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Old 12-05-2012, 01:15 AM   #1
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Want to go solar on my 25RR

Below are the solar panels and charge controller I'm looking at.

Panels (2 x 145 Watt)
Amazon.com: DM 145w Polycrystalline Solar Panel (2 Pack): Patio, Lawn & Garden

Charge Controller (30 amp MPPT)
Amazon.com: Morningstar ProStar 30 Charge Controller with Meter: Home Improvement

I'm unfamiliar with doing solar power. How hard will this be to hook up to a 25RR Toy Hauler? I was hoping I could continue to use the inverter that came with the camper.
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Old 12-05-2012, 07:33 AM   #2
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I took a quick glance at the charge controller. the link is to a pmw style controller. you'll get more power from a mppt type controller. they don't cost much more. a mppt type controller will get you power even on a mildly overcast day or later/earlier in the day when a pwm controller is shut down.
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Old 12-05-2012, 12:22 PM   #3
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Yep, noticed it was a PWM controller after I posted. Would have corrected it but it lends credence to my level of knowledge and might help somebody help me in the right direction..
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Old 12-05-2012, 01:44 PM   #4
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Quote:
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I took a quick glance at the charge controller. the link is to a pmw style controller. you'll get more power from a mppt type controller. they don't cost much more. a mppt type controller will get you power even on a mildly overcast day or later/earlier in the day when a pwm controller is shut down.
I noticed you are running T145 Batteries. Those are 6v correct? I just purchased a new trailer, and want to install good batteries for boondocking that will give us maximum charge life.

I may start a thread on this subject and would be interested in your feedback and input.

Thanks in advance!
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Old 12-05-2012, 02:43 PM   #5
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I wanted the most charge for the buck too. I found a good deal on 2 sets (4 batteries) of T145. A co-worker bought the extra pair for his coach. Yes they're 6v but in series it's12V.

If I need heat, I could get 2-3 days max from the T145. Or if no heat, I could go 5-7 days being very conservative with power all before adding the solar panels. Now bear in mind we don't use the inverter much if at all, but do run 12v led string lights outside, and all led inside.

BTW, next to the furnace blower, the lights are the biggest draw on the battery.
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Old 12-05-2012, 03:11 PM   #6
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Soooo, how much would a laptop and 32" flat panel draw? Is that doable on solar power? It wouldn't be camping if I couldn't watch a DVD or blueray. Nah, I'm not kidding.

I didn't know if solar could keep the batteries changed enough to run something like a flat panel TV. I have the small flat panel that came with the camper if I get desperate though I guess. I think it is made to run off of the inverter and batteries.
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Old 12-05-2012, 03:25 PM   #7
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with the setup you described, and good deep cycle batteries. And if you have clear sunny days, no problem watching some TV and movies. here's what you need ti figure out: amp-hours.


figure out how much power in amp-hours you'll use in a day, be realistic and add some fluff. then trippled that to get a battery size. tripple because you don't want to drain your batteries below about 1/3. then figure out how much power your solar panels will put out in a day. base it on 8 hours of sunlight to
start. there's inference tables to help you. if you make more power than you use, great! if not, you'll have to cut usage or increase generation.

just from experience, you could do well with that set up, if you are conservative with power.
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Old 12-06-2012, 08:39 AM   #8
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Quote:
Originally Posted by apollumi View Post
Below are the solar panels and charge controller I'm looking at.

Panels (2 x 145 Watt)
Amazon.com: DM 145w Polycrystalline Solar Panel (2 Pack): Patio, Lawn & Garden

Charge Controller (30 amp MPPT)
Amazon.com: Morningstar ProStar 30 Charge Controller with Meter: Home Improvement

I'm unfamiliar with doing solar power. How hard will this be to hook up to a 25RR Toy Hauler? I was hoping I could continue to use the inverter that came with the camper.
A few things:

1) Check out Solar Blvd for very competitive pricing on solar panels and associated hardware and electronics. (I do not have any relationship with them other than as a customer)

2) What came with your camper is, most likely, a "converter" not an "inverter." A converter takes 120 Volts AC and "converts" it to 12 volt DC required to charge your battery and run the 12 volt items (like lights). An "Inverter" is usually an after market add-on that "Inverts and boosts" 12 volt DC battery power and "makes" 120 volt AC. "Pure Sine Wave" inverters are preferred as they make the smoother waveform AC (makes computers and electronics more reliable) than the cheaper "Modified Sine Wave" inverters that make a "choppy, more square wave like" waveform. Most electronics will work with a Modified sine inverter, but some, like microwave oven magnetrons, hate it.

3) Inverters need LOTS of amps from your DC system to make 120 VAC.

250 watts of solar panels (at 20 volts output) in full sun with 90 degree sun angle will produce about 12.5 amps to your battery system. Your solar controller will take that 20 volts and moderate it to a 13.5 volt output with resulting loss of efficiency. Using the conversion "without loss" formula of controller output amps = (12.5 x 13.5)/20.5 You get a controller output of 8.2 amps at 13.5 volts (or

If you power your inverter directly (and ignore internal loss in the inverter), your 120 VAC output is 120 VAC x 8.2 amps = 110.7 watts This is not enough to run most AC appliances directly.

4) What your solar bank WILL do is replace amps pulled from your battery bank by your inverter powering your appliances over time and reduce dependence on your generator (which you will still need).

5) Since a 1200 watt AC load on your inverter (say a TV and computer) will require 100 amps from your battery bank (12 volts DC X 100 Amps = 1200 Watts), you will need quite a large bank of deep discharge batteries to feed that inverter. The solar system will reduce the load on your batteries from 1200 watts to 1100 watts; extending their useful life before needing recharge.

As you can see, a large capacity battery bank and generator will still be required even with solar panels to augment your system.

There are many online resources to explain this way better than I can, (in fact Solar Blvd has an extensive FAQ section). Good luck! Herk
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Old 12-06-2012, 11:12 AM   #9
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a couple of things from my experience with my set up:

my 280 watts of solar has on a many of occasions produced over 15 amps of charging current using its mppt controller. That's not even at 90 degrees solar inclination and the battery wasn't that discharged. (The greater the battery discharge, the more current a mppt controller can produce)

I loaded the panels on a bright sunny day by turning on everything in the camper, including the tv and DVD player to get the maximum output I could. That came out to over 19amps of solar generation after the controller. I wish I had taken pix of controller display.


I have a 23" tv and DVD player. my cheapo inverter, only draws about 7 amps from the battery when we watch a movie.
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Old 12-06-2012, 11:40 AM   #10
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First hand experience is always best and what I stated was just my math based on the given data. I am still trying to decide on a system myself and my procrastination is paying off as the cost per watt is still dropping.

In any event make sure you buy a controller that will work with the voltage output of the panels you select.

I would still refer to the Solar Blvd FAQ for more info.
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Old 12-06-2012, 11:49 AM   #11
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I bought my setup from SolarBlvd. Good prices there, shipping is a little slow sometimes. They are great to talk to.

One of the most important things to buy with a solar system is a battery monitoring system. it doesn't matter much which one is used, they all do about the same thing. Mine is all in one, the Blue Sky system with IPN Pro controller. Without such a monitoring system, there's no easy way to see what your system is doing.
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Old 12-06-2012, 12:19 PM   #12
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Thanks for the information. What I had in mind, bear with me, is mounting the solar panels so that they hang on the side of the camper and are hinged at the top. I still plan on the system being anchored on the roof but I'll use knob type screw in fasteners on the bottom. So when I'm going down the road they are anchored to the side and covered (no damage due to rocks please). When I'm camping they'll play awning and I can adjust via different length rods depending on where the sun is. This way they won't get in the way and I won't have to stumble around on the roof. I will be able to clean the roof easily also as well as the solar panels. If a storm is coming, I'll just drop my panels to the side. An aluminum frame will be made for the solar panels also so that when I lift them they all go at once.

I may even do 4 panels. Whatever it takes to be honest. Probably only two for now though. I'll just try and buy a charge controller that will be capable for an increase in amps.
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Old 12-06-2012, 12:22 PM   #13
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Something to consider, is sun angle.

I have not always had the luxury of parking so one side of the camper always faces south. If you have to park with your cells facing north, even with the panels fully elevated you might not get the output you desire.
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Old 12-06-2012, 12:57 PM   #14
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I really put some thought into tilting the panels. I wanted to be ready for any scenario. well, one season with the panels, I am not gonna bother with tilting them. no need to. my system easily makes enough power, so I'm happy.
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Old 12-06-2012, 01:21 PM   #15
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Here is my big unknown. I understand "Solar Panel --> Charge Controller --> Batteries <-- Inverter <--- Appliance" but I have no idea how the electrical system in a camper works nor where to connect everything. In my mind I put solar panels in and a charge controller connected to the batteries. Then by magic I can use my normal outlets for 120v appliances and everything is hunky dory. So, I'm tarded on getting my nice cheap solar generated electricity going through the existing electrical system of my camper.

Quote:
Originally Posted by herk7769 View Post
2) What came with your camper is, most likely, a "converter" not an "inverter." A converter takes 120 Volts AC and "converts" it to 12 volt DC required to charge your battery and run the 12 volt items (like lights). An "Inverter" is usually an after market add-on that "Inverts and boosts" 12 volt DC battery power and "makes" 120 volt AC. "Pure Sine Wave" inverters are preferred as they make the smoother waveform AC (makes computers and electronics more reliable) than the cheaper "Modified Sine Wave" inverters that make a "choppy, more square wave like" waveform. Most electronics will work with a Modified sine inverter, but some, like microwave oven magnetrons, hate it.

Herk
I've only done a couple days reading on solar panels, charger controllers, and looking at installs on rv.net (I think that is the site). Still a ways to go but I got a little fundamentals down before I came here to post.
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Old 12-06-2012, 01:24 PM   #16
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Something to consider, is sun angle.
I have not always had the luxury of parking so one side of the camper always faces south. If you have to park with your cells facing north, even with the panels fully elevated you might not get the output you desire.
It won't be a problem. I'm at work and not inclined to waste too much of my day drawing pictures but I may once I get home. I'm all for simplicity when I can make it happen. Or, complexity, that makes for simplicity later.
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Old 12-06-2012, 01:54 PM   #17
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5) Since a 1200 watt AC load on your inverter (say a TV and computer) will require 100 amps from your battery bank (12 volts DC X 100 Amps = 1200 Watts), you will need quite a large bank of deep discharge batteries to feed that inverter. The solar system will reduce the load on your batteries from 1200 watts to 1100 watts; extending their useful life before needing recharge.

Herk
The 32" TV says 51w (1w standby) and the laptop (alienware M11x netbook) is reported to pull 30ish watts while gaming (much less when streaming a movie or DVD). The laptop has a 65 watt charger. Is my math flawed? I'm thinking 100 watts total draw vs the 1200-1100 watts you mentioned earlier. No problems admitting that there is a good possibility of lack of understanding on my part. Once I know how it all works though I'll stop asking people questions.
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Old 12-06-2012, 02:45 PM   #18
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that'll put you at about 10amps from the battery. Bear in mind those wattage numbers are for maximum current draw. So you should be slightly less than 10amps.

oh, its only 10amps from battery if panels aren't generating.
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Old 12-06-2012, 03:48 PM   #19
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The 32" TV says 51w (1w standby) and the laptop (alienware M11x netbook) is reported to pull 30ish watts while gaming (much less when streaming a movie or DVD). The laptop has a 65 watt charger. Is my math flawed? I'm thinking 100 watts total draw vs the 1200-1100 watts you mentioned earlier. No problems admitting that there is a good possibility of lack of understanding on my part. Once I know how it all works though I'll stop asking people questions.
Not at all. Just saying that inverters have big appetites for battery amps. Remember also that those two items won't be the only two items demanding juice from your 12 volt DC system.

I found that out the first time I tried to make coffee with my 2400 watt inverter. My 2 battery (140AH bank) was dead before the coffee finished brewing.

See attached graph for the rapid decline of battery capacity plotted against amp draw.
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Old 12-09-2012, 12:38 PM   #20
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Hi all, I'm new to the forum and just getting ready to set up solar in our new Winnie 2013. We previously had a Class C with 415 watts of panels on the roof running to a TriStar 45 MPPT controller and feeding three 12 volt AGM batteries. We lived full time on the solar for the last two years (except a few months in the winters) with no problems, of course we didn't use the microwave except for an extra cupboard. We also got a mellita drip coffee pot where you heat water on the stove and then pour through the filter. I'm no expert on this and very challenged with the math, but I'm a little handy and willing to give it a try. We were amazed at how freeing the solar panels were. We bought most of our stuff from Northern Arizona Wind and Sun and bought these panels from Solar Panels, PV Systems and Inverters Distributor we're going with more power on the roof this time, but could probably get by with less. Anyway, I guess I'm just encouraging you and offering to answer any specific questions you may have.
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