am producing what I am consuming each day. If they are ever off by much at midday (consumption WH are much higher than production WH) I can conserve energy by not playing the radio, and not charging unnecessary electronics. I can also deploy a 100w suitcase panel to follow the sun. Running low on capacity hasn't been a problem as by mid-afternoon the production has usually caught up with consumption and the charge controller is just trickling watts into the battery.

I'm eager to see how you design your system and the results you get. Each builder that posts their designs and results help others decide how to proceed. The biggest variable seems to be personal needs on the consumption side and where your system is located on the production side. Fortunately efficiencies have improved in the last decade and hardware has become smaller and lighter as a result.

[Indiana Rambler]

Thank you for your inputs! I really want to build a almost complete off grid low carbon footprint system. I am looking for cost effectiveness, but I don’t want to skimp on anything up front.

That being said, what would a good DC-DC charger be to install directly into my unit? I’d like the camper to be completely dummy proof. Just plug in the camper for power/charging, and or reading my power outputs through Bluetooth technology.


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[mtbikernate]

I would posit that a dc-to-dc charger isn't so dummy proof for a trailer. Far easier to just rely on solar.

Renogy and Victron are good brands. Renogy offers a couple dual input solar controller/dc-to-dc charger models, depending on your power needs, as well.

[tony.latham]

I have read that the flexible panels aren’t the greatest either as they degrade...

The problem with flexible panels is that a lot of them are junk. And so they all get put in that category. There's a great variance in quality.



Calling them all junk is like saying all RVs are junk. This may be 90% true or so until you look at products built by Vistabule or Airstream.



Tony

[TimC]

...

Calling them all junk is like saying all RVs are junk. This may be 90% true or so until you look at products built by Vistabule or Airstream.
...

Or Tony, or John, or Tom, or George, or...

[friz]

I boondock exclusively on a 100 ah battery and 50 watts of solar. It runs a PWM motor control modified Fantastic Fan, lights and charge ports. No refrigerator. No heat. No AC. Heat up my coffee and cook meals on white gas and charcoal. This will be my 5th season camping like this. No plans to change anything.

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