A problem and an attempted solutiion: 12v fridge and solar charger...

[Bbasso]

My solar system is independent of my vehicle.
Since i'm still very new at this solar stuff I wouldn't want to give you wrong/bad advise.
But there are controllers that have a split mode for taking care of house and starting batteries, but as I mentioned I don't know enough...YET! I'm still learning.
I'm sure you are in the right place for a right answer, most of my knowledge has come from here.

But my question is why would you want to tie into the vehicle's system?

 

[Martinjmpr]

But my question is why would you want to tie into the vehicle's system?

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Main reason is because I don't want to have to carry another battery. I'm already carrying 2 (1 in the truck and 1 in the camper.)
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When we are "boondocking" with our trailer, we don't normally use the fridge in the camper because it's not very big and not very efficient. Instead we use the Truckfridge which stays in my truck. Obviously if I want my food to stay cold I have to have it hooked up to some kind of power 24/7 and if you go back to the beginning of this thread you'll see that the issue is that when I do that it runs my battery down to the point where the truck won't start.
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Now this only happens when we're not traveling every day - when we're driving 10-12 hrs/day that keeps the fridge charged up and of course since I'm generally driving in the hottest part of the day (when the fridge is working hardest) it stays charged up via the alternator and when we stop for the night and it's just running off the battery, it's cooler and the fridge isn't working as hard.
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The issue appears when we drive a couple of hours to a campsite and then stay there for 2 - 3 days. Unless we have a reason to start the truck up and run it the battery will continue to discharge. Over Memorial day this happened after just one full day of not starting the truck. And it wasn't even that hot.
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Certainly one solution would be to simply start the truck every day and run it for a while. Not terribly efficient, but it would keep me from having a dead battery. The problem here (besides the obvious waste of fuel in using my truck's engine as a "generator") is that I would think I'd have to run it at least 2 - 3 hours to charge because it will just be running at idle, not at "highway speeds" like it would be if I was driving.
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But if possible what I'd like to do is have the solar panel running through the truck's battery, that way it would keep the truck battery charged up and also keep the fridge running without having to carry an extra battery.

 

[228B]

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I've learned that a battery or a bank of batteries (connected together in parallel or in series) may have several different charging sources connected to it at all times without harm (provided each charging module is intelligent enough [microprocessor-controlled] to know when to stop charging). They will push against each other but nothing will blow up.
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There is at least one solar charge controller capable of managing two distinct batteries such as in your application. This is the Morningstar SunSaver Duo.
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http://www.wholesalesolar.com/products.folder/controller-folder/SunSaverDuo.html
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I'd think that for your needs, one panel (anywhere from 100 to 150 watts), some 10ga copper stranded, the appropriate connectors, and this SS Duo would be perfect for your two-battery setup to keep each separate battery charged when you're away. Just be sure the panel sees direct sunlight for at least 6 hours daily. You can expect just 30% of that output in cloud cover.

 

[FJR Colorado]

So would you be talking about something like this?
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http://www.amazon.com/Renogy-100W-M...d=1437069218&sr=8-2&keywords=100w+solar+panel
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What else would I need to run this setup?

BINGO!

I'm in Parker if you ever want to see the set-up first-hand.

I swear by it.

I did not even install it until I ran a test on my deck for a month. It has worked perfect from day #1.

 

[LandCruiserPhil]

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Main reason is because I don't want to have to carry another battery. I'm already carrying 2 (1 in the truck and 1 in the camper.)
.
When we are "boondocking" with our trailer, we don't normally use the fridge in the camper because it's not very big and not very efficient. Instead we use the Truckfridge which stays in my truck. Obviously if I want my food to stay cold I have to have it hooked up to some kind of power 24/7 and if you go back to the beginning of this thread you'll see that the issue is that when I do that it runs my battery down to the point where the truck won't start.
.
Now this only happens when we're not traveling every day - when we're driving 10-12 hrs/day that keeps the fridge charged up and of course since I'm generally driving in the hottest part of the day (when the fridge is working hardest) it stays charged up via the alternator and when we stop for the night and it's just running off the battery, it's cooler and the fridge isn't working as hard.
.
The issue appears when we drive a couple of hours to a campsite and then stay there for 2 - 3 days. Unless we have a reason to start the truck up and run it the battery will continue to discharge. Over Memorial day this happened after just one full day of not starting the truck. And it wasn't even that hot.
.
Certainly one solution would be to simply start the truck every day and run it for a while. Not terribly efficient, but it would keep me from having a dead battery. The problem here (besides the obvious waste of fuel in using my truck's engine as a "generator") is that I would think I'd have to run it at least 2 - 3 hours to charge because it will just be running at idle, not at "highway speeds" like it would be if I was driving.
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But if possible what I'd like to do is have the solar panel running through the truck's battery, that way it would keep the truck battery charged up and also keep the fridge running without having to carry an extra battery.

Just wire the output from your controller to the battery. My controller reduces the solar output to charging the batteries as they get closer to full charge. When the batteries are fully charge solar output is almost zero not matter how bright the sun is.

My dual batteries are wired in parallel (like many factory set ups) and are never separated. I charge them by the solar with no issues.

 

[gwittman]

Martin, I bought a 12 volt, 100 watt solar panel from Solarblvd.com. It has its own controller and is designed to charge a vehicle battery. It folds in half for easier storage. It is basically two smaller panels tied together. It could be hard wired to the battery with a quick disconnect that it already has in the wiring system. I just use the alligator style clamps directly on the battery posts. I only use it when I am at a race track for the weekend or am going to be camping at a site for more than a day. It has worked well for me so far. Some people have upgraded the wiring but I have not modified mine.

I don't think they have the folding type in stock now but I think they do have a non-folding equivalent. I think they run around $220 for a 100 watt unit.

 

[4x4junkie]

I use a portable solar setup for mine also (attaches straight to the vehicle battery... put panel in sun, attach charge controller w/alligator clamps (or you could also install a port hardwired to battery), then plug panel into controller). This way I'm not forced to park my vehicle in the blazing sun just to be able to charge my batteries (not to mention allows me to easily reposition the panel a couple times throughout the day to optimize solar harvest too). You could easily use a setup like this on either your truck battery, or your camper battery (I'd probably move the fridge to the camper having the solar to keep it charged, that is if you have room for it).

Setup is home-assembled: two series-wired 85W panels (folding), w/Morningstar Sunsaver MPPT-15 charge controller.
Wiring is 50' of #10 landscape lighting wire (Home Depot item, sold by the foot, about 75¢/ft IIRC) from panel to controller, plus another 3' from controller to battery. Vehicle battery is two Delco Voyager M27s hardwired parallel.

I went with MPPT to maximize the watts-to-weight ratio of the panels being that it's a portable setup (plus MPPT also helps harvest a little more power out of your panels on cloudy days). Though since putting it together almost 5 years ago I now see a number of new light/thin panels that have come out that are 1/3 the weight, allowing one to put together an even lighter portable setup with the same or more power.

My power demands are:
43qt Edgestar fridge,
LED campsite lighting (10-20W)
Occasional phone charging (not just mine either lol)
Charging of large R/C car batteries
Campsite music.


Without the lighting and R/C battery charging, a smaller 100W setup (2×50W panels, etc) indeed should be fine to keep a fridge going (and should still allow for some interior LED lighting use).

 

[Martinjmpr]

Martin, I bought a 12 volt, 100 watt solar panel from Solarblvd.com. It has its own controller and is designed to charge a vehicle battery. It folds in half for easier storage. It is basically two smaller panels tied together. It could be hard wired to the battery with a quick disconnect that it already has in the wiring system. I just use the alligator style clamps directly on the battery posts. I only use it when I am at a race track for the weekend or am going to be camping at a site for more than a day. It has worked well for me so far. Some people have upgraded the wiring but I have not modified mine.

I don't think they have the folding type in stock now but I think they do have a non-folding equivalent. I think they run around $220 for a 100 watt unit.

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Thanks, Gary, I'll have to check that one out.
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(I'd probably move the fridge to the camper having the solar to keep it charged, that is if you have room for it).

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Yeah, space is the problem. Our little T@B clamshell has very little floor space in 'sleeping' configuration. When we were camping in Ontario last month (near Niagara falls) we were at a commercial campground and running the fridge off of 120vAC power and just left the fridge outside under the canopy of the trailer. But obviously leaving a fridge outside won't work in bear country which is, honestly, pretty much the entire American West and that's where we do most of our camping.
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So the fridge can't really fit in the trailer and it can't sit outside which leaves the truck as the only practical place for it.
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If I get ambitious I may just see if I can remove the Norcold fridge from the back of the trailer and put a slide-out for the Truckfridge. The problem there is that the Truckfridge is longer than the Norcold so I'd have to get creative trying to shoehorn the bigger TF into that space.
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If we had to do it over again I think we might have custom ordered our T@B from the factory. They're actually pretty good about custom orders and I would have engineered a sliding shelf in place of the current Norcold fridge.

 

[Martinjmpr]

Just wire the output from your controller to the battery. My controller reduces the solar output to charging the batteries as they get closer to full charge. When the batteries are fully charge solar output is almost zero not matter how bright the sun is..

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So it sounds like it has some kind of regulator like a Battery Tender does? That makes sense.

 

[dwh]

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So it sounds like it has some kind of regulator like a Battery Tender does? That makes sense.

All solar charge controllers are regulators. They connect the solar to the battery until the battery voltage reaches a certain point, then they regulate the voltage by connecting/disconnecting the solar to/from the battery to hold the battery voltage at the set point. By holding the voltage at a set level, over the time, as the battery reaches a full charge, the amps flowing to the battery gets lower and lower.

It makes it appear that the solar charge controller is "tapering off" the current, but that's not what's happening. The charge controller is simply regulating the voltage, and as the resistance of the battery rises, the current tapers off on its own.

I agree with most of the advice on this thread - get yourself at least 100w of solar with any halfway decent charge controller, wire it to the battery by whatever means (hardwire, alligator clamps, quantum entanglement, whatever) and get a voltmeter and keep an eye on your battery.

And I also agree, that by repeatedly draining a cranking battery, you can expect to replace it more often.

 

[Paul B.]

I wanted to take a minute to thank everyone who has given info here and on this entire forum. I'm just beginning to build an expedition vehicle. I have little prior knowledge of any of it. Especially solar/battery/12v/etc. I actually think I might be able design/build/maintain my own RV electrical/charging/storage system.

Woo hoo!

:wings:

 

[xychix]

For europe where butane/propane is widely used in bottle systems a fridge running on 220V AC / 12V DC / Pro&Butane might be a suitable solution.
main brand is electrolux (now Dometic), they also produce loads of mall fridges for in caravans and campers.

additionally a 100 Watt peak system including charge controller would cost approx 250 to 300 euro's.

However can be build for ~150 system (battery excluded)

https://www.kleinezonnepanelen.nl/i...&action=page&group_id=12&lang=nl#.VbN-m-iqqko
for a complete system *(Europe, NL)

same shop has a 100Wp panel for 109E (I've got 2 of these powering an offgrid house, combined with a 40A DIY controller and 140Ah of semi-ttraction battery).
We mainly use 12V led lights and our fridge is propane driven.

 

[unseenone]

The performance of Gas fridge systems is significantly poorer compared to the DC only version. Due to the low power they use, I'd stick to DC. Here is a nice chart which may be handy. http://www.getaway.co.za/gear-reviews/12-volt-camping-fridge-buying-advice

 

[Scoutn79]

Here is what works for me solar wise in my pop up.
A quick Google search didn't turn up an power consumption stats so you might have to see what yours is actually drawing while running and in standby.
But for reference.....
I have an Engel 43 that draws 2.5a running and my run 1/3 of the time. The battery also runs interior lights for a short time and the water pump.
I use a 40 watt panel and my battery is always topped off by the end of the day even if it is raining half the time during the day.
I can easily go two days running the Engel in my Scout without running the engine. I would look into the actual power consumption of the fridge you are using. Something seems to be drawing more juice than it it seems should compared to similar fridges.
Darrell

 

[Big mike]

Did not read full thread but from the first post your going to need more then what your looking at on amazon . We use like product at my dealership in summer and winter to trickle charge batteries . The pull from your fridge I do not believe will be balanced by this product.
I use a made in China 125watt system on my chaser trailer and it handles everything with no worries at all .
I simply put in sun and leave hiking, crawling , fishing whatever . And when I return from the day full charge on batteries . Same at night it stored more than enough. Got to wonder about your car or truck battery if a fridge is going to take it out in a day anyway .
Mike