He would have an equivalent 5 ohm 20 watt resistor above the 3 paralleled injectors. If the 3 injectors are around 2.4 ohms, we are very close or over the power rating. In parallel, they are about 0.8 ohms. So more than 2 amps is flowing. But I bet it would work.
But we still have a situation where a majority of the voltage is dropped before the injectors.
There is a very cheap way to correct this. Have a capacitor with its + side 'noded' between the 'top' of the injector bank and the 'bottom' of the two 10 ohm resistors (that are paralleled). Its - side goes to ground.
As I understand it, the actual switching takes place under the injectors and then to ground.
So the capacitor will 'load' 12 volts through the two power resistors and then 'fire' the 12 volts when the transistor connects the bank to ground. This 12 volts provides the initial snap for the injectors. The 'battery' 12 volts provides the following holding current (which is at a lower voltage when the transistor is on). Once the transistor goes off, the capacitor is again seeing 12 volts through the top end (it charges as a RC circuit). We could even fly-back the injectors back emf to help charge up the capacitors. This even closes the injectors faster.
Very cheap and neat.
But we still have a situation where a majority of the voltage is dropped before the injectors.
There is a very cheap way to correct this. Have a capacitor with its + side 'noded' between the 'top' of the injector bank and the 'bottom' of the two 10 ohm resistors (that are paralleled). Its - side goes to ground.
As I understand it, the actual switching takes place under the injectors and then to ground.
So the capacitor will 'load' 12 volts through the two power resistors and then 'fire' the 12 volts when the transistor connects the bank to ground. This 12 volts provides the initial snap for the injectors. The 'battery' 12 volts provides the following holding current (which is at a lower voltage when the transistor is on). Once the transistor goes off, the capacitor is again seeing 12 volts through the top end (it charges as a RC circuit). We could even fly-back the injectors back emf to help charge up the capacitors. This even closes the injectors faster.
Very cheap and neat.
Comment