Posts: 35
Joined: Wed Jul 11, 2018 2:43 pm

New member, charging question.

Thu Jul 12, 2018 12:28 am

Hi all, new member to the forum living in the UK who has just placed an order for a 'new' i3 Rex. (It's got 4,800 miles on the clock and was previously a Bmw workers/company car.) The sales person was very polite, (as they are when going for the sale), but sadly didn't seem to know much about the car re charging and battery specifics. I'm trying to find out what users have had to do/done re charging points and the installation of them. Our garage is detached from the main house and I wonder if other owners had to upgrade power cables from the main consumer unit in the house to the charging point. Also I am confused as to what will be needed as I have seen that there are different cables (at an additional cost) which should be used to allow the car to be charged at a faster rate.
Any information will be greatly appreciated. We would prefer to be able to charge the car within the 4 hrs rather than have to wait the 12/13hrs I understand happens if the cable that comes with the car is used to plug it into a conventional wall socket.

Posts: 56
Joined: Sun Mar 11, 2018 11:48 pm

Re: New member, charging question.

Thu Jul 12, 2018 7:45 am

This is a difficult question to answer without knowing how your house is set up, and what charger you intend to use. But essentially the fastest at home chargers use about he same amount of power as a full size electric clothing dryer, or an electric oven. Check the breaker or fuse that is supplying power to the garage. If your charger is 20 AMP and your breaker is 15 AMP obviously that is not going to work.

The car does have setting to slow the charge rates so if you plugged in and trip a breaker/blow a fuse, you could go into the car's menu and select a slower rate of charge. Of course this means more time to charge to 100% but it does give you some flexibility. These settings are in the main computer of the car on the center screen. Make sure you check these settings as my car was delivered with them all set to charge as slow as possible, and it was a week before I knew why my care would not charge as fast as I'd been promised. My dealer seemed to know nothing about this.

I'm in the USA and my car (a 2017) included a 12 AMP 110 Volt AC charger. Referred to by BMW as an "occasional Use" charger. From 6% to 100% would take about 30 hours. Obviously that is too slow. But on a typical day I only use 25% of the battery or less so an overnight charge at this rate would bring me back to 100%.

My office provides 240 Volt chargers (not sure on the AMP rating) and these will take my car from 6% to 100% in about 8 hours.

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Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: New member, charging question.

Thu Jul 12, 2018 6:05 pm

For most customers, the on board charging in the i3 is limited to 7400W, so divide that by your supply voltage would give you the maximum amps. Generally, a 30-32A EVSE is the maximum that the i3 can handle, but because of the protocol, a larger or smaller one will still work...the EVSE announces to the car the maximum that it can provide, and then the car will adjust its draw to never exceed what it was told by the EVSE. IF you choose a smaller EVSE, it will still charge the i3, but it will just take longer.

Most EVSEs are rated for exterior installation, so it could be either outisde or inside. I don't know the rules in the UK, but in the USA, a 30-32A EVSE would require a 40A circuit since the codes require you to derate the circuit capacity to 80% when the device could be on more than a few hours continuously.

In the USA, the charging cable is generally tethered to the EVSE...that isn't necessarily the case in the UK. So, that depends on which EVSE you end up buying as to whether you'll need one. I don't know what the public EVSEs have...you might need a cable for one of those.

Depending on the market, and the model year, the vehicle may only have the ability to recharge at half that 7400W maximum. Also, not all vehicles sold will have a DC charging capability. You can tell if yours does by seeing if the charging port has two sections with a 2-pin one below the main upper one. If you do, you can charge at public DC fast charging locations. Generally, you'll end up with about an 80% charge in about 30-40 minutes.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

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Joined: Sun Apr 29, 2018 3:44 am
Location: New York

Re: New member, charging question.

Mon Jul 16, 2018 12:56 am

In the U.K., the basic mains voltage is 230 volts, which is about 2 times the voltage used in North America. So while my 'basic' charge takes about 30 hours, in the U.K. yours will take 15 hours.

I spent about $1000 to install a higher power EVSE at home (240 volts at 32 amps), which charges the i3 in about 5 hours. If a 15 hour charge is too slow, you should be able to install a higher power EVSE in the U.K. as well.

Also, it's interesting to note that I'm spending $500 at our summer home to install a 240v 15 amp circuit for faster charging, which is the basic power circuit used in the U.K. To make this circuit a bit more 'future proof', I'm having heavier wire pulled but to keep costs low, will use a less expensive (but less powerful) EVSE.
2017 i3 Rex, Juicebox Pro 40

Posts: 35
Joined: Wed Jul 11, 2018 2:43 pm

Re: New member, charging question.

Wed Jul 18, 2018 2:31 am

Thank you for your replies.
We had an electrician visit our home yesterday and sadly we won't be able to install a 'quick charging' unit as soon as we would have hoped. We have to lay a new cable from our main consumer unit to our detached garage and it won't be a cheap job. The existing cable does not have a high enough amp rating. In addition to that, a new consumer unit will have to be fitted in the garage. :-( Good bye to another few hundred quid and it looks as though it will be a few hours of hard graft for me digging a trench, once the ground softens!
This EV ownership is a costly thing for us to do. OK, should we have done more research before saying 'yes' to the car? Only time will tell. But for the time being we will have to live with using the supplied cable and slow charging via a 3 pin socket and if needs be, the Rex kicking in. There are no charging points where my wife works and she will be the main user of the car. It is planned to always be the second car in our household.
Pick it up today!

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Joined: Sat Oct 07, 2017 7:02 am

Re: New member, charging question.

Wed Jul 18, 2018 8:31 am

Have you looked on plugshare.com for stations near you or at work?
2015 REX / Participating on plugshare w/level 2 Clipper Creek 32 amp, Moclips, Washington coast

Posts: 35
Joined: Wed Jul 11, 2018 2:43 pm

Re: New member, charging question.

Wed Jul 18, 2018 12:02 pm

Thank you for that information JohnKelly, I guess this is where we start a steep learning curve! That looks to be a very interesting site which we will retain. Re my wife's place of work, no, there is nothing shown in that area.
I wonder how many forum members have found they are managing quite well with just the three pin plug charging lead that comes with the car in the UK and haven't found the need to fit a rapid charger unit. The car is intended to be her commuting vehicle and will be the secondary car in our household.

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Joined: Fri Dec 13, 2013 3:01 pm
Location: Australia

Re: New member, charging question.

Wed Jul 18, 2018 4:31 pm

Hi Mick,

If it is expensive to install the charger to your garage, are you able to park the i3 near to the house? Maybe start with the 30amp charger next to the house and later dig the trench and move the charger to the garage later, maybe near the end of summer/autumn.

The REX gives the option of waiting for improving plugshare near the work.
2014 BMW i3 BEV deposit placed 19th Dec 2013
Delivered in Melbourne 4/12/2014. Arrived locally 11/12/14, with 24km on the clock.

Posts: 35
Joined: Wed Jul 11, 2018 2:43 pm

Re: New member, charging question.

Thu Jul 19, 2018 2:16 am

Hi I33t, sadly no. The cost involved in buying a longer connecting cable to reach the closest point the car can be parked to the house, may as well be offset against installing a new supply cable. I will get started on it in a few weeks time once this hot weather we have had here for the last 6 weeks or so breaks and the ground once again returns to the usual conditions of a bog!
Our first charge last night following the mileage done returning from the dealership etc, we got a full charge into the car over the night on the Economy 7, (cheap tariff), we have, so it looks as though there will no rush to do this new cable installation job. We will know more at the end of today once we have put the car through the routine it will mainly experience for the next 5 years or so. I guess the only snag may be when we really run the batteries down, but even then we have the REX to back things up. Thats why we chose that model rather than the 'full' EV.

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Contact: Website

Re: New member, charging question.

Mon Jul 23, 2018 9:20 pm

I think It's quite hard, If your chargers is 20 AMP and your breaker is 15 AMP obviously that is not going to work
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