Complete noob RVer overwhelmed with all the information here!

[WattsItToYa]

I'm sure all the info is on this forum here somewhere but its a bit overwhelming trying to sort thru it all! If anyone can link me to some information or steer me in the right direction it would be much appreciated!....

I'm looking to add solar to my motorhome starting out with a small basic 12 volt system that can be added to in a well planned fashion over the next few years (hopefully installing oversized charge controller so i don't have to replace it later?) I was looking at the Rich solar 200 watt panels and Victron SmartSolar MPPT Tr 150-Volt 60 amp. I've got room on the roof for up to 8-10 flat mounted panels when the time comes to expand.

The basic info- 2007 34' class A, 50 amp shore power, 5 KW gen set, (2) Trojan T-105's 6 volt 225ah series wired for 12 volts, existing OEM 1800 watt inverter.

Eventually I want to expand to a full tilt 400ah plus lithium battery system with all the bells and whistles but for right now I would like to keep the flooded lead acid 2 battery set up (they are new). I understand the basics of what is needed to install the panels, charge controller and basic wiring. What I'm confused about is how to integrate it into my existing set up- Specifically what isolates the solar or allow it to work with the onboard charger, engine alternator, shore power or running the generator?

TIA!

 

[sunshine_eggo]

I'm sure all the info is on this forum here somewhere but its a bit overwhelming trying to sort thru it all! If anyone can link me to some information or steer me in the right direction it would be much appreciated!....

I'm looking to add solar to my motorhome starting out with a small basic 12 volt system that can be added to in a well planned fashion over the next few years (hopefully installing oversized charge controller so i don't have to replace it later?) I was looking at the Rich solar 200 watt panels and Victron SmartSolar MPPT Tr 150-Volt 60 amp. I've got room on the roof for up to 8-10 flat mounted panels when the time comes to expand.

The basic info- 2007 34' class A, 50 amp shore power, 5 KW gen set, (2) Trojan T-105's 6 volt 225ah series wired for 12 volts, existing OEM 1800 watt inverter.

Eventually I want to expand to a full tilt 400ah plus lithium battery system with all the bells and whistles but for right now I would like to keep the flooded lead acid 2 battery set up (they are new). I understand the basics of what is needed to install the panels, charge controller and basic wiring. What I'm confused about is how to integrate it into my existing set up- Specifically what isolates the solar or allow it to work with the onboard charger, engine alternator, shore power or running the generator?

TIA!

Explore the links in my signature, especially the energy audit.

If your goal is to slowly build a system, you need to design the END system and figure out how to step into it. Otherwise, you'll end up swapping out hardware along the way that doesn't get you where you want to be.

 

[Bluedog225]

Welcome. Also watch a dozen will prowse video and explore his links.

 

[pollenface]

Going with 48v allows you to make 100% use of your Victron 150/60. Staying 12v makes it very expensive with cabling and large SCCs.

 

[Rocketman]

To answer some of your questions…

What I'm confused about is how to integrate it into my existing set up- Specifically what isolates the solar or allow it to work with the onboard charger, engine alternator, shore power or running the generator?

TIA!

Assuming a Victron mppt solar controller 150/60 (SCC)…

Really it is very basic, the panels will have (probably 10awg) solar wire running to the SCC, the SCC will have wire (probably #4awg) wire running to the battery/bus bar. A breaker to turn the sun off for maintenance, and a fuse as the SCC’s wires hit the battery/bus bar and you are good to go.

Everything all works together… if you are cruising down the road, the alternator will be charging and the SCC will be charging- the batteries can only accept so much current- so they will both be working until the batteries get full, then the alternator will hold at 14.0-ish volts until you arrive and shut the rig down, The solar will show 0watts because they are in float - but as the battery settles down to float (assuming you are boondocking and not plugged into the grid) they will run the RV loads from solar.

If you start the generator, it uses the charger to fill the batteries and the solar does too. No issues. (Or on grid - no issues).

Also you can run multiple arrays of solar each with its own SCC. If that works out better.

I full-time in a 2000 Dynasty Motorhome. I have three arrays. ((All Victron)
1. 800w into a mppt 100/50 - my first array.
2. 400w originally- now 600w into a mppt 100/30. (Yes this one is very over paneled)
3. A 100w array into a 100/20 to keep the chassis battery charged.

The first two arrays both go into my house lithium bank - no issues…

So for your planning stage it may make more sense to put one array in now, but run wires from the roof to the SCC location for the second array at the that time. All panels on an array should be the same - but sometimes manufacturers discontinue them - that can lead to problems. So I would buy the SCC and then fully fill its array of panels out. Then next time you buy the SCC and panels and run the wire from the SCC to the battery/bus bar and it is done.

I would also install the Victron Smartshunt or BMV712 battery monitor at the same time as you install the solar. In addition to being a great battery monitor (so you know your batteries are 84% full - not just “three led bars full”) it can also pass voltage and current data to the Victron SCC (via Bluetooth network) that helps the SCC run much more accurately.

Get the 150/xx SCC’s now (instead of the 100/50) that way you are not locked into 12v - (and if you desire you can move to a 48v house battery- there are pros and cons both ways).

 

[Rocketman]

One more item…

Real estate is very precious on the roof, with all the antennas, air conditioners, vents, skylights, fridge roof vents, etc…

I used mostly 200w panels because they fit my area the best, if you can use the 330-ish panels and make them work - you can probably save a bit. I made a cardboard cutout of the panels to figure out where to put them. Figure out how many panels you can install and where they will be - at the beginning of the process. Be sure to leave room for shadows caused by air conditioning,etc.

 

[WattsItToYa]

One more item…

Real estate is very precious on the roof, with all the antennas, air conditioners, vents, skylights, fridge roof vents, etc…

I used mostly 200w panels because they fit my area the best, if you can use the 330-ish panels and make them work - you can probably save a bit. I made a cardboard cutout of the panels to figure out where to put them. Figure out how many panels you can install and where they will be - at the beginning of the process. Be sure to leave room for shadows caused by air conditioning,etc.

Thanks for the super detailed reply Rocketman…very helpful!
I will likely order the 150/60 charge controller this weekend.
When I measured the roof, I was working with the dimensions for a 200 W panel. I will remeasure this weekend for the larger 335 W panels that I’m seeing (Rich solar) and see how those fit. They are $.85/watt versus the $1.00/watt for the 200 W panels. Looks like you have to buy them by the pallet of eight panels though.
The 335 W panels are 24 V versus 24 V for the 200 W….what is your take on the debate of the “best” voltage to use? Lol
I recently watched Will’s video where he highly recommended going with 48 V.

 

[WattsItToYa]

Going with 48v allows you to make 100% use of your Victron 150/60. Staying 12v makes it very expensive with cabling and large SCCs.

Thanks pollenface I will look into the 48v! I did see Will‘s video recently where he highly recommended going 48 V.

 

[WattsItToYa]

To answer some of your questions…

Assuming a Victron mppt solar controller 150/60 (SCC)…

Really it is very basic, the panels will have (probably 10awg) solar wire running to the SCC, the SCC will have wire (probably #4awg) wire running to the battery/bus bar. A breaker to turn the sun off for maintenance, and a fuse as the SCC’s wires hit the battery/bus bar and you are good to go.

Everything all works together… if you are cruising down the road, the alternator will be charging and the SCC will be charging- the batteries can only accept so much current- so they will both be working until the batteries get full, then the alternator will hold at 14.0-ish volts until you arrive and shut the rig down, The solar will show 0watts because they are in float - but as the battery settles down to float (assuming you are boondocking and not plugged into the grid) they will run the RV loads from solar.

If you start the generator, it uses the charger to fill the batteries and the solar does too. No issues. (Or on grid - no issues).

Also you can run multiple arrays of solar each with its own SCC. If that works out better.

I full-time in a 2000 Dynasty Motorhome. I have three arrays. ((All Victron)
1. 800w into a mppt 100/50 - my first array.
2. 400w originally- now 600w into a mppt 100/30. (Yes this one is very over paneled)
3. A 100w array into a 100/20 to keep the chassis battery charged.

The first two arrays both go into my house lithium bank - no issues…

So for your planning stage it may make more sense to put one array in now, but run wires from the roof to the SCC location for the second array at the that time. All panels on an array should be the same - but sometimes manufacturers discontinue them - that can lead to problems. So I would buy the SCC and then fully fill its array of panels out. Then next time you buy the SCC and panels and run the wire from the SCC to the battery/bus bar and it is done.

I would also install the Victron Smartshunt or BMV712 battery monitor at the same time as you install the solar. In addition to being a great battery monitor (so you know your batteries are 84% full - not just “three led bars full”) it can also pass voltage and current data to the Victron SCC (via Bluetooth network) that helps the SCC run much more accurately.

Get the 150/xx SCC’s now (instead of the 100/50) that way you are not locked into 12v - (and if you desire you can move to a 48v house battery- there are pros and cons both ways).

Are there any issues running that 150/60 charge controller with my two flooded lead acid’s batteries? Is there a maximum number of panels not to exceed with the current battery set up or will the charge controller take care of any over-paneling?

 

[Rocketman]

I looked quickly and could not find recommended charging for number of amps. The data sheet had the voltage and temperature compensation numbers - but not max current (amps).

The data sheet for the 150/60 is:

https://www.victronenergy.com/upload/documents/Datasheet-SmartSolar-charge-controller-MPPT-150-60-&-150-70-EN.pdf

On your 12v battery it can handle 860w of solar. That will produce 60amps of current at 14.4v.

On a 48v system 60a is 3,440 watts. (More than you can fit).

Depending on how soon you are planning on moving to 48v - a better solar charge controller might be a 150/45.

That can handle 650w at 12v and 2600 at 48v. (And it is cheaper too).

Figure out exactly how many panels your finished system can handle, then work backwards to figure out the solar charge controller.

If you overpanel - say put 9 200w panels 1800w in a 3s3p and put that into the 150/60 - you will only get 60amps at 12v 860w into the battery- whenever you are producing more it will be clipped and lost.

When you setup the solar charge controller- you will set it up as a lead-acid battery- then when you change to lithium- you will reprogram it for the lithium.

 

[WattsItToYa]

I looked quickly and could not find recommended charging for number of amps. The data sheet had the voltage and temperature compensation numbers - but not max current (amps).

The data sheet for the 150/60 is:

https://www.victronenergy.com/upload/documents/Datasheet-SmartSolar-charge-controller-MPPT-150-60-&-150-70-EN.pdf

On your 12v battery it can handle 860w of solar. That will produce 60amps of current at 14.4v.

On a 48v system 60a is 3,440 watts. (More than you can fit).

Depending on how soon you are planning on moving to 48v - a better solar charge controller might be a 150/45.

That can handle 650w at 12v and 2600 at 48v. (And it is cheaper too).

Figure out exactly how many panels your finished system can handle, then work backwards to figure out the solar charge controller.

If you overpanel - say put 9 200w panels 1800w in a 3s3p and put that into the 150/60 - you will only get 60amps at 12v 860w into the battery- whenever you are producing more it will be clipped and lost.

When you setup the solar charge controller- you will set it up as a lead-acid battery- then when you change to lithium- you will reprogram it for the lithium.

Hey Rocketman- Thanks again for the help! If you get a minute can you review my tentative plan?
I re-measured to see if the larger panels would work out but the 200 w size fit much better- looks like my max is (8) 200w panels.
After watching more of Will's videos, researching specs and using Victron's charge controller calculator I've come up with the following plan:

Stage 1 w/existing 12 volt lead acid batteries-
(4) Rich Solar 200w 24v panels 2S/2P configuration 800 w
Victron Smart Solar MPPT 150/45
pv power ratio will be 123% oversized per calculator. Calculator is set up to allow up to 130% oversize.

Stage 2 upgrade to 48 volt LiPo battery system
add four more Rich Solar 200w 24v panels 2S/4P configuration for total of 1600 w
Keep Victron Smart Solar MPPT 150/45- Per the Victron calculator @ 48 volts I could do all 8 panels with a MPPT 150/35 but that one will not do 4 panels @ 12 volts without going over the 130% oversize cutoff.
150/45 pv power ratio will be 62% undersized per calculator
48 volt to 12 volt buck converter

PDF's attached with calculator results and Rich panel specs.
Inverter/charger upgrade to be figured out later.

What do you think?

Thanks!