Camping with solar energy

[kmchartrand99]

i've been doing a lot of research about solar energy for camping use. Here's my dilema, i'm thinking about getting a 12V, 15Watt, 1.3A solar panel to charge my 12 volt 650A car battery. What i would also like to do is install an inverter 120V 2000W to run AC appliances such as coffee maker, toaster, radio, and maybe even a small fridge (the fridge i know uses 1.3 amps, 165 watts). My concern is if the solar panel is enough to charge the battery while i use the devices. i realize that other than the fridge and the radio the other appliances won't be used at great lengths. Also how long would it take for the solar panel to charge a typical car battery? This is my first post, and i'm trying to be as specific as possible, so if any other info is needed, please let me know. Also by the way, this is being used in a 40 year old camper. If AC electricity is hooked up say by a generator, the battery doesn't charge. so we are trying to find an alternative way to use both DC and AC electricity at an affordable price. any help would be greatly appreciated. Thanks

[Mike90250]

DONT
skip the 15w panel. It's not what you need. To power all the goodies you describe, needs closer to 600W . Fridge alone will need 1,200 watts
See post http://www.solarpaneltalk.com/showpo...09&postcount=2
where I rant about the 15W panels

This short thread about loads, and recharge.

http://www.solarpaneltalk.com/showthread.php?t=756

It's real easy to use lots of power, fast. Solar takes a long time, and a lot of panels, to replace what you use in a few minutes. The idea
is CONSERVE as much as you can. LED lights. Coffee via propane. Cooling by ice. Small brushless 12V computer fans.

[Aussie Bob]

Yeah, I think a toaster uses around the 2000w mark, so very hungry on the juice off the batteries there for sure. The same with kettles. Leave them at home.

As Mike said, forget about the 15w panel. It's nowhere near energy to recharge your batteries for the load you'll be putting on them. Also backing up what Mike says, it's amazing how fast you'll use power off the batteries, especially if you're using an inverter to convert DC to AC. They'll discharge faster than you can recharge them, unless you have a bunch of PV panels.

I fitted our camping trailer out with 4 x 80w panels that charge 4 x 130ah deep cycle batteries. I'll get around 18A in peak sun there. I've actually added 2 x 80w portable foldable panels too, to beef up the recharging of the batteries. I get around 9A from those 2 panels, so all up I'm getting 30A in good sun. The foldable panels are 2 x 40w panels that fold up and they are stored in a great carry bag. They have a built in regulator, so they're just attached to the battery bank with the alligator clips. They take about a minute to setup and I like that they can be moved around for the best sun. I would suggest something like that for starters, and then maybe buy another 80w panel if you need more juice. You can start with the one 80w panel and see how that goes.

So that gives me a total of 6 x 80w panels, keeping the 520AH of batteries charged. I have also just added a small 300w wind turbine to the trailer, for some extra punch. That's kind of portable, but a bit of a pain to transport on the ute. I prefer solar over wind, but I figured what the heck, I'll add some wind too.

I power my home office with the camping trailer when we're not camping. Some days it's a struggle to keep up with the demands of my PC (150w), laptop (50w), router (25w), phone, UPS (20w), Fax, etc etc, especially if we get cloudy days.

When camping we mainly use the power for the 80 litre camping fridge, laptops, broadband satellite dish, lights, DVD players, etc etc. I'm a webhost, so I need to be able to access the net 24x7, so this was the main driving factor in going solar for our camping energy supply. The fridge will use around 58w when the motor's running, and then sits on 8w when the motor's not running. How much power that draws depends on how low the temperature is set. I have the temp set at around -3 and it keeps things super cold and the system can easily keep up with that load.

I got into solar because of camping, and the best camp sites didn't have access to power. I blame this on God for not putting power points in trees.

So my first camping setup was an 80w panel, a 130AH deep cycle battery, a 20A regulator and a 600w pure sine inverter. I then upgraded that setup to the panels on the trailer and the batteries in the trailer.

Hope that's not too much information for you. I tend to ramble on a bit. I would go with at least one foldable portable 80w panel and see how that goes. You'll have to experiment a bit and see what works for you and what doesn't work. But as Mike also said, conserve. That will keep the load on your batteries at bare minimum.

[kmchartrand99]

thanks, here's another question then.

to the both of you, i really appreciate the input, and it's been extremely helpful. Money is an issue, so the more expensive panels are probably out of the question for now. One thing i've seen others do, and have been suggested to try is hooking my battery to an inverter, and then plug a battery charger into the inverter, supposedly this will keep my battery charged and allow me to use as much DC and AC electric as i need/want. Is this possible and/or feesable? again, thanx in advance!

[Mike90250]

One thing i've seen others do, and have been suggested to try is hooking my battery to an inverter, and then plug a battery charger into the inverter, supposedly this will keep my battery charged and allow me to use as much DC and AC electric as i need/want. Is this possible and/or feesable?

It's possible, but you will not create "endless power". You will just run your battery down even faster.

Average mod-sine inverter is only 80% efficient.
Average charger is 95% efficient.
Charger on mod-sine power source -20%loss

So you are down 45% just in losses. You can try it at home, put a voltmeter
on your battery, and watch the voltage every 10 minutes, it will get lower and lower
and lower ...