6 ----> 24 volts

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Definitely, although the new Aussie pup is presently destroying the joint. Teething stages are terrible.

I'm sitting here wondering what kind of crap I would have caused if I took this voltmeter's readings for fact and used my other one to finish the wiring. Jesus. I recall this old supervisor I had way back when who used to insist we start electronic troubleshooting at its source. "Is it plugged in" and on from there. I thought it was patronizing at the time but have learned that he was right.
 
I don't wish to insult you but I am worried that if you can't hook up a volt meter properly you might not have the chops to wire up a solar project like this.
 
The only thing wrong is the color of the test leads.  They're reversed at the meter and also reversed at the batteries, with black going to the + terminal and red going to -.

So in this case two wrongs do make it right.  And in San Francisco, three rights make a left turn.
 
Back to the 24v vs 12v question, I think the sources used in your research are for static systems rather vehicles. The arguments for using a higher voltage are sound, but [in my opinion] the more overwhelming consideration in a mobile solar set-up is that the vehicle & RV systems all run off 12v. It would be much better if they upgraded their operating voltage, but until that happens it's a fact of life.  The conversion of the system run voltage down to 12v will surely cost whatever is gained by using 24 (or 48) volt for the storage system. It may even cost more than what can be gained at 24v.

Automotive designers have known they need to switch to 24v or 48v for over 25 years now.  There were plans in place to make the change-over back in the 1980's, but the cost & difficulty of making the transition has kept it on the back-burner all this time.
 
I value Gary's opinion as one of the most if not the most respected on this Forum.

I agree with what he said for several reasons.

I also have come to the opinion that your planning is more inline with a residential system than a RV or vehicle solution.

There is nothing wrong with thinking out of the box, However mobile electrical systems are built around a long established 12 volt standard for everything from light bulbs to electric motors to relays, entertainment systems and appliance controls.  I could list even more but I think the point is established.

Having said that if you are willing to address all of these challenges, you may well design a system that works for you.

There is also at least one more major hurdle that you will need to consider if you go with 2,000 watts of solar panels.

I have just over 1,500 watts of panels, (10 panels), and it take up much of the roof space of both a 40 foot diesel pusher and about half of a 30+ foot Stacker Trailer.

Here are two pictures of the 5 panels on the stacker and the 5 on the dp.

Edit for Lou:  Towing a Stacker I have been known to make three left turns to make a right turn.  LOL


 

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Gary [RVer Emeritus] said:
Back to the 24v vs 12v question, I think the sources used in your research are for static systems rather vehicles. The arguments for using a higher voltage are sound, but [in my opinion] the more overwhelming consideration in a mobile solar set-up is that the vehicle & RV systems all run off 12v. It would be much better if they upgraded their operating voltage, but until that happens it's a fact of life.  The conversion of the system run voltage down to 12v will surely cost whatever is gained by using 24 (or 48) volt for the storage system. It may even cost more than what can be gained at 24v.

Automotive designers have known they need to switch to 24v or 48v for over 25 years now.  There were plans in place to make the change-over back in the 1980's, but the cost & difficulty of making the transition has kept it on the back-burner all this time.

Maybe it won't work reliably but where I'm at is just adding a 24 > 12v step down. Very small, very easy, very efficient. I don't see the problem.

edit: I should be done with the wiring tomorrow and I'll be sure to update on my results (minus actual PV). The step down (image) is rated at 40 amps, and AIMS didn't see an issue with how I was to use it. I was initially concerned with its small terminals for connectivity, but I'll just use a bus to resolve. The only real 12v issue I've faced is with the slider motor which the manufacturer says needs up to 100A @ 12vDC to pull the slider in. I'm going to resolve that by adding a 13th battery, this one much smaller so I can fit it into a nook in my battery box. I figure a 200+ CCA unit will work fine but I may be test driving a few.
 

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HueyPilotVN said:
I value Gary's opinion as one of the most if not the most respected on this Forum.

I agree with what he said for several reasons.

I also have come to the opinion that your planning is more inline with a residential system than a RV or vehicle solution.

There is nothing wrong with thinking out of the box, However mobile electrical systems are built around a long established 12 volt standard for everything from light bulbs to electric motors to relays, entertainment systems and appliance controls.  I could list even more but I think the point is established.

Having said that if you are willing to address all of these challenges, you may well design a system that works for you.

There is also at least one more major hurdle that you will need to consider if you go with 2,000 watts of solar panels.

I have just over 1,500 watts of panels, (10 panels), and it take up much of the roof space of both a 40 foot diesel pusher and about half of a 30+ foot Stacker Trailer.

Here are two pictures of the 5 panels on the stacker and the 5 on the dp.

Edit for Lou:  Towing a Stacker I have been known to make three left turns to make a right turn.  LOL

I've mapped the roof out thoroughly. I'll have to relocate the TV and radio antennas, or maybe I'll just toss them. I don't use either anyway. Don't miss the video at the bottom https://www.altestore.com/store/solar-panels/solarworld-340-watt-solar-panel-sunmodule-sw340-xl-mono-p40538/
 
I checked out your website for the solar panels.

This site seems to mostly be geared to residential or commercial uses which may be fine and is in line with your wanting to use large panels in higher voltages than commonly used in RV applications.

That does not mean that they will not work, However I would look carefully at the mounting system, framework and frame systems needed to support and mount the panels.

They are rated for high winds but I would ask questions about going down the road and road vibrations.  Not being negative, just saying be sure that you know what you are getting.

There may be a difference in mounting a large array on a stationary platform and a mobile solution.

Each panel measures about 6.5 feet by a little less than 4 feet or 26 square feet.  Six panels would require about 156 square feet of roof space for 2,040 watts.

Be sure to mount them where no shadows will fall across the panels.  You might also try to plan the layout to allow you to move around them or otherwise access them.

The cost per watt is very low but you may make it up with the frame structure and mounting UFO's.

Good Luck and keep us advised of your progress as this will be a learning experience for us traditional guys.

Edit:  These 24 volt panels wired in parallel could certainly also be used with MPPT controllers to work with a 12 volt battery bank
 
Desert_Rat said:
If you notice, the red lead (standard + lead)  is tied to the + terminal, but my voltmeter is connected in reverse to get its positive reading. I'm just curious why the positive charge is at the negative terminal on the bank instead of at its positive terminal. It's obviously inherent to a series connect but I found it odd is all.
Sorry, but in the photo in the OP does NOT show where the meter leads are attached.  The leads go off the bottom of the photo.  I just went back and looked at the photo in the OP.  I suppose my Firefox browser doesn't show the full photo. 

Since I can't see where the meter is attached all I can go by is the way the battery is wired and it looks like the black cable comes to the top left neg terminal and the 4 batteries are wired in series to the red cable on the plus terminal.  Looks OK to me. 
 
If you look at the very bottom of the photo.....right side, directly below the negative battery terminal, you can just see the tip of the black probe being pushed into the end of a red cable that goes to the Positive battery post at the top right.  Now look at the meter....the black lead is plugged into the voltage lead of the meter.  That makes the red lead from the meter to be plugged into the common and that lead will end up at the negative post of the battery array.  The meter doesn't care what color the leads are, all it's looking for is a positive or negative voltage reading with respect to which lead is on which terminal.....thus the correct voltage reading, but visually, you would think something is wrong because of the meter lead color.
 
Can I do the attached, and would the result be 1840AH @ 24v?

edit: larger image: http://imgur.com/a/S923b
 

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Series connections add voltage, parallel connections add amp-hours.

I see (4) parallel connected rows of (3) 6 volt batteries in series.  That gives 18 volts per string, not 24 volts.  You need (4) 6 volt batteries in series for 24 volts.

Each series string stores 220 amp-hours, the same as a single battery.

If you reconfigure for (4) batteries in series per row, you'll have 24 volts with (3) rows in parallel at 220 amp-hours each.  This is 660 amp-hours total storage.



 
Yeah, I see that now. And it's how I presently am wired up.

just trying to get more AH. Any ideas? Can I connect 3 batteries in parallel, then connect 4 of those in series or does it not work that way?
 
Can't do that, I'm stuffed to the gills as it is. just appears to me (theoretically) that if 2 batteries in series make one bigger battery, why can't I connect those bigger batteries in parallel to get more AH? I guess the answer to that is I'm nuts, theoretically.
 
Amp-hours are only half the story - Amperage x Voltage equals power.

200 amp-hours at 24 volts is 4800 watt-hours ... twice as much power as 200 amp-hours at 12 volts.
 
Desert_Rat said:
Can't do that, I'm stuffed to the gills as it is. just appears to me (theoretically) that if 2 batteries in series make one bigger battery, why can't I connect those bigger batteries in parallel to get more AH? I guess the answer to that is I'm nuts, theoretically.
Two batteries in series doubles the voltage. Two batteries in parallel doubles the amperage. But either way you still are getting the same amount of wattage or amp hours. No magic tricks.
 
Lou Schneider said:
Amp-hours are only half the story - Amperage x Voltage equals power.

200 amp-hours at 24 volts is 4800 watt-hours ... twice as much power as 200 amp-hours at 12 volts.

For sure. But I've been looking into this series/parallel connect and it seems to challenge ohms law? Example attached. Source is indicating that 5040w of energy (8*6v*105a) can be wired to create 7440 (24v*310a) of energy with this series/parallel connect.
 

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