robertk925
Member
I see George posting the EMWorks Facebook site fairly often.
California Electric Vehicle Submetering Pilot Program
- Thread starter Dsinned
- Start date
Help Support Toyota Rav4 EV Forum:
The Wattbox is unreliable (for me)
Just wrote a lengthy email to ohmconnect/emtorworks.
My wattbox misses a lot of kWh while charging.
And I am afraid I will end up paying for it.
These are the graphs from my wattbox interfaces for last sunday:
http://postimg.org/gallery/1ipig9bzo/
and these are the 2 graphs from my main SCE meter:
http://pvoutput.org/intraday.jsp?id=7071&sid=6390&dt=20151006&gs=0&m=0
http://pvoutput.org/intraday.jsp?id=7071&sid=6390&dt=20151007&gs=0&m=0
the first session took 288 minutes, but only was 6.2 kWh, average power of 1.3 kW
where every other charging session is 6 kW.
In the first session in reality over 20 kWh went into my EV!
I urge everyone involved in the pilot program with a wattbox to keep track of your charges and compare them with the wattbox recordings.
In my case they are seriously out-of-sync.
Just wrote a lengthy email to ohmconnect/emtorworks.
My wattbox misses a lot of kWh while charging.
And I am afraid I will end up paying for it.
These are the graphs from my wattbox interfaces for last sunday:
http://postimg.org/gallery/1ipig9bzo/
and these are the 2 graphs from my main SCE meter:
http://pvoutput.org/intraday.jsp?id=7071&sid=6390&dt=20151006&gs=0&m=0
http://pvoutput.org/intraday.jsp?id=7071&sid=6390&dt=20151007&gs=0&m=0
the first session took 288 minutes, but only was 6.2 kWh, average power of 1.3 kW
where every other charging session is 6 kW.
In the first session in reality over 20 kWh went into my EV!
I urge everyone involved in the pilot program with a wattbox to keep track of your charges and compare them with the wattbox recordings.
In my case they are seriously out-of-sync.
Not sure (yet)srl99 said:
I write down the total measured kWh, like it is shown on the LCD on the meter itself, but I don't write down when I read that meter.
Currently I am not sure if it measured my missing 16kWh or it just didn't get reported
Waiting for EMW & Ohmconnect to chime in.
The other thing is that I haven't even gotten my first bill since I started the pilot.
Last bill is from Jul 28th, and they announced a new bill on or around oct 5th, has now been postponed till november 9th.
Real fun to be in a pilot.
emotorwerks
Active member
- Joined
- Oct 5, 2014
- Messages
- 42
Yes, absolutely. We sincerely hope that everyone responds to the Nexant survey truthfully. The PUC will need your feedback to decide how to rule about EVSE submetering in the future. This pilot will provide the necessary feedback and field experience, good and bad, to provide a better context for any future decision. Ideally, submetering would be integrated into the EVSE itself. This was unfortunately not possible due to certification requirements and the time available to complete it. All other MDMAs were equally affected.srl99 said:
emotorwerks said:
EV usage needs to be measured at the revenue meter. There is no other location that can accurately implement a different rate for EV charging. Losses in wiring, etc make measurement at the EVSE (any brand) useless for this purpose.
miimura
Well-known member
"Useless" is a strong word in this situation. Yes, it is true that the losses between the main meter and the EVSE will not be subtracted from the main meter if the EVSE is doing sub-metering. Is this a big deal? Well, I think 5VAC would be a big drop for an EVSE. Let's say you're charging a RAV4 EV at 40 amps. That is potentially 200W dissipation in the wiring that you will still pay on the house meter instead of the EV meter. If you fully charge the RAV with 35kWh of energy over 4 hours you will have a penalty of 0.8/35=2.3% Another way of looking at it is that you may be paying 35c/kWh on the house meter instead of 10c/kWh on the EV meter. So, you will pay an extra 0.8*25=$0.20 per full charge on the RAV.srl99 said:
So, you tell me, is that a big deal compared to the overall savings of sub-metering?
emotorwerks
Active member
- Joined
- Oct 5, 2014
- Messages
- 42
The PUC is looking at this and other issues. They are also offering to install loggers to measure the accuracy of submetering during the pilot. That said, I note that you have been hyper-critical of this program from the beginning, questioning its purpose, implementation accuracy, and potential savings. I'm surprised that you have signed up for it at all. This project has been in the works since 2010, and there were several opportunities for input and constructive criticism. It's still not late to provide feedback through Nexant.srl99 said:
In closing, I'm referencing a letter someone wrote to Michael Peevy. There is obviously no shortage of opinions on this matter. Early workshops included nearly everyone from the still-nascent EVSE industry. Several automakers were included as well. Everyone contributed something to this project. Transparency regarding EV energy usage and some special accommodations on the part of the utilities will help EV adoption. If you have any feedback and are a pilot participant, please provide it through appropriate channels.
Large residence voltage drop first brought to my attention by president of EMW.
LADWP's solution of a dual-meter adapter and two meters reliably provides the ability to submeter PEV usage, or any other usage.
It also preserves the utility's billing system, and ensures consumers and utilities have a measure as accurate as their existing use.
It's also a solution not designed by government.
LADWP's solution of a dual-meter adapter and two meters reliably provides the ability to submeter PEV usage, or any other usage.
It also preserves the utility's billing system, and ensures consumers and utilities have a measure as accurate as their existing use.
It's also a solution not designed by government.
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