How to start a car without a battery

As drivers, it can happen, especially in winter, that the battery fails and the car can no longer be started. The battery is too low to crank the starter. There are usual methods to help the car start like jump-starting it or push-starting it. But what if the battery is not present? Can the car be able to start?

There are some rare situations when the battery is stolen, for example, or when the battery is simply a decorative object. One thing is for sure, starting the car when the battery is low is much easier than starting it when the battery is not present.

It is possible to start a car without a battery?

The answer is yes, you can start a car when the battery is absent, but this depends on several aspects, especially if the car has a manual or automatic transmission.

As I said above if the battery is simply weak you can jump-start it using cables connected to another car’s battery or push-starting it if there are no cables. Using the second option can be possible only if you have a manual transmission car. You should not try to push-start an automatic car, because it can do more harm than good.

There are only 4 options to start a car with no battery:

  • adding a new battery;
  • using a starter-booster;
  • starting with the help of a towing car;
  • pushing the car until it starts.

But when there is no battery or it is simply dead because of cracks, the electrolyte has leaked out, shorted, boiled, then you will still need a start-booster

Regarding a car that has an automatic transmission and no battery, you should not try to start it by pushing it or towing it, because it is problematic and most often even impossible. It is necessary to have at least a weak battery attached to perform a jump start.

Also it will be a lot harder for a diesel car to start without a battery.

How to start a car without a battery when towed?

For starting the car with no battery, or a completely dead one, when towed it will still be necessary a power source that has 10-15 volts. For a correct start, you need to connect the plus power source with the excitation of the alternator, a thin wire to it that is separate, and the minus with the mass.

If there is a battery, but does not work at all, it must be disconnected, and the plus terminal must be properly isolated from the body to avoid short circuits.

  • Connect your car to the towing car with a rope;
  • Disconnect all consumers, radio, etc;
  • Switch on the ignition.
  • Tell the driver in the towing car to start moving;
  • After gaining optimal speed for the selected gear, slowly release the clutch and wait for the engine to start;
  • Remove the device used for excitation without turning off the engine and drive.

Whether you should use the second or third gear, that depends on the engine. If it’s cold use the second gear, if it’s warm you can use the third gear. The lower the gear, the more rpm, and torque are transmitted from the wheels.

Don’t use the first gear, because, when engaged, the engine resistance is higher and it will be harder to push or tow. Also, there is a risk for the timing belt to break or slip due to a sudden change in load.

How to push start a car without a battery?

Again, you will need a power source to excite the alternator when you want to start a car that hasn’t got a battery or its battery is simply dead. This is also valid when you push-start the car. If there is no power at all, then pushing the car will not be able to start it without a battery. They will have to be pushed some distance because the pump needs a little time to add fuel.

  • Before you begin to push-start the car, check if you have a small volume of gasoline in the tank and the presence of a flat area of the road;
  • Reduce the car’s weight by temporarily removing things from the cabin and trunk;
  • Try to find as much more people that can help to push the car;
  • When you have a speed of about 10 km/h (6.2 mph), press the clutch, engage 2nd or 3rd gear and try to make the engine start by releasing slowly the clutch.

If the car has a diesel engine, things will be more complicated since it is much more difficult to start the engine this way due to high compression. Also, until the engine is warmed up or power is supplied to the glow plugs, the diesel engine cannot be started by pushing it, especially in winter.

Common-rail fuel systems are extremely sensitive to stressful situations, which include forced launch, and their repair is expensive. Therefore, if there is a car available that can help, instead of pushing or towing, it is better to jump-start it, it’s much easier and safer, and yes, you should have a battery there, even if it’s weak.

How to drive a car that has started without a battery?

Things are simpler when driving a car that had a weak battery and was started using traditional methods. Here you just have to drive with higher engine speed, so the alternator charges the battery more efficiently and it is advisable not to use strong consumers.

But if the battery is missing, and you managed to start the car without a battery, then it is important to drive very carefully and correctly. Follow the steps below:

  • Try to avoid high engine speeds so that the generated current is not excessively big;
  • Turn on all the strong consumers available, like AC, headlights, radio, so that they take on excess alternator power;
  • Try not to make sudden accelerations to avoid the on-board power supply voltage to fluctuate;
  • Do not drive the car more than is needed. The less mileage, the better.

Driving a car that has not battery is risky, and you should be very careful not to generate a lot of power. The battery is the main consumer of electricity generated by the alternator.

If you start the car without a battery and drive like you are used to, the excess electricity has nowhere to go, which can cause surges and voltage fluctuations, and these are bad for sensitive electronics.

Conclusion

Starting a car with no battery is possible, but only under certain circumstances. Automatic cars and diesel cars are not part of the category of cars that can be started in these conditions. But I do not recommend using this method unless it is absolutely necessary.

If you have a battery, but it is faulty, leave it there, at least to take on all the load that the alternator dumps, thus protecting the parts sensitive to high voltage fluctuations. It is safer for the electronics to drive this way, than without battery at all.

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