When troubleshooting and fixing engine start issues, I often have to try starting the vehicle a lot. Eventually I kill the battery. Then I have to recharge the battery and wait. Not only is this inconvenient, but it's a cruel way to treat an innocent battery.

How can I work on starting issues without [ab]using the battery? Disconnecting the battery and hooking the car to the charger (I've never tried this) doesn't seem like the right thing to do, I haven't checked the charger specs but I doubt it can output the required crank current. I suppose I could leave both the battery and the charger attached to the car at all times but I'm not sure if that's a good idea or not, either -- I'd like to not damage the charger, and also, if possible, not damage the battery or unnecessarily reduce its lifespan.

This is for situations where the vehicle will not start, and so a quick jump start and letting it recharge itself is not possible.

  • there might be a way to create a device which uses AC power from the wall with a transformer to power the battery terminals, then it's up to the longevity of your transformer and your house's fuses
    – cat
    Commented May 20, 2017 at 18:37

1 Answer 1


I would do the following:

  • Keep the charger connected at all times except when you start the car. That way, you will be minimizing charger damage. More expensive chargers may withstand the fact that you are cranking, but better to be safe than sorry.
  • Do try to minimize the amount of times you try to start the engine. So, in other words: try to start only after you have reasonable belief that the engine will start this time, after you have fixed something.
  • If the battery fails, buy an enhanced cycling mat (ECM) battery instead. It will work just like a flooded battery, except it's designed to withstand the use in a start-stop system that stops the engine when at stoplights.
  • You can consider purchasing a higher current charger as well. It will in a shorter amount of time charge the battery to full.

I don't believe your fear of ruining the battery is warranted. Consider this: many cars these days have a start-stop system. They start and stop the engine very often, and still the system works very well. I had a 5 and half years old car with a start-stop system and a battery that didn't fail despite its age.

Also, consider this: if a battery lasts for 5 years, and you start your car twice per day, it's 700 starts per year or 3500 starts total. Are you going to try 3500 times to see if the starting problems has now vanished? Probably not. So, assuming you are charging the battery inbetween starting attempts, you should not have a battery lifetime problem.

  • Sounds good. My fear of ruining the battery isn't based on the extra cycles, but rather the repeated discharge and killing of the battery. The number of starts is fine, but I'm worried about taking the charge so low so often. But keeping the charger connected at almost all times (dunno why I didn't think of that) fixes that.
    – Jason C
    Commented May 20, 2017 at 13:53

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