1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Killed my Kill-a-Watt

Discussion in 'Prime Plug-in Charging' started by mveras1972, May 23, 2019.

  1. mveras1972

    mveras1972 Member

    Joined:
    May 23, 2019
    173
    63
    3
    Location:
    New Philachussetts
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    I just bought a Prius Prime 2017 and wanted to see the consumption when charging. So I used my Kill-a-Watt to measure. I noticed that the Prius does not draw constant power. Sometimes it goes up to near 1,400 watts, which comes close to 12A in my 120V line and then goes down to 200W or so then up again for a few minutes. Since the Kill-a-Watt is rated 15A I thought it would be ok. About an hour after I initially connected it, I went to check and noticed my Kill-a-Watt display was blank. I thought maybe my circuit breaker tripped. But my breaker is 20A and so is my outlet. I plugged in the charger directly to the outlet and it resumed charging, but I presume a fuse blew inside the Kill-a-Watt. I've since gone to Google this and read horror stories with molten Kill-a-Watts, disfigured Kill-a-Watts, etc. So the device doesn't appear to live to its expectations of 15A limit. Maybe it isn't designed for long term measure of 12A current? Moral of the story, don't leave your Kill-a-Watt plugged in if you're charging your EV. I guess I can consider myself lucky that my Kill-a-Watt simply stopped working and there were no disfigured or molten parts at all.
     
    #1 mveras1972, May 23, 2019
  2. noonm

    noonm Senior Member

    Joined:
    Feb 5, 2019
    575
    595
    0
    Location:
    NJ
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    I wouldn't be surprised if the internal wiring was undersized or not QC'd enough for a continuous 15A. The devices are pretty cheap and generally appear designed for lights or TVs energy measurement. My guess is the same would happen if you ran a space heater through the Kill-A-Watt.
     
    #2 noonm, May 23, 2019
  3. Salamander_King

    Salamander_King Senior Member

    Joined:
    Nov 8, 2015
    10,964
    8,840
    0
    Location:
    New England
    Vehicle:
    Other Hybrid
    Model:
    N/A
    Might be a bad unit of Kill-a-watt. I have been using Kill-a-watt to monitor my cost of charging for almost two years now without an issue.
     
    #3 Salamander_King, May 23, 2019
    jerrymildred and Mark57 like this.
  4. Rob43

    Rob43 Senior Member

    Joined:
    Sep 24, 2014
    1,373
    1,044
    0
    Location:
    VA, BMW Race Car, BMW R1200R, BMW 330Ci, Ford F350
    Vehicle:
    2013 Prius v wagon
    Model:
    Prime Advanced
    OP, I'm glad nothing went tragically wrong.


    Rob43
     
    #4 Rob43, May 23, 2019
    mveras1972 likes this.
  5. Tha_Ape

    Tha_Ape Active Member

    Joined:
    Apr 9, 2019
    271
    161
    0
    Location:
    Washington, DC
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    Like salamander, I'm also using the Kill-a-Watt when I charge on 120V. No issues yet, I've only had it a few weeks though.

    It seems to be accurate considering what others are reporting. I use about 5.5kW/day (~5-9mi on battery before charge)
     
    #5 Tha_Ape, May 24, 2019
  6. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

    Joined:
    Aug 14, 2009
    2,945
    2,735
    0
    Location:
    OK
    Vehicle:
    Other Electric Vehicle
    Model:
    N/A
    I've also been using the Kill-a-Watt when I charge @ 120V for almost 2 years, non-stop. It's worked flawlessly all that time and has never been unplugged from then loop..
     
    #6 Mark57, May 24, 2019
  7. Peng Xiao

    Peng Xiao Junior Member

    Joined:
    Apr 12, 2019
    83
    13
    0
    Location:
    New Jersey
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    I used for 2 days, no problem. Maybe you get a bad one.
    About 6.5 kWh each charge.
     
    #7 Peng Xiao, May 24, 2019
  8. m8547

    m8547 Senior Member

    Joined:
    Aug 8, 2018
    927
    615
    0
    Location:
    Colorado
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    I've used mine without any problems. I've also used it to measure the current on my miter saw doing a big cut (an 8/4 x 7 inch piece of maple), and I think it hit around 17A. The readout on the display flashes if the current exceeds 15A. But 17A for a few seconds isn't going to overheat anything.

    You should ask Kill-a-watt to replace your device (unless it's as easy as changing a fuse inside).
     
    #8 m8547, May 24, 2019
  9. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

    Joined:
    Feb 14, 2010
    6,035
    3,854
    0
    Location:
    Rocky Mountains
    Vehicle:
    2006 Prius
    Model:
    Three
    There are so many fake kill-a-watts out there, especially on Amazon and eBay and you'd never know without opening the case.

    The real Kill-A-Watts at least were designed to take the full 15A rating as peak and 12A continuously. I had a bunch of them on server equipment pulling near max draw 24/7 for years. However when I added a couple they were a slightly different colour but otherwise looked identical. After about 6-8 months, server UPS tripped online when the rest weren't and I go to check and the kill-a-watt is brown-ish and completely dead. Checked the other new ones and they were all hot. Old ones, still rocking. New ones, complete junk. Pretty sure they were fakes.

    I have a lot of them, and they looked identical. Someone who is just going off of pictures on the internet, I am not sure how you would know without opening it up, and that could be destructive.
     
    #9 2k1Toaster, May 24, 2019
    jerrymildred and mveras1972 like this.
  10. schja01

    schja01 One of very few in Chicagoland

    Joined:
    Apr 22, 2005
    1,732
    1,157
    0
    Location:
    Chicagoland
    Vehicle:
    2018 Prius
    Model:
    Prime Advanced
    My Kill-a-Watt says it's rated at 1875 Watts.
    My outlet is rated at 20 Amps
    I've never seen the Prime draw more than 1500 Watts when charging.
     
    #10 schja01, May 24, 2019
  11. CR94

    CR94 Senior Member

    Joined:
    Dec 2, 2014
    2,642
    1,134
    0
    Location:
    Northwestern S.C.
    Vehicle:
    2011 Prius
    Model:
    Two
    Did the ones that died bear ETL, UL, or CSA approval marks?
     
    #11 CR94, May 24, 2019
  12. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

    Joined:
    Feb 14, 2010
    6,035
    3,854
    0
    Location:
    Rocky Mountains
    Vehicle:
    2006 Prius
    Model:
    Three
    Of course. Chinese clones. The logo means absolutely nothing
     
    #12 2k1Toaster, May 24, 2019
  13. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    17,113
    10,043
    90
    Location:
    Western Washington
    Vehicle:
    Other Hybrid
    Model:
    N/A
    My first unit, very long ago, eventually suffered a failed solder joint on the current shunt. Re-soldering with an undersized home iron put it back in service for a while, but it eventually went intermittent, then failed completely again. A second one failed too, but I didn't troubleshoot it.

    Am wondering if it had a thermal problem, where different expansion rates predisposed it to mechanical joint failure.
     
    #13 fuzzy1, May 24, 2019
  14. mveras1972

    mveras1972 Member

    Joined:
    May 23, 2019
    173
    63
    3
    Location:
    New Philachussetts
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    Thanks for all the feedback. If it is so hard to tell if I have a fake kill-a-watt, then it may be possible I have a fake one. I've had it for nearly 2 years and used it occasionally for small loads. This was the first time I loaded it with high current approaching its limit. But to provide an update, I opened it up to search for a replaceable fuse. To my dismay, I didn't see anything that looked like a fuse or any removable parts inside. There aren't even signs of burnt parts while I examined it. I guess I will need to buy a new one. But now my concern is how do I make sure I get an original and not a fake?
     
    #14 mveras1972, May 27, 2019
  15. Salamander_King

    Salamander_King Senior Member

    Joined:
    Nov 8, 2015
    10,964
    8,840
    0
    Location:
    New England
    Vehicle:
    Other Hybrid
    Model:
    N/A
    Buy directly from P3 International site?
    Home Page | P3
     
    #15 Salamander_King, May 27, 2019
  16. Rob43

    Rob43 Senior Member

    Joined:
    Sep 24, 2014
    1,373
    1,044
    0
    Location:
    VA, BMW Race Car, BMW R1200R, BMW 330Ci, Ford F350
    Vehicle:
    2013 Prius v wagon
    Model:
    Prime Advanced
    I sent you a PM, did you see it ?


    Rob43
     
    #16 Rob43, May 27, 2019
  17. mveras1972

    mveras1972 Member

    Joined:
    May 23, 2019
    173
    63
    3
    Location:
    New Philachussetts
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    Yes I just saw it. Thanks.
     
    #17 mveras1972, May 27, 2019
(You must log in or sign up to post here.)