Snow plow use affects engine power?

[Marco#1]

This might be addressed somewhere else, but I’ve looked around for a while and can’t find any particularly useful posts about this issue, or very many discussions about snow plows at all.

I have a late 2018 JLU Moab with a snow plow that I use just around the house, and I noticed if I operate the plow while driving (lift, angle left, or angle right), the jeep literally slows down from the loss of engine power, especially once the blade has reached the travel limit (full height or fully angled left or right). I have the negative cable of the plow harness connected directly to the negative terminal of the main battery and the positive terminal of the plow harness connected to the relay, and the other side of the relay is connected directly to the positive terminal of the main battery. For the relay switch, I have the negative side also connected directly to the battery negative terminal, and the positive signal is provided from the hand controller whenever a directional button is pressed.

I get the theory behind high-draw electrical devices resulting in a loss of spark energy, which in turn can affect engine power, but this seems way excessive. It's like I've downshifted or pulled the parking brake, and as soon as I stop operating the plow the engine jumps back to life. The electrical hookups are pretty basic, but I'm wondering if anyone has any insight on this, thinks I should connect to something other than directly to the battery, or maybe has some other advice I might not have considered.

I do have the cold weather package, I do not have the towing package.

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[GtX]

2018... Original batteries?

 

[Beachcomber72]

Probably going to come down to just basic power struggle because of what you’re pushing physically with the vehicle. Are your operating in 4hi or 4lo?

 

[Quadjeeper]

Alternator load bogging the engine.

 

[Reinen]

If you're still on your original 2018 batteries they're due to go soon. My suspicion is that the alternator is drawing heavily on engine power trying to compensate for the weaker batteries unable to fully power your plow.

Here's a quick & easy test. Put your ESS screen on. If it often says ESS is not ready due to battery charging while you use the plow, the batteries are getting old and weak. The plow is overwhelming them and the alternator is working overtime drawing engine power trying to charge them back up.

 

[Marco#1]

The sudden lack of power isn’t related to pushing snow. The blade can be in the air, just swinging it from left to right causes the problem.

 

[Marco#1]

Yes, original batteries but probably going to replace before the snow hits this year.

Yes, definitely seems like alternator load is bogging the engine, but way more pronounced that I think seems reasonable.

I don’t know if I’ve ever seen ESS disabled because the batteries are charging. Usually it’s because I’m heating the cabin. And there doesn’t seem to be any lack of power to the plow. And as strange as this will sound, the Jeep seems to be running fine, just feels like someone pulled the parking brake a little bit while the hydraulic pump is operating. It’s not sputtering or anything like that. Just feels like I’m pulling something heavy uphill or something like that (even if the plow is completely in the air). I’ll have to put the plow on tomorrow and do a few tests. Haven’t had it on since probably February, but just thinking about it because the season is coming up soon.

 

[Reinen]

Yes, original batteries but probably going to replace before the snow hits this year.

Yes, definitely seems like alternator load is bogging the engine, but way more pronounced that I think seems reasonable.

I don’t know if I’ve ever seen ESS disabled because the batteries are charging. Usually it’s because I’m heating the cabin. And there doesn’t seem to be any lack of power to the plow. And as strange as this will sound, the Jeep seems to be running fine, just feels like someone pulled the parking brake a little bit while the hydraulic pump is operating. It’s not sputtering or anything like that. Just feels like I’m pulling something heavy uphill or something like that (even if the plow is completely in the air). I’ll have to put the plow on tomorrow and do a few tests. Haven’t had it on since probably February, but just thinking about it because the season is coming up soon.

It doesn't sound strange to me at all, everything you're seeing fits old weakened batteries. I'd go ahead and replace them. They've already lasted longer than average. Between your plow and Boston weather you've gotten a good life out of them. There's a good chance you'll see even stranger things happen this winter if they aren't replaced.

So replace the batteries as at least a preventative measure and I strongly suspect your plow issues will stop happening.

 

[Jebiruph]

If you don't have the tow package, you have the smaller alternator, maybe you need a higher rated alternator. Does the plow manufacturer give any guidance regarding the alternator output? Have you checked all of the electrical connections? A bad connection will draw more power. Also monitor the system voltage while you're operating the plow and see how low it gets.

 

[58Willys]

CANBUS based vehicles and their associated electronics, are very sensitive to voltage fluctuations. The JL is not engineered to support a snow plow or such. I doubt anything is wrong, just a lot of load on the electrical system.

 

[Marco#1]

If you don't have the tow package, you have the smaller alternator, maybe you need a higher rated alternator. Does the plow manufacturer give any guidance regarding the alternator output? Have you checked all of the electrical connections? A bad connection will draw more power. Also monitor the system voltage while you're operating the plow and see how low it gets.

Something I have definitely considered. The plow I have is specifically designed for jeeps and light pickups, so it doesn’t have the big commercial grade hydraulic pump (or the weight) found on other snow plows.

CANBUS based vehicles and their associated electronics, are very sensitive to voltage fluctuations. The JL is not engineered to support a snow plow or such. I doubt anything is wrong, just a lot of load on the electrical system.

Quite honestly my assumption too, which made me think there might be a better way to connect it instead of the traditional direct to battery terminals.

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