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HPWC 80 amp vs. 40 amp

Discussion in 'Model S: Battery & Charging' started by techMology, Feb 5, 2014.

  1. techMology

    techMology Member

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    Apologies in advance if this question/thread annoys anyone. YAATD (Yet Another Agonizing Tesla Decision).

    I get my car mid-March and need to install some sort of charging solution in my detached garage. I'm looking for opinions on which direction I should go.

    Here are the two options I'm considering:

    1. Install a HPWC with 80 amp service. About $2800, but an extra $20 a month in account fees.
    2. Install a HPWC with 40 amp service. About $1750, no extra fees.

    The above are all-in costs (including installations, rebates, incentive, and the HPWC cost). I can provide details if anyone is curious.

    I work from home, so I won't be running the battery down frequently. I've ordered a S85. While I won't be doing a lot of daily miles/km's, I do like the idea of being able to recharge quickly if I have to (and sharing the charger with other Tesla owners who may need a quick emergency charge).

    Is the extra $1100 or so up front worth it (plus the $20 extra a month)?

    Thoughts & opinions, please!
     
  2. Lloyd

    Lloyd Active Member

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    It depends on your driving, and time needed to charge. Most can charge overnight easily with normal miles used every day with less than 40 amps. If you will arrive home with an empty battery regularly and need to leave in several hours, then you will need the 80 amp ability.
     
  3. techMology

    techMology Member

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    Yep, I know. Trying to figure out if I'm being penny wise and pound foolish.
     
  4. SouthJerseyJon

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    I have the HPWC with the 80 amp service. I don't regret it at all...if you can afford, do it. The one day you will want that fast charge at home and you didn't do it, you will be kicking yourself.
     
  5. islandbayy

    islandbayy Active Member

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    I drain my battery fairly low daily, and my 14-50 is more then enough. I would really like the dual chargers for road trips though.
     
  6. MartinAustin

    MartinAustin Active Member

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    I paid $2700 for the HPWC option including twin-chargers, and an additional $3000 to get it installed at my house, which needed extra wiring, main breaker box etc..

    However, where I live, there's a rebate for installing this sort of gear, up to $1500 and after showing them the details of the installation, I qualified for all of that. So installation only cost me $1500.

    And I live in the USA!!! It's possible you might get more assistance for installations since you're in Canada. The $2700 for HPWC option may be unavoidable though.

    However, it has saved me a couple of times, I drive the car so much that I have needed to recharge it during the day, and it charges pretty quickly. (all relative, I suppose)
     
  7. dhrivnak

    dhrivnak Active Member

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    #7 dhrivnak, Feb 5, 2014
    Last edited: Feb 5, 2014
    In three years there has been one time I need to charge at a higher rate. And even then it was a want to not a have to. Normally I charge at 40 amps as I believe it is easier on the grid and the battery pack.
     
  8. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    I usually dial down the 40 amp UMC to 32 amps and only occasionally charge at 40 amps. The times I'd like the 80 amp charging is when I'm on a trip.
     
  9. Lloyd

    Lloyd Active Member

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    Yep, I have an HPWC able to charge at 80 amps, but I use the HPC and charge at 20 amps daily. It is enough for 99% of my use at home. For the 1% I have the HPWC there if needed.
     
  10. Todd Burch

    Todd Burch Electron Pilot

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    How about option 3: NEMA 14-50, for less than $500 (~$200, maybe less if installed yourself?)

    I can't think of a reason to get the HPWC and put it on a 40A circuit. You get the same charging rate as the 14-50, for many times the price!

    13 months, 22,000 miles and not once have I ever come close to needing more than a 14-50 at home. I drive 80 miles roundtrip a day.

    Everyone's needs vary, but stop and think if you'll really need to drive 200 miles in a day, come home, and leave to do another sizeable chunk of miles without 6ish hours of charging. For my driving habits, it's never happened.

    Do you have a backup car? If so, you could use it for those 0.25% of cases where this comes up.

    - - - Updated - - -

    To the OP's specific question, is it worth it: in my opinion, no. Do you realize how many kilometers you can drive on $20? :)
     
  11. cinergi

    cinergi Active Member

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    Personally I like the 80 amps especially in the winter because I burn through the range very quickly. There are situations where I'll commute or do something and return home which eats more than half the battery and then I'm like "oops, forgot something at that store" or whatever but can't make the trip until I charge more.
    What's the $20/mo for? Another meter? (meaning a new 100 amp drop from the street to your garage)
    Do you have time of use rates available there? With another meter, you can save on your electric bill by charging off-peak.
     
  12. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    I really like the HPWC for the clean installation and the fact that I can leave the UMC in the car. Though somewhat rare, it really is nice to have the dual chargers when you find an HPWC or high Amp J-1772 on the road!

    Remember that there are choices in between 40 and 80 Amps charging. The DIP switches allow settings at every 10 Amp increment for circuit breaker size. How about a 60 or 70 Amp breaker (48 or 56 Amp charging) with #6 wire or a 80 or 90 Amp breaker (64 or 72 Amp charging) with #4 wire?

    Why the monthly charge for the larger install?
     
  13. techMology

    techMology Member

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    The prices I quoted include any available government and/or utility rebates. The cost without would be $2900 more for the 80 amp option and $1500 more for 40 amp.

    Great points. The NEMA plug isn't eligible for a $1000 rebate from the Ontario government for installing an EV charging station. The HPWC is, regardless of the amperage you configure it to. (Short sighted on their part.) So when the math is worked out, the NEMA and the HPWC are only a couple of hundred dollars apart, and I do like the convenience of having a dedicated port to plug into instead of using the UMC or buying an extra one.

    I don't have a back-up ICE, but could always use a car share service (Car2go) if I need to.

    This is sort of my thinking. Is the $1000 savings worth the headaches of not potentially having a suitable charge when I really need one. However, what I'm trying to gauge is the likelihood of that.

    My local utility is providing an incentive to take part in a study of EV usage on the grid. The $20 a month is a charge for the dedicated meter. Part of the incentive is designed to offset that cost, and the incentive is larger if it's the higher amperage solution I choose.

    Thanks everyone for your opinions... It's not making things much easier, but it's helping provide some context!
     
  14. widodh

    widodh Model S R231 EU

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    What about safety? A HPWC is a lot safer then a UMC on a Nema 14-50 socket.

    I would strongly advice to install a HPWC even at 40A. It's designed to handle the current over a longer period. The Nema 14-50 is not.

    So for the TS: If you need 80A, take 80A. Personally I think you'll be just fine with 40A for 90% of the time.
     
  15. mnx

    mnx 2013 P85

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    Since you're putting in the HPWC regardless I'd opt for 80A. I haven't needed >40A charging at home in 12 months of ownership although it may have been useful to me once.

    I ran some #2 wire and a subpanel into my garage so I can always add a HPWC at a later date, I think I might bite the bullet eventually. (Either that or get a EMW Juicebox which is a j1772 capable of charging @ 15kW).

    I always thought it would be nice to have a HPWC to share with other owners who are roadtripping etc, although I think the days of that will be over soon once the supercharger network is fully built out...
     
  16. malcolm

    malcolm Active Member

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    #16 malcolm, Feb 6, 2014
    Last edited: Feb 6, 2014
    Another way to look at it is that your Home Charger only needs to give you a sufficient charge for you to reach your nearest Supercharger facility (which may be one built by Tesla or A.N.Other). These will nearly always be quicker than the fastest HPWC, even including waiting for a slot.

    Ball park figures: an 18kWh charge will get you 60 miles @ 300Wh/mile. Or 50 miles @ 350 Wh/mile

    If your emergency arises when you already have the necessary charge remaining for this initial leg of the journey, why wait?

    Conclusion: Depending on the rollout of Superchargers, investing in an HPWC may or may not be worthwhile.
     
  17. efusco

    efusco Moderator - Model S & X forums

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    For that much higher cost and the recurring fees I would forgo the 80amp. While nice to have and I use mine a couple times a month, I tend to take fairly long trips regularly and it is nice to be able to quickly top up when needed. That said, only a handful of times did I truly "need" the 80 amps. IMO, clearly not worth the additional cost to install that you're talking about.

    Now, I would still get the twin chargers since there are so many high amperage chargers in Canada, you'll want that when/if you travel.
     
  18. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

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    You are in Canada, which will likely have spotty Supercharger coverage for the foreseeable future.

    If you get an HPWC you could become a popular node on Plugshare. Then add a jar with a label saying "This fast-charging HPWC is 80A so adds $20 per month in connection fees."
     
  19. scaesare

    scaesare Active Member

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    I have a HPWC currently on a 50A circuit. I'm planning on upgrading that to 100A soon.

    While that will cost be somewhere in the neighborhood of $1500 to do, I'll get some relief in that I'll be able to take advantage of TOU rates to reduce my electrical costs somewhat (although that payoff will take a few years).

    That having been said, the real payoff for me will be for those times where fast-turnaround is needed. Not being able to take the car if needed is worth the initial outlay for me. The monthly surcharge you face sucks though...

    As for the suggestion that you simply use a UMC instead, in addition to the potenially faster charge rate I mention above:

    - I don't consider the UMC "permanent installation" device. As a matter of fact the "M" in "UMC" stands for "mobile". I understand leaving it plugged in most of the the time, but I'm not sure that time, flex, weight, etc... won't take it's toll on the plug-head/adapter combo.

    -The HPWC has a cable hanger and "plug hook" in addition to the above-mentioned slightly longer cable.

    - I want a charging cable in the car at all times. That means that if I want a permanent UMC for the garage, I'm already at $650. Spending the difference for the HPWC for the above reasons isn't that much of an additional expense in the overall scheme.


     
  20. stevezzzz

    stevezzzz R;SigS;P85D;SigX

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    I'm not buying your statement that an "HPWC is a lot safer then [sic] a UMC on a Nema 14-50 socket". That's FUD, pure and simple.

    To the OP: lots of good points on both sides of the question, but I go back to your original statement and say: No, you don't need an HPWC. And that extra $20 a month, in perpetuity, would really burn my chaps. If you drive, say, 2000 km a month and pay something like $0.10 per kWh, that $20 a month adds roughly 50% to your monthly 'fuel' cost.

    I drive my Tesla about 2000-2500 km/mo and have never felt cramped by having only a NEMA 14-50 in my garage, in over four years of Roadster and Model S ownership. The only time I unplug my UMC is for road trips.
     

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