New lessee with ? about trickle charging costs

Hi all,

Apologies if this is the wrong subforum or has been answered before but I didn't find anything on search. Please send me to any previous threads if this is old discussion.
New lessee of 2014 S w/ QC (Atlanta area) who rents a home with several friends, delivery date 6/14/14

I charge occasionally at home via 120V from 7 pm to 7 am or so and have been asked to pay for any differences in our monthly electric bill. I regularly charge at DCQC at local dealerships or at the Blink locations near my office but of course need to charge at home on occasion. I would estimate I charge at my home 8 times per month, maybe 12 hours per. These are all estimates. I couldn't find how much consumption the battery draws on the 2014 S so calculating my share has proven difficult. Plus I'm just really bad at math.

Below are the rates my local utility charges:
KwH 1-650: 5.3312 cents per
KwH 651-1000: 8.862 cents per
KwH 1001+: 9.1582 cents per

I'm fine with paying a flat fee even if it's more than I use some months, I just need help calculating said fee...can anyone assist?

If your friends are being sticklers about it I would just buy a ~$20 kill-a-watt that will tell you exactly how much you used and then you can just pay the exact amount. Will remove any possible doubts when they see just how little that amount is actually going to be.

The cord does not supply more than that and it will

Are you referring to this device? http://www.amazon.com/P3-P4400-Electricity-Usage-Monitor/dp/B00009MDBU" onclick="window.open(this.href);return false;

Can that be left outside? I charge in the rain sometimes, the outlet has a cover and is under an overhang but I don't doubt it gets wet sometimes... Looks like from the reviews that that one doesn't do calculations of cost. So I would just calculate kwh/hour with the pink button then multiply by my rate each time?

Thanks for the idea

What kind of driving do you plan to do?

After week or two of "normal" driving check to see how many miles per KwH you get. (Will probably be around 4 miles per Kwh)

Before you plug in, note the Estimated miles left on your GOM Say it 30 miles, Charge it to 100% = 90 miles

90 - 30 = 60 miles of "Power loaded" 60 miles / 4 miles per KwH = 15 Kwh * .10 (9,1582) cost of power = $1.50 To toss into the PowerBill Fund

At $0.10/kWh, it's <$2.50 to recharge from 0-100%
Keep in mind, 21kW delivered does not equate to 21kW stored. There is some lost in the charging process.

smr said:

Yeah seems kind of ridiculous considering one resident works at home all day, but like you said, they'll see how little soon enough.

Are you referring to this device? http://www.amazon.com/P3-P4400-Electricity-Usage-Monitor/dp/B00009MDBU" onclick="window.open(this.href);return false;

Can that be left outside? I charge in the rain sometimes, the outlet has a cover and is under an overhang but I don't doubt it gets wet sometimes... Looks like from the reviews that that one doesn't do calculations of cost. So I would just calculate kwh/hour with the pink button then multiply by my rate each time?

Thanks for the idea

Click to expand...

That is what I was referring to. I would not leave that one outside in the raid unprotected. You could probably just cover it with part of a plastic bag over the top part so it doesn't drip onto the screen area or the plug of the EVSE and be ok. One caveat with that model is it appears to lose the data when you unplug it so you could have to track your usage if you were moving it around. It would be easy enough to create an excel workbook with the cost per kWh and have it generate the total for the month. You would just have to put in the kWh amounts and it could add them together and spit out the number.

The other option is to estimate it based on battery percentage. The problem with this is it will not be exact and your roommates may be skeptical.

You need to check the usage of your household. Most don't reach 650 KWH a month, but some do. There are also "delivery" charges: you shouldn't have to pay more of those if you already have electric included in your rent. You want to pay a flat rate of KWH X lowest rate above. IF they are near 650 in usage, make sure you won't put them over the top into the next fee schedule, which would cost you more.

Trickle charge is about 1 kw. Make it 1.2 to make everyone feel better. 12 hours is 14.4. 8 times a month - 115 kwh. $10 covers it.

As a general rule, 10 cents a kwh = $20 a month for 10,000 miles. Sure trickle charging is less efficient so call it $25.

Atlanta should be well over 4 miles/kwh unless you are spending a lot of time at 65+mph. In NC, 5 miles/kwh is the norm for city driving and 4 miles/kwh for highway (unless going over 65).

davidcary said:

Trickle charge is about 1 kw. Make it 1.2 to make everyone feel better. 12 hours is 14.4. 8 times a month - 115 kwh. $10 covers it.

As a general rule, 10 cents a kwh = $20 a month for 10,000 miles. Sure trickle charging is less efficient so call it $25.

Atlanta should be well over 4 miles/kwh unless you are spending a lot of time at 65+mph. In NC, 5 miles/kwh is the norm for city driving and 4 miles/kwh for highway (unless going over 65).

Click to expand...

I've actually clocked mine at an average 1370W. Seems to bounce between 1368 and 1375.
Remember, it's rated for 12A draw. This means 1440W at 120V. 1500W would be a better guideline/estimate.

mctom987 said:

Remember, it's rated for 12A draw. This means 1440W at 120V. 1500W would be a better guideline/estimate.

Click to expand...

The factory 120 volt "trickle charger" can only charge at 12 amps, as mctom987 said above. So, at .09 per kWh, including a little extra for efficiency losses in the charger, that's 13.5 cents/hour, or $1.62 for 12 hours. I really doubt you are going to see >$20 a month that can be attributed to your charging.

keydiver said:

mctom987 said:

Remember, it's rated for 12A draw. This means 1440W at 120V. 1500W would be a better guideline/estimate.

Click to expand...

The factory 120 volt "trickle charger" can only charge at 12 amps, as mctom987 said above. So, at .09 per kWh, including a little extra for efficiency losses in the charger, that's 13.5 cents/hour, or $1.62 for 12 hours. I really doubt you are going to see >$20 a month that can be attributed to your charging.

Click to expand...

$20/mo at $0.10/kWh (including charging inefficiency) is about 720mi per month (assuming EPA 3.6mi/kWh).
1000mi/mo should cost closer to $30.