Forum

I have already talked about the brake system in earlier posts, and this is simply to bypass (observe?) the Swedish rules for changing cars. If you have any kind of inquiries pertaining to where and ways to utilize lithium ion battery battery pack (devpost.com), you can contact us at our web page. It has nothing to do with the electric conversion.

There may be another thing to the brakes though. Most trendy automobiles have vacuum assisted brake servo and so does my A2. However, when the ICE is removed there is no such thing as a supply for vacuum so I'll want a separate electric vacuum pump.

Motor and controller

The motor I plan to use is a Kostov K9" 220V. Kostov is a Bulgarian company who manufacture motors for fork lifts and now for DIY (Do It Yourself) electric cars. The motor develops 32 kW sustained and 78 kW peak. The peak power is simply accessible during short accelerations for couple of seconds, however this is usually what you want energy to. If you employ the max energy for for much longer the motor and/or controller will overheat and shut down. The motor is rated for a voltage of 220V DC and at peak power the present will be 500A! It is not very massive, solely 22cm diameter, 46cm long and weighs 45kg!

To control the velocity of the motor I need a motor controller. The controller applies voltage in shorts bursts thereby limiting the average voltage and the velocity. I am planning to make use of an Evnetics Soliton Jr which can handle as much as 340V battery voltage and as much as 600A motor current. This will probably be good for the motor. I good feature with the Soliton is that it's configurable through a typical Ethernet connection and an internet browser.

Transmission

Transmision? Do you really want a transmission in an electric automobile? Well, evidently the easiest method to convert a automotive to electric is definitely to keep the transmission and the clutch. The obtainable (inexpensive) electric motors have a torque curve that's usually flat up to around 3000rpm after which torque decreases down to the max rpm which is often around 6000rpm. This means that if you happen to go only one gear you either have to use a excessive gear to obtain a decent top speed. This implies sluggish acceleration and excessive currents at low speed. Otherwise you chose a low gear that gives you good low speed acceleration, but low top speed. A better method is to maintain the transmission and use two gears; second gear for city driving and fourth gear for highway, for instance.

Battery and charger

The most important a part of the conversion (and probably the most expensive) is the battery pack. I'm planning to make use of Lithiun Iron Phosfate (LiFePO4 battery) cells which have a very good mixture of excellent vitality density, life time, and safety (they do not go in flames in the event you overcharge them which I have heard some other LiIon chemistrys do). The newer cells additionally work fairly effectively at low temperature which is necessary if you live in northern Sweden. Each cell has a nominal (the voltage modifications throughout discharge) voltage of 3.2V and the battery pack voltage I am aiming for is 230V nominal. This means I will likely be utilizing seventy two cells. Each cell will hold a cost of 70 or 100Ah. I will decide which when I know the out there space for batteries in the automotive. If I'm going for the 100Ah cells some math tells us that 72 x 3.2V x 100Ah = 23kWh of energy. The weight of the cells will likely be round 250kg so the automobile will in all probability turn out to be around 100-a hundred and fifty kg heavier than earlier than the conversion. The cells I'd like to use are manufactured in China by China Aviation Lithium Battery (CALB), however I have never discovered a good price on them but.

To charge the batteries I obviously need a charger. The usual Swedish energy outlet is 230V,10A and a normal three phase outlet is 230V or 400V,16A. I have not selected charger but, but I might like it to be able to utilise both of these shops. It can most likely be a 3kW charger (230V,16A) since I haven't seen any moderately priced 400V chargers.

Battery management and monitoring

Basicly the concept about battery monitoring and administration is that you shouldn't overcharge nor overdischarge the person cells in your battery since it will lower their life time. So, so as to forestall over discharge and overcharge a battery monitoring system can be used to detect potential over discharges (low cell voltage) and potential over charge (high cell voltage). Battery administration methods then either disconnect a cell from charging utilizing a shunt or shuts down the whole vehicle during discharge. The act of disconnecting a cell from cost leads to a more even cost among the many cells in the battery. This is called balancing the cells and particularly this is known as prime-balancing for the reason that balancing is completed near the utmost allowed cost of the cells.

There's an ongoing debate within the DIY neighborhood about battery management and monitoring (BMS). The agument for not utilizing a BMS is that the most injury to a cell is finished when over discharging, not when over charging it. In order to prevent unbalance near the minimal allowed charge backside balancing can be utilized onstead of a BMS. This might be the route I will go and I will likely spend an upcoming put up on the subject.

Heating

Heating of the passenger compartment is important in northern Sweden. Without the ICE there isn't any heat supply. I imagine I'll need a minimum of 3kW and ideally 4kW of heat power. Many DIYers use ceramic air heaters which they put in instead of the heater core that is heated by the cooling fluod from the engine. Since my A2 has a ACC my idea is to keep the water heater core and put in a thermostat managed water heater and a water pump as an alternative. I figure the output from the ACC to the temperature flap can be used to control on/off of the water heater and pump so that the heater will no be on in the summer. The battery voltage of 230V means I can use European normal heaters. Still, I haven't decided on which to make use of. Maybe one or two Calix engine heater. Or a MES DEA heater with bulit-in pump.

Performance

My simulations of the automotive finally ends up in a prime pace of 140km/h, acceleration 0-one hundred km/h in 10s and an power consumption of 16 kWh/100km using the EU drive cycle. The theoretical range would then be 23/16 x one hundred = 144km when driving the identical speeds and inclinations because the EU cycle. A more practical computation ends up in a range of 130km when driving 100km/h and discharging the battery to 80%. Since my commute is around 60km/day I imagine that a range of 100km is ample. That will give me some margin for error and heat within the winter.

Steering

Many modern automobiles have power assisted steering powered by the ICE. The A2 has hydro electric power steering (powered by an electric motor) so it would hopefully work even without the ICE.

Instrumentation

Some new things will probably be nice to monitor in the electric automotive. For instance, the cost of the battery, battery voltage, motor present, power consumption. Some new instrumentation will likely be wanted to show all this and that i will also try to retain the unique instruments so far as possible. For example utilizing the prevailing tachometer and the fuel gauge to indicate battery charge. Most of this is managed by way of a CAN bus in modern cars so hacking into the CAN shall be one fun challange.

Budget

Well, I have already spent SEK fifty five 000 (EUR 6 100) on the car and my total budget is SEK 200 000 (EUR 22 200). More than half of the 145 000 for the conversion funds is for the Lithium cells. Then comes the motor controller, the motor and the charger as the next most costly components within the conversion.