Camper Solar - My first swing at going solar.

[Shaolin7]

Hello everyone, I was curious if I could tap into the community for help setting up my first solar system.

• I purchased 2 x Canadian Solar panels that are listed at 295 watts each
• The 60 Amp Solar controller I bought was http://www.ebay.ca/itm/181266898541
• I bought a brand new 12v fridge for the camper, I will come back with details on its power draw.
• 3 used RV/Marine deep cycle batteries and 1 new tractor battery.

Its going into a $1200 camper so its a bit of a budget build.

1. Am I setting this up correctly?
2. I am slightly confused what I should do with the ground points. Should they all go back to the final battery in the series?
3. If I wanted to charge from my 120v could I wire a computer PSU (evga 1000 watt) into the charge controller on one of the 12v outputs? (I have an extra one sitting around) Say if I ended up parking in the shade, but have my gas generator powering the 30 amp system in the camper. Because I do not have a 3 way fridge I can swap over to 120v I would have to keep the 12v power system charged somehow.

If I plug in the trailer plug into the system would I be okay to do that from the fuse block? The car's alternator would be charging through that line as well.

[SunEagle]

First off those "load" terminals are probably not rated for much and you will overload it. You should connect that distribution fuse block directly to the battery.

Also I am not sure how 4 different type of batteries will perform during the charge/discharge cycle. More than likely the weakest of them will bring down the abilities of the other 3 and cut their life short.

The ground wire should go to the negative terminal of the battery system which should then be connected to the RV frame.

I am not sure how you can isolate the charging of those batteries using solar, grid tie or alternator. Most RV's should be supplied with an isolation relay and circuitry to allow charging from multiple places without backfeeding anything and causing problems.

Last thought. With that PWM CC you are probably losing about 33% of the total panel wattage due to how the PWM works (amps in = amps out). If I were you I would look into getting a quality MPPT type CC rated 60A. They work (watts in = watts out) and use 100% of the panel wattage.

[Amy@altE]

The Canadian Solar panels are 24V, you are doing a 12V battery bank. You will lose around 1/2 of the power by not using an MPPT charge controller. (I was going to record a video of this today, but the sun went away. I'll do it Wed). Return the charge controller you have, and get at least a 50A MPPT, (2 x 295W / 12V output = 49A).

To use AC to charge your battery, you need an AC charger, don't try building something to save money, you will end up wasting money replacing damaged batteries. Speaking of damaging batteries, do not mix and match batteries, take the tractor battery out of the system.

[Shaolin7]

So now you have me thinking. I should do a 24v battery bank, move the tractor battery to the front of the camper to hook into the trailer light and 12v system that was already existing.
The fridge appears to say 12v/24v on the compressor so I will look into how to switch it to 24v.

I can then swap controller for mppt later on this year. Even if I lose half of my amps I should still be okay on the fridge running side. I understand the Tristar is the be all end all of charge controllers but I'm also not in a position to spend $300 at the moment.

The solar panels are http://www.ecodirect.com/Canadian-So...-cs6x-295m.htm

[Shaolin7]

My thoughts on why the 12v should be sufficient was that I have about 241Ah / 580 RC out of the battery bank (12v setup). The Fridge is a Waeco Running a Danfoss BD35F compressor which from what I can find looks to take about 40 watts or 3.33Ah. Panels are putting out 8 amps each as a max. I suspect 5-10 amps with two of them and somewhat shady environment. which should run the fridge and give me the ability to play a 12v car stereo for a few hours a day as well.

So the board feels I am better to do a 24v battery bank. I did see the fridge listed 12v/24v so It should have a setting I can switch over to 24v. I can take the tractor battery out of the equation and move it back to the original mounting for the battery on the trailer I will tie the trailer lights and connection to vehicle to the tractor batt and leave the 24v bank seperate from everything else.

Ill have to buy an inverter to go back to 12v for the car stereo. And I will look into MPPT when I have another $200 to do an upgrade.

Ill hook just the fridge into the load side of my charge controller for now and anything else would be inverted to 12v then to the fuse block.

[Sunking]

You made a huge mistake buying a PWM controller. You just turned your 590 watt panels into less than 200 watts. You must use a good quality MPPT 60-Amp controller if you insist on 12 volts, or 30 amps @ 24 volts.

Second mistake was the wrong batteries.

[Shaolin7]

okay I've ordered an MPPT controller as everyone has suggested.

I wouldn't agree that my mistake was wrong batteries. RV/Marine deep cycle seem to be the gold standard. Given the fact that I got 4 batteries in my bank for $140USD I would say that It was a good purchase for a test project and I think it would be hard to argue otherwise. I am on this forum for advise not criticism. I can see that the weakest point in my setup is looking like the charge controller so I will change that out with a MPPT.

Would everyone agree that a 24v battery bank is optimal then convert to 12v where required?

[Mike90250]

Whatever the battery bank is, it needs to be made with identical batteries. mix-n-match is just asking for trouble.

A computer PSU will not provide the 15V that are needed to charge the batteries with.

Ground in an RV is often simply just to the Frame for the (minus) lead, but because the chassis is often segmented, buffered and isolated, you can get some high resistance connections lowering your voltage. For large loads, I would run a (minus) lead back to the battery and not try to use the chassis as a power return wire.