Easy Solar Set Up

[Dahlia47]

I am in between solar and propane, but I am leaning solar. I need the easiest solar set up possible. During the winter it may run a 15 amp heater, maybe a phone. During the summer it would power a 12 amp ac and maybe a phone. There are a couple places Ill be going to that don't have hook ups.

Also...propane vs solar???

[absolutsnwbrdr]

I think your expectations for solar may be a little unrealistic. You don't necessarily run anything from solar. You use it to collect power which you store in a battery, and then run the items from the stored energy. Running a 15A heater from 12V batteries isn't going to happen, nor will running an air conditioner. At least not for very long unless you have a crazy amount of storage.

Solar panels operate at 12VDC (technically 18VDC) and the things you mention are most likely AC devices. If that heater is a 15A heater that plugs into a standard wall outlet, that basically draws 150A of 12VDC battery power.

[Dahlia47]

I obviously am clueless about electricity! lol!
How would I be able to run these without a noisy generator?

[GTS225]

I obviously am clueless about electricity! lol!

How are you with math? Look up "Ohm's law". The formula will tell you the basics of calculating electricity. You will also need the formulas for watts, (a measure unit for power), and that will help you get an idea of what's required in electricity, and how to use it.
WARNING!! Electricity is not something to take lightly! Doing something wrong can result in burns to yourself, fires, and death. The science is very unforgiving of mistakes or lack of knowledge. I can not stress this enough.

How would I be able to run these without a noisy generator?

You will probably not be able to, at least on a continual basis. As absolutsnwbrdr alluded to, what has to happen is charging a battery, or set of batteries, from your solar panels, (yes, plural), then pulling the 12VDC from them, and turning it into 120VAC in order to run your heater or A/C. Changing from 12VDC to 120VAC requires another piece of equipment called a converter. Both electric heaters and A/C's are "energy hogs".

You may be able to run one for an hour, but then have to recharge your batteries in order to do it all over again.

It might be wise to set your sights a little lower. Look into heating with propane, and use a fan for "cooling" in the summer.

Roger

[daveesl77]

Here is a way to think about it all.

A 100 watt (rated) solar panel can possibly put on 8 amps at 12v in the very best of conditions (8a x 12v =96watts). Those conditions seldom exist and panels are never perfect, so count on like 90% efficiency at best or maybe 80 watts available. So, in full sun, no clouds, nothing blocking anything, you could theoretically run something drawing about 75 watts during the daytime hours when the sun is hitting the panel full on and less during times of less direct sunlight. The panel is charging a battery to act as storage and cushion (say a cloud comes over for 10 minutes).

A heater runs from resistance, so a 1,500 watt heater is pulling 1,500 watts the entire time it is running, unless it has a thermostat, which turns it on/off as needed. But to start, it pulls that entire 1,500 watt load. Your panel is putting out 75 watts actual, your draw is 1,500 watts. That means you are creating 1/20th of the needed power to run the heater constantly. Say you have a battery bank that has a capacity of 40 usable amps at 12 volts (50% of an 80 amp rated battery). Those 40 amps can equal 480 watts. (40x12=480). That 1,500 watt load is going to wipe out your capacity in about 30 minutes or less. So the 1,500 watt heater is a no-go, unless you have a monster setup. And remember, solar only produces when the sun is shining.

As to the AC, this is a bit different. I test ran my little 5k, Walmart $90 special window unit a couple of years. I added in a "hard start" capacitor and yes it did work ok with 150 watts of panel and 80 amps of battery. The unit, in Florida, had an average draw of about 150 watts per hour. In compressor mode the draw was large, like 500 watts, but when the compressor kicked off, the draw was like 75 watts for the fan. That is still going to whack a small solar system, but it is usable.

What I primarily did with my setup, and this worked for years, was to run a small Haier $100 dorm fridge. I would use the panels to charge the golf cart batteries (mppt controller, not pwm). The batteries ran the inverter (cheap 1,200 watt HF modified sine) and the fridge was running at about 29* F. It was perfect. While traveling, the tow vehicle charged the batteries which ran the fridge. When stopped if I had shore power then I switched the fridge over to 120v shore. If not then I used either the solar or a small 2,000w Predator gennie. I could normally run the fridge non-stop, at medium setting with just solar, if the sun was going well. Hourly draw was like 60 watts. If no sun, then I'd either fire up the gennie or plug the tow vehicle in to charge the batteries. The golf cart batteries, with no input, could easily run the fridge for 12 hrs +.

As to the location of my panels, they would ride on top of the camper in an aluminum tray I made. They could be easily removed and set-up away from the camper, if needed. I could go out about 50'.

dave

[KTM_Guy]

I am looking into solar for my teardrop now. I am using a calculator at Renogy's website and for fun put in the heater running at 1800 watts for 6 hours in 24 hours for my area, Phoenix which has the highest solar gains in the country.

It can be done you just need to throw a ton of money at it. Not practical for mobile use.

You would need 1700 watts of panels. a 160 watt panel is $260 X 11 = $2,860 Panel size is roughly 2'X5' so roughly 110 sq ft. or 20' X 50'

Next is batteries. You would nee 1800AH in batteries. A 100AH battery is around $200 X 18 = $3,600. Each weighs 66 pounds so total 1,188 pounds.

You also need solar controller, inverter, mounts for the panels, wiring. So maybe just under $10,000.

It really makes the Propex heater look like a deal at $700.

I'm sitting at home with a neck/shoulder injury, so this gave me something to do for 30 minutes.

Todd

[featherliteCT1]

Well said KTM

[StrongFeather]

I concur that running an electric heater shouldn't even be considered. There are other options, e.g. Little Buddy, body heat... Air conditioning on the other hand should be doable, but the first thing I would do is consider downsizing. A 12Amp (1440watt) unit is probably overkill.

Something to consider if weight and cash aren't limiting factors. 6V golf cart batteries with ~250 AmpHour ratings sell for around $125 each. Together, wired in series, they give you ~500Ah of capacity. A 500 watt A/C unit draws a little over 4 Amps, giving you around 50 hours of use assuming you drain the batteries to 50%.

This of course only solves part of the issue. You still need to charge the batteries (solar, shore power, TV power or generator) and you still need to convert from 12VDC to 120VAC. This is a pretty broad topic, so I'm going to stop right here. Much has already been written about it.

Best of luck!

Steve

[KTM_Guy]

wiring in series does not increase capacity, AH will stay at 225 at 12 volts.

Todd

[StrongFeather]

I stand corrected. Thanks, Todd.

So, 25 hours of air conditioning. Still pretty good I guess.

Steve

[Dahlia47]

I dont have a lot of money to put into it. So the smallest, simplest and least amount of money would need to be put into it. Thank you all for the suggestions.