It’s been roughly 3 months of ownership of the recharge and I’m starting ti look into the most for my buck and kw efficiency.

A bit of background, car is located in New England, always kept in the garage, using the Grizzl-E level 2 charger. In addition our electric rates are the same all day and all year round. Car charge limit is set to 90%

So far every time the car comes home it is plugged into the wall. Also car is left plugged at all times while I’m home.
Because of the cold weather I precondition the car from the app before leaving every time.

What I have observed is that my monthly electric bill not only has increased but it has increased almost twice as much as it was last January at the same time.

Should I be doing something different? What are some of the best practices to follow to ensure the most efficient charging while saving on my electric bill?

Please be gentle, this is my first EV.

Thanks in advance.

The first thing you should do is change your electric service to a time-of-use plan.

 

Not sure if that is even offered in my area but it doesn’t hurt to check 👍

 

Ha! Same here brother 😂. Unfortunately it's all comes alright. If I put 40kwh charge that equals approximately 5 dollars at 0.11 dollars per kWh. That's one day. After these calculations everything comes alright. Yes I am paying 50 dollars more on top of my monthly usage.

 

One thing I was thinking and I’m planning on testing is not to plug the car every time it drives into the garage. Maybe just plug it in at night and let it charge overnight.
Im aware EVs charge faster from low SOC to 80% so if the car has to do that type of charge once then it might be more efficient. But I might be wrong. Is it more efficient to do multiple short charges at a high SOC or one longer one from low SOC to 90% 🤷‍♂️
Would love to hear from folks that have had EVs for a while.
I just wish I could live in place where the rates were lower overnight and I could then use the charge timer setting.

 

That lower soc charging rate is I believe only for level 3 charging. Level 2 is I think a flat charge rate and not dependent on soc.

 

Look at your car's trip meter to see how many Watt-hours per mile you are using per mile. This will probably be in the range of 350-400 watt-hours per mile. Then multiply that by how many miles you've driven to get how many watt-hours the car has consumed. Divide that by 1000 to get kilowatt-hours. Then look at your electric bill to see how much you pay per kilowatt-hour. Multiply the kilowatt-hours your car used by your cost per kilowatt-hour to get the total cost of your driving. Add about 10% to compensate for imperfect charging efficiency.

 

Pre-conditioning the cabin (or battery) is going to take up a bit more, too.

 

We typically charge to 80%. I used to charge my Tesla To 75%, but that’s not an option with the Volvo. We always have our vehicles plugged in when they’re in the garage.

 

This reply is for the OP, @B-mtrd … although it touches down on other comments above.

Here in Ohio my rate is similar to that of what @Rousie13 noted (my net in Cleveland is $0.12/kWH if you take the bill total, divide over the kwh used). Mine is prob no help being inside Cuyahoga county, the same as downtown Cleveland. But the point: many areas of the country do not have “time of day” or other plans that offer Benefit. So as noted by the OP — if you live somewhere that your rate is the same 24/7 then you should just keep doing what you are doing.

Also — don’t just look at your total bill— look at the kWh used. Many provides will see a jump/spike in rate, and in turn will actually bill you an “estimated” on a bill. If you look at your bills you should see “actual” and “estimated” — so you really want to go only off actual meter readings not estimated. It is possible the electric provider has given you a higher bill (or many) successively having only metered once. Just something to watch out for….

That said, our cars are rated at 43 kWh/100miles (EPA). You did not mention any hard numbers, so I’ll use my rate as an example. Assuming 100% of my charging was at home and we did 1,000 miles per month, that would be 430 kWh of energy (not accounting for loss between the wall and the car, which is minimal anyhow). At my $0.12/kWh that would be just shy of $52 per month that I’d expect my bill to go up. More miles, higher; less miles (or more charging away from home), lower. Obviously a lot of variables at play here. Since the average American drives almost 15k miles per year now, its more like 1250 miles per month, or at my $0.12/kWh Ohio rate that is around $65 per month that I’d expect on average (Again if 100% of my charging was done at home).

Another thing to keep in mind is that here in Ohio we’ve had a much colder January than we did a year ago. So our HVAC is running more than it did last year (I can pull reports from my Ecobee smart thermostat and compare). Those figures will impact your energy bills too (electric blower, natural gas heat, etc). So again lots of moving parts in here. IF you really wanted to get crazy you could isolate the power to the EVSE and record that, and record your miles each month, and see how it all compares, if you want to get that nitty gritty.

But the reality is that in a “fixed rate” (no time of day savings), you should just plug in whenever you‘re parked, set it to 80/90% approx SOC max — and not give it any more thought.

 

you should just plug in whenever you‘re parked, set it to 80/90% approx SOC max — and not give it any more thought.

Is there any real advantage to not plugging in every day? For example with my commute it would take 2 days to go from 90 to 25-ish SOC. From a long-term battery life perspective is it better to charge every other day and let the battery go from 90 to 20 SOC? Or is it better / no difference to just plug in every night and basically keep the battery between 90-50 SOC all the time?

Also would it be better to charge to only 80% SOC max and charge everyday? I notice that many on this forum say they charge only to 80% despite Volvo saying that 90 is ok.

 

If it is very cold the first 0 to 30 minutes may go towards heating the battery, even if the car is not going anywhere anytime soon. The battery may be cold again when it is time to leave. You may (not necessarily) use less power if the car is charged less often, but I have only seen 2 to 3 kWh delivered on the evse with zero miles added to the car before the car starts adding miles. There is always talk with EVs about how to maximize range, but charging efficiency is discussed far less often.

 

It might be worth setting the charge level to 80%. No reason to go to 90% if you don’t need the range every day. As a couple others have touched on, it’s possible the battery is heating at the beginning of the charge session (which as far as I can see in the documentation preheating battery will only occur if the charge level is set at 90% or 100%). I’m not clear on when the battery decides to pre-heat...it’s a bit of a mystery. However, if you’re charging to 90% every day, there’s a possibility that it could be heating the battery every day when U plug it in and start charging...which probably is wasteful if you’re charging slowly overnight.

 

We've been tracking our usage and the car's efficiency (kWh/distance) in a spreadsheet. Our charge efficiency is 86% (meaning what the car says we used divided by the amount of energy required to charge back up). We virtually NEVER use pre-condition of the cabin as we live in a temperate climate (rural Victoria, Australia). We also have the charge limit set to 80% except for a few times where we charged to 90%. This is all data gathered since we bought the car in late September 2021, and current km is 3770. Hope that's of use!

 

@JohnnyC — I am going to second what @Greg S wrote — and simplify it even further. If you said you are paying $0.11 per kWh and as Greg said we’re all seeing on average ~40 kWh/100mi —- that means $.044 per mile is what one might expect. If you take ANY of the data points on your chart, the are all $0.040xxx per mile -— so allowing for perhaps a small margin of error, I’d say SPOT ON! I’ve always told people here in Ohio (.12/kWh so almost same as yours) that it costs around four-cents-per-mile to drive na EV. So your numbers seem totally 100% good to me happy motoring!

 

11 or 12c per kW sounds lovely. Charging in the wild I got 32c per kW. Yet another reason to be excited about (one day) charging at home.
Thanks for the info.

 

11 or 12c per kW sounds lovely. Charging in the wild I got 32c per kW. Yet another reason to be excited about (one day) charging at home.
Thanks for the info.

$0.11 indeed sounds lovely...
Southern California has a few good sides $0.22/kW is not one of them($5+/Gallon isn't great either though)
...

 

This forum rocks, so many smart helpful people

I’ve been doing a bit more analysis and looked at a few more historic data.
I‘m currently averaging 40-45kwh of consumption on the car. It was lower I the warmer months.
My electric company’s rate is in average of $0.28 per kwh. In that rate I’m including fees and any other charges so I can calculate the final expense.

I got the Volvo back in October so I was able to look at the charged difference. Of course there are many more variables and I’m possibly over simplifying it.
November 2020 with November 2021 difference of $160
December 2020 with December 2021 difference of $200
January 2021 with January 2022 difference of $180

I am not sure how many miles I’m driving a month but starting February I’m going to start tracking that.

Anything i might be considering wrong or should be calculating differently?

 

Luckily my EVSE makes it really easy for me and is fairly accurate. I enter what we pay per kWh…..I include all fees,etc to get the actual amount I pay per kWh…..roughly $.095/kWh.

The EVSE then displays all kWh that have flowed through it and the approximate cost per month. The kWh display shows all kWh that have gone to the EVSE, not necessarily into the cars battery…..loss due to heat, heating the battery, cabin, etc.

My wife drives A LOT! Haha

 

@B-mtrd ... that looks good. Overall you may be able to track miles as a direct influence of the billing cycle. Although as I noted, do be careful of "actual" versus "estimated" meter readings. In my part of the world (Cleveland, Ohio USA) it seems like they have been doing more "actual" readings these days, since they have new RF transmitters and can just drive past the houses now to read them. So that seems to be the case.

FWIW-- as a worse case scenario, 45 kWh/100mi at $0.28 per kWh would result in a price of $0.126 per mile. For the average 15k/yr USA driver that would be $157.50 in increased rate. Again these are all just estimates, but it does jive with the pricing you've seen-- though if you deep dive there may be more interesting metrics there.

Your desire for data is why many people spring the extra $$ for the Wifi enabled EVSE at home. Those chargers give them data that allows them to see how much energy they use, on what days/months/etc. Good luck with your data collection

 

Grizzly-E smart chargers are supposed to be able to get usage data through ChargeLab soon so I can start getting more accurate data.
So far it seems I’m following best practices to achieve the most productive charging at home thus achieving good charging efficiency.

Keep the observations coming. Seems that we all might be benefiting from this 👍

 

We have two XC40s and so whichever one is at a lower SOC is the one that gets charged overnight. Haven't felt the need to pay for a second EVSE since we would need to pay the power company for that (can't use your own and be on their TOU program). So far it's working out well and every morning one of the cars is at 90% and can be used for a longer trip if needed.

I find threads like these fascinating if for no other reason than to see the widely variable pricing people are paying for power across the country. It's really surprising to me. In Minnesota the late-night TOU rate is 7.302¢ per kW all-in with fuel surcharges, program fees, sales tax, etc. But figuring in third-party charges and power company credits from a community solar garden we subscribe to, the net price for us ends up being 5.483¢ per kW.

 

We got a second evse because we got another EV. Our regular electricity all in costs 0.17xxx per kWh. Our time of use cost is 0.134xxxx from 9PM to 1PM. We have a two bay garage. My wife takes the left bay, I get the right. The xc40 goes in the left. Xc90 right. The bays are not even with each other, so the entire garage bay on the left is about a half car length closer to the curb. There is no convenient place for one evse that can also reach into the driveway. Maybe next to the 90 up front, but that would not work when the bolt was parked where the xc40 is now. We also want it to be convenient to plug/unplug. One more evse installation is not difficult...8g wire, 40 amp breaker and some tools and some time where the power can be shut off to the rest of the house.