Voltage drop with winch?

[HoosierJeeper]

Decided to use the winch today for fun since I haven't used it since summer. Started pulling the KJ and the battery light came on. Stopped winching for a sec, went off, winched a bit more and it came back on. Repeated this a few times. Turned off the headlights and revved it up a bit and that seemed to help.

Is this normal?

 

[tjkj2002]

Your typical winch under load will draw up to 400 amps.If you have good battery and connected correctly(top post only) the battery light should not come on.Mine never has but I also have a high draw rated battery.

 

[HoosierJeeper]

Maybe I should get the battery tested. I did replace the alternator with one from a junkyard, same part # and it tested ok before I installed it.

 

[LibertyTC]

Ya 400 amp that is severe duty. Your basic electronic load test is not going to help.
You will need a carbon pile 500 amp tester or something bigger, that can also check the Alt too! LOL.
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IDK if the Sear Platinum AGM's are still available, not here anyways, but the Odyssey PC-1500 DT will handle that load no problem.
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[HoosierJeeper]

This never happened when I had the factory alternator in that I can recall. Although this one should be the the same one. Is this more of a function of the alternator or the battery? The battery is about 2.5 years old, a Diehard Gold.

Also, when winching, should I always keep the RPMs up as opposed to just idling?

 

[M38 Bob]

I've had a couple different rigs with a wench, always held em at fast idle when using it. Best setup is a secondary battery,charging off vehicle alternator, but output available only to wench.

Bob


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[boboborino]

agree with tjkj and bob. I'm thinking your alternator just can not keep up, so revving it up would help and should be done. Some people upgrade their alternator for this reason.
On my vehicle with the winch I can increase my idle RPM with my tuner when I use my winch and my compressor, even though my alternator output is sufficient, it just helps.

Bert

 

[HoosierJeeper]

Which alternator do you have? I have 136 amp stock one. My factory stock one worked fine as far as I remember.

 

[boboborino]

I was not talking about my liberty, and after reading this:
http://www.jeepkj.com/forum/f196/high-output-alternator-45408/index5.html
looks like a higher output alternator is not an option, and as tjkj mentions a better battery is in order

Bert

 

[HoosierJeeper]

That's what I thought...
I just want to figure out if my battery is the shortcoming now or if something is wrong with the new (used) alternator.

 

[HoosierJeeper]

Just went out and played in the driveway with it and it worked just fine. Driveway is a mild incline and I set the parking brake a bit to give resistance. Did it at 3k rpm and at idle.

One thought I had is that yesterday when I got the light, I was down to the last few wraps on the drum. I know that winches have the most power at that stage but do they draw more power at that stage too? I had never pulled with that little of line on the drum.

 

[HoosierJeeper]

Got the battery load tested and it's working at 84% of its capacity. So I guess that would be the issue.