My NEW solar/inverter/battery setup

[Chad Heiser]

When I bought my DRV 5th wheel back in 2017, I immediately added solar and upgraded the batteries to go along with the factory Magnum inverter system I had installed as part of the trailer build.  Here is a topic I started discussing that upgrade.  I recently resurrected that thread because I swapped out the original solar array I installed for a larger array.  The array now consists of six 365 watt REC solar panels.  

I now plan to change out the Magnum components for Victron components and the AGM batteries for lithium batteries.  I thought about continuing the old thread with the new build out, but decided to start a new thread for the new system instead.  This topic will cover the new build as it happens.  

As I said, the solar is done and it has already proven to be very capable in less than ideal conditions.  The 2190 watts of solar kept us going for a week at the coast with cloud cover and rain for all but a day and a half of the stay.  We survived with no hookups for the week with virtually no generator run time.  (I ran the generator for half an hour one day for peace of mind, it wasn’t actually needed.) 

The new system will consist of dual Victron Quattro 5KVA inverters.  These are 5000 VA or 4000 Watt continuous output inverters.  That is a minimum of 8000 watts of power and up to 10000 watts of power under certain conditions.  As a comparison, a 50 amp power pedestal can provide 12000 watts of total power and a 30 amp power pedestal can provide 3600 watts of total power.  The inverters will allow me to run everything in the RV without issue, including all three air conditioners, from inverter/battery power.  Of course I will be limited on how long I can run all that “stuff” depending on solar production and battery state of charge 😉.  The inverters will be configured to run 120/240 volt.  This will allow us to run our 240 volt clothes dryer from the inverters.

The inverters will be powered by four Battleborn 8D batteries.  These are 270 amp hour lithium batteries, for a total of 1080 amp hours of storage.  That is approximately 14.5 Kilowatts of storage.  As most of you know, with lithium batteries all 1080 amp hours are actually available for use.  Lithium batteries can be drawn down to (effectively) 0% state of charge and recharged back to 100% SOC without harming them.   This is unlike lead acid or AGM batteries that can only provide half their amp hour rating for use, or 50% SOC, before they need to be recharged in order to avoid significantly shortening the life of the battery.  The battery bank I am replacing is 1040 amp hours of (four 8D) AGM batteries, so I am effectively doubling my available amp hours with the same number (and size) of batteries.  I am also putting my trailer on a diet and loosing approximately 350 lbs of battery weight.  I will use a 1000 amp Victron SmartShunt to monitor all the power going into and coming out of the batteries.  I am using the larger 1000 amp Shunt (instead of the typical 500 amp Shunt) because of the potential power the Quattro’s can draw from the batteries.

The 2190 watts of solar will power a Victron SmartSolar MPPT 150/100 charge controller.  This controller will be a bit “over paneled” by these panels, but that will help with production in marginal conditions.  It is a similarly spec’d solar controller to the Magnum PT100 I currently have hooked to the panels.  That controller has done very well so far and I expect the same from the new Victron controller.  (I have also installed this panel and controller combination on a different RV previously and I know it is a winning combination.)

All of these devices will be connected to a Victron Cerbo GX communication device and the new GX Touch 70, seven inch, touch screen display.  This will allow local and remote (from any internet connected device) monitoring and control of the system.

There are other parts and pieces to the system as well, but these are the major components.  The system will include integration with the on board generator to allow full control of the generator from the Cerbo GX.  I will also add a third inverter dedicated to the residential refrigerator.  This will be a Victron Phoenix 1200 VA inverter (1200 VA or 1000 Watt continuous power output).  My Magnum system has a second 1000 Watt inverter (in addition to the 3000 Watt Hybrid inverter) currently.  I really like having this smaller inverter to keep the refrigerator running while traveling without powering up everything else in the RV and I plan to keep that same functionality in the new system.  All of the 12 volt (yes this will be a 12 volt system) connections will run through (multiple) Lynx distributors and a Lynx power in.

The batteries and Victron (along with other) components are currently on order and should be arriving soon.  Stay tuned for updates and feel free to comment or ask questions along the way.  I will post a system diagram shortly for reference.

Edited November 9, 2021 by Chad Heiser

[Chad Heiser]

Here is the schematic I put together for the new system.

[Chad Heiser]

As you can see from the diagram, I will be running dual (two positive and two negative) 4/0 cable to each Quattro inverter.  This is because at 12 volt, the inverters can draw a lot of power from the batteries.  They need to be fused at a minimum of 750 amps.  With the dual runs of 4/0 cable each fused at 400 amps, that will properly cover the potential draw.  

Each battery will also individually be connected directly to the Lynx Power In with 4/0 cable.  This will allow each battery to be utilized equally and not overwhelm the battery wiring with the potential high draws from the inverters that could potentially happen with only one positive and one negative connection coming from a traditionally wired battery bank.  Each battery can provide 300 amps continuous power output and 500 amps surge for 30 seconds.  By individually connecting the batteries to the system, all of that power is available to the system with no impediments.  

The limiting factor for power draw will be the Blue Sea 3000 battery switch.  It is rated at 600 amps continuous, 900 amps intermittent (5 minutes) and 1750 amps surge (30 seconds).  I am using the Blue Sea switch and 1000 amp SmartShunt between the Lynx Power In and the Lynx Distributors rather than a Lynx Shunt because the Lynx Shunt doesn’t have Bluetooth capability to view battery usage information locally through the Victron Connect app like the SmartShunt provides.  

This Bluetooth connectivity isn’t necessary to get the battery information remotely with a Cerbo GX in the system.  It, however, is more convenient to get the data in and around the RV via Bluetooth rather than having to rely on an internet connection to get the data from the Cerbo.  As we all know, when you are boondocking, there isn’t always reliable internet connectivity.  Of course I could also just go look at the Touch 70 display to get the information, but who wants to get up and go look when I can stay relaxed in my lounge chair and see the information on my phone 😎.

[GlennWest]

All I can add is be mindful about the blue tooth range with the smart shunt. Mine is in the very front of the Teton. I have to be in bedroom to get connection

[lappir]

Can't wait to see photos of the install. 

Rod

[Rover]

Hi Chad,

We are in the process of upgrading the solar on our new to us 2016 Newmar Ventana LE. We already have 10 - 100 amp Battle Born lithium batteries. We are having 2800 watts of panels installed along with the same Victron controller, shunt and the Cerbo and Touch GX that you have.

Where our system differs from yours is in the inverters. We only have 2 ACs (w/HP) so we are installing 2 Victron Multiplus 3000W inverters.  Would we be able to run our dryer on this? I know we can run both ACs, so I would think so, but I hadn’t thought about it until I read your post.

 TIA,

Vicki

 

[justRich]

This is information overload.
I'll have to download the post, save to a pdf and print out when I need it.
The Schematic did not enlarge big enough when I clicked on it - could use a little help there.

 

[Star Dreamer]

It will be interesting to follow the install, thanks for your help! 

[Randyretired]

It is difficult to see on my phone but it appears you will use 2awg for the output of the 100 amp solar controller.  I normally size wire at 125% of the load but since I had 2awg I also used that from my 100 amp controller and I am thinking about changing it.  The welding wire doesn't get hot but warm.  However, there is enough of a voltage loss at peak amps that the controller voltage and the battery voltage are about .2v difference until tha amps ramp down.  That isn't a lot but for the cost difference I wished I went bigger.

[Vladimir]

I wish I had your setup at my off-grid house!!!  Nice.

[GlennWest]

Would not a 10k and autotransformer be less wiring and less cost

[hemsteadc]

Did you consider running at 24v or even 48v for this kind of power?

Edited November 9, 2021 by hemsteadc

[Chad Heiser]

16 hours ago, GlennWest said:

All I can add is be mindful about the blue tooth range with the smart shunt. Mine is in the very front of the Teton. I have to be in bedroom to get connection

I have installed a lot of Bluetooth enabled Victron products and there are limitations to the range (which can greatly be affected by the installation location), and I am aware of those limitations.  I have yet to experience the limited connectivity range I have seen you describe in other posts with your system though.  I have always been able to connect to the components from anywhere within the RV and from a reasonable distance around the RV.  I hope that track record continues with my system.

[Chad Heiser]

17 hours ago, lappir said:

Can't wait to see photos of the install. 

Rod

I will post photos here as I go and will have a full description and photos of the installation on my website once it is complete.  Along with running full size photos and documents here.

Edited November 10, 2021 by Chad Heiser

[Chad Heiser]

12 hours ago, Rover said:

Would we be able to run our dryer on this? I know we can run both ACs, so I would think so, but I hadn’t thought about it until I read your post.

 TIA,

Vicki

 

Yes you can run your dryer with a dual inverter system.  I’m assuming for the sake of this conversation your dryer is 240 volt (like mine).  The inverters have to be programmed properly on installation to get 240 volt from them.  Once the inverters are programmed this way, they will have the capability to produce 120/240 volt power regardless of the power source you are plugged into and also when you have no power source (inverting from the batteries).  (This is the way I will program my inverters.). When your inverters are programmed like this and your rig is plugged into a 50 amp (120/240 volt) power pedestal this power simple passes through the inverters and powers everything in the RV (like normal).  When your rig is plugged into a 30 amp, 20 amp or 15 amp power source, this power is passed through the inverter on line one (L1) and the inverter on line 2 (L2) will only invert from the batteries.  By doing this, the system is always capable of producing 240 volt power regardless of or independant of the power source.

Assuming you will not be programming your own inverters and assuming you have no desire to change the programming of your inverters on your own, the 120/240 capabilities will be there all the time.  There is a way to change this programming “on the fly” so that when you are plugged into something less than a 50 amp power pedestal both inverters can pass through shore power, but it takes a special interface device plugged into an inverter, a laptop, software and some knowledge of how to operate that software.  This is not something most end users want to do, so the functionality I described above is what you end up with.  There is no issue with this as the inverter that sees shore power (L1) will constantly charge the batteries while the inverter that does not see shore power (L2) draws from the batteries.

[Chad Heiser]

13 hours ago, Rich&Sylvia said:

This is information overload.
I'll have to download the post, save to a pdf and print out when I need it.
The Schematic did not enlarge big enough when I clicked on it - could use a little help there.

 

I just put a link in my signature that goes to a folder on my Google Drive with full photos and documents related to the system.  I will update this folder as I progress with the installation.  The full version of the schematic is there now, along with some photos of the solar panel installation.

Here is a direct link to the folder as well.

[Chad Heiser]

12 hours ago, Randyretired said:

It is difficult to see on my phone but it appears you will use 2awg for the output of the 100 amp solar controller.  I normally size wire at 125% of the load but since I had 2awg I also used that from my 100 amp controller and I am thinking about changing it.  The welding wire doesn't get hot but warm.  However, there is enough of a voltage loss at peak amps that the controller voltage and the battery voltage are about .2v difference until tha amps ramp down.  That isn't a lot but for the cost difference I wished I went bigger.

The MPPT 150/100 is limited to 2 AWG wire.  My wire run will only be a couple of feet (or less) from the MPPT to the batteries.  At 3 feet there is less than 1% voltage drop at the full 100 amps.  I can live with that.  I don't expect to see the full 100 amps all the time either.  I typically over engineer my wire runs as well, but I am limited to 2 AWG wire here because of the design of the MPPT.

On edit:  I am already running the panels with a Magnum PT100 MPPT charge controller (until I change over to the Victron system).  That charge controller is limited to 4 AWG wire max, so that is what I am using and I have had no issues with it so far.  It also puts out up to 100 amps.  Again the wire runs are short.

Edited November 10, 2021 by Chad Heiser

[Chad Heiser]

11 hours ago, Vladimir said:

I wish I had your setup at my off-grid house!!!  Nice.

Thank you

[Chad Heiser]

10 hours ago, GlennWest said:

Would not a 10k and autotransformer be less wiring and less cost

It would be less cost overall, but it would not work in my system.  The 10K quattro is 48 volt only and my system is 12 volt so that nixes it right off the batt.  I also like the the redundancy of having two inverters.

[Chad Heiser]

9 hours ago, hemsteadc said:

Did you consider running at 24v or even 48v for this kind of power?

I am not a proponent of higher voltage battery banks in RV's.  I have built them for others at their request, but I can make compelling arguments why they are not needed.  RV's already have a 12 volt system in them and therefore you always have to go back to 12 volt to run those systems.  As long as the inverter system is designed and built properly, it can run well at 12 volt - even at these potential power levels.  Part of the reason I am building this system is to show this in the real world rather than just theory.  There are a few other high power 12 volt systems out there, but they are not prevalent so people think they either can't work or shouldn't be built.  With this system, I will be able to show people first hand what can be done with a 12 volt system.

[Chad Heiser]

13 hours ago, Star Dreamer said:

It will be interesting to follow the install, thanks for your help! 

Your welcome.

[Randyretired]

31 minutes ago, Chad Heiser said:

The MPPT 150/100 is limited to 2 AWG wire.  My wire run will only be a couple of feet (or less) from the MPPT to the batteries.  At 3 feet there is less than 1% voltage drop at the full 100 amps.  I can live with that.  I don't expect to see the full 100 amps all the time either.  I typically over engineer my wire runs as well, but I am limited to 2 AWG wire here because of the design of the MPPT.

Designing wire to carry 125% of the load is standard NEC requirements and I don't consider that over engineering.  While we can skate by without meeting NEC in our RV's there is no way I would spec that. 

[Chad Heiser]

43 minutes ago, Randyretired said:

Designing wire to carry 125% of the load is standard NEC requirements and I don't consider that over engineering.  While we can skate by without meeting NEC in our RV's there is no way I would spec that. 

I typically design for more than 125% of capacity, which is what I meant by over engineering my designs. 

In this case I am limited by the design of the Victron equipment which can only accept up to 2 AWG wire.  The proper type of 2 AWG wire (THWN-2, THHN, XHHW-2, USE-2) can handle up to 130 amps, slightly above 125% capacity of the potential output of the 100 amp charge controller so no problem there. 

I actually only use welding cable, for my solar controller wire runs and battery cables, etc. The welding cable can handle even higher amperage.  The 2 AWG welding cable I use is rated to 250 amps, well above 125% of the 100 amp capacity of the charge controller.  Here are the exact specs of the 2 AWG welding cable I use:

• 2 AWG ROYAL/EXCELENE WELDING CABLE
• CONDUCTORS:BARE COPPER
• STRANDING:644
• JACKET: EPDM
• O.D:.411
• AMPS:250
• TEMPERTURE: -50*C TO 105*C
• VOLTS:600V
• HIGH DIELECTRIC STRENGTH INTEGRITY
• RESISTANCE TO FLAME,OIL,GREASE SOLVENTS,OZONE AND ABRASION
• (ROHS COMPLIANCE)

For information, here are the specs of the 4/0 welding cable I use for inverter and battery interconnections:

• 4/0 EXCELENE WELDING CABLE
• CONDUCTORS:BARE COPPER
• STRANDING:2052 JACKET: EPDM
• O.D:.720
• AMPS:600
• TEMPERTURE: -50*C TO 105*C
• VOLTS:600V
• HIGH DIELECTRIC STRENGTH INTEGRITY
• RESISTANCE TO FLAME,OIL,GREASE SOLVENTS,OZONE AND ABRASION
• (ROHS COMPLIANCE)

Edited November 10, 2021 by Chad Heiser
with updated wire information

[Chad Heiser]

Here are some pictures of the new REC 365 watt solar panels on my 5th wheel.

[lappir]

Thanks again Chad for the information and how you present it. At least for me it seems very understandable in a real life situation. I now more understand the reason for your current build I believe. 

The day I know I will need to start boondocking (or will have the ability). I hope to schedule an appointment with you to provide an estimate for a system that will allow me live off grid. 

 

Rod