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Portable charging with a wall mounted box?

Discussion in 'Charging Standards and Infrastructure' started by Alexjfrost1969, Aug 27, 2014.

  1. Alexjfrost1969

    Joined:
    Jan 8, 2014
    Messages:
    6
    Location:
    Cambridge, UK
    this may be a really dumb question but I'm going to ask it anyway....

    Is there any reason why I cannot use a wall mountable charging box as a portable charging unit? What I was thinking of was something like the attached. Instead of connecting the box to the wall, I would just put it in the frunk for the very odd occasions when I need it. The power end would be terminated in a 32A commando (RV) plug instead of being connected directly into a domestic fuse box. I already have a set of 32A ->16A camp ground, 32A ->16A European Schuko and 32A - >UK 13A domestic plugs (all single phase) and obviously I can set the maximum current to be drawn in the car itself. When arriving at a destination to charge, I can just suspend the charging unit from somewhere suitable, connect the plug (via an adapter if need be ) to the 32A/16A/13A socket, and then charge the car.

    Why do this? Well the British government has been subsidising the fitting of these wall mounted devices and increasing numbers are now coming onto the market second hand. I can pick one up for about a third of the price of a UMC and about 20% or less of the price of a Juice Booster. I know it would be much bigger than a UMC but for the amount of times it will be used I actually don't care.

    Any thoughts would be really welcome: I pick up my MS tomorrow night so I really need to decide by then whether to drop £500/$850 on a UMC or not as I am too far from the service centre to want to go back to pick one up later.

    Thanks
     

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  2. gavine

    gavine Petrol Head turned EV Enthusiast

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    Why not use this at home and carry the UMC with you? Seems to make more sense that way. Then again, the UMC is more convenient to open the charge port. Never mind.
     
  3. arg

    arg Member

    Joined:
    Aug 22, 2012
    Messages:
    741
    Location:
    Cambridge, UK
    Various thoughts:

    1. These UK government units have (as a condition of the grant scheme) a phone-home modem to report the amount of charging used. Hence two risks with units on eBay - the original owner has probably violated their contract by selling it, and/or the unit may not work in no-signal areas (mine - a Chargemaster unit - certainly takes a minute or two to boot up before it will charge, which would be irritating as a portable EVSE). Quite possible that you could take it apart and rip out this stuff, but something to be concerned about.

    2. I hope that isn't your unit in the picture - it appears to have a tethered type1 cable, incompatible with the Tesla.

    3. Not sure how much you are looking at for these 'grey market' units, but you can put together a new one without any of the government baggage for not that much - see:
      http://www.nuworldenergy.co.uk/shop/product/type-2-32a-7kw-mainpine-evse-kit plus about £80 of bits to complete the job - hence a total of about £ 300 (inc VAT) for a 7kW/32A unit. I have just ordered exactly that for another permanent installation (happy to show it to you when it comes - I am local to you). Not sure that I would have gone with exactly that for portable use however.

    4. What you want for portable use really depends on your circumstances and where you drive. In my opinion, almost everybody in the UK needs a portable 13A plug charging solution, since 13A plugs are everywhere and public charge points are not (and disappointingly many public charge points _ARE_ 13A sockets!). Charging rate is pathetically slow, but overnight it gets you a useful amount of charge, and worst case you charge for long enough to get you to a better charge location. Over and above that, how often do you find commando sockets at places you go to? Campsite 16A are maybe relatively common (and could be covered by the same solution you use for 13A charging), 32A rarer, and the holy grail of 32A 3-phase super rare. Maybe if you habitually travel to industrial premises where they have such sockets and it would be appropriate to plug in then you need something like this - personally I know of very few at places I go to, and even fewer that it would be practical to actually use (no, I am not going to ask permission to drive my car right inside the factory and plug in there).

    5. You are right to think about what to get from Tesla before picking up - I have been trying to get them to send me a 13A plug EVSE and nothing has arrived as yet (though they allegedly have them in stock).

    6. As above, if I were picking one of the items Tesla sells, I would go for the 13A plug version (£370+VAT) rather than the UMC (£500+VAT). The 13A version is safe for my wife to use (signalling the correct current to the car and having thermal protection in the plug); the UMC plus adapter would not have either of those protections and so needs careful monitoring: I would be OK with using it myself with knowledge of what can go wrong, but not to give to other family members.

    Tesla having failed to supply their (rebranded Mennekes) unit for the weekend when I needed it urgently (and now sourcing a permanent install for that location), I am back to thinking what I could DIY for the ultimate mobile charging solution. Might still end up with the Tesla/Mennekes 13A solution plus an adapter for 16A commando, as it's foolproof and neat and requires no effort...
     
  4. Alexjfrost1969

    Joined:
    Jan 8, 2014
    Messages:
    6
    Location:
    Cambridge, UK
    Thanks gavine....the point is that I don't yet have ANY portable EVSE (I have a Polar home charger but that is all). So (a) I wouldn't need this for home and (b) I don't have a UMC (yet) to cart around...

    arg, thanks for your thoughts. To be honest the whole issue of portable charging is driving me nuts. I am an electronics engineer and my brother in law is an electrician. We did look into the build your own but the cost is actually quite significant (a type 2 plug plus cable is about £100, so is the Mainpine unit, a decent breaker and RCBO will be a few tens of quid, a waterproof/splashproof DIN box will be another few tens of quid, plus then there is the current switch (I agree that relying upon maximum current by setting the software in the car is asking for trouble with my wife too, so I would want to build a rotary or press button maximum current switch)...plus then there all of the pigtails to build (to 32A blue commando/16A blue commando/13A BS1363 with built in thermal cutoff)...I totted up that it was going to be £300 or so plus an evening's work for something that will look like a breezeblock when finished.

    The UMC is £500 or so and I can buy the 32A single phase version and build my own adapters I think. But you are right that then leaves me with the risk of tripping things if I or Mrs F forgets to set the car current properly. I suppose I could build adapters with current limiters in them (so, say, blue 32A commando to 16A commando with a few feet of cable and a current limiter inline to prevent more than 16A being drawn; plus 32a to 13A with a current limiter and thermal sensor/cutout) but again this is all a bit of a faff.

    The Juice Booster is a nice piece of kit but I just don't have a grand to spend on it (the money is earmarked for a custom subwoofer and upgraded speakers :)) and anyway - which is where my point was headed - I really do wonder how much I will ever use a portable EVSE. 99% of my driving is to work and back or to see family, all bar one of which lives within 35 miles of our house. it's only one of my friends in Oxford and some family in Dorset where I will really need to think about "domestic" charging.

    Although I have been more aware of the issue over the last few months as I have waited for my MS, I have to confess that I don't see a lot of 32A commando sockets knocking around and I wonder for the sake of 3-6 times per year whether I should just forget about it and go for a 13A EVSE (there are several on the market, for about £300-£400 as you note, all with thermal cutouts built in).

    But then my issue is that there is a big (actually road trip deal breaking) difference between charging at 10-13A (let's say 10A for most domestic circuits) and the 16A that I know I can get quite regularly (my family in Dorset live 400m from a campsite with tons of 16A sockets, and my mate in Oxford is a sparky who has offered to stick a 16A commando socket in his garage for me). With 16A I can travel to Dorset (200 miles) on a range charge and be fully range charged to go home by the end of the weekend (I reckon it is about 20 hours of charging). With a 13A socket, it's just not going to work.

    Any thoughts/help most welcome....I have realised that there is no right answer, but I have recognised that I do need something, none of those "somethings" are cheap, and I don't want to regret what I end up buying!

    Oh, and, yes sorry the photo was simply a "serving suggestion", I did not look that closely at the plug on the end which is indeed a type 1 as you say. I had not however thought about the modem issue. The Polar unit that I had installed a few weeks ago does NOT seem to have one....well if it does then they are getting a magic mobile signal since I cannot get a signal at home on any of the networks!

    Thanks
     
  5. arg

    arg Member

    Joined:
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    Location:
    Cambridge, UK
    Well, I faced the same issue of "got to blow some cash on a portable charger NOW", and came down on the Tesla/Mennekes unit (albeit that I've now got the chance to change my mind).

    Since you seem to have more options for 16A, it may be worth checking out whether this is more flexible (the datasheet says it defaults to 10A and lets you dial up to 13A or 16A, but it's a generic datasheet and maybe the higher currents are locked out on the BS1363 plug version compared to the Schuko version):
    https://evconnectors.com/portable-ev-charger/Portable-Mode-2-16a-62196-2-EVSE-13A-UK-Plug


    Perhaps an anecdote about familiar places is helpful:

    A very common trip to me is from Cambridge to my family's place in Suffolk for weekends or sometimes longer. About 80 miles each way (about the same as your Oxford example), so easily doable as a round trip without charging - on that trip, I comfortably get 'typical' range (and my wife gets better than 'typical'), On UK cars, the 'typical' setting gives about 222 on a standard 90% charge, 243 on a range charge. However, I found myself with range anxiety when I got there because people always want to go on side trips for shopping/beach/wildlife/etc., which you don't know in advance exactly how many extra miles you are going to drive. Then one weekend my Mother was in hospital in Ipswich and we needed to go and visit - which would have put us needing to hypermile to get home. Fortunately we found a public charging point (SourceEast) nearby which actually worked, but charge-while-you-wait is painfully slow at 7kW (I have dual chargers, but there are few public 3-phase points in Suffolk). If we'd had a 13A-plug EVSE, all these problems would be gone - it would comfortably refill ordinary local-area driving no matter how many days we stayed there, and under almost any scenario waiting 3 times as long at home is going to beat hanging around a nearby town.

    Similarly for a trip of a few days we made to the North Norfolk coast at half term (made by ICE as the Model S didn't quite arrive in time, but I had been planning to take it). Again, the distance is a comfortable round trip without charging, but not much to spare for 'tourist' driving to the various attractions in the area. The hotel had 16A commando sockets in the carpark, so we could have charged with an adapter. In this particular case, we could also have taken advantage of our dual chargers and stopped at the Ecotricity point in Swaffham on the way past (if they were open - that one isn't 24-hour), which was my original plan since I didn't know of the hotel sockets in advance, but slow charging at the hotel would have been much handier.


    So, your Oxford example will be fine whichever EVSE option you pick. Your Dorset example feels uncomfortable to me unless you can pick up some charge on the way - otherwise the car will be 'grounded' for the duration of your stay. I dare say other family members can drive you around, but that just isn't fun with your shiny new toy parked outside. Hopefully a supercharger will show up before long that you can hit without too much detour; in the meantime, Ecotricity points on the motorway will help, especially if you have dual chargers.


    (this thread really belongs in the UK section, as it's very UK specific).
     

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