Solar Panel DIY on 2021 Newmar New Aire 3543

[TheFu]

OK, so I have read all the detailed threads here from many Newmar solar pioneers. Thank you! We recently purchased a near new 2021 New Aire 3543 and want to get solar going on it. I have what I consider really good DIY electrical experience at home as well as my prior coach where I installed an inverter along with additional electrical box and properly cascaded external ATS.

At first it amazed me the variety of information being put out there, especially regarding the factory wiring. A lot of talk about it being insufficient. At first glance I thought it might be as well. Then after digging in (and finding one other thread here confirming) I realized that many were not running their panels in series. Yes, I understand the drawbacks from shading, however some of the newer panels have internal diodes to help with that. Six 200w 24v panels, in 3-series 2-parallel, as an example, would be less than 17A on the Newmar 6awg prewire. Even accounting for line loss, temps, etc. There is more than enough capacity on that wiring by my figures.

So, I have decided for now to do the following, and I welcome feedback from any of the old-solar-salts on here as I have exhausted (I think) all available info here to come to these conclusions.

- Keeping my existing Harris Battery AGM 6V batteries which should have just under 900Ah of capacity so safely 400-450Ah available for use.
- Using existing Newmar pre-wire
- Building my own aluminum mounting frames to attach to existing roof trim side brackets.
- Grape Solar 330W panels - four in series (interconnect cable length TBD)
- Victron 250/100 MPPT
- Victron monitoring shunt
- Misc. fuses and shut offs
- 2awg wire from the charge controller to the batteries.
- 2/0 wire from the shunt to the neg- battery terminal
- plan to control and monitor from my phone
- might add screen to inside-coach front panel at a later date

I still need to find where the solar prep comes out in this particular coach year and model, so any help with this is appreciated.

I plan to video document the whole process and produce a YT video on a new channel I am launching next year.

Here is a diagram of how I see things at this point. I look forward to your feedback.

[TheFu]

Well, answered one of my own questions - looked up in the storage bay next to the inverter bay and saw this:



I removed the screws somewhat expecting that to be a panel cover over some sort of hole - no, just a screwed on "label"

So I removed the 24"x24" carpeted panel above (6 screws) and this is what I saw. A little studying and found the wires coming from the roof for the "solar prep"



Hopefully this will be helpful to others.

[DavidEM]

Sounds good. The only change I would suggest is to wire your panels in series/parallel. Yes that ups the current to 34 amps. But with the #6 wire you should be well below 0.5V drop which is my criteria.

Series/parallel also keeps the voltage down to safer levels and it gives some measure of shading protection. What's not to like!

David
David

[UMXHAULER]

If you really want to see this system crank, dump those AGM's and install Lithium batteries-you only need half the amount of batteries for the same usable storage capacity. Lead acid batteries just charge way to slow when your panels are laid flat on the roof and charging rates are much slower on lead acid as well. I did a similar array as you on my last coach and I was not pleased with the performance-though panel output was half of yours and I only had half the batteries as well. I still had to run my generator a lot.

[TheFu]

Originally Posted by DavidEM

Sounds good. The only change I would suggest is to wire your panels in series/parallel. Yes that ups the current to 34 amps. But with the #6 wire you should be well below 0.5V drop which is my criteria.

Series/parallel also keeps the voltage down to safer levels and it gives some measure of shading protection. What's not to like!

David
David

Great point. Makes sense. But those panels run at 34V so the current should be <20A peak by my calculation for a 2sX2p so I think you are spot on. I will make this change.

Originally Posted by UMXHAULER

If you really want to see this system crank, dump those AGM's and install Lithium batteries-you only need half the amount of batteries for the same usable storage capacity. Lead acid batteries just charge way to slow when your panels are laid flat on the roof and charging rates are much slower on lead acid as well. I did a similar array as you on my last coach and I was not pleased with the performance-though panel output was half of yours and I only had half the batteries as well. I still had to run my generator a lot.

Thanks for the real world feedback. For now I am going to see where I get with about 400Ah of usable storage and put some hours on these brand new batteries. Then I will see about a switch out. I really only need to run the refrigerator and some tiny misc phantom drains overnight. And, maybe if we are in a cold area, the oasis fans. So we shall see.

[TheFu]

So after some additional research I think if I can make four of these fit in a 2x2 configuration on a rack over the back area of the coach that I will switch to these panels over the Grapes. Just a little more money and (I believe) better tech and 20% more power. Thoughts?

https://www.solar-electric.com/rec-s...tt-module.html

[hclarkx]

Originally Posted by TheFu

So after some additional research I think if I can make four of these fit in a 2x2 configuration on a rack over the back area of the coach that I will switch to these panels over the Grapes. Just a little more money and (I believe) better tech and 20% more power. Thoughts?

https://www.solar-electric.com/rec-s...tt-module.html

Some idle thoughts .....

Over all a good plan.

Re going series ....... the solar controller will be a bit less efficient at 4x48.8V than at a lower voltage, but the lower wiring losses from lower current of series panels should cover that.

The concept that parallel panels provide some shade benefit over series panels is not correct so long as the system has an MPPT controller AND the panels have bypass diodes. Series has the advantage in this case.

I don't see bypass diodes mentioned in the panel listing you referenced. These are residential panels, right? Not having diodes is a deal breaker. I suppose one could add their own diodes, but that would take some engineering and would be messy. Without diodes you are limited to parallel .... a whole lot of current and some very messy fusing on the roof.

While 1600W will take you a long way, I personally would allow for expansion (I started at 200, went to 400, then 600, and currently 1000 with panels in the garage to take me to 2200). 200W panels are the sweet spot cost-wise and provide more flexibility in terms of layout (squeeze in more Watts if need be). Though maybe more brackets to deal with.

The 400W panels are long and probably need a bit more support along their length than the typical 100 and 200W panels. I.e., a mid-span support. I can't see the frame on the 400's in the listing. My home panels don't have much of a frame; far less than my Rich Solar 200's and the Renogy 100's that I started with.

H

[TheFu]

Both the Grape 330W and the REC 400W state that they have the diodes.

Not super concerned with mounting - the info on the REC shows them to be incredibly well built - and if I need a mid panel under-support, so be it.

If I can get all 4 above the back section of the roof, I will consider that a win. If not, I will have to go with the narrower panels, and more of them, which I would rather not do as more hardware means more chance for failure.

Call me a fool, but being a seasoned dry camper, I can't see me needing more than 1600W, especially down the road when I upgrade to Li. The key reason right now for me to get even that much solar is just the refrigerator.

[TheFu]

Went on the roof to see if these larger panels would be the way to go. As far as size, it could not get more perfect. To only have to mount and wire four panels and get 1600W and not really obstruct or interfere with any necessary roof access is perfect.

Mounting will be done by using uni-strut or 80/20 across from those big black brackets with a midpoint support that attaches to the roof with 3M adhesive tape. Then the panels will be set on top of those rails and angle brackets will be fastened to them and screws put into the panels or clamps fashioned to hold them down.

Solar prep hatch can be seen as well.

[hclarkx]

Originally Posted by TheFu

Call me a fool, but being a seasoned dry camper, I can't see me needing more than 1600W, especially down the road when I upgrade to Li. The key reason right now for me to get even that much solar is just the refrigerator.

Not foolish. You'll love it. I have 1 kW largely for the 12V fridge and CPAP. My upcoming upgrade is to cover liberal use of a 9k BTU-Hr mini-split A/C, including use for heating in fall/winter/spring when there is good sun. Helped by 800 Ah of LiFePO4.

[ransil]

Originally Posted by TheFu

Went on the roof to see if these larger panels would be the way to go. As far as size, it could not get more perfect. To only have to mount and wire four panels and get 1600W and not really obstruct or interfere with any necessary roof access is perfect.



Mounting will be done by using uni-strut or 80/20 across from those big black brackets with a midpoint support that attaches to the roof with 3M adhesive tape. Then the panels will be set on top of those rails and angle brackets will be fastened to them and screws put into the panels or clamps fashioned to hold them down.



Solar prep hatch can be seen as well.



Attachment 352437



Attachment 352438

That is how I plan to mount panels on my entegra, using the brackets.

Post pictures along the way.

[xbcsutter]

Great plan TheFu. Close to same the same install with same goal. 3 x 400w panels in series into Victron 250/100, still have the 8 flooded batteries. Not trying to run AC’s so lots of power for fridge, coffee maker, microwave. I ran 1”x1” square aluminum tube across roof brackets & for/aft to support rear panel. Will top out producing 1000w. Alum sheet material for branch deflectors.

[Generator]

TheFu
I'm going through the same process in my NA. Here are some tips for you.
1. Solar panel switch into MPPT Controller must switch both wires (black and red) per code since both are ungrounded. Switch must be rated for max solar panel voltage (250volts).
2. Your selected solar panels can put out 1600 watts, but 250/100 MPPT Controller is limited to 1450 watts. So your panels are somewhat oversized.
3. With AGM batteries, Newmar limits the on-board Xantrex output to 70% of rated, or around 105 amps. So 250/100 MPPT Controller is a good selection.
4. Newmar's #6 AWG prewire is not enclosed in conduit. With your design, the maximum solar panel total voltage will be around 210 volts at +25 degrees F. Do you feel comfortable with that high a voltage in your motorhome. Consider a different series/parallel connection to lower the voltage to a less lethal value.
5. There is no room in NA battery bay for MPPT Controller, so it will need to be mounted in an adjacent bay where the temperature is different. Consider adding a Victron Battery Sense module to provide accurate battery temperature and voltage data to the MPPT Controller via blue tooth. This is particularly important for AGM batteries which require temperature compensation.
6. If not using a Victron Cerbo module and display, consider adding a MPPT Control Monitor in the motorhome for monitoring the solar system. Inexpensive but valuable.
7. Consider adding a switch in the motorhome to turn the MPPT Controller on and off for when connected to shore power, generator, or when driving with alternator charging the AGM batteries. Victron has several ways this can be accomplished.

Hope these tips help.

[TheFu]

Originally Posted by Generator

TheFu
I'm going through the same process in my NA. Here are some tips for you.
1. Solar panel switch into MPPT Controller must switch both wires (black and red) per code since both are ungrounded. Switch must be rated for max solar panel voltage (250volts).

This is a good point. Good catch. The ground is not really a ground as it is floating.

Originally Posted by Generator

2. Your selected solar panels can put out 1600 watts, but 250/100 MPPT Controller is limited to 1450 watts. So your panels are somewhat oversized.

Yes, I realize this but I believe most times the panels will not be maxing out due to getting dirty, cloud cover, angle of sun, etc. Oversizing will allow me to get to that 1450w maximum whereas putting 1450w on there will never average me out to 1450w. Also, the panels degrade over time.

Originally Posted by Generator

3. With AGM batteries, Newmar limits the on-board Xantrex output to 70% of rated, or around 105 amps. So 250/100 MPPT Controller is a good selection.

Yes, this is what I figured.

Originally Posted by Generator

4. Newmar's #6 AWG prewire is not enclosed in conduit. With your design, the maximum solar panel total voltage will be around 210 volts at +25 degrees F. Do you feel comfortable with that high a voltage in your motorhome. Consider a different series/parallel connection to lower the voltage to a less lethal value.

Yes, I had already decided, after some input from others, to go 2s X 2p to halve that amount. Which should be fine. Only adds a tiny more cost.

Originally Posted by Generator

5. There is no room in NA battery bay for MPPT Controller, so it will need to be mounted in an adjacent bay where the temperature is different. Consider adding a Victron Battery Sense module to provide accurate battery temperature and voltage data to the MPPT Controller via blue tooth. This is particularly important for AGM batteries which require temperature compensation.


6. If not using a Victron Cerbo module and display, consider adding a MPPT Control Monitor in the motorhome for monitoring the solar system. Inexpensive but valuable.

Yes, plan is for the MPPT to go in the bay with the Xantrex. Temp monitoring is cheap and easy - and will likely add.

I already put the Victron BM Shunt on the coach. Pretty cool. I plan on discussing with Victron directly the right direction for physical control and monitoring in the coach (there is one prewire - i think a RJ45 - to the panel above the driver) if that might be helpful or work with any of their monitors.

Originally Posted by Generator

7. Consider adding a switch in the motorhome to turn the MPPT Controller on and off for when connected to shore power, generator, or when driving with alternator charging the AGM batteries. Victron has several ways this can be accomplished.

I still have to see what the best approach here might be. One thing to note, however, is that the alternator - at least on the F.L. chassis on a 2021 NA3543 - does not charge the house batteries. I asked F.L. on this when I was at a service center last week and they looked it up and confirmed. What I may need is another solenoid coming from the charging line from the Xantrex to the battery that disconnects when a switch is thrown and another on the MPPT output that connects when the switch is thrown in that same direction - flip flops so to speak. Again, I want to talk to the Victron guys to get their take as they have consulted on many of these.

Originally Posted by Generator

Hope these tips help.

Yes, absolutely - i am going to modify my drawing now and repost in a bit.