The third and final phase of our solar installation on our RV was installing an inverter to convert the 24V battery power into 120V for general receptacles and higher power appliances. We chose to install a Victron Multiplus 3000W inverter.
We also had to choose how to wire the inverter into the existing 120V AC system in the RV. We chose to install a transfer switch that would allow us to use power in 4 configurations:
1. Shore power only (Inverter Bypass)
2. Shore power to RV and Shore power to inverter to use it as a battery charger
3. Inverter power only using battery and solar
4. Hybrid power combining battery (and solar) and shore or generator
Disclaimer: While Tesla batteries are a very high quality and safe when handled and run within operating characteristics, if something goes wrong they can be quite dangerous. It is your responsibility to fully understand and make sure the system is safely programmed and installed if you choose to take on an install like this. Furthermore, this build is not endorsed or supported by any manufacturers of the compenents used in this build, and they may not provide support on an install like this if you run into trouble. I am not able to provide individual support on these builds. You might be able to find community support over in the Second-Life Batteries Facebook Group.
There are a few different ways the inverter could have been wired into the RV but we felt this would give us the most flexibility. This configuration however requires some monitoring as when running the whole RV you can easily overload the inverter if you attempt to run the AC, Fridge, Stove and other large appliances at once.
This is the schematic of how this is wired in our RV.
You can find a list of components in this blog post: Updated Tesla Module RV Installation You will notice that since our RV is a 50A split phase RV we needed to jumper the single leg from the inverter to power both sides of the RV’s breaker panel. The reason for this is explained further in the video we made on the install. http://www.youtube.com/embed/GKt9A93-CGY?wmode=opaque So far this configuration has been working very well for us. We love being able to power the entire RV including the AC through the inverter.
At this point our solar installation is finished! I am sure however we will be making upgrades and tweaking it in the future.
UPDATE: After running this system for a while I’ve made some tweaks to my design. Check out our post on Updated Tesla Module RV Installation that has a schematic and list of components I’d recommend for an installation.
Also, check out the previous 2 phases of our solar install:
Phase 1 – Installing the Solar Panels
Phase 2 – Installing the Tesla Battery module
*Note: This article contains affiliate links.
Hey Tom
Awesome video! I really liked how you solved the multiple leg 50A system.
One really big question: can you run the Air Conditioner from the inverter alone? Specifically, can you get the air conditioner started? I have been working on a very similar setup with a Victron dealer and they just didn’t feel that the 3000W inverter would be enough to get the air conditioner started (running, however, it would be fine). I have settled on a 4000W, 24V Inverter/charger with a 12000W surge. I really did not want to have a generator on top of the solar system. Certainly 4000W is overkill since I have a 30A system but I have also decided to wire the house so that in an emergency I can hook the camper into the house for emergency power.
Lastly, could you share the settings for the Victron battery monitor? I know that to accurately measure the lithium battery capacity some settings have to be changed to get an accurate reading of the battery. If you posted it and I missed it, I apologize.
If you’re ever in the Seattle area give me a shout. My wife and I would be happy to grab dinner and chat.
Best,
Jason
Hi Jason, thought I’d chime in. I have a Dometic 13.5kbtu/h roof ac that would not start on my Honda 2EU2000i. I installed an Easystart on the Dometic and now I don’t even notice the inrush during the start up cycle. The Honda starts and runs the ac just fine. Quite remarkable actually. I’m confident that with an Easystart a 3kw inverter or even a 2kw would work as well. Unfortunately RV roof acs are much better at turning kilowatts into decibels than they are at turning kwh into kbtu so now I plan to replace the roof air with a high efficiency inverter based mini split which should be nearly twice as efficient and much much quieter.
I’ve heard good things about mini-splits, however in most rigs I don’t see a place to put the condenser. What kind of rig do you have, and how do you plan to solve this?
I have an RPod 179. I plan to place the evaporator just above the window in the sleeping area and the condenser on the tongue where the PbA batteries currently are. Going to a Tesla pack will free up this space. I will have to move the propane tank forward a few inches but it should fit ok. While the airflow clearances will be somewhat tighter than the mfr suggests I think it will be ok because the surfaces the condenser will he near are curved not flat walls.
My objective with the project is to be able to cool the sleeping area overnight during campground quiet hours. So I will be adding a curtain to reduce heat transfer to the rest of the trailer.
I’m hoping to be able to get by with one 5.2 KWh Tesla pack but it will be close. Hence the need for the highest EER ac unit I can get. One of the biggest advantages of the inverter minisplits is that they reduce motor rpm and refrigerant flow rates rather than short cycle the compressor under low load conditions.
How about a bill-of-materials to go with the schematic?
Hi Tom,
Love your videos, very informative.
Just one picky correction and then a question. Around 15:48 into the video you show the peak ac voltage as 120V. AC voltages and currents are given as RMS values so the peak voltage is actually 120*sqrt(2) or about 170V.
And my question, which is related to whether or not cooling is needed for the Tesla pack I plan to install in my RV. Call me paranoid but I just want to be 100% certain I’m not going to get into thermal runaway on this pack which will be located under the floor of the RV in our sleeping area. In the application I’m planning, I calculate roughly a 4 deg F temp rise in an enclosed battery pack similar to what you have used.
I’d just like to confirm that with real world data. Assuming you’ve measured it, what kind of temp rise are you seeing in your pack?
Thanks!
Great videos on the whole project. I plan to visit the battery company in Hickory next month. Two questions…How many total amp hours are in the battery? Have you published a list of the items needed to duplicate your installation. I presently have 4 six volt AGMs with. Magnum 3000 watt inverter and 500 watts of solar.
Daviid,
Have you been in contact witht the guys in NC? The website seems to be under counsteuction and I have called the last couple days with no answer.
The 24v to 12v converter, does it know to stop when the 12v battery is full? Or do you need another charge controller for that ?
Tom,
Thanks for all the videos, they have been a great help as I develop my off grid camper system!
My question is, if I have 24Vdc solar and a 24vdc generator, should I plan on 2 Charge controllers to the Tesla bank? The generator should be triggered by the external contact of the battery monitor, however the solar panels will always produce some level of output, so should the solar be disconnected from the charge circuit when the battery level is low enough to trigger the generator start?
Regarding the 24/120 inverter, is there an auto switch when you go to “shore power”, and do the solar panels still contribute to the power usage?
Tom,
Check out the Samlex All In One System. It has everything in your block diagram (and more).
http://www.samlexamerica.com/products/ProductDetail.aspx?pid=575
Love to hear your feedback how it can improve and/or simplify your system.
For my own personal convenience, I plan to use a simple AC inverter (running off my RV battery (alternator) as an embedded AC generator.
Tesla battery can then be charged from 3 separate sources in listed priority.
1. Shore Power
2. AC generator via (RV alternator => 12V RV battery => simple AC inverter)
3. Solar Power
I plan to use 2 banks of Tesla battery with a manual isolated switch (for safety upon thermal runaway since I don’t plan to hook up water cool feature of Tesla banks). One bank should be enough for most case with second bank for back up (boondocks)
I plan on using Tesla BMC (as is) for cell balancing. Samlex has to programmable safety settings to BEEP then eventually disconnect itself from the Tesla bank.
Thermistor (connected to Tesla thermal lead) need to be used to trigger thermal shutdown to the Samlex.
Tom,
Great series, thank you very much. A while ago Eric Hakanson asked for a materials list. Could you provide? Specifically I’m looking for your manual transfer box and switches.
Thanks!
Sean
What things in the rv are not running on 12 volt?
Indoor residential fridge, outdoor dorm fridge, and some outlets.
I’m preparing to install the manual transfer switch (the one pictured in the video) and it didn’t come with a manual. Does anyone have a good resource for the wiring diagram? Thank you!
My best recommendation would be to test the impedance between terminals to figure out what connects to what when the switch is in different positions. The terminals should only connect to other terminals in the same row on the switch and each row will have the same configuration. Once you know what connects to what then it should be easy to wire up. I cannot give you a diagram or instructions because I installed another one for someone and the terminals were different! Test it out yourself before wiring and all should be good.
Tom,
I am trying to decide between the GoPower IC 3000 and the Victron Multiplus 12/3000/120. The GoPower allows passing through both 50 amp legs and would be easiest to wire into our system. However, I also like the idea of staying with Victron since I already use their BMV and solar charge controllers. Is there any other safe way besides the manual transfer switch to wire it so that the inverter powers both 50 amp legs on the breaker panel? Just trying to find some more options. A little info about my setup, currently we have shore power and onboard generator going to an automatic transfer switch and then the output of that goes into our progressive hardwired ems.
Thanks!
Question- I am looking to mirror this set up for a boat. I will have limited solar 400 watts. I will have 2 outboards pushing 70 amps each to charge. Did you look at a system like buck boost to use the RV alternator when running to charge the Tesla batteries? If so, would you share your research of a 12v dc to dc 24 to charge the batteries
Great help on the overall setup!!
Thanks for sharing informative blog. I get to know many things from this blog. Thanks again.
I am about to start a similar upgrade on my 43’ boat. The inverter/chargers that I am looking at all advertise an internal automatic transfer switch. When connected to shore power, it recognizes this and it passes through the inverter. Why would I need a manual transfer switch?
Hi, can you share your victron multiplus charger settings your are running with (ve configure if possible)?
Craig,
The 3000W Multiplus Tom is using only has single 120V output. His 5th wheel has a 50A power panel which has 2 120V inputs. He is using the transfer switch to connect the two halves of his circuit braeker panel to allow the to be powered from the single 120V output from the Victron unit.
Lee
Just got my Sprinter van. About ready to dive into a build with 600 watt solar output. Any changes to your three part design that I shouldn’t copy? Or new stuff on the market that I should use instead?
(Victron)
Thanks!
Interested to know which converter you would recommend with this Tesla battery thats a little lower if budget, if you were not running the one you have with the deal you got?
Kyle, I just purchased the MagnaSine 4024 (4000W/24V). I haven’t had a chance to play with it yet (weather delayed shipment to the PNW) but I have read the manual several time and I am really impressed with how versatile it is (as versatile as Victron). Namely, the MagnaSine has a CC/CV setting for charging the batteries. Do consider purchasing the remote panel and the battery monitor with it, however (more precise charging of lithium batteries and Constant Voltage cutoff when battery is fully charged). I looked at Victron and AIMS Power. Victron is just too expensive (unfortunately since all my other components are Victron) and AIMS wasn’t configurable (cannot change the charge profile). My only gripe about MagnaSine, which was the result of my own delays preventing me from returning the BMV-712, was that I had to purchase the battery monitor and remote for the MagnaSine. However, being positive about the situation, I now have two battery monitors (always good to have a backup). If you’re a little more organized than I was you could plan ahead and not spend the extra $150-200 for an extra battery monitor.
Two questions about wire gauge:
1. What gauge wire are you running from the Manual Transfer Switch to the Multiplus?
1. What gauge wire are you running from the Multiplus to the Manual Transfer Switch?
Question, what kind of manual transfer switch box is that? Can’t find anywhere. Keep up the good work, Joe
nice article. Thanks for sharing the great post…!
With EMF and/or EMR radiation exposure becoming such an issue in our lives, what are your thoughts or recommendations on shielding of the Generator, Inverter, Tesla Power Packs, DC battery legs to inverter, shunts, Solar Panels and other components of high EMF/EMR radiation outputs!
Would it be better “EMF/EMR Radiation Exposure wise” to setup the entire system on a box cargo trailer, that can be placed near by and connected into the RV shore power??
One benefit of a Tesla Power Supply equipment trailer would be if the Tesla packs were to go into a Run-Away condition, you would only lose the power supply equipment trailer!
Many states “Texas included” allow tandem pulls “RV Hauler, RV Trailer, Tesla Power Supply/Solar/Generator System Trailer”
My 2006 Thor Grand Design is basically a Faraday Cage because of the coach/body frame is entirely metal with a fiberglass outer skin!
I am a heavy equipment diesel mechanic with extensive experience with DC electrical systems and computer controls and automation!
If your are ever down in South Texas, Houston area, I have a empty lot with complete hookup “Well Water, Sewer, Shore Power” sitting on 5 empty acres and we would love for You and Yours to spend some time with us, Free!
I am in the process of buying all of the equipment on your systems list, but am torn between installing the system on the RV or a small box cargo trailer!
Thanks
Ben
P.S. I welcome any and all input concerning EMR/EMF radiation shielding.
This is what I have been thinking on the line of thought about having the entire Tesla/Solar/Generator system on a box cargo trailer!
I talked to my RV insurance carrier and they said the insurance company would NOT cover any loss of the RV or this Tesla Hybrid Electrical System due to a failure of the modified electrical system, UNLESS, and that is a big unless, Unless it was installed by a certified electrician with a Tesla certification or a off the shelf Tesla Power Wall installed by a Tesla technician!
My RV insurance carrier “Foremost” has NO problem covering the RV if I use a Box Cargo Trailer for the Tesla/Solar/Generator power system!
Here is the YouTube video on a Box Cargo Trailer with Tesla power!
https://www.youtube.com/watch?v=tvz2R164RU8
Hi Tom,
I am trying to figure out what transfer switch you used. I believe I have tracked it down to Blue Sea Systems. Since these are not cheap I would be grateful it if you could share the model you used. I’m guessing it was the 9019 AC Rotary Switch – OFF + 2 Positions 240V AC 65A.
Thank you for all you share.
Is this the switch in your video? The numbers match up. I’d like to use it with my system, but I’m on a 120V inverter, not 240V. I’d like to know if this would work. https://www.amazon.com/gp/product/B00NWDVI1M/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Thanks Jim. Much better than what Ii found.
It matches all the numbers he has in the video if that is the switch he stuck with. My question is: it is called a 660V 63A 3Position 3 Phase Universal Rotary Changeover Switch. Not sure what capacity that puts it for the 120v ac circuits x 2.
I’m pretty sure the Multiplus has a built-in transfer switch.
It does, but I like the idea of controlling what goes where and when. With the multiplus I bought, it only switches one pole The way I’m going to use this switch is to send power to both poles when using the AC output from the multiplus.
First I would like to thank you for all of the detailed information that you have provided in this solar project of yours. I found the schematics specially helpful. I have duplicated your system including the Tesla battery. What a great battery for the price. I have however have run into a problem setting up the Multplus Inverter. The program won’t allow me to create the charging profile I think I need to have to not damage the battery. I am hoping you have answer I would like to have my system working at 100% before I head southwest. And thanks again for the information you have already provided.
Richard, Victron recognized this as an issue (lack of compatibility with Tesla) and updated firmware for the multiplus in July. Update your firmware — you should be able to reduce the min inp voltage to 20 once the firmware is updated.
Steve, is there anyway to contact Victron Support directly? I bought the MultiPlus through Amazon, Victron wants support to go through dealer. I sent an email to Victron and got a reply that emails was being forwarded to the dealer. My concern is getting the right firmware update. I don’t want to do more harm then good by installing the wrong update.
https://community.victronenergy.com/questions/5217/tesla-model-s-battery-multiplus-can-not-turn-on-in.html
Thanks Steve, that info was a great help. Navigating Victron’s support is a bit of a challenge.
I’d be curious to see your inverter and charging values in the multiplus. I’m building a remarkably similar system.
Thanks
Tom I am using the exact same switch’s you installed in phase three. Baomain three positions. It would be a great help to know how to jumper the switch. I want it to do exactly what you did with it. Thanks.
I’m hoping for a hail Mary here. I’m installing this tomorrow on Canada day. I would love to know if you fould tell me what wires go to which pole numbers the wires all go to. There’s 12 terminals on this switch and I don’t want to make a mistake
Edit, I just read ALL the comments above and I see you said your friends switch was the same but different numbers. I guess that pooches my idea. 🙁