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I'm driving on sunshine (whooah)!

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  • Registered Users Posts: 581 ✭✭✭axe2grind


    Good thread. First time I have looked at solar contribution to car. Unfortunately with the DC battery, I don't think I can figure out exact figures, as the Zappi thinks that the battery contribution is from the grid.

    April Zappi figures

    293kWh from solar,

    131 from grid (59 in one day)

    I suspect that nearly half the grid figure is originally solar but via the system battery.



  • Moderators, Sports Moderators Posts: 18,873 Mod ✭✭✭✭slave1


    Two EVs but I’ve hybrid working so WFH two days, I only put 67kWh from the grid into my car last month. Been lucky with the days that I’ve been home have been the better ones. I’ve Zappi which makes it easier and large arrays to feed the house/water/battery/cars

    My stuff for sale on Adverts inc. outdoor furniture, roof box and EDDI

    Public Profile active ads for slave1 (adverts.ie)



  • Registered Users Posts: 11,112 ✭✭✭✭the_amazing_raisin


    We've got 10kWh, it does seem to do a good job of lasting through a cloudy day but it's down to 30% this morning

    I expect when the heat pump is being used in winter it'll barely last the day

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



  • Registered Users Posts: 11,112 ✭✭✭✭the_amazing_raisin


    Sounds like there might be an issue with the CT config on your Zappi. Have you got a CT clamp on the output of your inverter?

    I had mine set to Gen+Battery but that had some weird effects, it flipped the current reading and I started seeing grid import as export

    Apparently Gen+Battery doesn't work properly 😕

    I've got it set to generation only now and it works fine. I also set an export margin of 150W to stop the Zappi draining the house battery

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



  • Registered Users Posts: 6,187 ✭✭✭crisco10


    Just had a look at the stats on my HA for last 30 days:

    89kWh of Solar

    115kWh of Night Rate (€0.095) into the car

    Less than 50%, but my wife's wfh days and sunshine did not coincide well. Also, reckon I'll significantly up that number with the tip garnered on this thread about changing to Grid Feed in mode in the middle part of the day.

    So overall consumption of 204kWh, for about 1200km distance covered. Total marginal cost 115kWh x €0.095 = €11. That's just about 1c a km. Hope to bring that down further though.



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  • Registered Users Posts: 581 ✭✭✭axe2grind


    I didn't think this through enough. I have a Harvi which monitors import/export so the Zappi will know what comes in from grid. Everything else has to be from solar, whether via house battery or not.



  • Registered Users Posts: 4,477 ✭✭✭eagerv


    Am at home alone today, off to work shortly. Stupidly charged my car to 100% last night and the sun is continuous here this afternoon. Have dishwasher and washing machine on, had a very long shower to empty tank an hour ago and looks like will be exporting soon again.

    Any other suggestions? I think turning on a 3kW heater would not be appropriate..😁



  • Registered Users Posts: 11,112 ✭✭✭✭the_amazing_raisin


    Roast dinner should eat up a few kilowatts 😋

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



  • Registered Users Posts: 4,477 ✭✭✭eagerv


    Unfortunately not, on gas.

    It's nice to give a bit back occasionally, doing my bit of green washing...☺️



  • Moderators Posts: 12,371 ✭✭✭✭Black_Knight


    Heater no, air conditioner yes. Just bought one for the inevitable heatwaves we get. A luxury, but it'll run for free basically



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  • Registered Users Posts: 1,081 ✭✭✭silver_sky


    Had a quick look to figure out what my sunshine driving is in terms of driving kilometers. Based on a rough guess of 15% losses and overall consumption since new, roughly 650km of my driving since I got my Model 3 in mid-March has been from solar PV.



  • Registered Users Posts: 1,987 ✭✭✭allinthehead


    Snap. I just calculated mine and came to 625 km since the 17th March. I have 3.2kwp SE .8 NW and .8 W. It works out as about 25% of my home charging is from PV and that has risen to 30% in the last 3 weeks or so. Probably makes more sense to charge at the cheap night rate and let the excess go to the grid but I like driving on sunshine.

    ☀️



  • Registered Users Posts: 11,112 ✭✭✭✭the_amazing_raisin


    If you're on an smart meter and the export rate is higher than night rate then maybe it makes sense to send it to the grid.

    Otherwise if you're on deemed export then it absolutely makes sense to divert to the car

    I think I'd also prefer to divert to the car even if on a smart meter, as you say there's something cool about making free fuel from sunlight 😁

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



  • Registered Users Posts: 1,987 ✭✭✭allinthehead


    Agreed, we do have a smart meter but I'd still rather use what we produce. We're going for a spin now from East Cork to Ring in Waterford and some of the journey will be powered from yesterdays sunlight, so cool.

    ☀️



  • Registered Users Posts: 1,081 ✭✭✭silver_sky


    Same, financially speaking probably better to export; however, I'd prefer to use here as much as possible. My goal is limit grid use and keep costs down but it's a balancing act.



  • Registered Users Posts: 1,786 ✭✭✭DownByTheGarden


    I was using the granny charger last year. Put about 3kwh from the battery into it in the morning. Car is gone for the day. Solar bttery charges back up during the day. In summer its back in time to get another 3kwh or so in the evening. So nearly all driving in summer was already solar by utilizing the battery and the granny charger.

    Now we have a zappi. Can use the battery in the mornings for that too and then in the evenings even more juice goes through the zappy from the sun.

    The biggest problem is that the car is away in the daytime. The battery partially solves that problem for about 6 to 8 months of the year. In winter car charges on EV rate only as not enough sun.



  • Registered Users Posts: 11,112 ✭✭✭✭the_amazing_raisin


    My streak for the month has already been broken 😫

    I've had to head into Dublin every day this week so nothing to divert solar. I finally gave in and set the car to charge overnight

    I've managed to lose 26kWh to the grid already 😬

    Just goes to show what a difference not being at home in the middle of the days makes, I'm generally home before 5pm but there's not nearly enough sun to make up for my usage

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



  • Moderators Posts: 12,371 ✭✭✭✭Black_Knight


    Revisiting this (Still can't get my hands on the right wireless module for the inverter though). In "feed-in priority" mode, doesn't that stop the battery from being used at all? So if you're plugged in and charging, and a big cloud comes by and you drop below 1.4kW generation, you'll either pull from the grid to make up the surplus, or stop charging. Or is your home assistant constantly juggling between Self use, and feed-in priority. ie. If surplus gen<1.5kW - switch to self use, else if surplus gen >1.5kW && battery 80% - switch to feed-in-priority, else switch to self-use



  • Registered Users Posts: 1,081 ✭✭✭silver_sky



    The order in feed-in priority is load, grid, battery vs. self-use mode which is load, battery, grid.

    The battery will still discharge if there's a load and low generation e.g. turn on the kettle and only have 1000W generation.

    If you've the car plugged in and running on ECO+ mode, it would stop if the export wasn't sufficient and yes the inverter would still dump that <1400W out the door. I've not setup the automation part of this yet so just "manually" changing it with a switch in HA that sends the request to the inverter to change the mode, and then back again when I switch it off.

    I've an eddi and zappi so have a bit of logic to figure out for an automation on this.



  • Registered Users Posts: 17,849 ✭✭✭✭Mantis Toboggan


    Lads how many panels required to see a decent return?

    Free Palestine 🇵🇸



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  • Moderators Posts: 12,371 ✭✭✭✭Black_Knight


    What would you call decent?

    I've 10 panels (and a battery), and so far in May I've not had to pay for charging the car (I've not driven very far though, and put 55kWh of solar into the car). I've had 2 days where I imported 5/6kWh because they were cloudy days. Plenty of clothes washes and tumble drying too.



  • Registered Users Posts: 17,849 ✭✭✭✭Mantis Toboggan


    Sounds good, the most I can get would be 10 panels so trying to figure out if it's worth it.

    Free Palestine 🇵🇸



  • Registered Users Posts: 11,112 ✭✭✭✭the_amazing_raisin


    Here's my stats for May with 15 panels (total 6kWp) facing south, plus a 10kWh battery

    Worth noting the Zappi can't distinguish the energy coming from the panels and battery

    Almost all the import was during night rate and around 60% was into the car across two night boosts

    I'm expecting the system to pay for itself in 6-7 years at current prices. That includes charging cars and using the heat pump for heating and hot water

    If 10 panels is what you can fit then that's around 4kWp. I expect you'll see a good return on that with similar payback

    I would recommend considering a battery. They're expensive but something relatively small like 5kWh would suit most people and really helps the system efficiency

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



  • Moderators Posts: 12,371 ✭✭✭✭Black_Knight


    10 is all I've got. Another 2 would have been nice, but no more room to fit them.

    If the sunlight continues like this, I'll have no grid power for the summer, barring a few charges for long drives.



  • Registered Users Posts: 1,081 ✭✭✭silver_sky


    It depends entirely on your roof orientation, usage, and shading but 10 panels is better than no panels. I've 12 but they're slightly lower power than most new installs these days so may be roughly equivalent to a good 10 or 11 panel setup.

    This page will give you a rough idea on generation for your location

    If you get some quotes plug them in to the page below to see how they stack up


    There's also the Renewable Energies forum here on boards with a load of info and a quotes thread for advice/feedback on quotes.



  • Moderators Posts: 12,371 ✭✭✭✭Black_Knight


    Today I ran out of places to put my generated solar. Car is full, battery full, washes all done, and even had our newly purchased air conditioner on the go.



  • Registered Users Posts: 4,477 ✭✭✭eagerv


    We were the same today, I was away making the most of the great weather, missus did plug in her car when back from her work at 4pm for 2 hours, but we were exporting strong from about 2 till 4. (Washing etc on earlier).



  • Registered Users Posts: 11,112 ✭✭✭✭the_amazing_raisin


    Same here again, exported as much as we consumed even after charging one of the cars. Even tried some baking to use up the electricity

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



  • Registered Users Posts: 1,081 ✭✭✭silver_sky




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  • Registered Users Posts: 11,112 ✭✭✭✭the_amazing_raisin


    Wholemeal banana muffins

    I guess I'll need to change my username again to the outstanding banana or something 😂

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



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