For those with experience living with remote area power, you’ll know every watt counts, especially in winter.
If you want an EV, then you’ll almost certainly need more solar, and the best available management for charging the new car.
For months now I’ve asked every industry veteran and solarcoaster rider I run into a key question: how are we going to charge EVs for off-grid customers?
The best electric vehicle supply equipment (EVSE) — the charging station for your EV — available only uses available sunshine without touching your battery.
For this type of proper smart charging, at present the only answer seems to be Victron — but only if you have a Victron-based power system.
SMA haven’t bothered to bring their EVSE to Australia, so I haven’t bothered trying to determine if they’re going to play well with the thousands of Sunny Island systems across the country.
Selectronic have a solution that is quite functional if you have an SP-PRO. It’s a clever bit of circuitry that allows control of any EVSE, even though switching might be a little imprecise compared to true dynamic control.
What’s In The Blue Box?
For the first time ever, Victron is offering a choice of white or black covers! Like most, the Victron EV Charging Station can deliver up to 22kW AC in three-phase or 7.3kW in single-phase systems.
There’s a built-in LCD touchscreen so you can check or adjust things directly at the unit, which to be honest is a refreshing change in a world of screenless app-based devices. They’ll have on-grid customers demanding one for that reason alone.
Of course setup and monitoring can be done through the VictronConnect app via Bluetooth, or using the built-in web interface over WiFi — either through a LAN or the unit’s own access point.
If you’ve got a Victron Energy GX device and use VRM (Victron Remote Monitoring), the charger slots in neatly, so you can manage the whole thing remotely.
You can also choose manual or scheduled modes to better match your driving patterns or energy use too.
To top it off, there’s a funky RGB light ring around the charging port. It changes colour based on the charge status — disconnected, charging, fully charged — so you can tell what’s going on with just a glance.
With no less than 8 configurable priorities, this page is one of many used for flexible programming of an SP PRO.
Why Is Nobody Else Capable?
The Victron station can be configured to charge your EV using excess solar, making sure your car soaks up the sun instead of guzzling down your stored energy. It can do this because the entire system talks, the GX device has brains enough to know how much solar resource is available and so control what’s going on.
The grid is sort of like an infinite battery: it’s always going to accept some charge. Any other brand of “smart” EVSE needs to be able to measure current flow into the grid and divert what it sees going past into the car.
However, when you’re off-grid and your battery is full, there is no current to measure, so your EVSE is blind.
Give Your System Eyes
Selectronic have a technical note published as part of their excellent support resources which explains how to give the SP PRO some vision, so it can see how sunny the conditions are.
Adding a pyranometer, a solar light meter, and connecting it to the analog input means you can see whether your solar system is performing as it should.
Hooked into an SP PRO battery setup, this data can be used to switch loads on or off depending on how much solar is coming in, not just how well charged the batteries are.
Lightweight Grid Hybrids Are Just That: Lightweight
The only other way to control a heavy load such as an EV charger or pool pump would be a simple rule; say to switch on above, oh, say 95% battery state of charge. However if there’s little sunshine, you’ll just flog the battery by switching the charger on and off repeatedly.
If your EVSE has a DRM input (Demand Response Mode causes it to derate by a set percentage) this might also be useful for an off-grid system, to trigger a medium setting instead of just on/off, however it’s beyond the scope of this article.
While an SP PRO has 2 analog inputs, 2 shunts, 3 digital outputs, 4 digital inputs, and 4 relays, the thing is, a garden-variety grid hybrid system simply doesn’t have enough of these for your installer to customise. Nor do they have the flexibility to program hundreds of rules and priorities for time, date, days of the week, state of charge, input quality etc etc.
Most of all, grid hybrid inverters don’t have decent surge capacity. Sungrow might claim they can handle a generator, but their 5kW inverter can manage 6kW for 10 seconds.
A 5kW SpPro will deliver 12kW for 30 seconds.
More Solar Will Be Crucial
EVs require a lot of energy for a lot of hours, so oversized solar arrays are going to be the norm. If you’re considering electric mobility, my advice would be to build a new carport and cover it with solar first.
We’re lucky PV solar is now so cheap. I recall when most off-grid customers couldn’t afford more than 2kW of solar, they simply made the rest up with diesel, especially in winter.
A carport can be a good place to whack on some extra solar panels.
Grid To Vehicle To Home
If you can drive to work and suck up a full charge of mains power before returning to your off-grid home, there’s a good chance you’ll never need a generator.
While full bi-directional charging isn’t here yet, and will likely be a low priority for manufacturers to integrate with off-grid systems, most EVs now offer V2L capacity.
They put out 230 volts AC power, it’s like having a camping generator built into the car. This means it’s feasible to siphon off some fuel from your EV to top up the house.
While some customers assume their off-grid system will need double or triple the battery capacity to fill their new car, the opposite may be true. A stinking big car battery may mean your house only needs enough storage to run the fridge for a few days, because cooking tea each night is propped up by the car instead of a generator.
Victron’s One Big Flaw
The Victron EVSE is a great solution, as are many of their other products. I’ve installed lots of them, and they run rings around all the cheap garbage you find on eBay, your local camping forum or caravan group.
However I have it on good authority that in the first release, the EVSE simply didn’t do what it said on the tin.
The charge-on solar function did not work. It couldn’t, until the beta testing had been done, new firmware was written and updates were sent to enable the claimed features.
While I’m glad these problems are sorted, it does expose a weakness with Victron. They have good products, great monitoring and a mind-boggling number of options, but precious little support.
Your wholesaler is the primary contact to solve problems in the Victronisphere. Hopefully they have the time and expertise to help. Or you can try your luck with a large number of enthusiast DIY types on a Victron-hosted worldwide technical forum. It’s a great resource to teach yourself how these things work.
However there is no Victron Australia phone number, so when I needed a legacy manual for a discontinued inverter and it wasn’t on the web portal, then I was shit out of luck.
For more, check out our comprehensive guides on home EV chargers and off-grid power systems.
About Anthony Bennett
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Bi-directional charge is a solution that should be pushed by people and groups such as yourselves because the only lure for me to by an EV is if I can us that power in a black out or whenever. Having an EV would mean for me not having a home battery – need power have EV. While I accept the set up may be different for back to grid and off gird homes I will no be upgrading until this is a standard feature with the bugs sorted out . Would that be in the next 5 years?
Anthony, have to disagree with you about victron back up, while there is no physical presence here in Aus other than wholesalers, they have a very good online back up that works well. Have made use of this at times were we have tricky problem that there nrmal channels fail
This is well and good for an occasional product failure, however this will not be sufficient if there was a product recall…
What about Sigenergy? They seem to have a great Offgrid EV charging solution? I am in investigating installing a Sigenergy system and it looks market leading to me? Am I missing something?
Anthony,
Home Assistant (HA) can control an OCPP charger, but one would need to write the drivers for it. There are some routines written, which one can adapt, because it depends on your hardware. With OCPP, the current to the EVSE can be changed on the fly. (nb my HA system is not yet set this way, so I adjust the current manually, but I am on-grid).
Home assistant can also interface an irradience meter (pyranometer), & it is possible to DIY one (small PV panel, & rpi or arduino).
The advantage of HA is that it can interconnect disparate equipment. In my case I have Victron, SolarEdge, Selectronics, various energy meters, IoTaWatt (to measure loads), & ZJBeny OCPP EV charger.
HA already has EV Import & export ready for Bi-directional charging.
One ´problem´ I see with single manufacturer solutions (such as using only Victron) is that you are restricted to their offerings, & inherent limitations in their supplied software/firmware. By using HA & best choice hardware, one has far more control (an example being a pyranometer)
https://community.home-assistant.io/t/is-anyone-using-a-pyranometer/420076
What about the Sigenergy system that has an optional bidirectional charger? I know it’s prohibitively priced, but that’s another story.
Hi William – I agree, it’s seems that this article has missed Sigenergy? I think the ability to use their bidirectional charging will be delayed till there are EVs that can do it. But what is here right now is 12/25 kw ac/dc charging. Solar Quotes has identified them as rising stars in the battery and inverter markets.
It seems to me that they offer the best off grid EV charging as well and all that was discussed in this
article was seemed to be a quite complex Victron solution where SigEnergy claims they have an out of the box solution of high power charging in both ac & dc. I think it was a missed opportunity to give a review on this new fast growing player in the market.
Hi Wal,
I’m yet to be convinced that a lightweight hybrid grid connect inverter is any sort of solution for proper off grid power (and as you point out, V2G isn’t here yet)
Tesla tried offgrid and withdrew. Enphase have had a couple different attempts and gave up. Sungrow say they can handle a generator (which is adorable) but they don’t have the same level of flexibility with inputs & controls, nor do they have a native car charger.
Hi William,
As mentioned elsewhere in this thread, the bi-directional charger isn’t here yet and I’m yet to be convinced a lightweight hybrid has any place forming a grid for a remote area system.
For our E.V. off-grid charging I bought a 5kw Queenswing charger that claimed would work without a battery (liars) to provide 240V AC from a solar array. There is of course provision to add a decent house battery but with none it sure provides up to 15A AC and naturally when the first thick enough cloud intervenes,(particually giving higher output loads), the inverter goes into fault mode and WONT reset automatically after the cloud. It needs a manual reset, unless there is as little as a very small A/H capacity 48v battery connected (or what electrically sneakily behaves like one i.e. a decent electrolytic capacitor.) When the cloud goes away, and the “battery’s” state of charge appears ok, then the AC out restores after about 5 minutes. How I wished I could make a spare grid-tie inverter work as such, as a spare. Thery all ?? need to sync with 240A.C.
During thinner overcast cover with even light rain, the E.V. charger can keep up with 6A AC, and thats with 2 strings of 18 x 240W grid tie s/h panels. Could be even more impressive with 3 strings?
Sounds like a good setup Frank,
Even Enphase tried to off “batteryless” backup but found out the hard way it didn’t work.
Yeah, the initial Victron “Solar surplus only” EV charging would just sit there “Waiting for sun” – in full solar glare.
After a year of exclusively off-grid BEV charging, and 9,400 photon-propelled km, I’ll just note that my 27 kW of arrays have put over 38 kWh into the MG4 & HWS on a sunny winter’s day, but today, on the 4th successive day of early autumn heavy overcast, the yield is barely 1 to 3 kW, not always the minimum 1.6 kW EVCE supply. That means “solar only” would intermittently stop charging, and be quite inefficient the rest of the time.
So, on overcast days I postpone EV charging, as 300 km range suffices for a fortnight, even with a 65 km round trip to town. An occasional EV top-up from the 46 kWh house battery is negligible battery wear – 6,000 cycles go a very long way, even at 47 cycles in 399 days, so far.
If out daily, I’d uninhibitedly use the battery to time shift EV charging, and keep charging rate up in the efficient range. Or, if I had to charge in today’s murk, let the battery boost the variably dim insolation, to blithely thwart Huey. Fuel cost savings more than offset the modest battery wear. (More reliable return than any VPP too, I figure.)
Even in this murk, with daytime lights indoors, the battery was back up to 100% by midday, even while running the 3/4 tonne lathe, turning up a little adaptor spigot, to bring a 25.6 mm OD jerry-can pourer down to 21.6 mm to fit a Prado. The electricity consumption was minimal. The new aircons are magic – comfy heat without having to fuss with kindling and firewood. (And the one in the workshop can keep the Victrons cool. See p75 of Renew magazine, Jan-Mar issue.)
Off-grid: “Fill the Roof” is not just a suggestion, 25 kW bare minimum!
30 kWh of batteries would also be a minimum for full-time residence with multiple aircons, fridges, HWS, ‘n stuff. (My 46 kWh hasn’t been below 78% SoC, so 30 kWh might nearly do, with ample PV.)
When off-grid, with an adequate house battery for several days of autonomy without a generator start, is there much merit in solar-only BEV charging?
Today the MG4 is up to 100%. To date, the 9401 km travelled + 320 km in the battery has consumed 2081.31 kWh of photons, including charger losses.
Let’s pretend that all went through the house battery, i.e. time-shifting 100% of BEV charging, then it’s 2081.31/46.5 = 45 cycles of an $18k battery with a 6,000 cycle life. That’s 45/6000*18000 = $135 battery cost for 9721 km travelled. Or actually Zero, if 20 yr calendar life occurs first. (There’s no feed-in possibility.)
The petrol saving, at 10 km/L and $1.78/L is: 9721*.10*1.78 = $1730.34
OK, a very long daily commute, with night-time BEV charging, would hit the house battery’s overnight reserve, but the fuel saving could pay for ample extra capacity.
Here, I now mostly charge at 7 kW in daylight, letting the battery fill any gaps, then catch up later. Battery cycling? 10% maybe.
Ive had a zappi and eddi off-grid with a Selectronic SP Pro for two years, confirm both work well and will not draw from the battery unless instructed. The eSense input can be connected to the float relay to trigger them to boost once the battery is full. Export margin ensures the battery can get a set amount of solar before the charger or hot water
One comment I will make about EV charging is to look at efficiency: at less then 10A, the efficiency usually goes down, & is bad at about 6A. If you have heaps of excess energy, not so much of a problem, but the EV will charge faster at higher currents. eg I usually use 14A or so. If you have use for the low current PV generation such as topping up the house battery, consider only enabling the EV charge when the sun is really shining to allow 12A+ to the EV.
Confirming that Zappi can handle most, if not all of, the situations mentioned. However, it needs CT-clamps/sensors for battery, solar, and grid. Battery sensor is usually an optional extra.
We recently went into off-grid backup, due to cyclone Alfred, for 10 days and Zappi handled EV charging perfectly without discharging the battery. Set up has to be correct and there is a lot of flexibility in this aspect.
Single-phase battery.
Thanks for the heads up John,
We’ve struggled to recommend Zappi after having warranty problems with their EVSE which resulted in legal threats instead of a replacement unit.
I hope you have a better run with them.
I have just had a Zappi installed, interfacing with Sungrow Hybrid Inverter and SBR battery modules. Amber is my supplier
It would seem that there is no training of installers.
– charging from solar only, ie Eco+ 100%, isolarcloud registers the Zappi consumption as being exported.
– charging from grid, Isolarcloud registers nothing.
Seems obvious that the sungrow CTs need to be moved to correctly detect current from solar and grid to Zappi.
Add to that, the Amber Smartshit and Solar Curtailment mean that when FiT are negative, when there is the MOST solar power available, the Zappi Eco automation doesn’t work, because there is no excess solar.
Not sure what the solution to that is. A chicken and egg thing.
MyEnergi and Amber have been on to it for a week or more, and I think Amber are really trying to get to bottom it as is part of their trial. So kudos to them.
But am waiting for them both to get to bottom of it. MyEnergi looking at my daily and weekly consumption graphs apparently holds the key. How I don’t know.
What I need, to give to installer, is a wring diagram including location of CT clamps for both Zappi and Sungrow smart meter.
…anyone?
Wou
Hi Neil,
Sounds like your Zappi is set up so the Sungrow is blind to it. ie it’s on the grid side of the CTs to prevent your house battery going flat.
https://www.solarquotes.com.au/blog/ev-draining-home-battery/
Sorry I don’t have a good answer but you might enquire with CatchPower and ask if they have an integration.
We’re usually banging in about having solar/batteries & EVSE all from the same maker, so they talk to each other like Fronius for instance.
However Sungrow don’t offer an EVSE sadly.
Let us know what you find out.
How long ago was the issue? A lot has changed at myenergi with both their product and management locally. Perhaps its time Solarquotes bury their personal grudge against myenergi
Hi John,
We’ve got some fairly balanced reporting I think. Do you know if Zappi will actually handle more than 40°C these days?
https://www.solarquotes.com.au/ev-chargers/reviews/zappi-review.html
https://www.solarquotes.com.au/blog/zappi-ev-charger-review/
My zappi is on a north-facing brick wall in full sun, which is the worst possible location for an ev charger. On 40+ degree days the most I’ve seen it derate down to is 26A. I would expect any good EV charger to behave the same way in the same conditions. The temperature reading are available in the zappi menu so it’s never a surprise to see if the rate has slowed.
Thanks Anthony an important topic.
Well-designed Off Grid PV Systems must include “eyes” which will play a critical role in the overall monitoring and control of the system. Including Dynamic EV Battery Charging.
“Eyes” can also act as a dynamic “diagnostic tool” always available for both system owners and installers to precisely understand the state of health of the System Solar Array, at any point of time.
A pyranometer will measure solar irradiation; but is not the best choice for Off Grid Systems.
Better is an “Inferential PV Panel. This is a suitably ground mounted and easily accessible PV Panel, the best choice being one the same as those used in the Array. It should be oriented in both Azimuth and Inclination the same as the Array.
The output leads are connected together so it is used in an Isc configuration which will provide a precise snapshot of the PV Array performance after applying the suitable maths.
A CT sized for the Isc of the panel is included in the circuit with the CT output signal input to a PLC / Datalogger / Arduino, or other device: and the designer has created a very robust; reliable; self-powered monitoring and control unit [complete with Web, SMS, Global comms] outside of the inverter, the importance of which should be easily recognised by system designer / installers especially in mission critical Off Grid Systems.
Inferential measurement and manipulation by formulas is the foundation principle across all engineering disciplines.
Lawrence Coomber
That is a great idea. In fact, for DIY, any little panel could be ´mapped´ against the array for performance comparison.
Darn another project! Would work great with HA too.
If businesses can provide daytime charging for employees, employees could use their car batteries to take electricity home to charge house batteries even if they could not have solar.
An EV Charging circuit is simply a circuit, and what is not often discussed or well known by system designers is that specific purpose circuits for any/many functions can easily and cost effectively be implemented in system design in the hands of an experienced Power Plant Solutions integrator. Example:
You might have a 6.6 kW On-Grid System installed; you also have sufficient area at your property to work with. Consider installing another Off-Grid System, of any capacity up to 100 kW total capacity for the 2 installed systems. STC’s will be payable for the 2nd Off-Grid system up to its full kW nameplate capacity.
This dual system scenario is quite common for Single Circuit Loads that have an appropriate day time duty cycle; for example a metal guillotine; compressor; aerator motors for fish farms; water pumps for reservoirs on golf courses, mining operations, EV charging. The list is long.
Lawrence Coomber
I’m in this exact situation. I’ve got an off grid house for purely philosophical reasons using Victron gear.
Certainly the early firmware didn’t do what it said on the box, but they have improved it dramatically and it now works as advertised, and does remarkably well.
That said, I don’t use it that way. I utilise Node Red to manage my smart charging having messed around with the code tweaking and finessing over months to optimise it to maximise my use of energy.
I’ve now essentially have a PLC that considers:
Instantaneous solar generation
Maximum household instantaneous power
Forecasted solar generation
Home battery capacity
An input to ramp down power before I turn on a high power draw (currently only on the oven)
This enables me to plug the car in and forget about anything else whilst maximising my available energy into my EV
Hi Nathan,
Sounds like a great setup. The issue with home assistant, palladin, node red etc is they’re all a long way from plug & play solutions.
While this stuff is incredibly flexible & capable, there are no installing companies who can package it, set up all the integration & offer a warranty.
Sadly the commercial reality means the people with the knowledge aren’t willing to run the reputational risk or liability to wire it up and let people play either.
Even those who want to do it will struggle to find electricians to install hardware I suspect, but at least software isn’t as risky for unqualified fiddlers.
A caveat though, a *good* remote area power system installer is used to doing some fun integrations, hence Selectronic publish guidance on some common solutions.
Would you recommend the Victron charger even if it’s being used without the GX/VRM and on-grid? It’s well priced (~$600) and supports Modbus Ethernet, making it easy to control with stuff like Home Assistant or EVCC.io – but does it work well just as a “dumb” charger? Just plug the car in and it charges?
Hi Decryption,
It would be worth checking if the Victron EVSE is OCPP compliant.
Have a look at this article & there’s a hyperlink for SA Govt approved equipment.
https://www.solarquotes.com.au/blog/tesla-ev-charger-sa/
Interesting – I didn’t know EV chargers in SA need OCPP. I don’t live in SA so doesn’t really bother me if it doesn’t support OCPP. I just wanted to know if it works as a dumb charger without any of the extra Victron systems like GX/VRM.
Hi Decryption,
Flexible solar exports & dynamic load control are coming to a state near you soon I promise.
I know Victron are offering different coloured covers because not everybody appreciates the look of a blue box, obviously this is for general grid connect marketing.
However I haven’t installed one myself and haven’t found the will to read another install PDF on the weekend sorry 😉
Let us know if you find out.
Cheers
This will not happen anytime soon. I give you the reason. We have one party that has strong links to the industry and wants us to burn fossil fuels. Then we have another party with strong links to superannuation funds that have heavily invested in generators, distributers, and transmission.
What you sau makes perfectly sense, but is not happening any time soon. Unfortunately.