Solar panel help

[CgZito]

I believe i can fit two 150 watt panels at 3 ft by 3 ft on my roof. Renogoy seems to have a decent deal and claims to be top of the line.
So 300 watts should power a tv, laptop, various charging devices, lamps/lights/fans and a Playstation 4 gaming console(if i so choose to get one). What do you think? Im sold on 300 watts.

[alano]

Two 150 W panels will supply maximum power in direct sunlight to charge your batteries. This only affects how quickly your batteries will recharge. The inverter that you choose will limit the maximum power that you can deliver to your appliances. The batteries that you select will determine how long you'll be able to run those appliances.

So perhaps the next question for you is what appliances will you run from an inverter? TV, Playstation, computer and phone charger at the same time? If that's the case a 600 W inverter should be sufficient. Are there any other appliances that you must run that might take more than 600 W?

Also, I just wanted to ask if your house battery is in good shape? I took at look at a 1994 manual but it didn't say where the house battery is located. Where is yours?

[CgZito]

The solar panels are 39in by 39in each. I thought id need at least a 2000 watt inverter. Not sure why. Hair dryer, and any just incases.

Renigy recommended i get (4) 125AH AGM batteries for the two 150 watt solar panels. They also suggested a 40amp charge controller. What do you think? Are they fishing for money or is this accurate?

[shadrick5]

Check out handy bob's blog for more good info. It's at handybobsolar.wordpress.com

[alano]

A 1000 W inverter can support surges to 1500 W and even 2000 W, so I would recommend no more than 1000 W. Even better would be a 600 W inverter as it would consume less energy when enabled.

You only have 300 W of solar. If you buy four 125 AHr batteries, you'll have a total of 500 AHr, but only 250 AHr will be usable since you shouldn't deplete your batteries more than 50%. With your solar it will take you 250 AHr / (300 W / 12 V) = 10 Hr assuming the sun is bright and your panels are optimally positioned. This will take at least two days to recharge your batteries. A more realistic configuration would be two 125 Ah batteries, allowing you to fully recharge your system in 5 hours on a good day.

Two batteries will give you 125 AH of usable capacity. If you're running a TV, computer, Playstation and perhaps even some LED lights, perhaps the total will be around 200 W. So you'll be able to power all that for 125 AHr / (200 W / 12 V) = 7.5 Hr.

For all the calculations above, I neglected the losses in the inverter, solar charger and charging the battery, so you might assume everything I said is 10-20% worse than I calculated.

As for the solar charger, I would look at the BlueSky Solar Boost 3000i or the 2512i. Either would work just fine. I would add the IPN Pro remote so you have a battery monitor. I can't stress enough how important it is to understand the state-of-charge of your batteries so that they will last a long time. A battery monitor continuously measures the energy in and out of the battery and is extremely important if you're going to be boondocking with this system. Measuring only the battery voltage to predict state-of-charge is fraught with problems for most folks.

So what is the condition of your existing coach batteries. How many do you have and what state are they? Where are they? Does your converter work? Do you intend to connect to shore power once in awhile. Do you expect to bring along an external generator to charge your batteries when there's no sun for 3 days?

AM Solar (www.amsolar.com) has a nice education page that you should read to learn more about solar panels and how to size your system. They are a good resource for purchasing the Blue Sky chargers and will also answer questions.

[dznf0g]

Alano, although I find no fault with your reasoning, I wonder how many people use that much 12V power per day. I know some do, but we only use 28 - 50 Ah per day. Our 260 watts of panels are more than adequate for us.

[alano]

Rich, I agree that 500 AHr of total capacity seems an indulgence considering the size of the solar array and the expected loads. Two type 31 batteries should more than adequate.

In the Winter months, I've been using about 75 AHr of capacity each night when the furnace is running with my 30' classic. Even then, the thermostat is set to a cool 55 deg F.

Some general guidelines are necessary to get the most out of the available battery capacity like, convert to LED lighting, use propane to heat water, make toast and heat-up food rather than a kettle, coffee pot or microwave. Turn off your inverter at night when you go to bed, etc.

[dznf0g]

Yeah, I don't camp much after Halloween and don't start up till April. Furnace makes a big difference. Of course, there's always a generator, when solar gets behind.

[CgZito]

Aye. Now we are getting some where. I failed to mention i am running an ac unit and a refrigerator. I picked a few brains in person, a rep at renogy, a rep at NOCO and a rep at abtteries plus. I was told( after calculations and math) if drained all four 125 AH batteries dead it would take 20 hours to recharge with 300 watts solar power.. However i was informed not to let them get below 50%.

I will not be really using any kind of power u til the evening. Past 5. And generally be in bed around 10. So i may ustitlize power for anywhere between 2 hours and 8 hours(depending on the day)

Ideally id like to enhance my schedule to be in bed by 10 every night regardless of work. I wont be in front of the tv always. I have other things to do. The mornings are for gym shower and work prep so no electro ics there. Soits days off im mostly concerned about. I do plan to keep my generator and fix it ...eventually.

This system cones with a 40 amp charge controller. Not sure about a battery monitor but sure i see good reason to get one (if that isnt the charge controller too).

[CgZito]

Heres an update of my solar set up so far.

[alano]

CgZito, it's looking quite good! What type of batteries did you choose?

[CgZito]

Alano i used vmax 12 volt 125 amp hour batteries. I have a xantrex freedom sw2012 pure sine wave inverter on the way. My next project is to clean up the battery bank area and build extra storage.

[alano]

Nice. Just wanted to make sure you selected AGMs for use inside the trailer!

[CgZito]

Just an update for those interested. I have renovated quite a bit inside my 1993 b190 airstream. Took two days but i got a 32 inch tv and some style in there.