Which Kill-a-Watt are you guys planning on using?

Then I guess you can spend $30 to $40 getting a meter to help you decide.

But even then, which Tier pricing are you going to use to figure out how much money you owe them?

1 - Are you just going to take the entire bill and pay your "fair" share. (e.g., say you use 50kWh for the month and the bill shows 550kWh of total usage - so then you would pay 10% of the entire bill)

2- Or are you going to pay for the most expensive tier of usage? To do that you would have to back out the 50kWh at the highest tiers shown and then factor in all of the various tariffs, taxes, etc... into it. In my opinion, this method is the fairest valuation of your usage. (your car added electrical usage to the "normal" electric bill).

Ok, one more thing to make life difficult: How are you going to synchronize your readings with the meter man's readings? Technically, you want to read your meter at the same time as the meter man so that you can be precise in figuring out how much of the kWhs on the bill are actually yours.

And now for a hard part: Say you use option 2 for valuation as described above. A couple of months from now, one of your other roommates buys an electric heater for their bedroom... Will he have to pay the other roommates back for his new extra usage? And would he now be the new highest tier (and, by extension, the PiP the second highest tier)?

Anyway, just some food for thought...

 

What is a "meter man"? Around here, most people now have smart meters that report usage on a more-or-less continual basis over a wireless link.

 

I do not recommend the use of either Kill-A-Watt product with an EVSE. We have had many cases of them melting over in the Leaf forum. They are not built well enough to withstand 12a of constant load. I'd recommend something more robust, such as a TED or even a used utility meter (ugly, but accurate and safe).

-Phil

 

I just KNEW that somebody was going to say something about this! But I thought they would bring up meter person or meter lady.... but I completely forgot about the smart meter (not that the other is not "smart"... )

 

For any Prius owners who aren't familiar "pEEf" is a highly respected member of the EV community. I wouldn't brush off his advice lightly.

 

This post concerned me, since I am using a Kill-a-Watt with my L1 EVSE/Prius Plug-in. So I investigated this a bit more.

According to Nissan's website:

This means that Leaf owners should not be using a 15A rated Kill-a-Watt b/c the Leaf requires a 20A rating. They are using a Kill-a-Watt outside of specification, so melting is quite understandable.

A Prius Plug-in only requires a 15A circuit, so the Kill-a-Watt would be working within specification.

Unless someone actually experiences a Kill-a-Watt melting while properly charging a Prius Plug-in, I think pEEF's warning is unwarranted.

 

I was wondering how robust they were. I was just going to measure (once or twice) the current the old fashion way and measure it with a clamp multi-meter and an AC line splitter made for that kind of current.

 

While it is true that Nissan recommends a 20A 120V dedicated outlet, the LEAF does not actually draw more than the 12A maximum of the PiP so any concerns about the Kill-A-Watt would be equally valid.

However.... The PiP only draws that 12A for about 2.5 hours whereas the LEAF could be drawing power for 21 hours. Heat can build up so it's possible that a longer charge on a LEAF might have some additional chance of heat-related problems simply due to that difference.

 

At $20 on Amazon and free shipping, the P4400 is rated at 15amp and my PIP charges are only 11.6 - 11.8 amps. And Amazon is trustworthy.

In fact I bought 2 more, that I'm using to test my old Beer frig and a spare freezer before I replace them with EnergyStar units. I'll then use one of them at work.

To avoid plugging the EVSE in and out of the Kill A Watt every charge, I bought a 4' 12/3 right-angle cord to plug into the Kill A Watt and plug the EVSE into it.

 

He's also a highly respected member of the Prius community.

 

I checked the Leaf's Owner's Manual and found it interesting that the Manual states a 120V 15A circuit requirement. Perhaps Nissan only realized later that the circuit maximum current wasn't sufficiently derated for charging up to 21 hours at constant 12A current. That might explain why the website states a higher, and possibly more up-to-date, 20A requirement.

 

(I'm no EE nor an electrician.) There are a bunch of references on MNL about breaker ratings and continuous loads.

Example quotes from My Nissan Leaf Forum • View topic - 220V vs. 240V

Search the rest of that thread along with http://www.mynissanleaf.com/viewtopic.php?p=66578 and http://www.mynissanleaf.com/viewtopic.php?f=26&t=7689 for 80%.

 

i want this one, but i herd some of them will melt if you use them on a EV car charger

 

The Specs list 125 vac Volt Max and 15 amps Max.
So it's ok for the PIP that only draws 11.7 amps.

But it's more than you need.
The P4400 is $20 on Amazon.

 

Maybe. Or maybe they know that 20A dedicated circuits are unusual so by specifying it they implicitly require that an electrician wire up a new outlet that isn't old, worn-out, and possibly wired up wrong.

Actually, my PDF copy of the LEAF owners manual calls for a 20A circuit and I downloaded it when it first became available a year or so ago (I think).