Home charger woes
Discussion
Sambucket said:
Does it cost significantly more to charge per kwh using a granny?
It would depend on the car but have seen it mentioned that charging is less efficient at low voltages, I guess they’re also optimised for 3.6kW/7kW as opposed to the 2.3kW or so on a granny. NB The US EPA tests take charging losses into account.Ref figures, from a quick google 17.22% losses at 10 amps and 12.38% at 40 amps, YMMV ;-)
https://www.sciencedirect.com/science/article/pii/...
If you’re buying/leasing an EV I’d have thought that £300 on a dedicated 7kW charger was worthwhile, especially while you’re still getting £500 towards it. And then charge overnight on E7 or one of the new EV tariffs.
Failing that I’d want to be sure that my house wiring was up to scratch, as has been mentioned a 90kWH iPace is likely to be spending a lot of time on the granny.
Edited by danp on Tuesday 25th February 11:52
In typical UK Power Networks style, we received an email today (from someone different at UKPN) saying "Thank you for your application, to install your electric vehicle charge point at xxxxxxx , it has been approved." Thank goodness, as the only upgrade from a 100A fuse looks like 3 phase. https://www.ukpowernetworks.co.uk/electricity/fuse...
So Chargemaster is all paid up and they are coming to fit it on Monday, car arrives on Thursday. Hopefully I can make use of the solar panels and Eco7 electricity to charge up reasonably cost-effectively.
So Chargemaster is all paid up and they are coming to fit it on Monday, car arrives on Thursday. Hopefully I can make use of the solar panels and Eco7 electricity to charge up reasonably cost-effectively.
REALIST123 said:
Not true about ‘old electrics’. Modern houses are being fitted with 80A, often 60A fuses, because modern insulation standards should limit the amount of power needed. Little allowance for the use of EVs is being considered yet.
‘Older’ properties often have up to 100A fuses which would almost always allow an EV charger to be fitted.
We have a 100A fuse but also an 8kw heat pump and the other stuff.
We have an e-Niro on order but if I can’t get a 7kw charger we’ll be reconsidering. (Likewise if the EV grant is stopped, that’ll end the idea).
'Older' properties do not often have 100A main fuse, depending on property age, more likely 60A.‘Older’ properties often have up to 100A fuses which would almost always allow an EV charger to be fitted.
We have a 100A fuse but also an 8kw heat pump and the other stuff.
We have an e-Niro on order but if I can’t get a 7kw charger we’ll be reconsidering. (Likewise if the EV grant is stopped, that’ll end the idea).
Also, just because the label says 100A, doesn't mean it is fitted with 100A. It is the rating of the carrier.
kambites said:
I think the issue is more whether it's sensible to be constantly drawing 13amps from one domestic socket on the house's ring main than any risk of damaging the car. Obviously it depends how your house is set up, but if it has one ring servicing both garage and house, you can only draw 26amps total from that ring; if your car is constantly drawing half of that there's a far higher chance of exceeding the total current draw limit if you, for example, try to boil the kettle while the oven is running. Also some older sockets can get rather hot at a constant 13amp draw.
If your garage has its own ring off the consumer unit and your wiring is reasonably modern, I think long-term use of the granny cable is unlikely to be a problem.
Very true, we have been using the granny charger on our i3 for over three years without an issue or the plug getting even warm, it is constantly plugged into a good quality (MK) socket in our annexe which is only 7 years old and has its own supply board, the original granny charger supplied with the i3 was called an OUC (occasional use charger) but our granny charger is a KOPP built granny charger that BMW supplied for a few years around 2016> and was never called an OUC as it has a thermocouples plug which senses temperature to prevent over heating it also has a three step adjustable charge rate to enable lower rates/amps drawn on poorer supply systems.If your garage has its own ring off the consumer unit and your wiring is reasonably modern, I think long-term use of the granny cable is unlikely to be a problem.
The maximum amps the granny charger draws is only 10 amps rather than a full 13 amps so well within the rating of a well fitted domestic socket, and if even that worries you there is a domestic socket in the market now which is marked (on the rear) EV which has slightly better components and friction contacts for the pins which is tested for constant EV use, I have yet to find the manufacturer though, just read about the socket in a IET regulations leaflet.
Rate of chargers. # Granny Slow = 10 Amps (10 MPH). # Slow 3.3KW 16 Amps = (15 MPH) # Fast 6.6 KW 32 Amps = (30 MPH) # Rapid 50KW 110 Amps = (150 MPH) # Autobahn Rapid 100KW 212 Amps = (300 MPH) # Tesla Superchargers 150KW 300 Amps = ( 400 MPH ) # Note - all figures approximate. # NB. Porsche etc. may go faster with an 800 volt Super Rapid but not finalised yet with liquid cooled cables.
Supercharge V3 charges at 250kW and I think Taycan will charge at 260kW presently, the 800V chargers are 350kW capble when/if Porsche allow the battery to consume at that rate.
I need to work out of the wiring to my garage will support 32A as that’s ideal location for a charger. However more than likely I’ll need to come from the main meter box and have the unit on the front of the house woth the cable running along the lawn
I need to work out of the wiring to my garage will support 32A as that’s ideal location for a charger. However more than likely I’ll need to come from the main meter box and have the unit on the front of the house woth the cable running along the lawn
Edited by JonnyVTEC on Tuesday 25th February 23:36
JonnyVTEC said:
I need to work out of the wiring to my garage will support 32A as that’s ideal location for a charger. However more than likely I’ll need to come from the main meter box and have the unit on the front of the house woth the cable running along the lawn
Its highly likely. Most garages were only wired for a few lights and sockets, not something that can use around a third of your total supply to your home. Edited by JonnyVTEC on Tuesday 25th February 23:36
Amateurish said:
Sambucket said:
Does it cost significantly more to charge per kwh using a granny?
No, same cost. But, with a 7kw charger you can do all your charging overnight on cheaper E7 rates.
SWoll said:
I already do exactly that using a granny charger with 2 EV's. Adds between 50 and 60 miles dependent on which car I'm charging and that's winter range, should be quite a bit better once the warm weather arrives.
With the ipace you would only get max 35 miles of range if you charged during E7 hours with a granny charger. JonnyVTEC said:
I need to work out of the wiring to my garage will support 32A as that’s ideal location for a charger. However more than likely I’ll need to come from the main meter box and have the unit on the front of the house woth the cable running along the lawn
That's what I did with my house - buried the cable in the lawn. Edited by JonnyVTEC on Tuesday 25th February 23:36
Did you bury the cable yourself? My issue is similar to others, in that the garage is on a separate circuit but not 32amp. Apparently I need a new fuse box to accommodate this and coupled with the additional cabling to the garage the cost is coming in around £1,200 - that would buy a lot of Tesla Supercharger charges!
RTWalters said:
Did you bury the cable yourself? My issue is similar to others, in that the garage is on a separate circuit but not 32amp. Apparently I need a new fuse box to accommodate this and coupled with the additional cabling to the garage the cost is coming in around £1,200 - that would buy a lot of Tesla Supercharger charges!
No, bloke with a digger. I think it was about 100m in length. The cable was massive. The cost was more than your quote. Olas said:
The solution here is to buy a car that can be charged from empty to fill in under 5 minutes at a petrol station.
Rewiring a house for the purpose of
Increasing electricity bills is a very expensive undertaking
It's not though is it when you consider how cheap EVs are to run. Most of the time the charger install is free or very low cost. Once it's done it's done.Rewiring a house for the purpose of
Increasing electricity bills is a very expensive undertaking
Also your '5 mins at the petrol station' includes having to drive there each time and pay crazy prices. EVs are just full every morning costing a few pounds for a full charge.
jjwilde said:
Olas said:
The solution here is to buy a car that can be charged from empty to fill in under 5 minutes at a petrol station.
Rewiring a house for the purpose of
Increasing electricity bills is a very expensive undertaking
It's not though is it when you consider how cheap EVs are to run. Most of the time the charger install is free or very low cost. Once it's done it's done.Rewiring a house for the purpose of
Increasing electricity bills is a very expensive undertaking
.
The best I’ve seen is about £300 after the government grant and that’s assuming no special needs and a short cable run.
Many are a lot more expensive.
REALIST123 said:
Where do you get a free or very low cost charger install?
The best I’ve seen is about £300 after the government grant and that’s assuming no special needs and a short cable run.
Many are a lot more expensive.
£300 that's like 4 fill ups or say 1600 miles...….The best I’ve seen is about £300 after the government grant and that’s assuming no special needs and a short cable run.
Many are a lot more expensive.
the future is electric, people harp on, but the reality is that we will be getting chargers installed. were still at the VHS Betamax stage, they need to decide on an industry standard and uniformity with chargers so that they will charge a range of models and manufacturers.
They are looking at going forward having three phase supplies to houses, that helps reduce the overall current requirements.
Good times ahead, looking forwatd to seeing our cities and towns air quality improve..
ruggedscotty said:
REALIST123 said:
Where do you get a free or very low cost charger install?
The best I’ve seen is about £300 after the government grant and that’s assuming no special needs and a short cable run.
Many are a lot more expensive.
£300 that's like 4 fill ups or say 1600 miles...….The best I’ve seen is about £300 after the government grant and that’s assuming no special needs and a short cable run.
Many are a lot more expensive.
the future is electric, people harp on, but the reality is that we will be getting chargers installed. were still at the VHS Betamax stage, they need to decide on an industry standard and uniformity with chargers so that they will charge a range of models and manufacturers.
They are looking at going forward having three phase supplies to houses, that helps reduce the overall current requirements.
Good times ahead, looking forwatd to seeing our cities and towns air quality improve..
Where do you get a free or very low cost charger install?
sjg said:
Some manufacturers build it in to the cost of a new car. But they’re just covering the non-grant bit.
A few years ago you could just get one entirely covered by the grant. Prices are only going one way.
Thanks. A few years ago you could just get one entirely covered by the grant. Prices are only going one way.
The ones I’ve looked at seem quite overpriced for what you get, once you consider the grant they’re getting on top of what the customer has to pay.
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