"High" Capacity Solar with V2L-capable EV as Daily Driver

[snewojsnewo]

Hey there - I'm hoping to get some input and advice from this group! I'm planning out my 40ft skoolie with my family of 6 (wife, me, 2 kids, and 2 dogs). Here's what I think I know/think will work so far:
Daily Expected Skoolie Usage: 10-12kWH
Daily Expected Vehicle Usage: 5-10kWH
System Voltage: 48v
Battery Setup:
* 10kWH OR 20kWH Ruixu Batteries - https://www.ruixubattery.com/product-page/ruixu-lithium-batteries-kits-15kwh-20kwh-25kwh-30kwh
* 77 kWH EV6 Battery with V2L capability (this is our daily driver) - this is our “last 20%” when considering Solar coverage. Takes very little time to drive it to a high capacity charger and come back with 80%-90% if solar is not providing enough.
Ideally we’d like to be able to charge our car off our solar setup, but acknowledge we might need other options.

Solar Setup:
* Just under 7kWH of Rated Power
* 16 x SunPower 435W Solar Panel - we’re planning a slide out approach for when we’re parked
* Planning this to be 2S8P based on Victron’s calculator

“Guts” Setup:
* Victron EasySolar-II 48/5000/70-50 MPPT 250/100 GX
* Victron Cerbo GX System Controller

Main questions I have off of that are:
1. Does this system seem robust enough the handle what we’re aiming for?
2. I want to use my car as optional shore power. It can put out 120v @ 16 amps ~ 1.9kWH. Any major concerns or others using this approach that have advice?
3. I had a couple other items in my original plan when using the MultiPlus, but not sure I need them now. Do I?
* Victron Lynx Shunt VE.Can – Power Distribution System (M
* Victron Lynx Distributor – Power Distribution System (M
4. Do I need a combiner box for my solar panels? If so is there one you recommend and why?

I’m planning on doing all this work myself. I’m not an electrician, but I’m trying to learn what I need to make this happen.

P.S. Don’t hold back

 

[nikitis]

I don't think anyone here is charging their Tesla from their Bus as of yet. Not to say it could not be done. I'd imagine you'd need to match Powerwall voltages and amperages on your bus to make the car take it.

Getting that kind of voltage and amperage on a bus is also quite an undertaking. Especially if you plan to live in the bus on the daily. You'll be using up all of the electricity a Bus can possibly generate over solar panels just for that, much less charge a Tesla, or whatever battery vehicle you have. If the bus was idling and you parked your car you could probably do it slowly.

You also may want to consider a main switch to switch power from the Bus drawing to only the car from the Battery bank in the Bus. Trying to power both likely won't end well for your battery bank.

 

[cadillackid]

I don't think anyone here is charging their Tesla from their Bus as of yet. Not to say it could not be done. I'd imagine you'd need to match Powerwall voltages and amperages on your bus to make the car take it.

Getting that kind of voltage and amperage on a bus is also quite an undertaking. Especially if you plan to live in the bus on the daily. You'll be using up all of the electricity a Bus can possibly generate over solar panels just for that, much less charge a Tesla, or whatever battery vehicle you have. If the bus was idling and you parked your car you could probably do it slowly.

You also may want to consider a main switch to switch power from the Bus drawing to only the car from the Battery bank in the Bus. Trying to power both likely won't end well for your battery bank.

you dont need to produce the car's high voltage.. thats what the carge port and onboard charge controller does for you.


level 1 car charging is 12 amps at 120 VAC or roughly 1000 watts.. theres somewhere around a 10-15% loss.. at keast thats the way it was with my chevy volt.. the cars typically come with a 120 VAC adapter.. thats the easiest way.. so if your solar is producing an extra 1000 watts over what you are using for daytime accessories you can feed it to the car in this manner.. (plus the loss of your 48 VDC to 120 VAC inverter).



Level 2 car charging is 240 VAC and is typically at 3.3 Kw, 6.6 kw, and 11 /kw, there are higher standards, though im not sure what the EV6 handles as far as level 2 AC charging..



Level 3 (DCFC) is the type of charging nikitis talks about, this charge stations produce up to 50kw in most cases.. although higher standards exist..


so yes its easily possible to trickle charge your EV6 if it is parked and solar is producing enough wattage. I dont know the average miles per kwh on the EV6 so i dont know how many miles you gain per hour at 120 VAC charging..



getting level 2 is tougher as you need to have a level 2 charger with you to negotiate the protocol... and you need to produce the voltage and wattage to charge the vehicle.. i believe 3.3 kw (3300 watts) is the lowest level 2 negotiated rate .. and you would need to program the car to limit itself.. my home EV charger is limited to 6.6kw, it has dip switches to never negotiate a higher wattage rate.. some cars can be set with a max rate for the various levels... it would be in the vehicle settings someplace.. I dont own an EV6 and have only played with the onboard screens for a few minutes.. if your solar is producing well id see no reason you couldnt make the 3.3 kw rate..



the thing you want to avoid is shuttling power back and forth from one battery bank to another.. ie you dont want the solar to charge the car, then the car to put out its 16 amps all the time and excess charges bus batteries.. there is a lot of loss in that.. a single minisplit air conditioner running full blast will take 1000-1200 watts.. now it pulls much less when it slows down ..



is 16 amps at 120 VAC enough to run your bus?

 

[La Camioneta]

Give these guys a look for batteries: https://trophybattery.com/ I'm a totally satisfied customer, and Dan is working with me on my install. He's 100% on top of everything and super knowledgable. You can check Will Prowse's review, don't take my word for it.

I'm friendly with a guy living in a flat nose bus covered in solar panels. Idk what he can harvest on an ideal summer day - does 20kw sound right? but he commented that in winter due to length of day, cloud cover, shade etc it really dogs down his watts, to the point that plugging in is required. He has two gas generators as reserve power.

I don't pretend to understand what Mr Kid said, but imo the bus solar will be difficult enough to operate as a system without the ev you're referencing. I would treat them as two separate items and use the 120v outlet as the only connection between the two systems.

I went the other way - no solar and 46kW of house power topped off by a QG5500 as needed. As the system is not quite installed, I can't give you real-world consumption data yet.

Were I you, I'd bump my house batteries up a bit and get a dedicated genset wired with the option of charging house batteries or to fast charge the car when your 120v surplus is too low.

Interesting project for sure, keep us posted on your progress.

 

[Jono14]

A few thoughts

Sounds like a cool project!!

I don't know Victron's inverter line really well, but I think the EasySolar-II is just for the European market with 230V AC input/output.
You can shift to the Smart Solar MPPT 250/100 and then combine with a separate inverter or pair of inverter chargers (Multiplus) to provide split phase 240V. The Cerbo will manage the communications between them.

For question 1 it does seem pretty robust and will likely meet your bus needs with some EV charging left over. In theory, you can get about 34 kWh on a full sun summer day (435W x 16 panels x 5 perfect hours per day)

2. I've not tried it and I wonder if you will need it. Could be a clever backup method for cloudy days. Let us know.

3. Looks like the Ruixu batteries have CAN-Bus communication with Victron for "closed loop" communication (the BMS in the battery sets the charging parameters for the MPPT and charger) and shows the battery level to the Cerbo - so you would not need the Victron shunt. Also probably don't need the Victron Lynx "power in" because of the battery rack, but you might still like the Lynx distributor as it is a useful bus bar. (Note that you can add fuses to a "power in" and make it a "distributor" and save ~$50 if you are OK skipping the fuse lights.)

4. A combiner box is probably useful if you are doing 8P on the roof - you will want robust wire from the box to the MPPT as you could get up to 48 amps (Isc of ~6 amps x 8 panels in parallel). AM solar makes a custom one for about $100 that could work. I am sure there are others.

 

[Albatross]

Reserving my opinions on electric vehicles and specifically the amount of destruction that goes into producing them and their batteries; have you tried draining the battery on your Tesla and trying to charge it up using the solar array you've got?

I would do that first to figure out just how capable your system is before you try to fit it into a bus. If that rig can charge up the car with some juice to spare, then I would say that you have a chance, if not, then you would also have an answer.

Personally, where I am at, we just got out of a nearly week-long rainstorm complete with a couple of tornado watches--which is unusual, but also predictive. I can't see a solar system getting more than about 20%-30% for most of those days, so if it's your sole/primary system I would also plan for that, unless you never plan to leave the desert or some other place where it never ever gets clouds.

 

[Iceni John]

You can either fastidiously calculate all your expected loads/usage/etc and come up with lots of impressive numbers, or you can just do what I did. I carpeted my roof with as many panels as would fit there (with each panel tiltable for maximum insolation in winter or at higher latitudes), so I'll never wish I had more panels: I've simply got as many as will fit. I use this same MO for everything else: I have 220 gallons of water tanks, a 65 gallon poo tank and a 115 gallon grey tank for the simple reason they're the largest that will fit. Same for propane and house batteries. It's easier this way, and you'll never regret not having more. Keep it simple! You'll never have the same lifestyle as you have in a house, so just accept you'll be living in a fancy Tuff Shed on wheels: pretend you're Marie Kondo, and embrace it as an exercise in minimalism (or even monastic austerity...)!

John