Have you ever tried charging your EV using only excess solar power, only to find it falls asleep while waiting for the sun to cooperate? For some electric vehicles, like the BYD Dolphin, it’s more than just a minor inconvenience—it’s a frustrating glitch that interrupts charging altogether. Imagine plugging in your car, expecting it to juice up from your solar setup, and instead, it shuts down after a few minutes of no power flow, forcing you to reset it manually.
That’s what happened to SolarQuotes reader Gregory. Gregory has a SolarEdge EV charger which he tried to set up to use excess solar power to charge his BYD Dolphin.
According to Kiwi EV charger manufacturer Evnex, the BYD Atto 3 has the same sleeping issue but Evnex figured out a clever workaround.
A spokesperson for BYD’s Australian distributor EV Direct told me:
“Our engineers have informed me that the sleep mode for the ATTO 3, SEAL and DOLPHIN models does not correlate to the minimum charging power. The vehicles check for a detected signal, and if no signal is detected, the vehicle will go to sleep.”
That wasn’t a very detailed answer but luckily BYD customer service explained the situation to Gregory much better:
“To ensure proper charging of the vehicle’s battery, it is important to maintain a consistent supply of energy. If the voltage drops below 1.5V, the vehicle will automatically enter ‘sleep’ mode. In this state, it cannot recognize energy levels below 1.5V and will not accept any charge until it is awakened again. To wake up the vehicle, simply lock and unlock the car”.
“For those using a solar charger with the ECO mode selected (which utilizes surplus solar energy to charge the car), please note that the vehicle will also enter sleep mode when there is no surplus energy available as the voltage will drop below 1.5V”.
“Ensuring a steady energy supply and keeping the vehicle properly charged will optimize its performance and avoid unnecessary interruptions”.
Good News: Zappis Keep Your Car Wide Awake
Readers shouldn’t worry that all EVs have problems falling asleep while waiting to charge from excess solar.
Dual EV household owners Evan (Volvo XC40 Recharge) and Beau (Polestar 2) told me that they keep their Zappi charger:
“In Eco+ mode which cuts it off completely if the solar drops away or the house load exceeds any excess. Doesn’t seem to be an issue it can sit idle for hours and then kick in once there’s solar“.
BYD Seal owner Campbell agreed, telling me that he also has a Zappi charger set to ECO+ Mode.
“So far I haven’t seen any issues on my Zappi with paused/stopped charging … Sometimes I also use ECO (Not ECO+) mode, which always provides 1.4kW of base load charging towards the vehicle, with it ramping up if excess solar is available”.
“This is useful on intermittent cloudy/sunny days as it prevents the EV Charger from pausing the charge frequently, and also it stops it from pausing when it is only a few hundred Watts short of a 1.4kW charge limit. (e.g. Exporting 1.2kW back to the grid, whereas I could just pay 5c an hour for that extra 0.2kWh of energy)”.
Teslas Stay Awake Too
Finn charges his Tesla from excess solar power and has had no issues with his EV falling asleep waiting for a charging session to start.
Why Do EV Chargers Need A Minimum Of 6 Amps Per Phase?
Campbell’s mention of the Zappi Eco Mode piqued my interest so I researched why it was set to 1.4kW. Turns out that 1.4 kW equals 5.83 amps (so roughly 6 amps) in a country like Australia that has a residential power supply of 230 volts.
6 A x 230 V = 1.38 kW
Germans are known for their precision and love of rules so I trust SMA when they say:
“The minimum charge current of the EV Charger is 6 A. According to the IEC 61851 standard, a lower value is not permitted”
Zappi concurs:
“According to the EV charging standard, the minimum charging current is 6A (which is ~1.4kW for a single phase EV charge) so if you have less than 1.4kW of surplus generation the extra power has to be taken from the mains”.
“In Eco mode, the EV should start charging as soon as it is plugged in and will continue charging at 1.4kW (or more if there is spare generation) until the EV is unplugged or the battery is full.”
What To Do If Your EV Sleeps While Waiting To Charge
So if you have an EV and solar charging doesn’t work because your car gets sleepy, there is a workaround: charge at a minimum 1.4kW.
That should keep your EV awake and charging up to your set limit without glitches.
Furthermore… advice from resident SolarQuotes sparky Anthony is that:
“Cycling anything on and off too many times isn’t going to be good for it. Cars often have big contactors/relays that switch main pack voltage to different components, and they’ve got a certain cycle life. I would think that the BMS may struggle a little with estimating State Of Charge if it doesn’t get a good run at charging”.
I’m not a sparky, but it seems sensible to avoid unnecessary wear and tear on car and home charger electronics by supplying a minimum of 6 amps (as per IEC 61851 standard) from a home EV charger during your scheduled home charging period.
That way, both the EV and the home charger aren’t sent start/stop charging signals every time clouds lower solar generation or someone turns on the kettle. And if you are charging during the day, any electricity taken from the grid is likely to be mostly solar anyway.
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Hi, I will put my 2c worth in to say that charging at 1.4Kw on many (perhaps all?) EVs is less efficient than charging at a minimum of 8A.
The issue is there is an efficiency curve & at 6A one is on the bottom of that curve.
My thought is that running at 8A minimum might actually be more economical (but I have not done the maths!)
If you think about it, on shoulder rate, charging at 8A (or about 12Kms/Hr) would cost about 60c, without taking any Solar PV. But if the PV ramps up,
one will be inputting much more as well as offsetting that basic 60c/hr.
To my mind, all a lot of Shakespeare! (Much ado about nothing). Stop charging in Peak rate, but really not worry about 60c/hr the rest of the time.
btw, the only time I charge at 8A is on the Granny charger on a less than ideal power point. Usually my minimum is 10A, which is still only abt 70c/hr.
(Warning: check that power connections are not getting excessively warm at 10A: I have seen plugs melt. One reason I like Screw ring retained
industrial 3 pin plugs.)
Doug, I take your point about charging efficiency. My MG4 has done 5,095 km on 1.009 MWh delivered to the charger, which is 198 Wh/km, but the car reports 176 Wh/km, and that is just 88.8% efficiency, admittedly charge + discharge.
Off-grid here, the charging has been predominantly at 6 to 7.2 kW, and occasionally down around 3 kW, in poor sun. I’d consider it nutty to go any lower, as the 46 kWh house battery effortlessly fills any cloudy patches.
I’m guessing that at 20% capacity (1.4/7 kW), an EV’s on-board battery charger might be around 60 – 70% efficient, if it’s 95% efficient at full capacity.
I’ve given up on the “Surplus Solar” caper, as my Victron EV charger fails to auto-start even in bright sun with 20 kW of spare generation available. I just use manual mode. If I draw from the house battery, it’ll recharge later, when I’m miles down the road. That’s much quicker, and it’s hard to get the cycles up on a big battery anyhow. (18 cycles in around 6 months means calendar aging is the way these’ll end their days.)
We have had a Zappi charger for our Nissan Leaf which we replaced with a Tesla Model 3 a couple of years ago.
We normally charge on ECO + not ECO ++ as we like the reliability of continual charging, but incorporating excess solar. On full sunny days no issues, but even small amounts of cloud can turn off charger if ECO++
So normally run ECO+ which delivers 1.5kW (according to Zappie display) no problems with either vehicle turning off charging. Works well we rarely use boost mode unless we need to charge in a hurry, a very rare occurrence,
We export a lot more electricity to grid than we import, ¼ year power bill usually $50 to $100 credit to us.Like using our Zappie in ECO+ mode simple and works well for us.
Thank you for the interesting article Neerav,
I have an Atto 3 and a Fronius Wattpilot and have encountered this sleep issue for over 18 months now.
As I charge mainly from excess solar, it is very frustrating when the car goes to sleep and the solar panels are generating lots of power.
My workaround is to check the Atto App on my phone on a regular basis and this seems to wake up the car if it is asleep.
On nice clear sunny days, it charges all day long but on cloudy windy days, it starts/stops and if the cloud hangs around a while, the car goes to sleep and I need to wake it up via the App.
In Eco mode, I don’t think I can configure the Wattpilot to keep charging when there is cloud cover.
Hi Peter,
If you don’t mind, have you spoke to BYD and if you have what are they saying or doing?
Bob
Hi Bob,
I haven’t spoken to BYD directly.
I’m a member of the Aus/NZ Fronius Wattpilot Facebook Group and the topic has been discussed a number of times and there does not seem to be a solution that I am aware of.
It doesn’t worry me too much but will I raise it with BYD at my next service.
@Neerav I have the BYD Atto and have no issues with keeping my charger ‘awake’.
I have CATCH Control, controlling my Fronius Wattpilot.
When in Solar Tracking mode, the charger requires 1.5 kW’s to establish a stable connection, if surplus drops below this then the charger disengages. Then when the site is exporting 1.5 kW’s again, it acts as a new connection and wakes the car up.
I can’t speak for the BYD Dolphin but I’ve had no issues with my Atto3
Hi Erin,
Are you worried that start/stop may cause issues?
Thanks.
Bob
I’ve had an Atto 3 for 18 months.
My understanding is that the vehicle goes to sleep if it detects the EVSE’s pilot signal, responds and then charging hasn’t started for a significant period.
The “OpenEVSE” I use has a simple solution which is a “Pause State” setting to disable the pilot signal until enough solar is available again. It describes the setting in this way : “Some vehicles will shutdown if left in sleep mode (pilot signal enable) and then can not be woken up by timers/PV divert. Changing the pause state to disable should resolve this issue, however this removes the ability for the charger to detect if a vehicle is connected when paused.””
This worked flawlessly for my car.
Thanks for interesting article. I have a Tesla which I manage via Home Assistant and EMHASS. I pass to EMHASS the amount of time I want to charge and at what amperage (or kW) and the fact that it’s a variable load and EMHASS matches that demand with the cheapest periods and amperages to charge. This signal is then passed to the Tesla via the Tesla cloud API. I don’t drop below 3A at the moment and the car takes that command without issue (awake or asleep) but I always wondered if it was better to set the lower limit to what is possible in the Tesla app (5A minimum). I use this to avoid negative FiT so it can be a bit off and on again in the morning but through the day it usually sits at whatever max I set. Wondering if I should raise the min to 5A?
I too bought the SolarEdge Smart charger, and I regret it every single day. The product is the furthest thing from ‘smart’, and direct contact with the company has illustrated their complete unwillingness to make the following software changes:
1) User-specified charging rate.
2) User-specified floor rate for when charging on Excess Solar. Otherwise, the charger drops out with every cloud or turns off before 10 am and after 4 pm with the lacklustre Melbourne sunshine. Naturally, I would set this minimum charging rate at 1.6kW to avoid the above-identified issue.
SolarEdge – never again.
Tristo,
is the SolarEdge OCPP compliant? If so you have the possibility of controlling your charger with Home Assistant. (Home assistant is an Open Source Home management software, that runs on a microComputer, eg RaspberryPi. The best way to get a HA controller is to buy a Home Assistant Yellow kit. (Do some research if interested). There is an OCPP module that runs under Home Assistant, & can run full control of the EV charger (as well as much, much more). Personally, I run a ZJBeny OCPP charger controlled by HA.
Checked: SolarEdge Charger is OCPP compliant.
I encountered a different problem using a Zappi charger with my Ioniq. In the beginning, I thought it would be clever to leave the Zappi permanently attached in Eco++ mode whenever the car was at home. That way, excess solar would be mopped up automatically.
The problem arose the first time I left the car waiting ‘for a while’ (overnight). In the morning the 12 volt battery was flat. It was an unexpected experience to have the RACV jump start my EV!
Nowadays I use Eco+ mode most of the time but never Eco++.
No issues with Volvo (aka Geely) EX30 and Fronius Wattpilot with Mode setting as Eco (and saved) and starting power level at 1.4kW.