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Help with SCE...Charged car & went over my monthly demand by 1/2 KW

Plugged in the new MS at work and went over my monthly demand allowance of 20 KW demand by 1/2 KW. Now they want to charge me the difference between GS1 (light commercial) to GS2 (medium commercial) for last year and next year (about $8000). They don't really seem to care that it was a simple charging configuration mistake and won't happen again. I always try to manage my machine loads during the day to keep away from that 20KW ceiling.

I am looking for ways to manage my loads and have a program knock off the car charger is our usage gets too close to 20Kw. I have some CNC machines and compressor that cycles all day. They don't make it easy.

Does anyone have any connections at SCE...I am pleading with them to give me a pass on that one mistake.

I should probably get some solar since I car charge during the day. We lease the building so I am apprehensive.

Thanks for reading.
 

swaltner

Active Member
Oct 13, 2012
1,711
1,813
Kansas, USA
No help for the current situation with your bill for past transgressions, but for help going forward, I'd suggest some kind of real-time power monitoring system. I like the Energy Detective TED - The Energy Detective system that I have at home. They offer both residential (split single phase) and commercial (three phase) systems. I don't have this configured, but I'm pretty sure they support alarms (e-mails, text messages) for things like going over a certain limits (kW, current kWh per day/month, estimated kWh for the rest of the day/month, etc...) Theoretically, you could use this to send a signal to an EVSE like the OpenEVSE to automatically throttle/disable charging as needed.

While they haven't released the exact details on what they did, this is very similar to what they did at CalTech, but your triggering event for throttling would be different. Free Destination Charging: 50x L2 80A Stations @ Caltech, Pasadena, CA

Several thread have been here discussing the problem/expense of the demand charges themselves in relation to EV charging, but this is the first that I remember where the person was concerned about different billing classifications based off the peak demand charge for the year. I feel your pain. This is something that the EVSE manufactures need to assist with.
 
No help for the current situation with your bill for past transgressions, but for help going forward, I'd suggest some kind of real-time power monitoring system. I like the Energy Detective TED - The Energy Detective system that I have at home. They offer both residential (split single phase) and commercial (three phase) systems. I don't have this configured, but I'm pretty sure they support alarms (e-mails, text messages) for things like going over a certain limits (kW, current kWh per day/month, estimated kWh for the rest of the day/month, etc...) Theoretically, you could use this to send a signal to an EVSE like the OpenEVSE to automatically throttle/disable charging as needed.

While they haven't released the exact details on what they did, this is very similar to what they did at CalTech, but your triggering event for throttling would be different. Free Destination Charging: 50x L2 80A Stations @ Caltech, Pasadena, CA

Several thread have been here discussing the problem/expense of the demand charges themselves in relation to EV charging, but this is the first that I remember where the person was concerned about different billing classifications based off the peak demand charge for the year. I feel your pain. This is something that the EVSE manufactures need to assist with.

Thanks for the advice. I will probably get a TED and try to find a way to control a circuit breaker to kill some loads if I get close to going over
 
Ya, SCE is a treat aren't they. Sorry I can't speak for commercial rates. However, as an SCE "Small Generator", residential customer, I too follow my usage carefully. I love data and statistics. Perhaps I need something like the power monitoring system called Sense or some other. There are days when I think SCE is overstating my electric usage, which I've been tracking daily, by hour, for the last two years. From that, I subtract my solar generation to arrive at my net usage (I'm on Net Metering). It sounds like a lot of work but isn't.

Having a proven and reliable power monitoring system would verify what I think I'm seeing. However, I'm still over-generating and need my BEV to drain off the excess! I think there are two seasonal rates for my area. For those interested, here are the rates for my area and current billing:

Tier 1 - 17 cents/kW - 0 - 483 kWh
Tier 2 - 24 cents/kW - 484 - 966 kWh
Tier 3 - 30 cents/kW - 967 + kWh

I sympathize with you. Good luck!
 
Have you modeled what a TOU rate would save you?

I do need to research that as far as charging the BEV. I'll go with ToU so long as my excess solar generation is qualified to offset its use. I'm on Net Metering, so I'm not sure I can also have both ToU and Net Metering billing and have my solar generation pay for everything. I'm also wondering if ToU requires a separate meter. Currently generating almost 13 mWh/annually.
 

shokunin

P85 & M3
Supporting Member
Feb 28, 2012
1,214
653
Irvine, CA
I do need to research that as far as charging the BEV. I'll go with ToU so long as my excess solar generation is qualified to offset its use. I'm on Net Metering, so I'm not sure I can also have both ToU and Net Metering billing and have my solar generation pay for everything. I'm also wondering if ToU requires a separate meter. Currently generating almost 13 mWh/annually.

I'm on SCE and solar with TOU-D-A rate schedule with net metering. Buy low / sell high mentality of selling back power at off-peak and peak rates while charging at super off-peak rates. If you run the AC all day long during peak hours then ToU may not be the best.
 
If you run the AC all day long during peak hours then ToU may not be the best.

I have two homes. The one where I plan to charge the Tesla is located up in the high desert, where it's hot as hell during the day, at least for five to six months. I run the AC from about 9 AM to 6 PM during the summer (even now in mid-September). I would charge the Tesla after 8 or 9 PM, so i'm wondering if that would work. I use all the power I generate from 9 AM to 6 PM and beyond, especially when the temps go well over 100ºF.
 

swaltner

Active Member
Oct 13, 2012
1,711
1,813
Kansas, USA
Thanks for the advice. I will probably get a TED and try to find a way to control a circuit breaker to kill some loads if I get close to going over

Good luck, when you get that gear installed you might want to look into a program called IFTT (If This Then That). Some on the board have used IFTT to do little automation tasks. If you matched that with the TED and an EVSE from OpenEVSE with their Wi-Fi module, "you" could adjust the current limit on the EVSE to keep your whole building below some peak kW limit that you decide. A way simpler setup than that full-featured setup at Caltech, but should do what you want it to do.

I just tried the OpenEVSE RAPI (Remote API) on my system in the garage. I used a browser to retrieve http://192.168.x.x/r?rapi=$SC+20, which set the current limit to 20 amps. Very slick. There's not a lot of info on it, but EVSE control over WiFi : OpenEVSE Support has some details. Basically, connect to the web server on the OpenEVSE with a web browser and then add /rapi to the end of the URL to get to the RAPI interface. You would use something like curl to retrieve a URL to adjust the current limit up or down on the OpenEVSE.

At some point, I'd like to add RFID badge access, automated current limiting, and maybe some other features to the OpenEVSE project.
 
I have two homes. The one where I plan to charge the Tesla is located up in the high desert, where it's hot as hell during the day, at least for five to six months. I run the AC from about 9 AM to 6 PM during the summer (even now in mid-September). I would charge the Tesla after 8 or 9 PM, so i'm wondering if that would work. I use all the power I generate from 9 AM to 6 PM and beyond, especially when the temps go well over 100ºF.
I live out in Lancaster, CA and everything works out fine with my 5kW PV array, SCE net-metered TOU-D-A billing, and the Model S (all on one meter). That said, I usually don't have the AC set lower than 80 during the day while I'm home and I typically pull down to 75 or so once I hit the super-off-peak rate at 10:00pm.
 

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