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Old 02-17-2012, 01:31 PM   #1
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Name: Brooke
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Need help connecting my solar panels

The last one or two owners did not have a battery and so they didn't connect the solar panel wires.

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This is my converter.


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And this is my fuse panel.


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I now have an AGM battery.

Where do I attach the wires from the solar panel?

This came with Mouse.


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Is it needed? How does it all fit?

Mouse is a U Haul CT13.
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Old 02-17-2012, 01:54 PM   #2
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I don't think that is the original inverter, but in any case, use a multimeter to verify which of the leads from your solar panel is positive and which is negative. You can connect the solar panel to the controller then, from the controller to the battery terminals or to the connectors in the fuse area. It looks like they are using the top, black as positive and the bottom white as negative, but trace the wires to the battery to confirm.

Standard coding for DC is red for positive (+) and black for negative (-).

Probably the ring terminals go to the battery and the plug, which you'll need to cut off, goes to the solar panel. The controller may be marked to identify which is input and which is output.
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Old 02-17-2012, 02:27 PM   #3
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Brooke - you actually dont need to attach the panel to your trailer converter at all as the solar charges the battery directly via the little solar controller you have in the last photo. A solar panel controller is needed to keep your battery from over charging - it has two types of connections on it - as Tom has indicated connect the little controller box to the battery and then connect the other wire directly to the solar panel -the solar panel should have a connection coming off of it that it plugs into.

The solar controller needs to be kept dry - I leave mine connected to the battery all the time and run the wire from it into a small water proof box which I attached to the side of the battery box - easy to open up and attach the solar panel when needed (I dont have my panel mounted as I like to be able to move it around to the sun) - some folks run the controller wire back into the trailer and put the controller inside the trailer to keep it dry.

Edit: Just looked at your photos again and wondered if in the first photo if the wire shown is already attached to a solar panel? if so thats the wire that needs to connect to your little controller.
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Old 02-17-2012, 02:55 PM   #4
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As Tom said Red + Black - Right to the battery from the controller, your solar panel will show which is positive an negative
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Old 02-17-2012, 03:21 PM   #5
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Thank you.

My understanding from your responses is that
1) I should connect the SunForce charge controller to the battery (red to red and black to black).
2) then determine which of the wires coming from the solar panel is positive
3) connect the positive wire to red and negative to black of the SunForce charge controller wires
4) keep the SunForce charge controller in the trailer so that it stays dry.

Great!

Now is this a good idea?

Is it important to know how much power the solar panel is supplying?
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Old 02-17-2012, 03:36 PM   #6
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If I am not mistaken, Uhaul trailers came with a solar panel. Is this the case here? If so, I would first take some measurements to see if it is still viable as it is over 25 years old. Just a thought. Raz
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Old 02-17-2012, 03:37 PM   #7
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Youve got it! You probable already know this but the wires on the controller with the metal rings are the ones that go to the battery.

Yes you should make sure that the controller you have can handle the out put of the solar panel.
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Old 02-17-2012, 03:46 PM   #8
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Quote:
Originally Posted by Mouse View Post
..............Is it important to know how much power the solar panel is supplying?
Knowing the output of the solar panel is not necessary, but you shouldn't discharge your battery more than 50% if you want it to have a long life. You can determine it's state of charge by measuring the battery voltage with a digital multimeter.

http://www.energymatters.com.au/rene...-discharge.php

Quote:
Originally Posted by Carol H View Post
...............Yes you should make sure that the controller you have can handle the out put of the solar panel.
That controller is good for 7 amps. Your solar collector (if original) is less than 1 amp.
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Old 02-17-2012, 03:49 PM   #9
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None of the photos look like original Uhaul equipment, the converter or fuse panel. The Uhaul solar panels were only intended to prevent sulfation in the battery, not to charge it. On a recent sunny day I connected a multimeter to our panel and only got a 6 volt reading so I'm going to disconnect it. I've also had a problem with the battery going dead without being used, so I suspect that the converter may be bad somehow so that is being disconnected for now and replaced at a future date. Bob
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Old 02-17-2012, 04:07 PM   #10
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Quote:
Originally Posted by Carol H View Post

The solar controller needs to be kept dry - I leave mine connected to the battery all the time and run the wire from it into a small water proof box which I attached to the side of the battery box - easy to open up and attach the solar panel when needed (I dont have my panel mounted as I like to be able to move it around to the sun) - some folks run the controller wire back into the trailer and put the controller inside the trailer to keep it dry.
Hi Carol,
Where did you get your waterproof box? I'd like to use my solar panel the same way as you have and can't seem to locate a suitable box. Thanks for your help.
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Old 02-17-2012, 04:09 PM   #11
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Yes, this is the original solar panel, so it is working but probably not putting out much power. I need to get a multimeter to tell me how much.

The last owner told me that he rewired to trailer. So maybe everything except the solar panel has been replaced. I added the AGM battery because it sits inside the trailer under the bed and a sealed battery seems safer. The battery box has an exhaust tube to the outside. AGM batteries are less prone to sulfation than other batteries.

So if the little panel isn't able to charge the battery, I shouldn't connect it.

It seems a shame though to have a solar panel and not use it.

How big a solar panel do you need to charge a battery? Could I put it on the roof in place of the one I have there now?
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Old 02-17-2012, 04:17 PM   #12
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The box looks something like this one. Picked up at a camera store.
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Old 02-17-2012, 04:28 PM   #13
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Quote:
Originally Posted by Thomas G.
Knowing the output of the solar panel is not necessary, but you shouldn't discharge your battery more than 50% if you want it to have a long life. You can determine it's state of charge by measuring the battery voltage with a digital multimeter.

http://www.energymatters.com.au/rene...-discharge.php

That controller is good for 7 amps. Your solar collector (if original) is less than 1 amp.
I agree.



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I use this device to show me the battery charge state.

It also gives feedback on how much the different lights and the fan drain the battery.

I replaced a floresent light with two LED lights and am getting much more light for much less energy.
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Old 02-17-2012, 04:55 PM   #14
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How big a solar panel do you need to charge a battery? Could I put it on the roof in place of the one I have there now?
Your going to get a big range in answers to your question. It all depends on how much power you are using in your trailer on a daily bases.

You will find a whole section about solar on the forum.

I see you are in the land of the sun so a lack of sunshine for charging should not be an issue for you. If you are like me and have no micro wave and don't run the TV or AC when dry camping and your fridge runs on propane and your lights are LED and your fan is a Fantastic Fan and you only use power to run your water pump, charge up cellphones and to run the computer for an hour or so a day in IMHO you will find that a 60 watt panel is more than enough - I actually only have a 30 and on a sunny day it will top up my battery nicely even if I have have run the Fantastic fan on warm days/evenings or the furnace a little bit on cold nights/mornings. The furnace is a *big* power eater so will your fridge be if it does not run on propane. I am actually looking at going to a 60 watt as I am doing a bit more winter camping and would like not to have worry as much about the power consumption of the furnace. Having said that the price and size of the panels has come down a lot in the past few years so it doesn't hurt to buy more than what you think you need
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Old 02-17-2012, 05:04 PM   #15
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Here is another good site worth reading on the topic of 12 volt.

The 12 volt side of life
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Old 02-17-2012, 05:22 PM   #16
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Originally Posted by Mouse View Post
Yes, this is the original solar panel, so it is working but probably not putting out much power. I need to get a multimeter to tell me how much.

The last owner told me that he rewired to trailer. So maybe everything except the solar panel has been replaced. I added the AGM battery because it sits inside the trailer under the bed and a sealed battery seems safer. The battery box has an exhaust tube to the outside. AGM batteries are less prone to sulfation than other batteries.

So if the little panel isn't able to charge the battery, I shouldn't connect it.

It seems a shame though to have a solar panel and not use it.

How big a solar panel do you need to charge a battery? Could I put it on the roof in place of the one I have there now?


To check your panel: with your multimeter on DC volts, use the 20 v. scale and measure the voltage across the solar panel leads with the panel unconnected to anything. I would expect about 17 v. in full sun. Next set your meter to DC current using the highest scale on your meter, probably 10 amps. Again in full sun measure the current flow between the two leads. This is the maximum current the panel is capable of providing. I would expect less than an amp or so based on the size of the panels I have seen in pictures and what was suggested by others. As was also suggested, good for a trickle charge in most cases. Important, while it is safe to measure the short circuit current of a small solar panel, don't even think of doing this to a large panel or your battery. Don't forget to switch your meter back to voltage when done with the current measurements.

AGM battery. Good choice in my opinion.

Expect lots of advice on solar panels and the peripherals.
Raz
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Old 02-17-2012, 06:11 PM   #17
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Originally Posted by Mouse View Post
..........

So if the little panel isn't able to charge the battery, I shouldn't connect it.

It seems a shame though to have a solar panel and not use it.

How big a solar panel do you need to charge a battery? Could I put it on the roof in place of the one I have there now?
Connect it! The worst that will happen is that it will only help a little. Also, depending on the voltage the controller puts out, the solar panel may add some charge where the inverter leaves off. For example, if the controller supplies 14 volts and the inverter only 13, the inverter won't fully charge the battery, but the solar panel will help top it off.

The price of solar panels has fallen a lot in the past year or so. You can get a 60 watt panel for $130 on eBay any day of the week.
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Old 02-18-2012, 10:04 AM   #18
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I just put a 50 watt on my U-Haul VT, from E-bay, works great
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Old 02-18-2012, 10:58 AM   #19
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Wait! What is this device?
On our sailboat we had an E-meter to keep track of 225 Watts of solar and 5 batteries, it seemed like $$ overkill on the Compact II. What is this little device, and is it more reasonably priced?

Attachment 43230

I use this device to show me the battery charge state.

It also gives feedback on how much the different lights and the fan drain the battery.

I replaced a floresent light with two LED lights and am getting much more light for much less energy.[/QUOTE]
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Old 02-18-2012, 11:13 AM   #20
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I bought the Equus 3721 Battery and Charing System Monitor on Amazon for $15.33. I've seen other similar units available.

It is a simple device that goes into a car charger and shows you the current battery charge level.

It doesn't replace an energy monitoring system that you need if you have many batteries and solar panels.

But it can tell you when you should plug your trailer into shore power. it also appears to show the drain on the battery of your individual lights and other power drains.
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