[SCE Customers in SoCal] Easy Way to View your Charging kw Usage

[Though this post is for all SCE Customers in Southern California, your own local power utility may also offer something similar]

For SCE Customers, it's pretty easy now to gauge how much $ it costs to charge your Prime, especially if you charge it overnight (at a time when, if you weren't charging it, you'd know about how much your energy usage would be). You can create an online account at SCE, log into their website, and view your power usage on a daily basis, as well as for each individual hour for the last couple months. Then you can compare your usage when charging at night to the nights/hours when not charging and figure out the difference to get the cost. After creating an account, log in, click on MY ACCOUNT, then click on the VIEW RECENT USAGE tab. It'll show you your usage for each day, and you can then click on each date to view an hour-by-hour usage graph (hover the cursor over the bar for any hour to have it display that hour's exact kw usage).

For me, power usage during the middle of the night when NOT charging is always around 0.08kw per hour. When charging, it jumps to around 1.47kw per hour. Add up the power used for the obvious "charging hours" and compare. So for the 5-hour-ish charge, it seemed to take a total of about 8.2kw more than it would have if I hadn't charged. Multiply 8.2 * 16c (current price for rate tier I'm always in), and it cost me $1.31 to go from empty to a full charge.

Not sure if PG&E or other power utility companies let you see your usage in such detail, but perhaps they do. For SCE owners at least, it replaces an approximate/theoretical cost of charging with real, hard numbers.

 

Just an update to my previous post.
I did a more thorough examination, and found out the charging cost was actually slightly less, as before I forgot to subtract what the normal (very small) usage would've been even if I hadn't charged. I also did an empty-to-full charge starting it all after midnight (so it would be all on one date, instead of starting it around 10pm and having it go over two days) so now my figures are more accurate I think.

My energy usage when I'm asleep (middle of the night) is surprisingly consistent (very tiny: .08 per hour, pretty consistent for those hours).

Here's the kw used for charging (for each hour I will minus -.08, as that's what my normal usage is for that time of night when not charging):
12AM-01AM: 0.74 (-.08) = 0.66 (I started in the middle of the hour, like 12:20am or something like that)
01AM-02AM: 1.50 (-.08) = 1.42
02AM-03AM: 1.50 (-.08) = 1.42
03AM-04AM: 1.50 (-.08) = 1.42
04AM-05AM: 1.50 (-.08) = 1.42
05AM-06AM: 0.57 (-.08) = 0.49

Add up 0.66, 1.42, 1.42, 1.42, 1.42, 0.49 and you get: 6.83kw used for charging.
6.83kw x 16c (price for lower-tier SCE rate, if you're in the lower tier) = $1.09

Battery was just about depleted (something like 0.4 miles left) -- so we'll say about $1.14 or so is probably an accurate assessment.