Q: My question deals with jumping a dead car that has not been started for over a month. The battery is eight months old. I tried jumping the car with no success. I had good cable contacts on both batteries and had the running car idling at 2,000 to 2,500 rpm (sometimes higher but not over 3,000 rpm) for several minutes before trying to start the dead one. And I kept it at high idle throughout the process. All I could muster was enough power in the dead car to get something to continuously click and a few lights to come on. I just could not get enough cranking amps into the dead car.
I tried another host car with the same disappointing results. Periodically, I would re-jiggle the cable claws to make sure I had a good battery contact. The temperature was about 80 degrees. The next day when the tow truck came, he just connected his portable battery jumper box to the dead battery and it immediately started! Evidently the portable unit was providing way more cranking amp power than jumping between two cars.
So is there anything I could have done in the jumping process to increase the odds of success? Or should I invest in a real good portable unit (>500CCA) and throw the battery cables out? The cables were middle of the road quality and on the long side which may not have helped? I assume shorter and real heavy gauge are best to prevent amperage loss?
A: It sounds like you applied sound procedures in your jump starting attempt. My hunch is possibly the non-starting vehicle had a dirty battery terminal connection and the service provider raked one or both of his/her cable clamp sides across the top of the battery posts, the other side of the clamp on the battery terminal, circumventing the poor connection. Or one of your jumper cables suffered from a poor connection within one of the clamp/cable assemblies. Heat is a great indicator of electrical resistance! You are correct: Short and thick is best on the cables. I'm also a fan of portable jump start units. Thanks to modern battery technology they're lightweight, robust and convenient. Perhaps other readers can share recommendations for units they are pleased with.
