Ugh. Installed battery backwards and tried to start it. Really tried to start it.

[E30-Ellerman]

FLAME AWAY

Can't post on my local forum as I actually have to make face with those people. Not really too sure what I was thinking or how I managed to do this, but I did and it was bad.

Put the battery on backwards, it didn't like it but I kind of massaged the terminals on. Tried to start it, it just turned over and turned over but didn't fire up. After, noticed a real bad smell and smoke coming from the engine bay. No fire, smelt really bad. Realized what happened, swapped battery around, fired it up and it started and ran fine but the battery light stayed on while the key was out of ignition?

Took everything off the top end, intake, etc to prep for a turbo build and it was the alternator that smelt really burnt. Replaced that, smell is gone, hoping nothing else is fried.

Anyone know what else I may have fried in the process? Hoping that battery light was due to me frying the alternator or a diode in it.

Thank you!

[M-technik-3]

Won't be the last one to do it. Have fun chasing down toasted wires. Sorry to hear of your pain. I had a mouse chew threw my under dash wires and I had a fire going down the road, NOT FUN but killed the mouse. Didn't know it was in there, was an e36 so no worries.

[E30-Ellerman]

Eeek, that is kind of terrifying.

Fortunately, the only thing in the car right now is the bottom end so I've been able to inspect all the wires, they seem to be in fine shape, alternator definitely smelt fried. No fuses were blown fortunately either.

Guess I'll just have to put everything back together and go from there.

[mamzak]

I feel your pain. This exact scenario happened to me years ago. For whatever reason the neg cable on my car used to be red? Don't ask me..Have since replaced that to prevent future fuck ups. Anyways...had the car at a storage facility for the winter and when I went to hook up the battery like 6 months later I wasn't thinking and hooked it up backwards. Cranked and cranked and cranked, even fucking boosted it with the battery backwards. Fuck me.

Same thing happened, really really bad smell. Finally clued in what the fuck was going on and was devastated. I ended up replacing the alternator and the main power wire that connects the alternator because that was melted to shit. This was about 5 years ago now though and I haven't had any electrical gremlins or anything. My radio wasn't working for a while and then all of a sudden it started again and I thought maybe it was an aftershock of my fuck up but I think it's more likely a case of it just being old. It's an aftermarket pioneer deck circa 2004. Haven't replaced it yet because it's working again.

So anyways. Don't feel too bad. You're probably fine!

[E30-Ellerman]

I feel your pain. This exact scenario happened to me years ago. For whatever reason the neg cable on my car used to be red? Don't ask me..Have since replaced that to prevent future fuck ups. Anyways...had the car at a storage facility for the winter and when I went to hook up the battery like 6 months later I wasn't thinking and hooked it up backwards. Cranked and cranked and cranked, even fucking boosted it with the battery backwards. Fuck me.

Same thing happened, really really bad smell. Finally clued in what the fuck was going on and was devastated. I ended up replacing the alternator and the main power wire that connects the alternator because that was melted to shit. This was about 5 years ago now though and I haven't had any electrical gremlins or anything. My radio wasn't working for a while and then all of a sudden it started again and I thought maybe it was an aftershock of my fuck up but I think it's more likely a case of it just being old. It's an aftermarket pioneer deck circa 2004. Haven't replaced it yet because it's working again.

So anyways. Don't feel too bad. You're probably fine!

Thank you! Hoping that it was just the alternator I fried, if the radio too I'll see if it magically comes back on or hunt down a fuse, not too concerned about it though.

[Das Delfin]

some quick facts about car batteries ~

the positive and negative terminals are actually different sizes. The positive is slightly bigger. This is to prevent hooking it up backwards by mistake

traditionally germans use brown for earth (negative). Also you know the earth cable is earth because you can see it's bolted right into the side of the car.

while you're in there thinking of this stuff, batteries vent acid in the form of vapor through a tiny hole in each side of the battery. You want to plug one hole and run the other to a plastic tank using a clear rubber hose. Otherwise the vapor will condense back into acid and rust out your battery tray

The battery light is actually an alternator light - it lights up when your alt is bad

might want to give your fuses a one-over just to be sure.

Good thing this happened in an old car and not a newer one!

[E30-Ellerman]

some quick facts about car batteries ~

the positive and negative terminals are actually different sizes. The positive is slightly bigger. This is to prevent hooking it up backwards by mistake

traditionally germans use brown for earth (negative). Also you know the earth cable is earth because you can see it's bolted right into the side of the car.

while you're in there thinking of this stuff, batteries vent acid in the form of vapor through a tiny hole in each side of the battery. You want to plug one hole and run the other to a plastic tank using a clear rubber hose. Otherwise the vapor will condense back into acid and rust out your battery tray

The battery light is actually an alternator light - it lights up when your alt is bad

might want to give your fuses a one-over just to be sure.

Good thing this happened in an old car and not a newer one!

Fabulous info, thank you.

You see, BMW is good to make the terminals a different size. In my mental stutter, I figured the terminals needed to be 'massaged' (I hammered them with the back end of a screw driver) to make them fit.

Thank you about the battery or alternator light thing too, that has been changed.

Think I am lucky! Will know these tips for future.

[Johnnyboy101]

Hey - I did the same thing with my car. In fact, here is my shameful 'HELP' thread:

http://www.r3vlimited.com/board/showthread.php?t=378867

In my case, both of the cables were black, and I also used a screwdriver or wrench in my attempt to bash the cables on the terminal. First thing I did afterwards was wrap the + terminal in red electrical tape.

Like you, I ended up replacing my alternator, and I also had to replace the ABS relay and my radio. Didn't run into any other issues, luckily! Hope the same goes for you!

[E30-Ellerman]

Haha glad to know I'm not alone! Thanks for the post and happy to know it shouldn't be too bad.