The Charge of the BMW i3

My i3 came with two charge leads a type 2 to three pin, and a type 2 (Mennekes) to type 2,

Type 2 to three pin, the three pin refers to a standard three pin plug (yes you can plug into a standard house socket).The type 2 is the attachment to the car! This connection is the slowest charge and would generally take over night dependent on how flat the battery is it is a 13 amp charge which equates about three electrical units which if you need 27 kwh should take about  9 hours however I would expect that the chargers work at different stages bulk charging upto 80% and then trickling in for the last 20% at a slower rate so the battery does not overcharge over heat and go into thermal runaway (more about this later)

The other lead is a type 2 to type 2 this is normally the type used in public charging and the type you would possibly have fitted at home or at your office. It is suggested that it should charge in 3 hours I think the figure may be four especially if the battery is totally discharged.

There are a growing number of charge points all over the country. BMW themselves recommend Chargemaster they issue you with a swipe card that is free to use for the first six months. The most popular app for finding charge points appears to be Zap Map this seems to have the most comprehensive list of charge points.Zap Map also will tell you if the point is in use what type of charge connection there is and the speed of charge plus much more. Your i3 does have the charge points on the sat nav but I have found Zap Map better.

Charge points connectors  are another point of interest you can have tethered or untethered the former means that the charge lead is connected to the charger the later the opposite so with an untethered charger you would carry the lead with you.

Once you have had your charger fitted at home you will want to know how much the cost of charging at home is. This obviously depends on how much you flatten your battery the BMW battery is a 94ah 360 volts making a 33kWh battery with the battery extender taking over at 6.5% battery capacity that gives a useable capacity of about 27 kWh (or 27 electrical units) From here it is quite simple to work out the cost of the charge. At home I pay just under 12p per unit so the cost to charge a flat battery would be 27 x 12p £3.24 we do however have economy 7 at home the cost of this is 6.5p per unit the same sum adds up to £1.75. One of the things I have learnt at County Battery Services is that chargers and batteries are never 100% efficient and the faster they are charged the less efficient they become I would assume the lithium battery in the i3  at the low rate of charge 95% efficient but there seems to be little data published.

There are a multitude of different chargers with government grants available as long as you are prepared to share your charge data with the bureaucrats. I decided not to bother as it was cheaper to have a charger with no meter than it was to get the grant and share the information, I also have an issue with bureaucracy. It is worthwhile to note that there are grants available of £300 for both home and business metering. I have ordered a basic model from Rolec for work at a cost of about £360 inc vat just need a friendly electrician (Ross Stoneman) to fit it! There are quite a few adverts on the web for home chargers but I am quite happy to use the three pin plug.

Just whilst we are on the charging of the batteries I guess we should look at that side of the car. There are numerous types of Lithium batteries used in electric vehicles for this article I will only look at the three marques I consider to be market leaders which in my opinion are are the Tesla  and the BMW i3. Each manufacturer uses a different technique and battery type to get the range it requires for the job.

The heavier the vehicle is, the more energy will be needed to drive it. Different manufacturers handled this is different ways. Tesla has an aluminum body (heavier) with Panasonic high-energy 18650 cell of  nickel cobalt aluminium these cells are virtually the same as you might find in and electric drill or laptop computer only in the Tesla there are 7000. I am not sure that there is much chance of improving the battery capacity with these as they are already high energy and in my opinion a battery with 7000 cells is far too complicated . The BMW i3 has a very light body being made of carbon fiber, but  a lower energy-density cell. The battery consists of eight modules of 12 batteries. When BMW wanted to increase the range Samsung the battery manufacturer increased the energy density of the battery and the capacity increased by 50% I am sure it will not stop there!

There is still more to come please follow me to find out more about the BMW i3








One thought on “The Charge of the BMW i3

  1. Pingback: BMW i3 The Electric Highway | The little fat guy from Mansfield

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