Will my car be damaged if I do this?

amackayj said:
That's a very clever system. We didn't go for battery storage because we dump excess energy in hot water and after charging two cars (the MG and a Mitsubishi Outlander PHEV) there wasn't going to be enough going into battery storage to justify the cost... We exported about 100kwh per month before we got the MG, I suspect that is going to decrease dramatically!

Would you mind sharing a link to or details of your pi system? If it provides a way to stop the car charging when the draw from the grid exceeds a threshold and if there's a way to set a limit between switches (to give the car time to settle down), then I'd be interested in giving it a go!
Click to expand...
We had battery storage so we could charge from the grid on off peak rates during the winter and use the cheap electricity during the day. Our water is heated by a separate solar thermal system so it makes no sense for us to dump excess electricity into the water heating.

The raspberry pi system I built myself. I'm a bit of a raspberry pi addict and have them controlling lots of things around the house (heating, rainwater flushing toilets and car charging). They are a great way of adding smart tech to your home without paying a fortune for smart devices or giving the big tech companies your data.

For charging the car my system uses the following:

Other than that, battery voltage gets read from a sensor on the battery management system via an API and sunrise/sunset data comes from 'the Weather channel' API. The code to make it all work is written in python.

I'm not an expert programmer but this stuff is really easy to get working and the total cost of all the components is less than £50.

Chip shortages have made Raspberry pi's a little hard to get hold of but the wait isn't usually too long if you add your name to the waiting lists at the various retailers.
 
I have an EO Mini Pro 2 home charger and for solar charging the manual says:
If the solar output drops below the specified minimum rate (e.g. sun goes behind a cloud)
then the vehicle will charge at the minimum rate. It is not advisable for a vehicle to repeatedly stop and start charging and so the minimum rate will always guarantee the charging rate. The extra power shall be taken from the power grid. The Recommended minimum rate is 6A.
Hope this helps.
 
The advantage of having 4.8kw batteries is if have more than 50% battery that's is 1hour on a granny charger so you should not need to be switching on and off. In the UK just relying on the sun is going to be a problem as we have often get clouds even on the warmest of days.
 
How many miles would that add to the car?
Surely you won't completely draining your battery.
How low would you let the battery discharge every night?

I can't make my mind up if it's cost effective to have a battery, and of that size.
 
1MGEVUSER said:
How many miles would that add to the car?
Click to expand...

6A ~ 1.4kW ~ 5-6 miles range every hour
10A ~ 2.3kW ~ 9-10 miles range every hour

It all depends on how much solar generation you have above those figures and how often it dips below them. My 4.5kWp even in the summer often dips below 2.3kW net of my summer background of 0.6kW, and even below 1.4kW net. But the details depend on how long you intend to charge each day and for how many days each year. This year has been very good so far with few dips in output for my nominal 6 hour charging day apart from the relatively few days of bad weather, but this will normally drop off in September to give either shorter charging days and/or many more dropouts.
But it depends on your setup and charging requirements. I'm in the Midlands and my roof is close to optimum for solar with no shading and low light capable panels oversized for my G98 allowance. What is your plan?
 
Last edited:
1MGEVUSER said:
How many miles would that add to the car?
Surely you won't completely draining your battery.
How low would you let the battery discharge every night?

I can't make my mind up if it's cost effective to have a battery, and of that size.
Click to expand...
As above for milage. I don't drain my battery with the car as I don't need to charge every day. I can charge at work on the granny charger most days so charge at home only when needed. Solar with battery reduces my bills including gas for heating as we also have electric heaters the best I can do to explain the use of this is my household fuel bill is currently running at £10-£15 per month.
 
Last edited:
One of the problems with depending on the cheap overnight rate is that it might not last forever, or it may only be available for EV usage. That seems to me to be the thinking behind the Octopus Intelligent tariff.
 
MarkLynn said:
As above for milage. I don't drain my battery with the car as I don't need to charge every day. I can charge at work on the granny charger most days so charge at home only when needed. Solar with battery reduces my bills including gas for heating as we also have electric heaters the best I can do to explain the use of this is my household fuel bill is currently running at £10-£15 per month.
Click to expand...
THAT'S CHEEAP!
What is the size of your solar PV in kWh?
 
smokie said:
One of the problems with depending on the cheap overnight rate is that it might not last forever, or it may only be available for EV usage. That seems to me to be the thinking behind the Octopus Intelligent tariff.
Click to expand...
That's a very real issue. Intelligent currently gives some cheap hours apart from EV charging, so who knows whether it's with nefarious intent or to demonstrate their ability to the grid to timeswitch EV charging centrally.
 
Zappi.
I have 5kw Solar panel installation and have installed a Zappi charger. When charging I leave the Zappi set on eco mode with a maximum of 50% grid electric. As the minimum rate of charging is 1.4kw, the maximum it will consume from the grid will then be 700w (when clouds go over). Generally my house runs on just under 1kw, so on average the Zappi is sending between 1.5kw and 4kw to the car. Rarely does it shut down due to cloud cover (as it only requires 700w solar + 700w grid to keep charging) and at the end of a full charge it will equalise the batteries. This method of charging suites us as A) its free and B)we generally do not use the car before 5pm weekdays. The Zappi allows you to configure exactly how you want to charge, ie on completely free solar, a mix or entirely from the grid. Being an electrician I could quite easily rig up a system to charge from a socket only when solar is available but it would never be as reliable, configurable or as simple as the Zappi and all generating and consumed data can be looked at in realtime on the app. Also as far as I could find, the Zappi is the only charger with solar capability that didn't require a lap top to set up. Not sure if this method of charging has anything to do with it but so far it seems I am getting great mileage from the battery, WLTP 167miles, I covered 102 miles at the weekend and still have 59 miles on the gauge. Just looking forward to when all ev cars will be capable of reversing the flow and powering the house, save buying solar battery storage.
Also some good advice given to me by a nissan technician when I looked at the Ariya, when asked best way to charge , his reply was "whichever is best for you, the battery has 8 year warranty, so it doesn't matter"
 
My son has a three phase set up with batteries, PV and a Zappi. Yesterday I got 31KWhr from him over about 6 hours. The Zappi manages the whole thing by varying the charging rate so there is no import from the grid and the battery isn't drained but my understanding is that this can be tweaked fairly easily. He usually manages to use everything the panels generate and has hardly any need to import. Based on experience over 7 months he is going to double his battery capacity to 16KWhr as 8 is a bit too small and inflexible for the 8 KW of PV.
 
Support us by becoming a Premium Member

Latest MG EVs video

New EVs from MG: MG S9 & MG9 plus hot topics from the forums
Published
Subscribe to our YouTube channel
Back
Top Bottom