Home Charging costs

Hello
Any view on extra cost per month for home charging plus any analogy on comparing it to other home appliance - eg charging for 4 hours overnight, 3 times a week is equiv to running dishwasher every day?

I know depends on energy provider/charge rates & time used + no.of times used, but interested to hear if people are seeing elec bills way above/below or more or less bang on what they estimated.

ta

Unless you have timed rate changes, it should be quite easy to tell what your costs will be...figure an average of 4 miles/Kw. Knowing your rate and how many miles you drive, use that figure with maybe a 20% additional buffer and you'd be close (the conversion process from ac to dcv isn't perfect, and there are some losses in the process, so 1Kw in won't add 1Kw to the car's batteries).

It will be very hard to compare charging EV to other appliances. As mentioned above - the easiest way is to calculate how much do you drive and divide it by about 3.5. That will tell you how much electricity you're going to use daily or monthly.

Typical dishwasher uses 1.8kW, so 1h of dishwasher use equals 1.8kWh. multiply that by 3.5 and you can say that 1h of dishwasher use is worth about 6.3 miles in your car. If you drive 63 miles a week it's equal to 10h of dishwasher working.

sithsmith23 said:

Hello
Any view on extra cost per month for home charging plus any analogy on comparing it to other home appliance - eg charging for 4 hours overnight, 3 times a week is equiv to running dishwasher every day?

I know depends on energy provider/charge rates & time used + no.of times used, but interested to hear if people are seeing elec bills way above/below or more or less bang on what they estimated.

ta

Click to expand...

There's no real useful comparison to domestic appliances, an EV consumes far more than anything else you would normally encounter in a domestic setting. If you look at a dishwasher or washing machine they draw electricity very unevenly for instance this trace of my dishwasher running, see the two spikes on the green channel between 08:00 and 12:00



Whereas the i3 charging looks like this on the far left in orange - note the vertical scale and the area under the line (which represents what you are charged for).



Bill

I've been trying to keep track pretty closely as to what the increase in my electricity bill is for the i3. Near as I can figure, I used an extra 220kWh in December, which translates to ~$25 ($0.105/kWh in the winter in CO). That was to travel ~900 miles in the car. I'm not sure what my total December bill was, but I think we typically consume ~400 kWh/month in the winter, so the car increased my home usage by over 50%. No kitchen appliance is going to do that.

The closest electrical appliance would be an electric shower, the UK basic showers are just over 7KW, like the I3. However, a shower is constant and the I3 drops power draw after the batteries reach around 80%

My electrical dryer takes about 3kW. That is the highest load in my house. And even that runs only few times a week, for few hours. Nothing comes even close to electric car. The question you should be asking yourself is not how much more you'll pay for electricity, but how much you'll save on gas. Than number will make you much happier.

Tomasz said:

My electrical dryer takes about 3kW. That is the highest load in my house. And even that runs only few times a week, for few hours. Nothing comes even close to electric car. The question you should be asking yourself is not how much more you'll pay for electricity, but how much you'll save on gas. Than number will make you much happier.

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I would not say nothing comes close. A few months back I was doing some Litecoin mining and I was running a "mining factory" that drew 5kW 24/7. Took my monthly usage from 500kWh to more than 4000kWh. Stopped that now since it is no longer economically viable.

i7fan said:

I would not say nothing comes close. A few months back I was doing some Litecoin mining and I was running a "mining factory" that drew 5kW 24/7. Took my monthly usage from 500kWh to more than 4000kWh. Stopped that now since it is no longer economically viable.

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Hehe not exactly your normal domestic appliance application though was it?

Bill

Its quite common in the UK to have 10kW electric showers. My latest house has one. 40A circuit breakers at 240V.

As peak rate elecricity is about 12-16p/kWh & natural gas is only 4p I've had a bath shower splitter installed so i can use hot water in the tank I've already paid to heat.

Before that a 6 minute shower (1/10 of an hour) was costing me the same amount as driving 3 to 4 miles. I.e. 1kWh.

I've never understood how those electric showers became available and so popular in the UK.

I would think that a decent HVAC system would come close to matching the power load of the EVSE, and possibly run for longer.

Really, why try to compare it to an appliance at all, so stupid in my book. It is a separate appliance like no other in your house, usage is based on miles driven and nothing else. I use $ 0.03 per mile as a very close approximation. That is real close and yes does vary by temperature and driving style too. The car is not an appliance in those terms. $ 0.03 per mile with electricity at 12.5 cents per KWH. It is all quite simple how far do you drive times $ 0.03/ mile for me.

I33t said:

I would think that a decent HVAC system would come close to matching the power load of the EVSE, and possibly run for longer.

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HVAC drawing that much power is nowhere near decent in my book. Decent HVAC uses geothermal heat pump and draws fraction of the cost of older units.

Tomasz said:

I33t said:

I would think that a decent HVAC system would come close to matching the power load of the EVSE, and possibly run for longer.

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HVAC drawing that much power is nowhere near decent in my book. Decent HVAC uses geothermal heat pump and draws fraction of the cost of older units.

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Well, yes and no. The efficiency of the HVAC is one thing, but the total heat load is the measure that decides on the HVAC output specification. A more efficient geothermal heatpump reduces the electrical load required for a given heat load, but it doesn't reduce the heatload - you have to alter the thermal envelope for that.

We have a waterfurnace geothermal heatpump HVAC, I think I know what I am talking about. It's a decent system Looking at the current waterfurnace range, its not hard to find 32A/240v or higher specs. Ours is 415v and pulls under 5Kw at peak output, so a bit less than a 32A L2 EVSE charging the i3. There are plenty of larger units than that in homes all across the US, but hardly any of these units here in Australia.

I33t said:

I've never understood how those electric showers became available and so popular in the UK.

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Nor me. It's not like sticking a shower in a bath means a long pipe run from the existing pipes. It's not cheaper to stick a 40Amp circuit, shower unit and separate cold feed than it is to stick in a splitter. The flow isn't increased - especially in winter when they almost trickle out as they work by slowing down the water flow to increase the temp. they aren't even a good backup if the gas boiler goes - as most hot water tanks have an electric immersion heater - which heats the water for all taps not just the shower. Plus you don't need to retile changing the bath taps, sticking in an electric means chiselling out pipe runs and retiling.

Bizarre.

It's more expensive and more difficult to install and run and is inferior in every way. And as they don't use the tank you can't even use solar heated water.

Never understood why people fit them. I think they assume they are saving money somehow. I've rented a few places and they seem common in landlord rental properties. Even my current house which I purchased was previously owned by a landlord who rented out - I think he stuck in the electric shower as the pipes in the attic are newer. I can only think maybe the perceived total install cost is actually lower - though I doubt it. I spent £60 on the tap and paid £35 for a plumber to install them.

Arriving in Blighty from Germany in the late 90ies, I rubbed my eyes when I saw my first "Power Shower". Actually scratch that, it's seperate hot and cold water taps that surprised me the most.

With regards to the shower, I was told once that the lack of water pressure in Britain made these showers so popular. But anyway...