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12/120 volt power system build

7K views 59 replies 14 participants last post by  AstroWill 
#1 ·
My plans are still evolving and may change at a moments notice. If anyone has any advice or would like to make equipment recommendations, I'm all ears.
First I'll lay out what I want to be able to do, then I'll tell you about what I already have, finally what I am planning to get.

So here is what I want to be able to do:
Power various 12 volt loads, some continuously (IE electric cooler), some on demand.
Power assorted 120v loads on demand.
Be able to charge 12 volt system with engine, solar and shore power
Make everything as stealthy as possible. No one standing near or riding in the van should be able to tell that anything weird is going on. The solar panel(s) will be the main thing that are likely to get noticed.

Sounds simple right? :shrug:

Currently I have Yakima tracks mounted on the top of the van. I've successfully made my own "Nuts" that will slide up and down the tracks and are tapped for 1/4" 20 bolts. I have 1", square tube, aluminum bars that can be mounted across the top of the van to hold ... various things to be determined.

I have a 1' x 4', 40 watt solar panel. It has an integrated aluminum frame. I also have a cheap solar charger that was purchased with this panel 20 years ago. I know that I will want more (different) solar power eventually, but I figure I will start with what I have.

I have a Coleman 400 watt continuous, (800 peak) power inverter. Again, I'll probably want a bigger, pure sine wave inverter at some point, but I already have this now. I'm considering mounting thus under the driver seat, on top of the EBCM "bulge" in the floor. I would mount the solar charger in the same area so it will not require a separate power run.

I am considering buying a 12v trolling motor quick disconnect socket/plug and mount it on the roof. This will allow the solar panel to be removed/installed without any wiring difficulties. I would like to mount this in the roof, near the roof rack track, and have the wires come down just behind the drivers door, hidden within the side panels. This way I can easily remove the solar panel and increase the "stealthiness" factor.
https://www.amazon.com/gp/product/B00434SEKC/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A1YUR915BM42I1

I am also considering attaching a "Shore Power" socket to the trailer hitch. When not is use (cover in place)it should look similar to a 7 wire trailer hookup. This will connect to both a power strip (inside the van) and an on-board battery charger.
https://www.amazon.com/gp/product/B000NI38MG/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER

Next is the on board charger. I'm looking at a NOCO, 1 bank, 10 amp charger. It will be attached to the shore power hook up.
https://www.amazon.com/gp/product/B003JSHQW0/ref=ox_sc_sfl_title_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER

I have not even touched on batteries yet. I know that the starting battery won't last long with any kind of load on it. I may start by upgrading it to a decent AGM, but what I really want is at least 100 amp/hrs of additional, hidden battery.

OK, that's all I can type for now...more to come soon. Hopefully with pictures.
 
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#2 ·
Might want to consider getting native 12volt equipment I.E. 12volt Dometic Freezer, 12volt adaptors for Laptop, Monitors etc... An inverter will drain batteries way faster than Native 12V accessories. (Yes the Dometic Freezer will put a pretty big drain)

I built a Teardrop Trailer for my brother and we went through the pros and cons of inverter and native 12v accessories. His Shore power is basically an extension cord and power strip. You can then plug in a 12V power supply and or charger to keep your batteries topped off while still running your 12v accessories.

Do some research on Solar Charge controllers there's some good inexpensive models out there. (Youtube is your friend) I don't have the specs on my brother's Solar stuff right now but I will get them and post it Soon.

Best of luck,

P@ul
 
#3 ·
Hi Paul,

Yes, a Dometic is what I have in mind.
I do intend to run as much as possible off of 12v, but there will occasionally be times when I need to run something off of 120v. A 120 volt AC might be nice, when shore power is available. :)
The inverter is only for occasional use, mostly when the motor is running.

The solar charge controller I have now is almost certainly a PWM model. At some point in the future when I am upgrading my panel(s) I will get a better controller. For now, I plan to work with what I've got. At least I can get the wiring in place.

Ideally I would like a MPPT charge controller that will also charge off of 120v AC...but that might get expensive.

I know that the 40 watt panel I have doesn't have a snowballs chance of running a Dometic cooler by it's self, but it may slightly extend my running time. When no big loads are attached it will at least let me keep my phone charged without worrying about running down the starting battery.
 
#5 ·
When the time comes for the new panels...I'm leaning toward 3 or 4 of these flexible 100 watt panels.

https://www.amazon.com/gp/product/B017OMTAV6/ref=ox_sc_sfl_title_9?ie=UTF8&psc=1&smid=A2D22KZJD14Y8Y

I think that some 1/8" aluminum could be bent to follow the roof line and secured to the roof rack track, then mount the panels onto that. It would sit just above the roof, allowing the panels to get some ventilation, but would still be very low profile. They would only extend about 1/2" above the roof at the highest point.

If I sandwich the straps between the roof rack track and some 1" box section aluminum, run front to back, you should hardly be able to see the panels at all.

The closest I've seen to what I have in mind is this:



But he used rigid panels in thick aluminum frames. The panels I want weigh a lot less and are only 1/8" thick.
 
#6 ·
I have built several solar systems for boats. These are full time, detached systems that need to work independent of shore power... much more involved then what we need for our vans unless we are traveling out and staying put.

you said 'Ideally I would like a MPPT charge controller that will also charge off of 120v AC...but that might get expensive.'

You will be more likely to find an inverter with a built in charger then a regulator. Xantrex makes a good product.

The newer MPPT controllers have gotten much less expensive. Just bought one from Amazon for $32, ill post more info once it is in use.
they do give you an appreciable increase in charging efficiency.

Your 40w panel is going to help, and is likely a fair match for what you want to do... more is (of course) better.

There are a few considerations for a system. The first and most important is your 'energy budget'. How many amps will you use FOR HOW LONG.

That is why refrigerators are really the biggest consideration. I like Engle, have used several models on boats. A reliable 2.3a draw when running and the smaller (the 17 - the 27) are a reliable 25ah draw. The cheapest part of the equation is to lower your AH budget.

Next you have to look at storage. You can only ever draw your storage down to 50% (lead acid) without seriously dropping the life. A 25ah budget (ref and LED lighting) is supportable with solar on the stock battery...

Keep in mind an increase in storage is useless without the ability to charge it.. just as an increase in charging capacity is useless without the storage.

You have to 'tune' your system... best way to start is with what you have and see what works.
 
#7 ·
One more thing,

Flexible solar panels have a long history of problems. Low output (poly crystal construction) and internal failures are common.

I have owned 3 different flexible panels and have never had them make anything like their rated power, and all 3 were either returned, or failed after they were eligible for return...
 
#8 ·
I appreciate the warning.
The flexible panels I'm looking at are monocrystalline.
Renogy used to sell them, but quit after having issues.
The ones available now, I believe, came from the same factory, so there are reports of sporadic issues with them.
But the much lower profile and much lighter weight, offer a considerable advantage when placed on the top of a van, so I'm still considering them.

As for my "energy budget," my plan is, as you suggested, to use what I've got and see where it takes me. Then I'll make adjustments as needed.

BTW, the Dometic's aren't cheap, but the only prices I've found on the Engle's are much higher.
 
#9 ·
Just remember that you want a space between your panels and the roof. Solar panels get HOT, and as they get hot they not only put out less, but the closer they are, the more heat gets transfered into the vehicle.
 
#10 ·
My plan is to use the 1/8" x 1" aluminum strap under the panels and that will be a little above the roof. The panels will have about 3/8" clearance above the high "ridges" on the roof and much more in the "valleys." It isn't a lot of space, but it will allow some air flow.
 
#11 ·
I think(?) I have the same Coleman inverter. On mine at least, it will not cycle on by simply applying 12v power and leaving the switch in the always ON position. It has to be manually turned on with the switch every time you want to use it. It's a PITA for that inconvenience.

Lots of current day ham radios are similar. Can't cycle them from the power source, requires a "boot up" process.

Lump
 
#12 ·
I decided to go pull out the parts I'm planning to use. They were just where I remembered. But the inverter isn't WHAT I remembered. It turns out it is an 800/1600 watt Coleman inverter. It is ALMOST too big for the location I had in mind, but I think it will still work. I'll just butcher an old pair of jumper cables to connect it to the battery.

I also mocked up the panel in one of the possible mounting locations. I'm still considering adding two cross bars and mounting the panel fore and aft, rather than side to side.

Pictures always make everything better, so here are a few.
 

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#13 ·
The bump under the drivers seat holds the engine computer doesn't it?
I'm very slightly concerned that having too much high power stuff sitting right on top of it might cause weird radio interference issues.
So I'm considering alternate locations for:
Power Inverter (800/1600 watt)
AC battery charger (15 amp)
Solar charge controller (??? TBD)

They all need to be connected to sizable power cables, so I want to put them together, as close to the front as possible, with easy access and out of the way.
Under the passenger seat might be OK, but then I will have to worry about passing the battery cables around more of the exhaust.

I plan to put extra batteries under the van, either in front of the gas tank or somewhere near by.
 
#17 ·
So...if a bunch of high voltage stuff right on top of it does cause problems, all I need to worry about is the air bags exploding in my face?
Believe it or not, that sounds better to me than trying to track down some crazy, inconsistent "mystery" issue with the engine.

At least, if the air bags explode, I'll know where to start looking for problems. :)

But my guess is that the air bag system is probably less likely to have issues. If GM has computer issues is results in profitable service calls. If they have mysterious air bag explosions, it results in law suits.

I think I'll take another look at placing the equipment under the drivers seat.

BTW, I'm now considering a VMax 20 amp charger. I may use it on the starting battery at first (way overkill for that). When I get the AGM's under the van I'll use it to charge those. It is about the same price as the one I was considering, but has twice the output and a very convincing sales pitch with their "7 mode" charging cycle and automatic battery type selection. The 20 amp version is recommended for 60 to 80AH minimum, 300 to 500 AH maximum, depending on which factory documentation you read.

Soon I'll need to decide on a charging solenoid to use, so the engine will charge both battery banks, but the starting battery will be reserved for starting. I'm leaning away from the solid state "diode" style as they use a lot of power, get hot, cost more and are big. Any recommendations/personal experience?
 
#18 ·
After looking at that panel on my roof for a while, it got me thinking.
How much gas mileage will having that on the roof cost me, compared to a clean roof?
If I get 1 MPG less, I might save money by starting the engine to charge the battery and leaving the 40 watt panel at home.

Now the 100 watt semi-flexible panels that I have in mind will be a lot more powerful and a lot less wind resistance. So I suspect that they will push the equation in the other direction. They should also be a lot more stealthy.
 
#19 ·
esc said:
After looking at that panel on my roof for a while, it got me thinking.
How much gas mileage will having that on the roof cost me, compared to a clean roof?
If I get 1 MPG less, I might save money by starting the engine to charge the battery and leaving the 40 watt panel at home.
About the same as having a roof rack, whatever the difference there is, aka not enough to reliably calculate.

esc said:
Now the 100 watt semi-flexible panels that I have in mind will be a lot more powerful and a lot less wind resistance. So I suspect that they will push the equation in the other direction. They should also be a lot more stealthy.
There are those things, more heat as well as a few other things to consider:
gonewiththewynns said:
Cupping - Extreme temperatures can make the flexible panels slightly warp causing water, dirt, dust and sand to buildup in these little "cups" on the panels.
Flat Roofs - Our RV has a pretty flat roof, so when we park and level our coach the panels are basically flat. Water does not run off the sides evenly and sometimes the water just sits on top of the panel causing more sediment to collect on the panels.
Scratches - When cleaning the flex panels the sediment caught in the "cups" can scratch the surface of the panel (to be clear you're not scratching the solar cells, just the coating that covers them).
Gouges - We go on some crazy roads with low hanging branches when driving into National Forests, BLM lands, Wineries, Farms and even some national or state parks. We've picked up a few small gouges in the panels from these low hanging branches over the past year. I am not sure if the gouges are deep enough to damage the solar cell or if they have just damaged the coating around the cells, to my untrained eye it appears to be only in the coating.
Non-Tilting - When we installed our brand new flexible solar panels we glued them down so there were no screws penetrating through the RV roof, the issue here is the solar panels can't be tilted for maximum sun exposure which is especially beneficial during the winter months when the sun is lower on the horizon.
Warranty - Currently the warranty on our flexible panels is 10 years which is perfectly fine by us because 1) we know we're not going to have this RV for more than 10 years and 2) in 10 years I bet there will be much better, more efficient solar technology, so in theory I probably won't want to keep any solar panels for more than 10 years. That said the 10 year warranty doesn't come close to the standard 30 year warranty on the tempered glass solar panels.
http://www.gonewiththewynns.com/flexible-rv-solar-issues-review
 
#20 ·
They have some good information. The panels they have look substantially like the ones I want. The one year review is the longest review time I have seen. Thank you for pointing it out o me.

I don't believe that all of their cons will apply.
Flat roof - nope. The panels will have a slight arc to them so should drain well.
Non-tilting, this will apply to any/all panels I use.
They also mention heat, but since I will not be mounting them directly on the roof, I don't think that will be more of an issue than with traditional panels.
Warping. The examples I have seen show the panels buckling in the middle. I believe that this is an issue with having the panels mounted directly to the roof. I plan to mount them in such a way that they will be able to move a little as they heat and cool. I'll use small diameter bolts in the mounting holes with washers on the top that will allow the panels to move a little.
Cupping- This the first I have seen of this, but again, with the panels mounted on an arc, I suspect that potential issue will be reduced.

Warranty? I'll have to check. But really, I don't care much about warranties, they are, more often than not, more trouble to cash in on than they are worth.

On the Pro side:
80% lighter
Will fit contour of roof much better making them more stealthy and more aerodynamic.

So, even with the cons, I'm still leaning toward these.
 
#21 ·
Unfortunately, they moved to a different setup, so that setup didn't stay on too long, no more reports :(

It will be interesting to see your results. make sure to post pictures.
 
#22 ·
Hi - this may or may not be my first post on astrosafari... :)

I just wired up a 12v aux power system in my 2000 awd astro and used this amazing device which you may want to consider. The only thing it doesn't accommodate is shore power - but you can just use an extension cord, multi-strip, and battery charger for most everything you'd ever need from the shore...

https://amzn.com/B005LBCVL4

This thing is a 5 stage, 20A battery charger which functions as a battery isolator (ctek told me it's VSR) and MPPT charge controller (max input of 22V so you have to wire your panels in parallel). You just run 4 awg cable from you starter to this thing and it will balance inputs from solar and alternator to draw the most efficient current to charge your battery depending on temperature and current charge. AMAZING!

This solved a lot of needs for me - hope it helps!

Surly
 
#23 ·
Surlyvan said:
I just wired up a 12v aux power system in my 2000 awd astro and used this amazing device which you may want to consider. The only thing it doesn't accommodate is shore power - but you can just use an extension cord, multi-strip, and battery charger for most everything you'd ever need from the shore...

https://amzn.com/B005LBCVL4

This thing is a 5 stage, 20A battery charger which functions as a battery isolator (ctek told me it's VSR) and MPPT charge controller (max input of 22V so you have to wire your panels in parallel). You just run 4 awg cable from you starter to this thing and it will balance inputs from solar and alternator to draw the most efficient current to charge your battery depending on temperature and current charge. AMAZING!
This is the same way that I went. 4awg is probably a bit overkill, but it does make it a lot easier if you want to upgrade later. To get more than 20amps by adding the smartpass. I wish they would have made the dual a bit better by including the smartpass with it ;)

Just make sure you are fused properly. We don't want to see viewtopic.php?f=9&t=88954
ctekdual.png
 
#24 ·
Thanks for the info.
That looks interesting...but it is kind of an expensive little box. Without the "smart pass" (another expensive box) it is basically just a MPPT solar charger isn't it?
The battery temp sensor is a nice touch. Being able to pull some power (20 amp max?) from the alternator is an interesting feature, but it is kind of limited without the extra "Smart Pass" box.

The reviews on amazon don't seem to come from anyone who has been using it more that a couple of months.

I think that my limited budget might be better spent on a less expensive MPPT charger, a battery isolator solenoid and more solar and battery.
 
#25 ·
I just ordered up the "VMax" 20 amp, 7 stage 120v charger.
I still need to measure one more time to make sure it will fit under the van, then I will order a 100 AH AGM off of Amazon.
I'll also get an inexpensive(<$50) battery isolater solenoid.

I am also looking at how I will mount the panels on the roof. Here is a picture of a piece of 1/8" x 1" x 4' aluminum that I am considering mounting the semi-flexible panels on to. I added a little extra between the mounting holes to make it bow up a little, so it would not touch the roof. It seems I added too much as I want it to sit a lot closer. It is also a little more flexible that I had hoped. If it doesn't stiffen up when the panels are mounted on it, I may step up to 1/4" thick aluminum.

In any case, it gives you the general picture of how the panels will mount. I'll have one of these straps on the front and back of each panel. I may also put some angle aluminum on the side to make the panels harder to see.

One last thing, the screws that came with the Yakima rack tracks were starting to rust. The roof was also starting to rust (just a little) where the screws touched it. So I went ahead and replaced all 22 screws with stainless.
 

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#26 ·
This does not directly relate to my power setup, but is is part of what I'm trying to do.
This suits my needs better than some elaborate bed that takes up the back of the van all the time. Easy to set up, I can store stuff under it, fold it up and it stows in no more space than a folding chair. There is even enough room for two, when I bring my son.
 

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