I'm not sure what's going on with my Jeep, but here's what happened. I used my winch for the first time pulling out an old brick column from my yard. I know, I'm supposed to use the winch on my own Jeep or some other vehicle, but I just couldn't resist. Anyway, while I was pulling the column from the ground, my engine quit on me. In fact, the engine died about four times while I was pulling in the column. I figured that maybe I should have increased the RPM to compensate for the electrical drain on the battery, but this was just an after-thought. The winch is wired directly to the battery and I didn't have anything else, such as the air conditioner, running at the time. Is this normal? Should I have kicked up the RPMs while using the winch? Was I supposed to wire the winch directly to the battery, or should I have used a relay? BTW, the winch is a Superwinch EPi9.0 and is less than a year old.

 

Are both the positive and negative winch wires connected directly to the battery?

Yes, you need to kick up the idle when putting such a large load on the battery. Probably what happened is the voltage dropped below a threshold where the computer turns the whole works off.

 

Yes they are.

 

That's what I was thinking; just wanted to make sure this was normal. Next time I'll kick it up. Thanks guys.

 

My 2 cents. It is normal, I've done it a few times. Voltage drops and the engine shuts down. I use an Odyssey battery, so there is plenty of juice left to restart.

 

Even with high idle the alternator puts out 140 amps tops. The battery has another 100 amps available. It doesn't take long to pull the battery down with the winch drawing 3-4-500 amps. Just takes a bit longer with the engine running.

Don't be fooled by the 650 (or whatever) cranking amp rating of the battery. That rating is only good for a few seconds. The true reserve capacity of a JK-sized battery is only about 100 amps.

Its probably a good thing the computer shuts everything down when the voltage gets low. Otherwise the winch would drain the battery and then suck on the alternator until it fails.

Dual batteries seems like the best approach. Even then some common sense is needed. Depending on the type of dual battery system, both batteries may supply the winch while the engine is running. This means the system can still go dead, same as a single battery. A really good dual battery setup should protect against this happening. Even a simple contactor type dual setup can provide protection, but it takes a manual switch and an operator who understands what is happening.

Really good AGM batteries like the Oddysey provide another option, but any single battery can be drawn down with enough load over time. The group 34 Oddysey that fits the JK can provide 62 amps for 135 minutes. That's only about 150 amps reserve capacity - better than most but small compared to what a winch can draw.

 

Hmm... I have a superwinch EPI 9.0S and with it directly hooked to the battery I have pulled myself a few times deep in the mud with just the engine idling and never had it die yet... However I do have the superchips set at 87 maybe that’s the difference?

 

It's interesting when you look at the numbers like cranking amps, reserve voltage and the amps required to operate the winch. Perhaps the battery wasn't completely charged to capacity because the sometimes sits for a coupls of days.

 

I, too, run the Superchips 87 Octane tune, so maybe my battery was charged up all the way.

 

Your winch draws 350 amps at full load. If you pulled a little harder than the winch's rating, the winch would ask for a lot more amperage.

The winch pulled hard enough that it caused a short term voltage drop and triggered a computer shut-down. The Jeep's computer acted like a breaker switch - a really good thing because the overload could have caused a smoked electical system.

A tuner chip will let you raise the idle while pulling which helps a lot. Fast idle will only add maybe 80-100 amps however, so if your winch wants 350 amps but the battery+alternator can only provide, say, 275, then you could still get a voltage drop that triggers a shutdown.

Its a numbers game. Seems like your Jeep is doing just what it should.

BTW, I'm with you. The winch is a power tool. Used correctly it should be good for more than pulling vehicles.