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Adding dual/twin on board charger

Discussion in 'Model S: Battery & Charging' started by Blup85, Oct 8, 2017.

  1. Blup85

    Blup85 Member

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    I wasn't able to come up with much on the forum. I popped my rear seat to take a look at how hard adding another charger to my recently purchased p85+ would be. Looks rather straight forward as far as install, but I'm wondering if there is a part number difference for "right side" and "left side". My p85+ is a mid September build, and the existing single on-board charger says "2gen p/n 1014963-00-G". Looking on ebay for chargers, I found two chargers: 1 and 2. the part number is the same, except the last number "C" and "L". I'm guessing its a part number generation, but not sure. The current on-board charger ends with "G".
    Yeah, I know I really don't need twin chargers.. but my last p85 had them, I like splitting the load between two chargers (regularly charge @ 50amps, 25/per charger to ease the load on each charger), I already setup my HPWC for 100amps and pulled wire. I figure if I can upgrade for ~$450, its worth it to me to have dual chargers. With new Tesla's coming with 72amp single chargers, I'd like to take advantage of any destination chargers while on the road.
    Thanks!
     
  2. bob_p

    bob_p Active Member

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    Our S P85 has dual chargers and was getting 80A off the HPWC.

    When our S 100D arrived, with only the standard (at the time) 48A charger, we moved the S P85 to a 14-50 outlet and set the charging down to 30A - and the S 100D charges at 48A off the HPWC.

    And both cars get a full charge overnight.

    While we could order the upgraded 72A charger on the S 100D, doesn't seem to be any real need for that...

    Since getting the S P85 in early 2013, really haven't needed to use the 80A charger, once the supercharger network was available.
     
    • Like x 2
  3. Blup85

    Blup85 Member

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    Yeah, I can't really justify the need either, the only justification I have is I like to charge at 50amps, which is easier on the chargers @ 25 amps a piece. I'll be charging at 30 amps (not maxing @ 40) just for piece of mind.


    Not sure I'm going to take this on regardless. I found the SB to add a dual charger. Looks like you need software (toolkit?) to set chargers to slave/masters.. So doesn't look likely.. If anyone has experience with this please let me know.

    https://static.nhtsa.gov/odi/tsbs/2016/SB-10081836-5448.pdf
     
  4. boaterva

    boaterva Supporting Member

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    The only cars that (now) come with 72 Amp chargers are the 100s. All the others are 48. (And 3’s are another story...).

    In your case, it’s useful to have two 40 Amp chargers, and run both at the same time at a lower rate, but that’s about the only advantage (reducing the load on the single charger). I got the larger charger (well, had no choice on my 100, but I would anyway) because if you are a destination charger (HPWC) that can give the extra power, it’s good to be able to get off it more quickly so others can perhaps use it.

    That’s about the main case for the current (no pun intended!) situation of having a large charger on the road.

    And, yes, you would have to have the SC install it or at least tell the car it has the two chargers. It’s still an option on shop.tesla.com last I looked, at a hefty price.
     
    • Informative x 1
  5. FlyingCookie

    FlyingCookie Member

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    I'm interested in if you can make the software bits happy (or have the SC do it for you) as I spend a LOT of time working out of town, and dual chargers would make "Dinner fill ups" much more useful. (100 miles of range gained vs 50 is significant) It would also make 80 amp 208v destination chargers that I commonly find in parking garages not as sucky. I'm completely willing to install the second charger (it's not hard) but I know that there's software that has to be enabled and the second charger has to be set as slave, and I don't know that I'm on friendly-enough terms with the SC folks to get that done at all.. (Or just by paying labor for it)
     
  6. Blup85

    Blup85 Member

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    Big goose egg with my SC adviser... bummer. i even offered cookies! Man we really need some INDYS out here for these cars ASAP! This would literally be a 1 hour job at most from what I can see. everything is completely accessible. My car is under warranty but I can't justify 2k for a twin charger.. like others have said, unless you find yourself around a lot of 100amp HPWC's, it really doesn't make sense. Talk about no ROI on investment ;)
     
  7. FlyingCookie

    FlyingCookie Member

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    It would make sense for me, as there are a lot in the wild... but for $2000, I would essentially wipe out a years worth of gas savings. I just can’t justify $2000. $700 + $200 for labor is more easily justified, but $2000 is just crazy. I wouldn’t even be able to really justify it on a newly built car...

    I’m sure @wk057 knows how... but I doubt he’ll spill the beans...

     
  8. Blup85

    Blup85 Member

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    Found this video. Long video but it shows this guy installing another unit. Who knows if he was successful, not very informative and maybe he got lucky and installed an already slave charger. There are also cables in the high power relay that need to be added that he doesn't show.. car looks like a mess.

    Argh..So far dealer or nothing.
     
  9. Ugliest1

    Ugliest1 S85: "Sparky"

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    I could be wrong, or Tesla may have changed things, but I thought the way the dual chargers worked was, the primary takes the first full 40A, and the secondary takes whatever’s left (I.e. 8A on a 48A charger). There was lots of discussion about this back in 2014 or so.
     
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  10. BigMskiman

    BigMskiman Member

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    Speaking of dual charges, has anybody ever seen this? It's in Gilroy, CA
    There are 16 total charging slots there, a mix of back-in and forward-in, but only this one slot is double.......

    IMG_4633.JPG
     
    • Funny x 1
  11. Blup85

    Blup85 Member

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    Double or just allows a vehicle to pull in to charge? Something on the other side of the model x must have prohibited a standard install of the SC, the Roseville Chargers are all setup for pull in charging.
     
  12. Blup85

    Blup85 Member

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    It's been verified that with the dual chargers, they split the load over 40 amps. So if you set charging for 42 amps, it will put 21 amps on each charger (which is the primary reason I want dual chargers) I always charged at 50 amps with my P85.
     
    • Informative x 1
  13. Ugliest1

    Ugliest1 S85: "Sparky"

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    Ok, thanks for the correction.
     
  14. BigMskiman

    BigMskiman Member

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    No, nothing prohibitive on the other (right) side of my X, just several other back-in only slots. Mine was the only double option I've ever seen, redundant SC slot.
     
  15. bxr140

    bxr140 Member

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    Not at all redundant; not a double option slot.

    You were parked in 5A. 5A-6B are pull ins. To the south of your spot is 3A then one south of that is 4A (don't ask me why they did it that way...) which are both back in slots.

    When you have a back in next to a pull in, the space in between has two pedestals (or no pedestals) since our cars charge on the drivers side.
     
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  16. BigMskiman

    BigMskiman Member

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    I see, yer right! Not redundant because a back-in next to me would be using the unit at my front fender.
     
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  17. RandyS

    RandyS Fan of Elon

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    I verified this exact question a few months ago with a Tesla tech whom I trust very much. My example was setting up a L2 charge at 60 amps, would the primary charger go to 40 and the slave unit (for lack of better terms) pick up the remaining 20, or would they split the load at 30 amps each? His reply was that the first unit would load all the way up to 40 amps and the second unit would supply the remaining 20 amps...This is a tech that is still working at Tesla and is working on the Model S every day....Anyways, thought I'd throw my two cents worth in...Seems like it would be more complex to split the load between the two units....
     
  18. scaesare

    scaesare Well-Known Member

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    I've experienced this a bit in reverse, so have a few observations...

    I had a dual-charger car. I had my primary charger die about 3-1/2 years in. Red-ring, and because it was the master, the slave could not kick in to charge (I wish this behavior could be changed).

    Tesla wanted ~$2500 to replace the charger. Because I very rarely charged at greater than 40A, I opted to instead just have the charger removed and the car converted to a single charger car. I have a good relationship with the technician at the service center, and although he had never done this before, agreed to give it a shot. They succeeded, and had to do the following:

    - Remove primary charger, and swap secondary in to the primary location.
    - Re-program the charger to be a primary
    - Add shunts to the HVJB
    - Add coolant bypass plumbing in place of secondary charger (and purge air form coolant system)
    - Update car configuration to be single-charger

    The above cost me about $350 for parts/labor. I've subsequently learned Tesla has told the service center to not do this again. (Incidentally, they also didn't want to return the failed charger to me, and I had to be firm in insisting my property be returned)

    So, in order to add a secondary charger, you'd need to remove the shunts and bypass plumbing. You'd then need to do the charger and car programming/configuration. Forum member @Ingineer can do the latter part as a part of a service he offers. I'd urge you to contact him if considering doing this.

    I didn't know it at the time, but it was a blown fuse on the charger. I've since replaced the $17 fuse and expect that, as has been the case with a number of other folks, it would be perfectly fine. However now I'm in the situation where I'd have to reverse the programming/plumbing, so I've not bothered to reinstall it.

    Hope that helps..
     
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  19. scottm

    scottm Active Member

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    Couple people on this forum have converted their secondary charger into primary when something in the primary went bad... there's work involved and software / firmware ... so it's going to take Tesla to recognize changes in number or positions of on-board chargers.

    --- edit --- wow! talk about timing thanks for stepping in @scaesare and sharing your experience

    I'm running strong with 2 x on-board and 80A capable, but seldom use it. Mostly supercharging now, using destination chargers less and less. I used to enjoy sucking up all the full 68A many J1772 chargers around here were offering.. Now I drive by them.

    Charging all day at work at 120V pays for my commute, couple percent short actually. Then hit a SC on Friday to top up for the weekend. Rinse, repeat.

    Hardly charge at home any more, so anything more than about 40A at home would be rarely used. I think Tesla has it right with the new mix of chargers on model S. Model 3 seems a bit skimpy.
     

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