Can I use a Quick 220 off of two Growatts in parallel to charge a tesla?

[Visionguild]

I posted earlier about trying to use two growatts with two signature solar batteries to charge my tesla like Will does. If I run them in split phase for 220 I can't use them for anything else correct? This is the mistake I think I have made. I was hoping this set up would serve all my power needs. Now I'm under the impression that what I have can either do the car, or I set them up in parallel for 110 power but then will have a really slow charge for my car. I see a video about a guy running two in parallel split phase, but he doesn't say whether he's outputting 110 or 220. I thought parallel meant 110 and split phase was 220. Not the case? Bummed to think I might have to buy two more growatts and two more batteries, several more thousands of dollars and more waiting in order to do what I need. Or... will one of these Quick 220 inverters work? Sorry to be so confused. I guess I didn't realize what I was getting myself into. Will makes it look too easy. Thanks for any help!!

 

[sunshine_eggo]

I posted earlier about trying to use two growatts with two signature solar batteries to charge my tesla like Will does. If I run them in split phase for 220 I can't use them for anything else correct?

No. In split phase, you also have 120VAC between each hot leg and neutral. IF you use 120VAC loads from either leg, it will reduce the total available to both legs for 240VAC loads. Example:

2X 3000W inverters in split phase 120/240VAC. 25A per leg.

If you use 5A on L1, you only have 20A available on both legs for 240VAC loads, but you still have 5A available on L2.

if you were to only pull 15A from 240VAC (3600W) for charging, you would still have 10A per leg available for 120VAC loads.

 

[Visionguild]

No. In split phase, you also have 120VAC between each hot leg and neutral. IF you use 120VAC loads from either leg, it will reduce the total available to both legs for 240VAC loads. Example:

2X 3000W inverters in split phase 120/240VAC. 25A per leg.

If you use 5A on L1, you only have 20A available on both legs for 240VAC loads, but you still have 5A available on L2.

if you were to only pull 15A from 240VAC (3600W) for charging, you would still have 10A per leg available for 120VAC loads.

I really appreciate your answer but I don't understand it. lol. I'm not that knowledgeable on this stuff. Sorry. I'm literally googling what split phase even means and I still don't get it. So should I run these in 240? I thought it was 220. Imagine you had two Growatt 3000tl's 2 sig solar batteries and 16 300 watt panels. You have tesla and other none 220/240 needs. Will what I have work? Your last example says if I pull 15A, (a is amps I'm assuming) from 240 I still have 10A available for 120VAC loads. I thought the two were separate. Meaning if I set up something in 240 then that's that. Nothing that needs 120 can use the 240. No? I'm trying to find someone local that can come explain this stuff to me as I know this is a pain in the ass for this forum to have guys like me asking dumb questions. Thanks again though.

 

[Dzl]

 

[sunshine_eggo]

If you are in North America, typical residential power is 120/240VAC split phase.

Watch this:

One inverter will output L1 and N. The other inverter will output L2 and N. These are literally wires coming out of the units that go to a breaker panel:



Between L1 and L2, you get your 240VAC.

Between L1 and N, you get 120VAC
Between L2 and N, you get 120VAC


You get to use 120VAC and 240VAC. They just affect each other in terms of amps available.

 

[Visionguild]

Ok, so this is helpful. So I need a breaker box. See, I naively saw Will's video of installing one of these with one of my batteries. He literally has the inverter, the battery and nothing else. Says, "that's all you need"

So this video isn't complete at all huh? He doesn't have anything else and even says you don't need any of that. This is the exact stuff I have but this only applies to one correct? If I use two I need breaker boxes and other stuff?

 

[Visionguild]

I need to do something like this huh,

 

[MichaelK]

This is a bit more complicated than just wiring. To go into a bit more detail, there are now three generalized standards for electric vehicle charging.

Level 1: 12A at 120VAC or 1440W; This is slow charging, designed to happen off a regular 120V NEMA socket.
Level 2: 20A to 50A at 240VAC or 4800W to 12000W; Fast charging that can be accomplished at home via a 240V clothes drier circuit
Level 3: 480V DC current; Very fast charging. Commercial charging docks only.

If you have the inverters wired for split-phase 240VAC, then there is the potential for charging, but the published specifications don't mention anything about charging amperages less then 20A for level two charging.

So, it becomes an issue of whether or not your system can supply that many amps at 240VAC? I know that my system could supply at least 10A at 240V for about 8 hours each day, but I don't know if home chargers can be "set" to charge at specific amperage rate? Can anyone else here provide info about 240V charging at home?

 

[Samsonite801]

This is a bit more complicated than just wiring. To go into a bit more detail, there are now three generalized standards for electric vehicle charging.

Level 1: 12A at 120VAC or 1440W; This is slow charging, designed to happen off a regular 120V NEMA socket.
Level 2: 20A to 50A at 240VAC or 4800W to 12000W; Fast charging that can be accomplished at home via a 240V clothes drier circuit
Level 3: 480V DC current; Very fast charging. Commercial charging docks only.

If you have the inverters wired for split-phase 240VAC, then there is the potential for charging, but the published specifications don't mention anything about charging amperages less then 20A for level two charging.

So, it becomes an issue of whether or not your system can supply that many amps at 240VAC? I know that my system could supply at least 10A at 240V for about 8 hours each day, but I don't know if home chargers can be "set" to charge at specific amperage rate? Can anyone else here provide info about 240V charging at home?

I know on my brother's Tesla, he just uses the standard 240v charge adapter cord in his garage plugged into the house dryer plug (which is only a NEMA 14-30R 30a receptacle), but his Tesla has a spot in the settings where you can adjust the max charging amperage. I think he said he can set it up to about 28a on the Tesla side, any higher and it will blow the dryer breaker on the house.

So you might have to turn the max charging amps down enough on the Tesla charging settings to make it stay within what the Growatts can provide.

It is the Level 2 based on your above note.

 

[MichaelK]

his Tesla has a spot in the settings where you can adjust the max charging amperage. I think he said he can set it up to about 28a on the Tesla side, any higher and it will blow the dryer breaker on the house.

That's good to know. For my own system, I think I could meet level one from 7:30am till about 4:30pm. That would be 13kWh of charge. At 240V, I could match 10A at 240V from 8:00am till 4:00pm (summer). That would be 19kWh of charge.

Assuming I'm going to someday drive something like the new all-electric Ford F150, I'm guestimating that it will take me about 30kWh of juice to get me into town and back. So, one trip is going to cost me at least two days of charging.

 

[Struc]

If your *only* goal is to power your Tesla, then buy 1 Growatt SPF5000 for 5kw (~20A@240v) or 2 of them for 10kw (~40A@240v) charging ability. They ONLY put out 240v (not 120v for normal household loads) as they come. You can parallel them together if you buy 2 or more. Each additional SPF5000 would give you another 20A of charging. Keep in mind you would need the solar panels to support this as well.

Also keep in mind that Will has some insane amount of battery hooked up.... probably like 40kwh or more (I know he mentioned it, but I can't remember off the top of my head). Each of those Signature Solar batteries is 5.12kwh.

Combine all the outputs from the Growatts into a circuit breaker panel, making sure L1 and L2 are correct on each termination breaker. Then, use 1 more breaker for the output to your charging station.

This is all a very simplistic overview, obviously.

 

[rowbiker]

Does anyone know if the Growatt models that output single phase (non-split, e.g. L1 @240V, L2 is neutral) can be used to charge a modern Tesla directly via a 240VAC outlet, plus the Tesla's mobile charger? I'm assuming the Tesla will also require the earth ground connected somehow.

 

[Hedges]

This whole "Charge a Tesla from a GroWatt" (or any other inverter) has an issue.
You've got a variable amount of power coming from PV panels, and a fixed amount of battery storage (which is much less than a Tesla).
Depending on how many kWh the car needs to charge, if kW charge rate exceeds what PV is producing the battery on GroWatt will discharge until inverter shuts down. If rate is below what PV produces, battery on GroWatt will become fully charged and some PV production goes to waste without car getting fully charged.



Ideally, you would have a car charger that is informed about available power, and adjusts charging rate to use it. For instance, draws enough power to keep GroWatt battery less than full and more than empty.

Because hardware is always cheaper, easier, faster to implement/install/repair than software, here is my idea: Given a signal from inverter/SCC/battery that says "More than 90% full", enable a 240V charger. When that signal turns off, enable a 120V charger.
Ideally have another signal "Less than 20% full" disable all charging.

The brute force approach would be to have enough battery on GroWatt to supply all charging needs, and this would let you charge at night. Less cost effective.
Alternate, enough PV to provide more than enough steady power to recharge during the day.

Does anyone know if the Growatt models that output single phase (non-split, e.g. L1 @240V, L2 is neutral) can be used to charge a modern Tesla directly via a 240VAC outlet, plus the Tesla's mobile charger? I'm assuming the Tesla will also require the earth ground connected somehow.

Use an isolation transformer to take in 240V, output 120/240V split-phase. You just ground center-tap of secondary.
I saw a used 15kVA one on eBay for $300.

 

[rowbiker]

Thanks, terrific response! Nailed both my specific question, as well as putting the whole project in perspective.

I'm not driven by cost, but rather the desire to be independent of the the world's grid as far as my personal transportation goes. I don't drive much (currently have a Tesla Y), so trickle charging the car is usually sufficient. I'm putting up 10 370 watt solar panels and want to remain totally off the local grid. I'll add whatever 48V battery capacity makes most sense, and will hope to implement your philosophy, possibly using some combination of voltage sensitive relays and microcontrollers plus software if necessary. I obtained some Enphase microinverters (IQ7+ and IQ8A) for testing, but it turns out that you have to go 'all in' with Enphase proprietary hardware for it to make any sense, and my small side project doesn't fit that approach.

Given that, any recommendations as to PV hardware or batteries? Go with all-in-one box inverter like GroWatt or MPP Solar, or discrete functional components? How much battery capacity (probably going with lithium iron chemistry)?

 

[Hedges]

Now is not a great time to be shopping, supply has been bought up by newly interested consumers.
SanTan Solar is one good source for panels (limited selection right now.)

PV array consisting of one string oriented SE and one SW will produce more uniform power over the day.
PV panels cost about 1/10th as much as batteries (per kWh over usable life), so better to "use it or lose it" charging the car rather than banking power in batteries. Used to be "net metering" was a very cost effective alternative, but utility tariffs are changing.

A "batteries optional" all in one could be a good way to go. It could provide battery backup for critical loads.
Another choice, something like SMA -41 series Sunny Boy has "Secure Power" outlet, 2000W at 120V. While PV produces more, than can feed a level-1 charger.

Consider an inverter with "zero export" option, backfeeds into your house but doesn't backfeed the meter, uses a current transformer to measure what comes from or goes to the grid.

 

[MichaelK]

I'm not driven by cost, but rather the desire to be independent of the the world's grid as far as my personal transportation goes. I don't drive much (currently have a Tesla Y), so trickle charging the car is usually sufficient. I'm putting up 10 370 watt solar panels and want to remain totally off the local grid. I'll add whatever 48V battery capacity makes most sense,

Given that, any recommendations as to PV hardware or batteries? Go with all-in-one box inverter like GroWatt or MPP Solar, or discrete functional components? How much battery capacity (probably going with lithium iron chemistry)?

What you implement will eventually be determined by whether you want Tier-1 charging or Tier-2. Tier-1 is 1440W at 120VAC, whereas Tier-2 STARTS at 2400W at 240VAC. Sounds like Tier-1 will work for you.

So, if electing Tier-1 basically any good-quality 120VAC sine-wave inverter >3000W will work for you. If you decide to go with Tier-2, then that automatically means split-phase 120/240VAC, which ups the price tag. Doable, but will cost more. Magnum, Outback, and Schneider can all be wired for both 120VAC and 120/240VAC.

BTW, 10 panels is not likely to be an optimal number of panels because your only wiring choices are 5S2P and 2S5P. 10S1P might be doable with a rare few inverters, but that will depend a lot on your winter lows and the max Voc. You might be better off getting a dozen panels, then you can add 3S4P, 4S3P, and 6S2P configurations to your wiring scheme. I've never seen anyone complain they had too much solar.

 

[rowbiker]

Now is not a great time to be shopping, supply has been bought up by newly interested consumers.
SanTan Solar is one good source for panels (limited selection right now.)

PV array consisting of one string oriented SE and one SW will produce more uniform power over the day.
PV panels cost about 1/10th as much as batteries (per kWh over usable life), so better to "use it or lose it" charging the car rather than banking power in batteries. Used to be "net metering" was a very cost effective alternative, but utility tariffs are changing.

My main reasons for including a battery in the design is to prevent the inverter from shutting down every time a cloud passes overhead. Even if the inverter could cope with this, I doubt the car would handle it -- although I really don't know how the car would respond to a charging source that constantly powered up/down. The idea is to use the car's battery for "banking" the power/energy!

A "batteries optional" all in one could be a good way to go. It could provide battery backup for critical loads.
Another choice, something like SMA -41 series Sunny Boy has "Secure Power" outlet, 2000W at 120V. While PV produces more, than can feed a level-1 charger.

Consider an inverter with "zero export" option, backfeeds into your house but doesn't backfeed the meter, uses a current transformer to measure what comes from or goes to the grid.

Thanks -- I'll take a look at these other options.

 

[rowbiker]

What you implement will eventually be determined by whether you want Tier-1 charging or Tier-2. Tier-1 is 1440W at 120VAC, whereas Tier-2 STARTS at 2400W at 240VAC. Sounds like Tier-1 will work for you.

I prefer the Level 2 (240VAC) charging because it gives me a wider range of charging current. If my panels aren't producing near their capacity due to poor insolation levels, I can easily program the Tesla to charge at a lower level. Maybe other EV's don't allow this, but I currently 'throttle back' my charging rate to about 5 amps anyway, even though I have a Tesla "wall charger" that can do up to approximately 40 amps from the grid connection.

So, if electing Tier-1 basically any good-quality 120VAC sine-wave inverter >3000W will work for you. If you decide to go with Tier-2, then that automatically means split-phase 120/240VAC, which ups the price tag. Doable, but will cost more. Magnum, Outback, and Schneider can all be wired for both 120VAC and 120/240VAC.

It would be worth some added cost to have the flexibility to go either way. The manufacturers you mentioned sound familiar, so I guess I'll have to check reviews and availability. Thanks for the recommendations!

BTW, 10 panels is not likely to be an optimal number of panels because your only wiring choices are 5S2P and 2S5P. 10S1P might be doable with a rare few inverters, but that will depend a lot on your winter lows and the max Voc. You might be better off getting a dozen panels, then you can add 3S4P, 4S3P, and 6S2P configurations to your wiring scheme. I've never seen anyone complain they had too much solar.

I certainly agree with you about the never "too many" solar panels concept, but I'm severely constrained spacewise. Due to this, 10 is already a stretch. Would dropping back to 3S3P make more sense?. Or, maybe the neighbors wouldn't notice if I put two more panels on *their* roof!