So I have been messing with the alternator on my 2005 Honda Civic out of boredom, as well as educational purposes. But I have been wondering about the consequences of running the car without the alternator functioning. And if you were wondering, I have not seen any definite efficiency gains from disabling the alternator. Maybe 2 and 3 explain this?
I have an Optima Yellowtop D34 deep cycle battery in the trunk, which can run this car for quite a while as long as accessory usage is minimized. I have driven this car for 2 hours on the highway running off the battery before no problem, although I didn’t use any accessories. But the bad news is that I’m not sure how much efficiency I actually gained, if any.
I have been wondering what the negative effects could be though. I know that the battery life may be shortened by charge and discharge cycles, but I am not worried about it because it is a deep cycle battery and I don’t usually cycle it that deeply, so I am more concerned about how the lower voltage can affect the car’s overall performance.
In no particular order, a few ways I can think of that a lower voltage can adversely affect performance:
1. Reduced accessory performance, such as somewhat dimmer lighting. All of my lighting is LED, but the brightness of some of the bulbs seem to be adversely affected by lower voltage. My fog lights actually flicker a little bit when the alternator is disabled, although I am not sure why. The windshield wipers also run a little slower, the HVAC blower isn’t quite as strong, the power windows aren’t as quick, and the rear defroster seems to take a little longer to clear the window.
2. Reduced ignition coil performance. I am not sure if the ignition coils lose performance when fed a lower voltage. I have heard that the spark wouldn’t be as strong, and I have also heard that the coils will work just as well and will just draw a little more current to compensate. I am not sure
3. Reduced fuel injector performance. The fuel injectors will not open as quickly when fed a lower voltage, potentially throwing off fuel delivery timing and adversely affecting the engine’s performance. But for all I know this ECU may have voltage compensation since the car has a dual mode charging system and is designed to run on lower voltage when commanded by the ECU.
4. Reduced fuel pump performance. When fed a lower voltage, the fuel pump won’t be able to pump as much fuel. This doesn’t seem to be a problem for me, but worth mentioning nonetheless.
Did I forget anything? Thank you in advance! Any input would be greatly appreciated
