Sparks when connecting battery

[stuartrubin]

I'm finally able to take my '75 124 Spider out of winter hibernation. First thing, I went to reinstall the battery which had been on a maintainer for the last five months or so. When I make the second connection (negative/black after the positive/red has already been connected) sparks are drawn. These are not huge sparks (not like a dead short across the battery or anything), but visible, sizzly sparks.

I don't see any obvious loads (lights, etc.) which would draw current.

Is this normal?

Is this SAFE? I mean, if I were to connect the battery, could I start a fire, blow up the battery, etc.?

Electrical stuff scares me (ironically since I have an Electrical Engineering degree), but maybe I'm over thinking this.

Thanks!

Stuart

[So Cal Mark]

connect a ammeter between the post and cable and see what the draw is

[124JOE]

yes thats normal
nothing to worry about

[spider2081]

On a 75 Spider what would on to make the battery connection spark?? All I can think of is the clock and I don't think that draws enough current to make a visible spark.

[RRoller123]

Something is on, or shorted, and is pulling a bit of current to cause sparks like that. And more than just the clock. Mine never sparks, and obviously the clock is on when the connection is made. +1 on Mark's suggestion, see if the current draw is significant.

[spider2081]

Are you sure you are connecting the battery correctly?? There have been a number of posts here where folks have connected the battery reversed.

[DieselSpider]

Some aftermarket radios or alarm systems do have a large enough parasitic draw to cause minor sparking. You may be able to isolate it by pulling a one fuse at a time until you find the circuit that has the load on it and is causing a spark when you connect the battery. An automotive test meter set on the battery as Mark suggested would be the best tool to show you how much draw you are dealing with to dimension the level of the issue.

[GeorgeT]

I assume that the ignition switch was in the full "OFF" position: your clock has a parasitic drain, if you have a digital radio there is a parasitic drain to maintain station pre-sets, if a door was open the courtesy light would have come on and finally the "parking" lights would have come on if the lights dash switch was in the "ON" position.

[stuartrubin]

Thanks for everyone's info. I really appreciate the help. Here is some more:

First off, I am color blind and asked my wife to confirm that I had the red and black wires correct. She informed me that there was NO black wire, but in fact, the wires were red and green! So I need to back up and figure out which polarity is which. The battery is in the trunk and looking into the trunk from the back of the car, there is a short red wire on the right (passenger) side that appears to be connected to the chassis (but it might be insulated?). There is a green wire on the left (driver's) side going into the body of the car. Currently (not pun intended), I have the red wire connected to the positive (+) side of the battery. I have momentarily connected green to the negative (-).

Intuitively, red seems like it should be positive. Of course, the fact that it's connected to the chassis makes it look like it might be ground (-).

Soooo.... is my battery in backwards? What would I expect from that?

Unfortunately I have a blown fuse in me multimeter so I have not been able the measure the current. (It's possible that when I tried to measure the current, that's what blew the fuse!) I will try to replace it today and get a current measurement.

Also, the doors are closed, no key in ignition, I don't have a radio connected, etc., so current draw from accessories should be negligible.

All comments and ridicule welcome!

Stuart

[aj81spider]

On my 74 and on my 81 the passenger side wire, connected with a short wire to the chassis is ground. The driver side wire is plus.

Any wire connected to the chassis is either ground or connected wrong (on a negative ground car like the Fiat).

[So Cal Mark]

you have the battery connected backwards. That could damage the alternator

[stuartrubin]

So I go back and forth between thinking I'm an idiot and/or over my head with this car, but sometimes I feel like I'm just being tricked and people are out to get me.

If in fact I did have the battery backwards, then the guy who had it before me put RED on the Negative! It's an abomination! Red it positive in the civilized world, right?

I have one theory. The guy who had the car before me used to work on MGs and this was his first (and presumably last!) Fiat. I believe someone once told me that MGs have "positive ground", that the chassis was connected to the positive side of the battery. So, maybe he just connected a battery with a red wire to the chassis the way he did it on MGs. It's just a theory, and I'd like to give him the benefit of the doubt. Otherwise, it's criminally lazy, negligent, or just downright malicious! Any thoughts on the MG theory?

I only momentarily connected the lead and never had the key in, so hopefully there was no damage beyond my ego. I will try it tomorrow.

Thanks

Stuart

[DieselSpider]

He may have replaced the black ground cable with a red one if that's all he had on hand. The green on mine is the positive on the left and goes through the body inside the car under the rear seat and along the left sill to the front of the car. I would put a disconnect on the ground which is how mine is set up and either replace the red with a black wire or paint it black. I don't rely on colors for the ground connections any more as I have seen too many make due with what they had on hand or was available at the first store they stopped at and put a red cable in place of a broken battery ground.

[spider2081]

I have seen a number of Spiders that have the battery in the trunk use a red battery cable for the ground. I am not sure but I think that black battery cables may not be easily found that short so people use red. There is another potential problem with using a red battery cable for the ground. On many batteries the positive post is larger than the negative post, therefore the cable end openings are slightly different sizes. In some cases a red battery cable will not properly tighten on a negative battery post. With the cable tightened to its limit the cable can be rotated on the post making a poor connection.

Reversing the connections on the battery can certainly damage the alternator diodes. Just touching the post as you state may not have damaged the alternator diode but might have damaged the voltage regulator. If you have a Bosch alternator with the regulator on the back of the alternator it can be replaced with the alternator on the car.

[lglade]

And don't let a little frustration get to you. These cars are can be challenging, but there are few issues that a bright and studious owner can't resolve on his/her own, especially with the help of the really great folks on this forum.