Solar setup for First-time RV'ers

[deryk]

I do some cold weather camping.... would like to be able to go out for 2 days and not have to run my generator because the blower on the furnace drinks electricity.

[Kudzu Asheville]

Mmcwhort,

Thanks for the analogy. I think I may actually understand volts, amps and watts now!

Sent from my SM-G900V using Fiberglass RV mobile app

[andywickstrom]

Agreed--that graphic is perfect for explaining it watts/volts/amps. Love that analogy!

So it sounds like shadows and the like really affect output which is something I had no awareness of until this week. I will definitely keep that in mind as we move forward.

With regards to theft, I think we will do most work while around the camper and present and then put it away when we are away.

Another factor is our dog which we were hoping to leave in the trailer sometimes while we go into town or do something else which doesn't allow her to be with us.

If we were leave her in there with the fan on, how many hours might we have based on a charged battery? Since the panels would dictate us parking in or very near total sun, I would be wondering how hot the trailer might get - hence the interest in running the fan to keep her comfortable.

Right now, I'm seeing the Renogy 100w foldable for about 270.00 plus shipping. The reviews seem solid and it would put out the power we need for the most part.

[Roy in TO]

This is a good reference
http://www.amazon.com/Managing-12-Vo.../dp/0964738627

[Bob Miller]

[QUOTE=andywickstrom;463156]

Another factor is our dog which we were hoping to leave in the trailer sometimes while we go into town or do something else which doesn't allow her to be with us.

If we were leave her in there with the fan on, how many hours might we have based on a charged battery? Since the panels would dictate us parking in or very near total sun, I would be wondering how hot the trailer might get - hence the interest in running the fan to keep her comfortable.

Gotta tell you, you are headed for the perfect storm with Fido.....

You need maximum sunlight to make the solar system charge your battery but, in the sun a fan alone won't keep the pup cool, so you park in the shade and hope that the battery lasts all day and that night have a dead battery.....

You need to carefully list your loads and capacity and, at the very least, be planning on two battery's for the capacity you need.

And before you ask, no, you can't really run your A/C off of an inverter.

This is getting complicated isn't it....?

[andywickstrom]

Yeah, definitely a little complicated - but I'm confident we'll figure it out. I think it makes most sense to park in shade whenever possible, and locate spots that would allow us to run the panels in direct sun very close by - which I think the Renogy panels would allow for.

In cases where we have absolutely no chance for shade, we'll have to work around it and make certain adjustments to our plans.

Thanks everyone for all the input - so much stuff to consider! Unfortunately, money is a factor, so keeping our purchases to affordable, but quality units and accessories will be key. It drives me nuts to save money upfront only to kick myself later due to build quality, etc. I would much rather put the money into something that will last and be happy with it—something to consider as we make these, our first solar purchases.

[mmcwhort]

I would also look for ways to conserve electricity. A lot of people like LED lighting. The bulb on the right is what comes standard in the Scamp. The bulb on the left is an LED replacement, which puts out the same amount of light with less power.



RIGHT SIDE:
Standard 921 Bulb
Power Consumption: 18 watts
Light Output: 260 lumens

LEFT SIDE:
LED Replacement Bulb
Power Consumption: 3.5 watts
Light Output: 250 Lumens

(Just stay away from the cheap ones. You want a "warm white" bulb with at least 200 lumens.)

There are also 12V electric refrigerators that you can run full-time on Solar power. I have an Engel SB70 that's pretty sweet. It's cold enough to make ice and it only uses 30 watts. I run it full time with a 68 watt panel.

[deryk]

That is nice, they have been making strides in dc powered fridges.... maybe when my 3way goes in hopefully no less then 10 years lol I might consider it!

[Roy in TO]

Originally Posted by andywickstrom

Another factor is our dog which we were hoping to leave in the trailer sometimes while we go into town or do something else which doesn't allow her to be with us.

If we were leave her in there with the fan on, how many hours might we have based on a charged battery?

One of these and a small portable battery power pack and you are good to go for at least a long weekend.
Amazon.com: Fan-Tastic Vent 01100WH Endless Breeze 12V Fan: Automotive

[carlkeigley]

Flexible Solar Setup:

http://www.fiberglassrv.com/forums/f...ozy-63494.html

[andywickstrom]

Wow. Awesome input everyone! This all sounds great! Not sure I can afford the fridge, but, maybe someday I could install such a thing. That fan sounds really great though. Thanks for that!

[RogerDat]

Since you are asking about duration of power to run fan what you want is a way to compare and calculate power storage (battery), solar production (panel) and device draw in one common denominator. I would suggest amp hours.

First step:

• list devices that you will need to power.
• add how many amps they draw.
• estimate number of hours each device will be used per day.
• multiply amps time hours for each device to find amp hours.

The total of all those devices amp hours is how many amp hours you need each day to be off grid.

Second step:
Look at battery amp hours ratings.

Deep cycle battery is storing the power, these batteries have a rating for amp hours. Roughly how many hours battery can deliver 1 amp. Not exact because actual load makes a difference (high load draws down faster) but a standard.

Say your battery has a 100 amp hour rating. You should not discharge it below 50% to avoid damage that will reduce battery life. So you have 50 amp hours you can use to run your devices.

Third step:
Solar panel amp hour output.

Solar panels are typically specified by watts BUT they also have an amp output. approx amp ratings for 100 watt might be 5.2 and a 50 watt might be 2.7 amp.

The panel amp output is equivalent to saying in full sun for one hour this panel will replace its rated amp output amp hours in the battery.
E.G 5.2 amp hours in the case of our example 100 watt panel.

Then as a ball park figure solar panel will provide its full amps for 4 hrs. of the day and half the amp rating for 2 hrs. in the morning and evening.

So a 100 watt panel that produces 5.2 amps would roughly provide 4 hrs. x 5.2 and 4 hrs. x 2.6 amps so it would feed 31.2 amp hours back into the battery per day.

Ideal situation is solar that can provide enough amps to totally replace the amps you draw from the battery in a day, with a little surplus amp production. BUT even if your panel falls short of daily needs you can draw down the battery as long as you don't draw it below 50%.

E.G if you use 20 amp hours daily and your only able to add 10 amp hours from solar it would take 5 days for that deficit to equal 50 amp hour drop in battery charge.

You could camp for 5 days without plugging in if your battery was 100 amp hour battery and you had a 10 amp hour a day deficit. Even though your solar was "undersized" however you would have less wiggle room for overcast or rainy days when you could not get the 10 amps from you solar panel.

Most devices will have an amp rating on them but it can be calculated from voltage (12) and watts of the device using ohms law to provide amps. Fantastic fan I think would be about .45 amps per hour so less than 5 amp hours in 10 hours of running.

Devices such as laptop that you charge from an AC inverter will draw more amps from battery than the laptop charger specifies due to the inverter having some inefficiency in the conversion from 12 volt DC of battery to 110 volt AC. Not enough to matter in general unless you are cutting it close in your capacity. Don't forget camera battery, mine the charger does not draw much but takes a long time to charge.

If you go with portable panel consider dimensions of location where you will store it in the camper or tow vehicle. One member (Carol) set up bungee cords to strap her panel to a closet wall out of the way, this of course means the panel had to fit in that location.

[David Tilston]

The Fantastic fan uses 3 ADC at full power, the Maxxfan uses 4.4 ADC at full power. More than a 12 VDC fridge would.

[RogerDat]

Originally Posted by David Tilston

The Fantastic fan uses 3 ADC at full power, the Maxxfan uses 4.4 ADC at full power. More than a 12 VDC fridge would.

So Fantastic fan would use 30 amp hours in 10 hours? That is a lot of draw if leaving it on during the day to keep a pet cool.

Well I was sort of close if you move the decimal place over for the wrong manufacturer. Not bad for someone that can't remember where he left his cell phone.

I plugged 3 watts and 12 volts into ohms law calculator to get amps and must have screwed up someplace. Thanks for the correction or someone could have come home to a pretty low battery.

[Roy in TO]

The specs are posted in this thread http://www.fiberglassrv.com/forums/f...fan-52868.html
The Endless Breeze moves 900-1000 CFM on high (3 amps), that is > 3X the volume of your average 13' trailer. (Rough calculation of 6' x 6' x10' = 360 cu feet, less benches, closets and cabinets) Low speed that we find works quite well consumes 1.25 Amps.
Keep in mind, the fan is not kept on 24 hours a day in typical use.

Does that change user perspective?

[Night Sailor]

If you want a remote panel set up while parking in the shade, you might come back to find your pets sick or dead and you remote "steal me" panels gone.

I keep pets in my camper. Here is what I did this weekend. My panels fully charged my batteries early. They were completely topped off when I parked in the shade. I left two fans on. A fantastic fan on medium setting to bring in outside air, and an internal Marine fan set on low to keep the dogs themselves cool. I checked back on the several time and walked them also.

My solar panels provide shade for my roof, as well as power for charging my batteries. You would probably be better off having more panels mounted on your roof and an extra battery so that you have more power than you need. It os better to have too much than too little.

There is a price associated with having dogs. You are responsible for them, and must ensure their safety and well-being.


With extra panels you should be able to charge even on cloudy days and in shaded areas.

I started with four panels and increased them to six specifically because I wanted to be able to charge on cloudy and rainy days. And that is something I can do now.

You don't have to go crazy with panels as I did but I would think 2-100 Watt panels mounted on your roof be a good start, and plan for some other place to mount extras. Perhaps you could have one or two more folded down over a window, that could be folded up when you're stationary to keep out the sun and provide more power.

Fixed Mount panels are the cheapest. You should be able to buy two for the price of the 100 W folded panel set up you're interested in.

Another option is a fan outside in a cool area with the dogs on long leads.

[andywickstrom]

Great tips! Thank you! Lots to consider.

[RogerDat]

I guess no one else has mentioned it but most parks will not allow dogs to be left unattended in a camper. You might get away with it if yours do not bark while you are gone. Or not.

I think there are two schools of thought on solar/battery requirements. Some go sort of minimal approach and are conservative in power use. Others go with enough capacity that they just don't have to worry about it. Both have good points in their favor.

I think it all starts with what does your 12 volt system need to provide. How critical is what is provided by 12 volt system to the camping experience. Then moves to how long a camping stay does it need to provide it for. A 100 ah battery can run a 10 ah a day deficit for 5 days before you are at the 50% charge level. Fine for a weekend boondock trip.

Not having power for ventilation needed by pets, the water pump or a CPAP machine is certainly more critical than say TV or blow dryer. Weekend in rustic campground vs. week would change requirements. I tent camped without any power, have a manual pump for water in the camper so I lights and charging devices are all I need. I don't go anyplace without the dog so I could probably do a typical for me 4 day camping trip off of the battery with even a modest solar charge. Different needs warrant different focus and expense directed at that focus.

Comes down to what will work for the individual and their needs.

[Timber Wolf]

The previous post got me to thinking.I do not leave my girl in the trailer.Too much chance of stuff going wrong IMHO.I do take a folding crate in the back of the truck and set that up if we must be away (down at the beach) without her.I leave her a water bowl, drape a light cloth on top for additional shade, and leave a (120v) fan blowing on her.Sure beats a leash.

Concerning a 12V fan.I attended an outdoor Solar “event” a few weeks back and they had a 10” or so battery (normally 8 D cells) fan running directly from a little 10 watt panel.No batteries or nothing in between.The panel was just leaned up against the pole of a shade canopy and it was spinning the fan moving some air under the canopy fine.10w panels are cheap, and the little fan is under $20.
They were also cooking hotdogs and Ramen noodles with solar power. But that is another discussion.