Battery hooked up backwards,OOP!

[sola mesa]

What did I fry by hooking up my new battery backwards on my John Deere 850? Yes, I am an idiot!

 

[Scotty370]

Don't beat yourself up so quickly, "idiot" !. What happened when you put it back in correctly?

 

[ultrarunner]

Speaking from the collector car world... you shouldn't have a problem unless you have an alternator and/or electronics.

Happens a lot on cars with generators and the worst thing is the battery meter reads charge when it's discharging and vice versa...

Does it start normally and charge ok?

 

[sola mesa]

Nothing! No lights no nothing. It also smoked when I first hooked it up backwards. I changed all the fuses.

 

[Bird]

I did that to the mayor's Plymouth when I was 17. That was when I learned that some cars had a positive ground. I'm not sure just how far he drove it, but it didn't hurt the car; just ruined the new battery.

 

[ultrarunner]

Some vehicles have fusible links to protect wiring...

Looks like you will need to start tracing the wires back from the battery, checking for power as you go...

Wish I could give you specifics on Deere.

 

[jimainiac]

If your local dealer has a good service department, a call to them might yeild some good suggestions.

 

[kennyd]

Have you checked or replaced the battery? It was probably damaged.

 

[kenstrac]

I have 3 prints for 850 none of them have a fusible link what I think happened is you blew the voltage reg or alt taking the switch with it press the temperature test switch and if you have a light then the power is getting to the switch if not the wire is burnt from starter.Find a white wire w/black tracer at the fuse block and see if you have 12V make sure key is on and light sw is on if you don't have power either the Ing switch is blown or the wire is bad if you find the problem do not leave the alt or voltage regulator in the circuit or you will be going through this again. I hope the starter did not run reverse polarity because it is a PM starter and will turn backwards.

 

[waynokakid]

Don't feel alone. I did that to my 300zx, once. Won't do it again. Fried it's little brain. $800 repair. Not sure what it will do to a tractor, not as many electronics to mess up.

 

[Scotty370]

How long did you have it reversed? Smoke=Bad!

 

[Deano]

Had a friend do something similar. He hooked up jumper cables backwards and attempted to start it for about 15 minutes. When he realized it and finally did get it sterted, it would not shut off. Fuse or a fusible link was damaged if I remember correct.

Deano

 

[AndyMA]

How long did you have it reversed? Smoke=Bad!

As an EE I'm not sure time matters much. Any components damaged by reverse polarity and not high current would probably be damaged in way under a second. Many engineers,, myself included usually design for reverse polarity protection. The ones are that is difficult to design for are the high current circuitry to solenoid and starter, but that should not have been energized. Lights, wipers, fans etc don't care. Computer's and the like are easily protected with a single diode or a diode bridge. I would think JD would have them. If some high current pulled enough current to smoke I would like for burnt wiring and blown fuses.

 

[biggerten]

As an EE I'm not sure time matters much. Any components damaged by reverse polarity and not high current would probably be damaged in way under a second. Many engineers,, myself included usually design for reverse polarity protection. The ones are that is difficult to design for are the high current circuitry to solenoid and starter, but that should not have been energized. Lights, wipers, fans etc don't care. Computer's and the like are easily protected with a single diode or a diode bridge. I would think JD would have them. If some high current pulled enough current to smoke I would like for burnt wiring and blown fuses.

As another EE, I agree about the time issue, things blow very quickly. I'd be concerned about the voltage regulator/alternator. The alternator diodes would have been forward biased and conducting heavily. I'm less sanguine about reverse-bias diode protection, I'd bet there isn't any. It's common enough elsewhere, sure, but I doubt it in this application. Have been wrong before, could be wrong here, but...............

Good luck!

 

[AndyMA]

I'm less sanguine about reverse-bias diode protection, I'd bet there isn't any. It's common enough elsewhere, sure, but I doubt it in this application. Have been wrong before, could be wrong here, but...............

Good luck!

I agree.Having spent quite a bit of time working on auto electrical systems leading the electronics team that did the first Bose car stereo, I learned 2 things. One is the environment is worse than the space shuttle and what is done doesn't always make sense at first glance.

Andy

 

[kebo]

I'm an electronics tech and we have an old saying in the business.... Everything electric runs off of smoke but when you let the smoke out, things quit working! I would try Kenny's suggestion first, make sure the battery is NOT the problem by trying another known good one. If it still doesn't crank, then you might have burned a wire in two, but it could be covered by the insulation. That would make it tougher to fix meaning you'll have to trace it down with a meter. If you haven't already figured it out by now, inspect the wiring and everything else tied to the wiring VERY closely. Good luck. Let us know what you find out. It could help someone else here.

 

[dcyrilc]

I'm an electronics tech and we have an old saying in the business.... Everything electric runs off of smoke but when you let the smoke out, things quit working! I would try Kenny's suggestion first, make sure the battery is NOT the problem by trying another known good one. If it still doesn't crank, then you might have burned a wire in two, but it could be covered by the insulation. That would make it tougher to fix meaning you'll have to trace it down with a meter. If you haven't already figured it out by now, inspect the wiring and everything else tied to the wiring VERY closely. Good luck. Let us know what you find out. It could help someone else here.

We have the same problem over here in Washington. Things just don't work after you let the smoke out!

 

[Dead Horse]

Look at the wiring diaagram. See where there are diodes in the circuit(s) you energized. It is likely that one or more of them got fried.

Take a look at them........if they unplug, test them with a continuity meter. if not, replace the highest probability ones first.

Good luck.

 

[Soundguy]

As an EE I'm not sure time matters much. Any components damaged by reverse polarity and not high current would probably be damaged in way under a second. Many engineers,, myself included usually design for reverse polarity protection. The ones are that is difficult to design for are the high current circuitry to solenoid and starter, but that should not have been energized. Lights, wipers, fans etc don't care. Computer's and the like are easily protected with a single diode or a diode bridge. I would think JD would have them. If some high current pulled enough current to smoke I would like for burnt wiring and blown fuses.

Ditto that, a simple diode or bridge would likely protect the entire dash cluster.. could even build an EZ circuit to protect the alt as well.

soundguy

 

[Matt_Jr]

I would check the wires to and from the ignition switch. Especially if the key was in the run position when the battery was hooked up wrong.