Leaving in flat tow overnight

[kcmusa]

We tow the bronco and sometimes don’t disconnect and wonder if leaving it in tow mode will drain the battery or cause and other issues?

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[Valhalla]

 

[Bykerboy]

I do it all the time with no issues.

Update: I do have a charge line attached.

 

[kcmusa]

so first time and got the battery warning message in the morning.

 

[ksdon]

We have a charge line attached to our hook up system. It is in the same cable as the brake and turn signal cable. We have had the Bronco in Flat tow for up to 3 days without disconnection.
It has never drained the battery.

 

[Bill K]

We tow the bronco and sometimes don’t disconnect and wonder if leaving it in tow mode will drain the battery or cause and other issues?

Assuming you have a brake booster for the towed Bronco, I would power this down at night. That's the biggest draw for me as that system is around 2 amps. Other than that, it would be just like parking your Bronco with its battery shared with the towing vehicle's battery assuming you have run a charge line which I did.

 

[evofxdwg]

Yep I would suspect your aux brake system has signficant load even when not being used. Maybe break in the power wire and measure it with an amp meter? Or measure at the battery and then verify it is parasitic from the braking system by turning it off or disconnecting. (Note there are normal parasitic loads but not sure of their magnitude, as my Bronco has some relays that click occasionally with me just being nearby with a fob).

I leave mine hooked to motorhome in flat mode frequently but never had a problem in the morning (except that stupid check brake system light, which always happens exiting flat tow). I have a 12V charge line but it is only live when motorhome ignition is on. I know my aux braking system draws very little when on (and not actually braking). I have the Demco Stay and Play system.

I suspect battery drain is responsible for some of the catastrophic flat tow failures/transmission damage we used to hear about. I would be very careful until you get it sorted out what is causing it and fixed. Maybe as simple as turning the braking system off or disconnecting.

 

[BB5]

After setting your Bronco to Neutral Tow, remember to turn the ignition 'Off'. Just wandering away with it still in Accessory is what I suspected put my bronco into a battery protect mode once. It took three days to draw down the battery to protect mode, as I recall. The battery was still at 12 volts, per the dashboard.

 

[dgorsett]

I do it all the time with no issues.

Update: I do have a charge line attached.

This, plus I disconnect my brake system power wire overnight

 

[grtharris]

After setting your Bronco to Neutral Tow, remember to turn the ignition 'Off'. Just wandering away with it still in Accessory is what I suspected put my bronco into a battery protect mode once. It took three days to draw down the battery to protect mode, as I recall. The battery was still at 12 volts, per the dashboard.

I keep the key fob in my pocket while I'm doing the hook up. That way if I walk away with the ignition on the horn will honk a couple of times. Only did it one time way back in the begining.

 

[Bill K]

I keep the key fob in my pocket while I'm doing the hook up. That way if I walk away with the ignition on the horn will honk a couple of times. Only did it one time way back in the begining.

Me too. One of the reasons I didn't disable the double honk as it was a reminder for me as well...

 

[kcmusa]

I have found the installer did not connect a charge line. So I found the 12v wire but it’s not working correctly. Think I need a diode on the line.

 

[Bill K]

I have found the installer did not connect a charge line. So I found the 12v wire but it’s not working correctly. Think I need a diode on the line.

My line is fused within my RV towing vehicle. That being said, I put an auto reset circuit breaker in between on the RV +12V and the Bronco battery.

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