Adding a 2nd Meter for your EVSE

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Joined
Dec 20, 2016
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Can someone tell me more about adding a 2nd electrical meter which is dedicated to the EVSE? Have any of you gone this route? I'm told this allows owners to delineate exactly how much they are paying to charge their car. The local utility supplies the 2nd meter and you pay an electrician to install. It might be overkill for some but I have a close friend who is an electrician. He'll install for a minimal cost.
 
uncleGarage said:
Can someone tell me more about adding a 2nd electrical meter which is dedicated to the EVSE? Have any of you gone this route? I'm told this allows owners to delineate exactly how much they are paying to charge their car. The local utility supplies the 2nd meter and you pay an electrician to install. It might be overkill for some but I have a close friend who is an electrician. He'll install for a minimal cost.

You need a city permit to install one of these.

Expect it to take a month and cost you over 1000.
 
If you want to charge your car with separate billing from the utility, you need them to provide a new meter and an electrician to install. It will take a long time to save enough on your electric bills to recover the typical installation cost. There are is also a Sub-Metering pilot program going on in California, so you can get the EV rate for your car and keep the rest of your house on a different rate plan. This is most advantageous if you live in an area where you need a lot of A/C and putting the whole house on EV TOU would raise your air conditioning cost too much.

If you just want the information for your own edification, you can install an EVSE that will collect the data for you. ChargePoint Home and JuiceBox can do this. You could also install a home energy monitoring system to collect the data for you. The really low tech way is to buy an old electro-mechanical meter off eBay and just wire it up inline in front of your EVSE. You would have to manually read it and record the data yourself, but it could be really cheap to set up.
 
My municipality (which has its own power utility) required a dedicated meter for the EVSE, and also required the EVSE be hard-wired in. They claim they need it to be able to track the increase in demand due to plug-in cars so they can plan for future infrastructure upgrades. They don't offer a specific EV rate but as I charge my car during the day (due to my work schedule) I wouldn't be able to take advantage of it anyway.

The readings from the second meter also show up on my bill, so I can track exactly how much electricity I am using to charge the car. Despite that, I keep getting annoying letters from the utility saying I am using "more electricity than the average household of my size." Well, duh!

As I live in a townhouse development, I also had to get approval from the HOA (since the meter would be visible from the outside), which wasn't an issue.
 
You can add this to just about any EVSE. It will show voltage, current, power, and a reset-able KWH display.

http://www.ebay.com/itm/100A-AC-LCD-Panel-Digital-Power-Watt-Meter-Monitor-Voltage-KWh-Voltmeter-Ammeter-/271952136069?hash=item3f519c4785:g:6~YAAOSwLVZVxiLV
 
NeilBlanchard said:
Does the pickup coil go around the AC power cable coming to the EVSE?

No, going around the whole cable would cancel out the signal. It goes on either of the power leads but not both. Both would be like a GFCI where it will only see an unbalance.
 
Any inductive probe can only go on one conductor. I have a commercial device that breaks out the one conductor. My clamp on amp meters are fine with this. This is very handy for units with a two conductor power cord like a lamp for example. It also has a section that multiplies the current by ten for very low current devices. I have had it for years but as I recall it was less than twenty dollars. It sure beats separating the wires!
 
GlennD said:
NeilBlanchard said:
Does the pickup coil go around the AC power cable coming to the EVSE?

No, going around the whole cable would cancel out the signal. It goes on either of the power leads but not both. Both would be like a GFCI where it will only see an unbalance.

Ok. Let me see if I have this. My Clipper Creek HCS-50P is hardwired with a black, red and green and terminate in a junction box where we tie into a 50AMP back to the main panel. You guys are saying that I can use this device by passing either the Black or Red through the coil. Can I do this inside the junction box?
 
uncleGarage said:
GlennD said:
NeilBlanchard said:
Does the pickup coil go around the AC power cable coming to the EVSE?

No, going around the whole cable would cancel out the signal. It goes on either of the power leads but not both. Both would be like a GFCI where it will only see an unbalance.

Ok. Let me see if I have this. My Clipper Creek HCS-50P is hardwired with a black, red and green and terminate in a junction box where we tie into a 50AMP back to the main panel. You guys are saying that I can use this device by passing either the Black or Red through the coil. Can I do this inside the junction box?
Technically, you can do it in the junction box, but I don't know if it's allowed by code. You also have to connect the Black and Red to the meter so it has power and can read the voltage.
 
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