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Re latest editorial, does anyone else see a major error?

I’t about putting a charged battery upside down over an uncharged battery, with the terminals touching.

Click and Clack state that this puts the batteries in series, and the resulting 24 volts caused damage to the electrical system !

Sorry, guys. That is just not possible. You have only two choices in this connection. First, you match + to + and ? to ?, which puts the batteries in parallel. That was the intent. Or second, you get them reversed, and then you try to reverse charge the dead battery, which probably kills it, and applies a reverse polarity voltage to the car’s electronics.

The only way to put two batteries in series is to remove one of the connections and connect a second battery there.

Now I once owned a MG1100 where I jump started it with reverse polarity. The car ran fine in that mode, but killed the battery. Newer Autos won’t run with reversed polarity, as none of the electronics will operate. But they probably are protected against reversed voltage, but I wouldn’t bet on it.

I think you’re right, Bill. Only way to get 24v is to disconnect the old battery and wire them up in series.


Yup, Bill, you are correct.

Tell me, how did T & R create such a good living doing what they do?

My question is how did this error get by two MIT grads?

And are they going to correct it?

Yep! The guys goofed on this one. They’ll be issuing a correction in an upcoming column.

Happy holidays,

Doug Mayer
Web Lackey

thanks Doug

And while you’re here, Doug, any chance of getting a link on these pages to the ‘find a mechanic’ page? Seems like lots of the question posters end up being advised to use it…

What if they had batteries that had the plus and minus opposite from eachother. What I mean is the batteries were not identical. I don’t listen to the show so I don’t know if this was ruled out.

then there are 3 possibilities.

  1. no contact
    • to + and ? to ?, same as using jumper cables
    • to ? and ? to +, same as cables connected backwards.

Tell me, how did T & R create such a good living doing what they do?

They do it by being more entertaining than they are correct.

Hi Texases, let me see. First up for us is to get the new, drop down navigation in the rest of the site, into the Car Talk Community area. It’s not playing well together, due to different javascript libraries. But we’re working it out. That will help a bit…

Or you could just use this link.

Note also that this weekend’s show was a repeat. I remember the battery to battery jumping proccedure from a while back. Long as it’s + to + it ought to work. It’s definitely dangerous, but it ought to work.


I listened to the show and don’t remember them saying antything about series or 24 volts. They correctly stated that the Albanian would be doing the same thing as jumper cables but that it risked a spill, Hydrogen ignition etc. The point to me is that there’s no reason to assume that the poles would line up (plus to plus). Most likely, battery acid would leak out. I think it’s unlikely that even an Albanian wiould try it!

This is about the editorial, not the show. In the editorial, they state that the upside down battery could result in 24 volts applied to the cars electrical system.


"I think you’re right, Bill. Only way to get 24v is to disconnect the old battery and wire them up in series.


If they were + to - etc they would be in Series, but short-circuited.

The Boys once claimed that the hole in a metal toroid would get smaller when heated. A notion regularly refuted in the Physics 101 Lab.

Monte Haun

Saying the brothers create “editorials” is like saying Glenn Beck is a “News Anchor”

I have read every column in the archives over the years, and learned a lot. I am not claiming they don’t make mistakes, but overall they are a great learning source.

still waiting for that correction.

No comment !