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by IndrekR 1347 days ago
If you buy electricity at the (hourly) market rate, you want to charge when it is cheapest and charge reasonably fast. On a typical 11kW home charger here in EU, that means about 6 hours for full charge or 1..2 hours for daily top-up. All the benefits for buying the electricity at hourly demand based rate disappear when full charging times approach 24h.

This has two benefits: it is cheaper to charge and the grid works more efficiently — price is lower when the demand is low and/or production is high.
4 comments
smileysteve 1346 days ago
> when full charging times approach 24h.

200 miles a day is not the median driving pattern. It's closer to 30 miles

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natch 1347 days ago
In our area the higher price (peak demand time) was during a window about 6 hours long. So we were able to charge a maximum of 18 hours a day while avoiding that window. Now we have 220 which makes things easier, but still no need for a charger installation.
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natch 1346 days ago
An installed charger is not needed for scheduled charging if the car already does it. Buy an EV with good modern features and you’ll be fine with just an outlet.
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IndrekR 1343 days ago
To be cost efficient with day-ahead hourly pricing, you need a faster (level 2) charger as there are only few extra-cheap hours in a day.
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maximus-decimus 1347 days ago
How long before you recoup the cost of the charger though?
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natch 1346 days ago
There is absolutely no financial advantage to having an installed charger versus an outlet. There are other advantages. It might fit your hand better during the 2 seconds it takes to plug in. It might be better in the rain if your outlet is exposed to driving rain in wind. It might look more impressive to the neighbors. It looks more impressive to the landlord or wife or anyone who might be approving a budget for upgrading wires inside a wall or upgrading a panel. It does not save any money.

If you are thinking of charge scheduling, the car does that. Or should… if you buy an EV from a good EV company, not an old crusty legacy automaker.

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maximus-decimus 1346 days ago
The point with scheduling is that on a normal plug, it make take long enough to charge your car that you can't charge it completely during the time window where electricity is the cheapest. So the parent comment was arguing you need faster charging to save money by doing all your charging in that time window.

But yeah I have a hard time believing it's gonna be a big enough saving to offset the cost of the charger.

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natch 1343 days ago
Cars have the scheduling built in.

Unless you buy an electric car from one of the companies that is actively promoting gas cars and trying to make their own electric cars super crappy in hopes the entire concept will fail. Meaning, any gas car maker.

Yes, scheduling saves money. But even paying high electric rates during peak hours can still be way cheaper than gas, depending on what exact rates we're talking about, which varies by location.

But the plug has nothing to do with scheduling if you just use the car's own scheduling or plug/unplug yourself.

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IndrekR 1343 days ago
Being able to charge with 11kW (level 2 charger) instead of 3.5kW (level 1 charger) allows to charge daily 20kW within 2 hours instead of 6.

Two days ago kWh was at 0.03€ For two hours only, after 0.41€ peaks during the day. Of course this scheduling is automatic. Using Gridio (https://www.gridio.io/) for that.

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IndrekR 1343 days ago
Payback time here is about 100 full charges (IONIQ5, Nordpool day-ahead pricing).
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