RV News RVBusiness 2021 Top 10 RVs of the Year, plus 56 additional debuts and must-see units → ×
 

Go Back   Thor Forums > Thor Industry Towables - Travel Trailers & Fifth Wheels > DRV Luxury Suites
Click Here to Login
Reply
 
Thread Tools Display Modes
 
Old 08-14-2018, 02:18 AM   #1
Senior Member
 
Brand: DRV
State: Texas
Posts: 300
THOR #9543
24v solar panels

Have any of you wired your solar panels in series producing 24 volts? I have Renogy panels and the tech informed me that 24 volt series would be more efficient that 12v. My controller is also maxed out at 800 watts for 12v and I'm considering adding 2 more panels, taking my total to 900; 24 volts, according to him, would cut those watts in half. I'm out of my element here and doing research. Any advice/information is appreciated......except from the 2 that I don't want to hear from.
__________________

__________________
2017 36RSSB3--2012 F350 KR, LWB, SRW, bilsteins, 1 1/4" anti sway bar, bilstein steering stabilizer, airlift air bags, on board wireless compressor, 295/20 tires at 4080 pounds each, oversized finned aluminum diff and trannie pans, all synthetic fluids; KEM, Tyrant, and PIP tunes with SCT X4 programming, G37 2017 Turbo, ATS Stage I towing transmission and torque convertor, Edge CTS gauge monitoring.
clev is offline   Reply With Quote
Old 08-14-2018, 02:43 AM   #2
Senior Member
 
Long & Winding road's Avatar
 
Brand: Thor Motor Coach
Model: 2017 Axis 25.4
State: Arkansas
Posts: 2,602
THOR #12231
I have "read" about the 24v systems. I dont know a lot but I think if I had like 6 to 10 panels (600 to 1000 + watts) like you have I would split them that way the if the front half of RV was in shade that back half will still work and charge the system. But run 24 volts which they say is more efficient. Plus you should be able to still use your current solar controler and wiring.

Tons of tread and website on this subject..... do your research first but it sounds like it would work for you.

Hopefully someone can chime in that is currently running 24 v.
__________________

__________________
2017 Axis / 25.4: Big Foot Levelers, Aims 1200 Watt inverter, Ceramic Window Tint, Full River AGM 6V batteries, Front Hellwig Sway bar / Rear Track Arm, Safe T Plus Steering Stabilizer, PD 4655 converter, Hard Wired Surge Guard, WEboost + WiFi Ranger, LED Headlights/Driving lights, TPMS, Surge tank, Tornado flush, Viair Compressor
Long & Winding road is offline   Reply With Quote
Old 08-14-2018, 05:03 AM   #3
Senior Member
 
mtntrek's Avatar
 
Brand: DRV
Model: ES 38RSSA
State: Montana
Posts: 134
THOR #5034
Generally, yes as you increase Voltage, you decrease Amperage. Other things being equal the Wattage would remain the same. Some go to 48V or more.
Series panels can have other issues though, such as shading of any small portion of the said string "could" result in a large reduction of output to all panels in a series string.
Unsure of your controllers capacity and you battery bank type and capacity it would be difficult to determine what actual output might be.
You can only shove so much at your batteries at a given rate and temp to avoid overheating damage etc. If your tech thought it should work, go for it.
__________________
mtntrek is offline   Reply With Quote
Old 08-14-2018, 07:51 PM   #4
Senior Member
 
Brand: Thor Motor Coach
Model: Axis 24.1
State: Florida
Posts: 611
THOR #4366
Series panels will work best in none shade conditions like out west. You need to make sure that Voc of the series combination doesn't exceed the controller max voltage input. It also requires using MPPT controllers. The reduction in wire size may not offset the increase in cost of an MPPT controller.
__________________
2016 Axis 24.1 E-450 6 spd tranny
300 watts portable solar.
200 watts solar on the roof.
Wrangler JK dinghy
scrubjaysnest is offline   Reply With Quote
Old 08-22-2018, 01:25 PM   #5
Senior Member
 
Brand: DRV
State: Texas
Posts: 300
THOR #9543
At this point, I have four 150 watt panels producing a max of ~33 amps into a 60 amp Renogy MPPT controller that feeds six Life Line 6-volt batteries wired in series for a total of 660 ah,
__________________
2017 36RSSB3--2012 F350 KR, LWB, SRW, bilsteins, 1 1/4" anti sway bar, bilstein steering stabilizer, airlift air bags, on board wireless compressor, 295/20 tires at 4080 pounds each, oversized finned aluminum diff and trannie pans, all synthetic fluids; KEM, Tyrant, and PIP tunes with SCT X4 programming, G37 2017 Turbo, ATS Stage I towing transmission and torque convertor, Edge CTS gauge monitoring.
clev is offline   Reply With Quote
Old 08-22-2018, 04:14 PM   #6
Senior Member
 
wingnut60's Avatar
 
Brand: DRV
State: Texas
Posts: 677
THOR #3109
clev,
You mean 6 batteries seriesed in pairs, then paralleled? Otherwise, you have 36 volts output.
Joe
__________________
2016 Tiffin 40QBH
2015 38RSSA--traded
2005 36TK3--retired, but it was a good one
2017 F450 KR
wingnut60 is offline   Reply With Quote
Old 08-22-2018, 04:38 PM   #7
Senior Member
 
Brand: DRV
State: Texas
Posts: 300
THOR #9543
Good morning, Joe. Your correct, but with our trailer system bring 12v, I thought that part would be understood. My oversight.
__________________
2017 36RSSB3--2012 F350 KR, LWB, SRW, bilsteins, 1 1/4" anti sway bar, bilstein steering stabilizer, airlift air bags, on board wireless compressor, 295/20 tires at 4080 pounds each, oversized finned aluminum diff and trannie pans, all synthetic fluids; KEM, Tyrant, and PIP tunes with SCT X4 programming, G37 2017 Turbo, ATS Stage I towing transmission and torque convertor, Edge CTS gauge monitoring.
clev is offline   Reply With Quote
Old 08-23-2018, 03:51 AM   #8
Senior Member
 
wingnut60's Avatar
 
Brand: DRV
State: Texas
Posts: 677
THOR #3109
Sorry, clev, should have known...
__________________
2016 Tiffin 40QBH
2015 38RSSA--traded
2005 36TK3--retired, but it was a good one
2017 F450 KR
wingnut60 is offline   Reply With Quote
Old 09-01-2018, 07:59 AM   #9
Member
 
Brand: DRV
Model: 40KSSB4
State: California
Posts: 46
THOR #5723
I am running three parallel strings of two panels in series on my fiver. My panels are 36 volt panels, so each series string can potentially produce 72 volts. I have a Magnum PT-100 charge controller that needs high voltage like this to work properly. Each panel is 235 Watts for a total potential wattage of 1410. This set up works very well for me.

As stated above, as long as your charge controller can handle the higher panel voltage and still output 12 volts to your batteries (which is what MPPT controllers are meant to do) the biggest problem to watch for is potential shading issues.
__________________
heiser252 is offline   Reply With Quote
Old 09-01-2018, 01:21 PM   #10
Senior Member
 
juicesqueezer's Avatar
 
Brand: DRV
Model: 39RESB3
State: Florida
Posts: 240
THOR #5499
Quote:
Originally Posted by heiser252 View Post
I am running three parallel strings of two panels in series on my fiver. My panels are 36 volt panels, so each series string can potentially produce 72 volts. I have a Magnum PT-100 charge controller that needs high voltage like this to work properly. Each panel is 235 Watts for a total potential wattage of 1410. This set up works very well for me.

As stated above, as long as your charge controller can handle the higher panel voltage and still output 12 volts to your batteries (which is what MPPT controllers are meant to do) the biggest problem to watch for is potential shading issues.
Question; with that wattage, can you run at least one air? We are considering 1200 watts with the Magnum controller and I believe it still won't run an air.
__________________
Joe & Dottie Allen
2014 Mobile Suites Estates 39RESB3
2014 Ford F-450 DRW
juicesqueezer is offline   Reply With Quote
Old 09-01-2018, 02:38 PM   #11
Senior Member
 
wingnut60's Avatar
 
Brand: DRV
State: Texas
Posts: 677
THOR #3109
Joe,
Even IF you could run the air off the solar, you could not replace the power as fast as it is used. We have 1260 in panels, but the ACs and fireplace are not powered by them--the microwave is and works well for 2-5 min draws.
Still learning about the use and replacement time needed in full sun...
__________________
2016 Tiffin 40QBH
2015 38RSSA--traded
2005 36TK3--retired, but it was a good one
2017 F450 KR
wingnut60 is offline   Reply With Quote
Old 09-01-2018, 03:03 PM   #12
Senior Member
 
Brand: DRV
State: Texas
Posts: 300
THOR #9543
I think that I am finally beginning to understand more of this. 1. Panels can be wired
in series, but must terminate in some multiple of 12 volts; 12, 24, 48. If that is correct, must the panels be paired so as to double the voltage each time, or can the string have an odd panel? Ex.- three 12 volt panels wired in series to parallel, to produce 36 volts? 2. Regardless of the voltage coming into the MPPT controller, it will step it down to 12 volts. Is that correct?
__________________
2017 36RSSB3--2012 F350 KR, LWB, SRW, bilsteins, 1 1/4" anti sway bar, bilstein steering stabilizer, airlift air bags, on board wireless compressor, 295/20 tires at 4080 pounds each, oversized finned aluminum diff and trannie pans, all synthetic fluids; KEM, Tyrant, and PIP tunes with SCT X4 programming, G37 2017 Turbo, ATS Stage I towing transmission and torque convertor, Edge CTS gauge monitoring.
clev is offline   Reply With Quote
Old 09-01-2018, 03:09 PM   #13
Member
 
ewacowboy's Avatar
 
Brand: DRV
Model: 38RSSA MS
State: Washington
Posts: 53
THOR #5214
Quote:
Originally Posted by juicesqueezer View Post
Question; with that wattage, can you run at least one air? We are considering 1200 watts with the Magnum controller and I believe it still won't run an air.
Joe,

I agree....it all depends on your battery bank capacity. Chad is running a 1040 amp hour capacity battery bank. If you want to look at his system he has a thread on Escapees here: My Solar Installs - Now with Solar Output Data - Technical Tips and Tricks - Escapees Discussion Forum

I'm currently installing a system with 1200 watts of panels but my battery bank isn't enough to run the a/c. Maybe when the new lithium technology becomes more affordable I'll change out to a bigger/better battery bank.
__________________
2017 DRV 38RSSA
2016 Western Star 5700xe
Our YouTube Channel
ewacowboy is offline   Reply With Quote
Old 09-01-2018, 07:05 PM   #14
Senior Member
 
wingnut60's Avatar
 
Brand: DRV
State: Texas
Posts: 677
THOR #3109
Keep in mind Chad's batteries are Lithium, not lead acid--he can utilize almost all of his AH capacity; I have 1200AH capacity, but mine are AGMs and are 6volt in series, giving me only 600AH and should not go below 300/50%.
Chad is one heck of a designer/installer...
__________________
2016 Tiffin 40QBH
2015 38RSSA--traded
2005 36TK3--retired, but it was a good one
2017 F450 KR
wingnut60 is offline   Reply With Quote
Old 09-01-2018, 07:14 PM   #15
Senior Member
 
Brand: DRV
State: Texas
Posts: 300
THOR #9543
Yes, wing, Chad is really great with these systems, and I have nothing nearly as elaborate as what he has designed/installed. If he is monitoring, hopefully he or you can clear up my questions in the other post.
__________________
2017 36RSSB3--2012 F350 KR, LWB, SRW, bilsteins, 1 1/4" anti sway bar, bilstein steering stabilizer, airlift air bags, on board wireless compressor, 295/20 tires at 4080 pounds each, oversized finned aluminum diff and trannie pans, all synthetic fluids; KEM, Tyrant, and PIP tunes with SCT X4 programming, G37 2017 Turbo, ATS Stage I towing transmission and torque convertor, Edge CTS gauge monitoring.
clev is offline   Reply With Quote
Old 09-02-2018, 07:57 AM   #16
Member
 
Brand: DRV
Model: 40KSSB4
State: California
Posts: 46
THOR #5723
Quote:
Originally Posted by wingnut60 View Post
Keep in mind Chad's batteries are Lithium, not lead acid--he can utilize almost all of his AH capacity; I have 1200AH capacity, but mine are AGMs and are 6volt in series, giving me only 600AH and should not go below 300/50%.
Chad is one heck of a designer/installer...
Thanks for the compliment. I appreciate it. As to my battery bank, unfortunately I am running AGM batteries. I wish I had 1040 amp hours of Lithium instead of just AGM. It would give me more useable amp hours at a lot less weight. (My AGM bank weighs about 700 lbs).
__________________
heiser252 is offline   Reply With Quote
Old 09-02-2018, 08:07 AM   #17
Member
 
Brand: DRV
Model: 40KSSB4
State: California
Posts: 46
THOR #5723
To the question about running an AC from solar/batteries, it can be done and one of these days I will probably do it as a proof of concept. There are however some limiting factors. First you need an inverter capable of putting out enough power to handle the initial surge of the AC compressor kicking on. Not a lot of inverters are capable of this. If I go this route, I intend to add a micro air easy start module to my AC unit before I try to wire it to my inverter sub panel.

Lithium batteries are also better than other types of batteries for trying to run an AC. This is because they produce a consistent, linear power output all the way from full charge to almost completely discharged. AGM and Lead Acid batteries output power more on a curve, with higher output at full charge and then ever decreasing output as the charge diminishes. Additionally, Lithium batteries can be discharged more deeply and don’t have to be fully recharged regularly like AGM and Lead Acid. This is more conducive to trying to run high draw items like an AC. This doesn’t mean you can’t run an AC from an AGM or Lead Acid battery bank because you can. It is just that a Lithium bank is better suited to do it, but I am digressing from the original topic. Of course you still need to replace the power drawn by the AC back in whatever bank you use, which is where solar comes in and why this topic was started.
__________________
heiser252 is offline   Reply With Quote
Old 09-02-2018, 08:22 AM   #18
Member
 
Brand: DRV
Model: 40KSSB4
State: California
Posts: 46
THOR #5723
Clev asked me his original question from this topic (with a little more detail included) in a pm on another forum. I haven’t been monitoring this forum as closely recently, but with the pm, I came here and decided to add some additional information. I also wanted to post my response to Clev’s pm here so that others might benefit from the information. (Clev, hopefully I am not overstepping my boundaries here.)

Basically, Clev has an existing system with four 150 watt panels installed for a total of 600 watts. His existing MPPT charge controller is limited to a maximum wattage input of 800 watts and he wants to add two additional 150 watt panels to his system. This would give him a total of 900 watts. He wants to know if there is any way to wire the six total panels to keep them within the specifications of his existing controller. Here is my basic response to that general question:

“Sorry, I haven’t been keeping up with the Thor forum that much lately. To start with, here is a basic equation that should help:

Watts = Volts x Amps

For example, my panels are Canadian Solar 235 watt panels. I have six panels for a total of 1410 watts (235 x 6 = 1410). The Vmp rating of my panels is 29.8 and the Imp rating of my panels is 7.9 (29.8 x 7.9 = 235.42). This is why my panels are rated at 235 watts.

I run my panels in three parallel strings of two panels in series (six total panels). When you run in parallel, the voltage stays the same and the amperage is cumulative. When you run in series, the voltage is cumulative and the amperage stays the same. So in my case, I have two panels in series. This gives me 29.8 + 29.8 which is 59.6 volts at the same 7.9 amps. I then have three of these series strings. This gives me 7.9 + 7.9 + 7.9 which is a total of 23.7 amps at the same 59.6 volts. Again, Amps x Volts = Watts, so 23.7 x 59.6 = 1412.52 total watts, or basically the same 1410 watts (when you account for rounding). In other words, series or parallel makes no difference in my total watts. Hopefully this example helps you with your calculations.

If you go to six of your 150 watt panels, no matter how you wire them you still have a potential of 900 watts. In other words, you can overpower your existing charge controller. You can re-wire your system (with six total panels) into any combination of series/parallel and it will always come out to 900 watts, which is more than your particular controller is rated for.

MPPT controllers in general can take high voltage input and convert it to lower voltage at higher amperage output. Your controller could take the higher voltages of various series/parallel combinations of your six total panels (assuming they were within the maximum wattage rating of your controller) and still put out the appropriate voltage to your 12 volt battery system. This is what MPPT controllers are designed to do. They take the additional voltage input from high voltage panels and convert that extra voltage to additional amperage going into your batteries at the proper voltage.

You also do not want to mix one series string into your existing parallel set of panels. You will be mixing different voltages, which will pull down the voltage to the lower of the two. When you mix panels of different voltage (your two additional panels in series essentially become one panel with a higher voltage), the maximum output will be the lower of the two voltages. This is based on electrical theory that is too difficult to explain here, but it is what happens. This, in essence means you would not be getting any benefit from this new string any more than just adding one single additional panel (of the same ratings) to your existing array.

Hopefully this helps. Let me know if you have any more questions. I am happy to help.

Chad”

The Renogy tech that Clev mentioned in his original post did not give Clev completely correct information. He was correct in that running panels in series can be more efficient. This is because you can use smaller wire and components related to the wiring than the same wattage array run in parallel. Higher voltage can use smaller wire than lower voltage (this can be seen by plugging numbers into any wire size calculator). However, when the tech said running in series would lower the wattage of the array, he was incorrect (as I explained above).

Hopefully this information is useful. Again, Clev, I apologize if I overstepped by mentioning our PM conversation.
__________________
heiser252 is offline   Reply With Quote
Old 09-02-2018, 01:30 PM   #19
Senior Member
 
Brand: DRV
State: Texas
Posts: 300
THOR #9543
Good morning, Chad. Thank you very much for this lesson and you have not overstepped anything. This grasshopper is extremely grateful.
__________________
2017 36RSSB3--2012 F350 KR, LWB, SRW, bilsteins, 1 1/4" anti sway bar, bilstein steering stabilizer, airlift air bags, on board wireless compressor, 295/20 tires at 4080 pounds each, oversized finned aluminum diff and trannie pans, all synthetic fluids; KEM, Tyrant, and PIP tunes with SCT X4 programming, G37 2017 Turbo, ATS Stage I towing transmission and torque convertor, Edge CTS gauge monitoring.
clev is offline   Reply With Quote
Old 09-02-2018, 02:06 PM   #20
Senior Member
 
wingnut60's Avatar
 
Brand: DRV
State: Texas
Posts: 677
THOR #3109
Chad,
I apologize for spreading misinformation on your battery type--I remember your original posts on your system and thought it was lithium.
Thank you for the time you put in trying to explain solar to us guys.
Joe
__________________

__________________
2016 Tiffin 40QBH
2015 38RSSA--traded
2005 36TK3--retired, but it was a good one
2017 F450 KR
wingnut60 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Thor Industries or any of its affiliates. This is an independent, unofficial site.




All times are GMT. The time now is 04:46 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0 PL2
×