Beginners Sizing Questions

[Dart0366]

We bought a new to us 5th Wheel Toy Hauler, we want to park it off grid and plan to live full time. We will still travel so system has to be mobile. Think Northern Washington, Northern Idaho or NW Montana area. So winter can be overcast and dark. 5k Generator as back up.

We have one component that will run 24/7. It runs on 110V 20A 9-11 amps per hour. Couple computers, phones, tv, microwave, freezer, refrigerator, washer dryer, water runs off pump so need to power pump, lights, possible heater we might sub with wood heat but to start at least will be forced air heat. We do not spend tons of time in high heat areas if we do we will run the generator when running AC.

Was looking at 6 roof mount solar panels, already bought 4. Is that going to be enough? Was looking to start with at least 4 Lithium Battleborn 100AH batteries and add 2 more as funds allow. Or do I need 6 to start. To live comfortably how many should I have. I have 2 40Amp charge controllers w/Bluetooth. I will look this weekend to find out inverter original 3k went out and he has put in a new one he just didn’t know which one for sure. Behind a wall takes a bit to get to it.

Lucas

 

[DThames]

Welcome. There are several questions that you need to supply information on before anyone can say much, correctly.

You need total load in watt hour or kilowatt hours. There are ways to measure each device and add them up. But to be clear, you have a 9-11 amp load that runs 24 hours per day?

What size panels did you buy, what is the watt rating?

 

[chrisski]

It is winter in AZ and my 6 roof mounted 100 watt panels would not give me enough power to run your load at 9 amps an hour, and if you meant 120 volts at 9 amps, that is the equivalent of about 90 amps from 12 volt batteries, so totally out of the question.

I can get 36 amps an hour if I believe the panel stats, but with shading from things like AC vents at least part of the day, 4 to 5 real solar hours out of 10 hour sunset to sunrise time, and flat panel orientation, I get around 40 to 50 amp hours a day. I do supplement this with 400 watts of ground portable panels so when I draw 150 amp hours off my batteries overnight and its sunny, my bank is recharged by 1:30, at which I can switch from propane to electric on my fridge for 2 and a half to three hours, and this is because my portable panels that are angled better to the sun and I rotate to follow the sun three times a day out perform my 600 watts of flat panels by 1/3.

I also do not like the idea of a 3kw inverter installed on a 12 volt system.

I also found my largest load is the DC fan for my propane heating. It pulls about 8 amps and cycles on through out the night and uses 80% -90 % of my 100 ah - 150 ah of battery draw a night.

The more you run your 5 KW generator, the less this will apply. Other people can do it cheaper and this is an estimate, but I would spend at least $20k on the system you are describing and it would end being 24 VDC. As much of the things a possible like washing machine and microwave usage would need to be done in full sun shine, and I’d have a small fridge or a propane fridge. With this, you’d still be limited to one large energy appliance at a time, so that means not making coffee or doing laundry at the same time.

 

[Hedges]

We bought a new to us 5th Wheel Toy Hauler, we want to park it off grid and plan to live full time. We will still travel so system has to be mobile. Think Northern Washington, Northern Idaho or NW Montana area. So winter can be overcast and dark. 5k Generator as back up.

We have one component that will run 24/7. It runs on 110V 20A 9-11 amps per hour. Couple computers, phones, tv, microwave, freezer, refrigerator, washer dryer, water runs off pump so need to power pump, lights, possible heater we might sub with wood heat but to start at least will be forced air heat. We do not spend tons of time in high heat areas if we do we will run the generator when running AC.

Was looking at 6 roof mount solar panels, already bought 4. Is that going to be enough? Was looking to start with at least 4 Lithium Battleborn 100AH batteries and add 2 more as funds allow. Or do I need 6 to start. To live comfortably how many should I have. I have 2 40Amp charge controllers w/Bluetooth. I will look this weekend to find out inverter original 3k went out and he has put in a new one he just didn’t know which one for sure. Behind a wall takes a bit to get to it.

Lucas

When you say, "We have one component that will run 24/7. It runs on 110V 20A 9-11 amps per hour." do you really mean 110V x 20A = 2200W continuous? Or maybe 110V x 10A (+/- 1A) = about 1100W continuous?

If so, that's 52,800 Wh/day or 26,400 Wh/day.
Would take at least 10 kW (or 5 kW) of PV panels (more likely needed in winter) and at least enough battery to last through a 12 hour night. About 26,400 Wh or 13,200 Wh usable capacity.

This is very doable on a house, in fact just about what I have. But relatively impractical for an RV.

Maybe you mean an 110V load to be powered by an inverter, drawing 20A 12V when on but about 50% duty ratio so 12V x 10A average, 120W average, 2880 Wh/day?

If so, much more reasonable.
About 500W of panels in the summer, but 1000W to 2000W needed for shortest days.
150 Ah 12V lithium might make it through one night. Multiple of that can get through a cloudy day, but with generator you can always start that if no sunshine, recharge while running the load.

"Was looking at 6 roof mount solar panels, already bought 4. Is that going to be enough?"

You need to list panel wattage. Volts and amps to plan series/parallel arrangement and see if SCC fits.
Flat on roof? Good for summer and as good as it gets (least bad) in overcast winter days.
For sunny winter days, flat will produce a fraction of what tilted would. Need double the panels, or tilt mount, or extra as awning/portable.

"Was looking to start with at least 4 Lithium Battleborn 100AH batteries and add 2 more as funds allow. Or do I need 6 to start. To live comfortably how many should I have."

My math for 2880 watt hours suggests 100 Ah x 4 is good enough for one night and some other loads. 80% DoD, OK for lithium, would be 320 Ah, 3800 Wh.

If price is an issue, consider how weight, capacity, lifespan of FLA or AGM compares.
Some DIY Lithium costs fewer dollars than AGM, but I think top name commercial lithium batteries are still much more expensive.

 

[Dart0366]

Welcome. There are several questions that you need to supply information on before anyone can say much, correctly.

You need total load in watt hour or kilowatt hours. There are ways to measure each device and add them up. But to be clear, you have a 9-11 amp load that runs 24 hours per day?

What size panels did you buy, what is the watt rating?

Harvest Right has taken every precaution to make this appliance run as affordably as possible. Our small and standard freeze dryers use a standard 110 volt outlet. At peak, the freeze dryer draws about 16 amps, but on the average about 9 to 11 amps (990-1210 watts) of power per hour.

 

[Hedges]

1200W, 14400 Wh during a 12 hour night.
That's what your battery will have to supply.

Similar to my home's battery backup. I have 405 Ah 48V AGM battery, about 20 kWh gross. It can supply 14 kWh before my inverter disconnects at 70% DoD. The battery is 1000 pounds and cost $5000.

You can use LiFePO4 batteries for lighter weight, deeper DoD, longer cycle life.
Commercial assembled units will cost more than my AGM, but DIY with 280 Ah cells bought direct from China or as part of a group buy with other forum members can be lower cost.

Freeze drying on your toy hauler. How many days per year?
Fossil fuel generator is an option.
Can the unit be turned off every night, just coast at freezing temperature and operate when the sun shines? Little battery needed then.

PV array size - 14 kWh at night, 28 kWh per 24 hour day.
Divide by 5.5 to get approximate PV watts (not including winter, when there is less sun.
You'll need at least 5 kW of PV panels. About 25 square meters if tilted toward the sun. Perhaps 50% more if flat on the roof, depending on season.

 

[Dart0366]

As I said we are brand new to this and exploring options. The one appliance is a Freeze Dryer we use to store food. At peak it draws about 16 amps. It’s recommended to be on a dedicated 110v 20amp circuit That’s what I meant about 110v 20amp above. On average it draws 9-11 amps an hour. One cycle runs 22-28 hours straight. As someone noted above maybe it draws much less for some of that period of time. I am writing to the manufacturer to ask that question.

so far we have just 4 Rynogy 100volt solar panels. Am very open to suggestions. If need to start from scratch is no big deal will just put this system on my parents trailer.

Was looking at starting with 4 Lithium SOK batteries 12.8 volt 206 amp hour. So if I am understanding correctly that is 800amp hours. Eventually could go 4 more batteries totaling 1600amp hours.

As far as other draw I don’t have the freezer we would run yet nor the refrigerator. Forget the laptop or other electronics I will provide for them separately. So that leaves lights and heater fan and I will see if I can find heater fan specs might be a bit difficult but will look. As far as lights they are all Led lights.

I am not against going 24v or 48v if there are good reasons to do that in our applicatio.

 

[Hedges]

4 x 100W solar panels is 400W
400W x 5 effective hours sun per day is 2000 Wh/day.

110V x 10A = 1100W
1100W x 24 hours is 26400 Wh/day

26400/2000 = 13.2
You need at least 13.2 times as many panels as you are considering.
More due to efficiency losses.
More if the 52 panels aren't all in a big array tilted toward the sun, not casting a shadow on each other.

4 batteries x 12V x 200 Ah = 10,000 Wh
That's enough to run the freeze dryer 9 hours with about 100% DoD.
Not quite enough to get through the night.

Not a practical mobile PV system.
It is something you could install at a house. Fairly typical.

 

[HRTKD]

I'm active in the RV community. Of all the interesting things I've seen people put in their trailers, this is the first I've heard of the Freeze Dryer and had to look it up. Maybe if you were going to be parked at campgrounds with full hookups it would be OK. Boondocking? Not going to happen. Even for long drives between campgrounds I'm not sure it's feasible.

Just because you have a toy hauler (which I have also), doesn't mean you can take everything with you. Living in an RV usually means some compromises need to be made.

 

[chrisski]

So that leaves lights and heater fan and I will see if I can find heater fan specs might be a bit difficult but will look. As far as lights they are all Led lights.

Found out my heater fan draws 8 amps. With 16 hours when I get no solar from the sun, that adds up on my 458 AH battery bank where I want to draw only 120 AH a night. Being 55 at night and 25 at night made a huge difference. Sub freezing temps I used nearly twice as much power. I typically use around 110 AH a night with the temps around 45 and 55, but between 25 and 32, that soared to 165 ah as the fan ran all night.

I have four golf cart batteries. I plan to use 120 AH a night, which is about an entire battery’s worth. Most to run the heaters. My outdoor LED Strips for the awning draw an amp, and my the front blue LEDs draw .3 amps. I leave those on all night and don’t lose sleep. I worry every time the heater fan comes on.

I have a typical to slightly large RV system at 1000 watts of panels for this forum. People I meet in person have only 300 watts oof Olaf and 2 golf cart batteries, and I’ve had a few comments about never seen so many panels.

Unless you want to sacrifice probably 2k of weight and an entire pass through storage compartment, what you’re asking for is not going to happen. It’s possible, but very challenging and will be amongst the first out there.

 

[Dart0366]

From the manufacturer

670 Watts per Hour (W.P.H.) for Condenser
+
936 W.P.H. for Vacuum Pump (1,003 W.P.H. TOTAL)
+
820 W.P.H. for Heaters (Shelving Unit)

2,426* W.P.H. Total power usage with condenser, vacuum pump, and heaters on

I think I almost understand Amp and Volts but have no clue on watts per hour. I swear someone tries to make this ten times more confusing then it needs to be. Batteries are Amp hours. Amps= volume or lake of water to flow into your creek/river. And of course Volts. Volts= size of flow. Think 12 volt is a small creek. 24 volt is like small river. And 48 volt being the Columbia river, I live in the NW so of course Columbia. Of course I could be a moron with what I just said. Please don’t forget I am a serious beginner intent on understanding.

 

[Dart0366]

Ok let’s say I can get enough charge by generator, solar and wind. How much battery do I need to run the 24 hour cycle. When I say portable think more 3-4 months stay at a time, maybe longer. Not trying to confuse and I might have to accept it can’t conveniently be done. But I certainly want to explore all options.

 

[Hedges]

Is this a portable food processing plant you would take to a farming area, preserving their food?
It sounds too large for just personal use.

You previously said, "110V 20A 9-11 amps per hour"
110V x 20A = 2200W while it is operating. You need an AC inverter capable of producing that continuous output.
If that is actually 120V x 20A, then 2400W. We often say "110V" or "115V" or "120V". They are all the same thing, power line voltage can vary and any of those are correct.

You now added up the components for 2426 watts per hour. Same total as before.

"9 - 11 amps per hour" probably means amp hours per hour, i.e. during an hour the equipment is on half the time, off while temperature coasts half the time.
That means although power draw is 2426 watts, it isn't on continuously (2426 watt hours per hour) but rather 1213 watt hours per hour. That x 12 is how much battery you need as a minimum, to get through a night.
That x 24 / 5 hours effective sun per day is how much PV panel you need

Sometimes you have no sunshine so a backup generator would be good.

1213 W x 12 = 14,400 Wh of usable battery capacity is minimum to get through one night. For example, 400 Ah 48V of lead-acid batteries cycled to 70% Depth of Discharge.

1213 x 24 / 5 = 5000 W of PV panels for summer operation (would need more during shorter days of winter months.)

2426 W is minimum inverter output

(670 + 936) x 5 = 8000 W surge capability of inverter needed to start motors.

These are all minimum; a bit more of each is more likely to meet your needs.
You could deploy PV panels on portable rack. Would have to drive stakes in the ground to secure against wind.
You could carry a system like this in a toy hauler.
If operating in winter, might need 3x to 4x as many PV panels.
Should have a generator as backup to keep running on cloudy days.

 

[chrisski]

Ok let’s say I can get enough charge by generator, solar and wind. How much battery do I need to run the 24 hour cycle.

That's kind of like asking how long is a rope? You take half its length and multiply it by two.

@Hedges did a good job of telling you 14400 WH of batteries for one night. That comes out to 12 - 14 golf cart batteries, but you can't take those down past 50%, so that means 24 - 28 Golf cart batteries. You want two days, now you need 48 to 56 golf cart batteries.

5000 watts of panels is not undoable, perhaps you can squeeze 2000 watts in an ideal roof configuration, but the rest will need to be towed behind in a trailer, or if you have a toy hauler, sacrifice the side y side compartment to take these panels with you. A trailer might be a good thing, because with that much power, you may be able to configure your batteries and SCCs, etc to take up the entire pass through storage, but besides losing the space, you've just put perhaps 1500 LBS lithium or 4000 LBS Lead Acid Batteries.

So, now with how long you want to run the generator, you can cut down on the golf cart batteries and storage panels. My 2000 watt generator goes through .5 gallons of gas an hour at 1000 watts continuous production. Whatever your generator is, this is where some formula could used to not run the solar at night, and perhaps cut down on battery storage where you could manage this without toting a trailer behind.

I'd love to have an RV system like you're asking, but after seeing hedges calculations, I would not do it without a pickup hooked to the fifth wheel, and an additional pickup with a 10000 LBS trailer towed behind it with my panels and batteries and power equipment. This solar production trailer would have a 50 amp RV jack out of it. We have a lottery pool at work and if I win, I think I will build that.

What I wrote above is my opinion with my calculations done on a napkin.