New Alternator = Sparking Battery Terminals ????

[rndcomp]

I just installed a new alternator for my 87 Merc 170 (it already had the aftermarket charging, I only replaced the alternator), and now I am getting sparking at the battery terminals.

There is more to this story. I am also trying to test the compression of my cylinders so I have removed the plug wires and the center coil wire, and the the electronic ignition plug.

When I go to crank the engine, the engine does turn over, however you see itermittent sparks on the + and - battery terminals.

Anyone ever see this before? Did I screw something up. The alternator is a simple single wire 63 amp v-pulley.

Thanks!

 

[Gary H NC]

Re: New Alternator = Sparking Battery Terminals ????

Only time i have seen that was with dirty battery terminals. Clean the posts and terminals with sand paper and see what you get..

 

[evilratgirl]

Re: New Alternator = Sparking Battery Terminals ????

Replacing the alternator itself nor plugs/ should have caused the battery arcing.

I agree with Gary that the battery connections need to be cleaned even though I don't agree with the sand paper use. There are terminal cleanersfor this purpose. They're cheep and work much better.

Hopefully you have properly terminated battery ends rather then the universals. I've seen both terminals and clamps melt due to poor connections.
Not to mention the possiblity of explosion.

 

[rndcomp]

Re: New Alternator = Sparking Battery Terminals ????

I think that I am going to just get new + and - wires all together, as well as new terminals. They are in pretty bad shape. In addition, I have already replaced the ignition, starter, alternator, and battery, seems only right to finish the job off with new cables.

Thanks!

 

[Coors]

Re: New Alternator = Sparking Battery Terminals ????

Are you sure you re-installed the wires correctly?
I have seen batteries send pieces flying at sub-sonic speed, when hooked up wrong, or alt hooked wrong.

 

[WAVENBYE2]

Re: New Alternator = Sparking Battery Terminals ????

Are you sure you re-installed the wires correctly?
I have seen batteries send pieces flying at sub-sonic speed, when hooked up wrong, or alt hooked wrong.

I agree with COORS, any time I have ever seen that happen wires are crossed some where...

 

[Coors]

Re: New Alternator = Sparking Battery Terminals ????

My step son stopped quick, new boat to him; thru-hull exhaust, flappers frozen open.
Water ingestion, he cranked on it, and blew pieces off the battery, including a terminal.
I epoxied the hole in the battery, and it is still working, as a back-up.
I mean it blew a hole in the case, and blew a terminal off.
Glad no-one got hurt.

 

[rndcomp]

Re: New Alternator = Sparking Battery Terminals ????

The only wire in question is the single wire from the alternator. No other wires were changed. Should there be a ground lead from the alternator? It appears to get it's ground via the direct contact with the mounting bracket. Does the fact that I have the plug wires and electronic ingition plug removed make a difference? Where should I be looking for crossed wires since nothing else was changed.

I am now confused....

 

[WAVENBYE2]

Re: New Alternator = Sparking Battery Terminals ????

What color is the wire???

 

[rndcomp]

Re: New Alternator = Sparking Battery Terminals ????

What color is the wire???

The single wire that is connected to the alternator is the red wire.

Does it make sense to try to remove all accessory wires and only keep the primary + and - cables connected to the battery? Also, if it were crossed wires, wouldn't they spark anytime the ignition is turned to on? From what I saw it was only sparking when the ignition was turned to 'start'.

When we say crossed wires, are we saying that one of the hot leads has been grounded out? Please help, I am not able to do a compression test until I get this resolved.

Thanks!

 

[WAVENBYE2]

Re: New Alternator = Sparking Battery Terminals ????

Its just my opinion, but I firmly believe you shouldn't be sparking at all if the termanals are tight, loose then I could understand, but not when there tight. Are the battery cables worn out at the connectors? what I would do is check every thing you did when you installed it, I'm looking at mine right now. could be a faulty alternator(new) has happened before. Did it come with installation in instructions ?

 

[rndcomp]

Re: New Alternator = Sparking Battery Terminals ????

The battery terminals and wires are in pretty bad shape. As for the alternator, it didn't come with instructions, however, it was only one wire, 2 bolts, and a pulley to install. I am hoping that even I could could do it right. I will swap out the cables and terminals and see what happens.

Thanks!

 

[WAVENBYE2]

Re: New Alternator = Sparking Battery Terminals ????

Let us know what happens. Bad cable ends hopefully is the cause, good luck!!

 

[wire2]

Re: New Alternator = Sparking Battery Terminals ????

When you remove the clamps from the battery posts, I believe you'll find a black oxide coating on one terminal. That coating is highly resistive and must be totally removed. When you have the posts clean & shiny, apply a coat of silicone grease all over them, then clamp your new cables on. The grease will prevent oxidization indefintely, but not interfere with the electrical connection.

 

[rndcomp]

Re: New Alternator = Sparking Battery Terminals ????

Problem solved. I replaced the cables and connectors and all appears OK. The old ones were pretty rusted, and my guess is that since my old alternator was bad, there was never enough juice on the battery to cause the sparks.

 

[WAVENBYE2]

Re: New Alternator = Sparking Battery Terminals ????

Good, some times its the little things that cause the most probs. I am glad to hear that what it was...Pat