Accelerate Your Home Charging – home charging explained

Table of contents

1. Type 1 (J1772)

1.1.Type1 cable included with the car (factory cable)

1.2. Type 1 accelerated cable

1.3. Type 1, Type 2 & Tesla US dual phase charger

1.4. Tesla US imports (Tesla Model X and Model S cars imported to Europe from USA)

2. Type 2 (Mennekes)

3. Table of EV and PHEV cars along with charging capabilities

4. Mitsubishi Outlander PHEV special case

5. Conclusion

6. Postscriptum – what do I use at home and why

7. Questions and FAQ according to this text – tpirowski@vtechtuning.eu (in English please).

Prologue

There are three popular types of plugs for EVSE charging with AC current (home current): Type1 (J1772), Tesla US proprietary connector (a variant of Type 1) and Type2 (often called Mennekes).

1. Type1 (J1772)

Type1 is popular in Japan, so it is common in Japanese cars. Also, in countries where single phase power is common home AC source (like USA), Type1 is in use.. Even US Tesla uses Type1 charging, while using proprietary socket – but there is no problem to use Type1 charger with an adapter, included with any Tesla. So home charging of US Tesla = charging of Type1 car.

Type1 has a simple limitation – it is a single (one) phase system. All the current must be drained from one phase, even if you have 3-phase system in your home/garage.

1.1.Type1 cable included with the car (factory cable)

Because people can have different limitations of current per phase (protected by fuse), home charger included with the car must accomplish the lowest common current limit. This is 10A. Such current means that the fuse protecting the charging circuit is not B10 (10A fuse), but B13 – to avoid loading circuit to 100%.

So if your single phase wall socket is protected with B13 fuse or any higher amperage – there is no problem to drain 10A = about 2,2 kW of power.

Now you may ask – why 2,2 kW, and not 230 V * 10 A = 2,3 kW? Simple. Loading home circuits with a current like 10A causes voltage drop of about 10V so your real power is 10 A * 220 V = 2,2 kW.

1.2. Type 1 accelerated cable

As communication protocol for Type1 permits higher currents than 10A, there are many aftermarket cables with current of 16A or even up to 32A. Of course setting the amperage too high causes the fuse to break the circuit, or in the worst scenario – a fire is possible. Standard Schuko or similar home socket is theoretically capable to do 16A, but all depends on cables behind. So for amperages higher than 10A it is important to have a dedicated circuit (or at least a perfect insurance for house and good luck). Charging with single phase at 16A will cause voltage drop of about 10-15V (of course less if we have dedicated line with thick cables) so real power will be around 3,3 kW.

Important: NEVER connect your car with any EVSE cable through retractable extension cord, as induction will generate huge voltage losses and generally may be dangerous.

Disadvantages of accelerated cables (like 16A cables) are simple: overloading power sources with high amperages causes voltage drop and the overall efficiency is lower. Also, heat losses reduce overall efficiency and increase cost of charging – as up to 10% of energy may be converted directly to heat in wall cables due to high amperage.

1.3. Type 1, Type 2 & Tesla US dual phase charger

Such charger (Accelev) must have 3-phase connection. Also it is not a simple cable that controls charging, but it is a high-efficient AC/AC converter, that builds one „super-phase” from two normal AC phases. Such „super-phase” has slightly higher nominal voltage and dynamic voltage stabilization against load, enabling faster charging even in current limited cars. It is still portable, but heavier, than simple EVSE cable.

For average European house, where 3-phase power is delivered, protection fuse is B16 (16A) or 20A. Usually higher power may be possible, for extra cost. So max charging speed may be 16A per one phase.

As a simple example we can compare charging speed of empty Nissan Leaf battery with double on-board charger. We have a house with B16 or B20 protection, 3-phase 400V is delivered to the house. Such power supply is common in Sweden, Germany, Poland, Denmark etc.

Factory cable: 10A * 220V = 2,2 kW (voltage drop due to load is assumed to be 10V)

Aftermarket 16A cable: 16A * 215V = 3,4kW

Accelev 2-phase charger: 2 * 12A * 250V = 6,0 kW (every phase is loaded with 13 A, as we need energy to boost up voltage)

Advantage of 2-phase charger is simply visible. No overloading of phases, fastest possible home charging without any special power delivery line. No high currents = no heat losses = high efficiency.

1.4. Tesla US imports (Tesla Model X and Model S cars imported to Europe from USA)

As standard charging method in USA is Type 1, Tesla uses the same protocol for AC charging, except that they use proprietary design of plug & socket (but connections are 1:1). In Europe, where 3-phase power delivery is common and max. amperage is much lower than in USA, owners suffer with slow charging speed. It is enough to say that factory EVSE cable delivered with Tesla US will charge the same Tesla in Europe with “astonishing” speed of 6-8 km/h (2.0 kW or less).

With dedicated Accelev (with proper Tesla plug) or with standard Accelev + Tesla Type 1 adapter you can see speeds of charging like 30 km/h – at home. Without any special high amps installation.

So +80 km over the night, or +300 km… The decision is simple.

Please note that Tesla dedicated version of Accelev uses Tesla plug and it can be used to charge other Type 1 cars only with Tesla Type 1 adapter (see photo)!

Tesla dedicated Accelev will be a bit slower for cars other than Tesla (comparing to standard Accelev) or even, in some circumstances it can refuse to charge a car, as it is especially designed for Tesla and focused on fastest possible Tesla USA charging.

2. Type 2 (Mennekes)

Type 2 is a simple evolution of Type 1 that enables using more than one AC phase within same protocol and communication rules. There is no oblige to use all these phases, so one, two or three can be connected. Cars can accept current from more than one phase in case when equipped with multi-phase charger (that means in most cases that they have two or three separate chargers for every phase installed onboard).

As you can simply check in table in section 3, where most EV and PHEV cars with their charging capabilities specifications are listed – almost all Type 2 cars use single phase 3,6 kW charger (16A max). Two phases are used solely in Q7 e-Tron, three phases can show their potential in Tesla, Renault Zoe and newest version (2017+) of BMW i3 (older use single phase charger).

Accelev is compatible with most of actual EV and PHEV cars with good gains of speed. As delivery cable (cable from Accelev to car) is replaceable, so you can have and change Type 1 to Type 2 (or even to Tesla US) connectors.

3. Table of EV and PHEV cars along with charging capabilities

Table below consists of most of known EV and PHEV cars, number of phases and type of plug they use, max charging power theoretical (gross) and approximated real (net), and gain of speed, while using 2-phase Accelev EVSE instead of 16A aftermarket charging cable.

Colors represent:

Green – perfect gain for Accelev over other chargers

Pale green – good gain for Accelev over other chargers

Orange – not applicable or slower than direct EVSE connection.

In simple words: If you live in Europe, or other region where energy delivering for private separate properties bases on 3-phase 400V or similar system – green will mean “must have” – you will accelerate 2 or more times your charging (for Outlander PHEV there is a special trickery to accelerate charging more than the numbers show – see below to paragraph 4). Pale green – 20% acceleration, no phases overload, orange – no idea to use Accelev (no gain).
Red – incompatible.

The last column shows 3h charge with 16A EVSE as a time of same charge for Accelev – so you can see time savings (beside of other advantages like lower phase loads).
Time saving versus factory 10A charger is not presented (Accelev is 2-3 x faster than any factory 10A EVSE cable).

4. Mitsubishi Outlander PHEV special case

PHEV on-board charger limits current at 14A, so typical power delivered to empty battery is about 3 kW max (with factory cable it is 2.0 kW or so).

During charging, PHEV has two special periods, used to prebalancing, with length of about 15 minutes, where charging is reduced to 0,2 kW (10x slower). This prebalancing has some sense, if you focus on charging battery a bit (like up to max 80%). There is no reason to do that (and loose time) if you need your car quickly charged, and final balancing can be processed overnight.

Accelev cancels both these periods, and postpones prebalancing to the last, slow phase of charging. This saves a lot of time – for example with 16A charger you will measure about 2.2 kW charged within first hour (first prebalancing occur after 10-20 minutes from start of charging of empty battery). And with Accelev – 3,5 kW.

This explains additional time gain for Accelev – it saves about 25 minutes (slightly less than half an hour) extra due to postponing prebalancing to the last charging phase (night phase).

This is valid for all PHEV model years – 2013- 2018.

5. Conclusion

Using 2-phase charger in an average European house, where 3-phase 16A or similar power is delivered, gives an opportunity to double charging speed without high amperage and thus – heat loses (ecology & costs cut). It is fast, safer and efficient.

For Tesla US imports 2-phase charger gives similar speeds like EU Tesla can have from home 3-phase connection – so it is a “must have” for them – 3 x acceleration of charging is worth it.

6. Postscriptum – what do I use at home and why

This will be more private… I live in a village where power supply is not as it should be. If I measure voltage in wall sockets, it is usually 210V (it should be 230…). Ok, many new houses, no new energy transformers nor lines.

My fuses at energy meter are C20 (3 – phase, installed by energy supplier) and in home – B16. So theoretically I can take 16 A from one phase – but if I charge EV car with 16A charger and my wife switches on even a lamp, PC or so – fuse switches off.

Please do not laugh, but while charging my wife’s Leaf with factory cable - charging power was 1.8 kW/h because of low voltage (do you believe you have 230+V in your wall sockets? Check with voltage meter – my Swedish friend was so proud of their power grid until he measured his voltage – 215 V..). So for Leaf it is 18-20 hours to charge it fully with balancing from zero (and girls love animals, especially turtles at the dashboard;) And we have also Outlander PHEV and Tesla. Where to connect them?

So I have invented Accelev. I have Accelev 5kW. It is enough for me, as I have 16A protection. Now, with phases monitoring I charge my wife’s car with 5 kW/h, and my Outlander with 3 hours max (see paragraph 4 for explanation). And we still use electric cooker, boiler, etc. No risk of blackout. All monitored by my Accelev.

If you focus on max speed – Accelev 6 kWh is for you. If you focus on low load per phase – Accelev 5kWh is a perfect compromise.