Strange jump start issue

Maintenance/Repairs
1

I have a 2010 Honda CRV. I forgot to turn off a light in the car last night and today the car couldn’t start. A similar problem happened three months ago when the car was parked without usage for three months, and I fixed it with a jump starter. However, this time I tried jump start using a jump starter and another car, but it didn’t work. Finally the car started after I connected the negative clip to the negative terminal of the battery, instead of to the stud bolt. According to the manual and many websites, connecting to the negative terminal is not safe. I am wondering why it worked this way. Thanks.

2

That simply means there’s a poor connection at the battery.

Tester

1 Like
3

The best electrical connection is positive donor battery to positive receiving battery and same for negative. But this is the most dangerous as batteries off gas hydrogen and a nearby spark at the battery terminal can ignite the hydrogen with unfortunate results. So best practice is to make the final negative connection away from the battery. When there is a spark, it is far enough away from the hydrogen to be a non issue. As @Tester said you have a poor connection from the battery to the rest of the cars electrical system. Clean and tighten the connections (carefully please)

4

The jump start stud proved to be a poor connection. The battery terminal is much larger, therefore a greater clamping force from the jump start clamp.

5

Thanks all for the information! This really helps. I know little about car. Does this problem mean the positive-side connection between the booster battery and the car is poor? The connection looks fine to me and I brushed the positive terminal beforehand, but maybe that is not enough.

Regarding safety, yes I did see sparks when connecting the negative side to the battery. I hope I don’t need to do it in the future.

6

It is possible that the stud bolt is the source of the bad connection, but probably less likely.
Big reminder: when working on the battery connections, a specific order of work is important:

  1. Remove the negative cable first, then remove the positive.
  2. Clean both terminals.
  3. Replace the POSITIVE first, and then replace the negative.
    Doing this in the correct order protects YOU. When the negative battery is connected, your entire frame and engine are all negative. Touching the positive and the frame at the same time is not good! (Similar instructions go for the use of jumper cables.)
7

If you ever do, make sure to wear safety glasses to help protect your eyes if the battery does explode.