After flat towing start battery is dead!

[colt]

I have a charge line going to the appropriate place under the hood . On two different trips the charge line fuse was blown a 10 amp. Fuse and then a 15 amp fuse also blew. The charge line is only #14 wire . What size fuse should I use! The start battery ends up dead at the conclusion of distances from 225 to 400 miles any help would be much appreciated on this subject the charge line I think carries 13 to 14 volts the vehicle is a 2024 lariat hybrid.

Sponsored

 

[DefiantDJ]

To prevent battery drain and ensure proper engine lubrication while flat towing your **2024 Ford Maverick Lariat Hybrid**, Ford recommends a specific maintenance routine during long-distance towing:

Periodic Engine Start Procedure While Flat Towing

To **protect the hybrid system and lubricate internal components**, follow this routine **every 6 hours of towing or every 300 miles**, whichever comes first:

#### Step-by-Step Instructions:
1. **Stop the tow vehicle** in a safe location.
2. **Start the Maverick Hybrid** (press brake and push Start).
3. **Shift through gears**:
- Move the rotary dial from **Park → Neutral → Drive → Low**, then back to **Neutral**.
4. **Let the engine run for 5 minutes**.
- This circulates fluids and maintains lubrication in the hybrid transmission.
5. **Re-enable Neutral Tow Mode**:
- Use the steering wheel controls to go to:
- *Settings* → *Vehicle Settings* → *Neutral Tow*
- Hold **OK** to confirm.
6. **Turn off the ignition**, but **leave the key fob inside** the vehicle.

> **Important**: If you skip this step, you risk damaging the hybrid transmission due to lack of lubrication.

---

### Battery Maintenance Tips

To avoid 12V battery drain during towing:

- **Install a Battery Charge Line Kit**:
- Connects your RV’s 7-pin connector to the Maverick’s battery.
- Keeps the battery charged while towing.
- **Use a supplemental braking system** with low power draw (e.g., Blue Ox Patriot or RVi Brake).
- **Avoid leaving accessories on** (interior lights, infotainment, etc.).
- **Check battery voltage periodically** with a plug-in voltmeter.

---

### Pro Tip
Some owners also recommend installing a **voltage monitor LED** in the cabin to visually confirm battery health while towing. If the LED dims or flickers, it’s time to stop and recharge.

 

[Dave O]

To prevent battery drain and ensure proper engine lubrication while flat towing your **2024 Ford Maverick Lariat Hybrid**, Ford recommends a specific maintenance routine during long-distance towing:

Periodic Engine Start Procedure While Flat Towing

To **protect the hybrid system and lubricate internal components**, follow this routine **every 6 hours of towing or every 300 miles**, whichever comes first:

#### Step-by-Step Instructions:
1. **Stop the tow vehicle** in a safe location.
2. **Start the Maverick Hybrid** (press brake and push Start).
3. **Shift through gears**:
- Move the rotary dial from **Park → Neutral → Drive → Low**, then back to **Neutral**.
4. **Let the engine run for 5 minutes**.
- This circulates fluids and maintains lubrication in the hybrid transmission.
5. **Re-enable Neutral Tow Mode**:
- Use the steering wheel controls to go to:
- *Settings* → *Vehicle Settings* → *Neutral Tow*
- Hold **OK** to confirm.
6. **Turn off the ignition**, but **leave the key fob inside** the vehicle.

> **Important**: If you skip this step, you risk damaging the hybrid transmission due to lack of lubrication.

---

### Battery Maintenance Tips

To avoid 12V battery drain during towing:

- **Install a Battery Charge Line Kit**:
- Connects your RV’s 7-pin connector to the Maverick’s battery.
- Keeps the battery charged while towing.
- **Use a supplemental braking system** with low power draw (e.g., Blue Ox Patriot or RVi Brake).
- **Avoid leaving accessories on** (interior lights, infotainment, etc.).
- **Check battery voltage periodically** with a plug-in voltmeter.

---

### Pro Tip
Some owners also recommend installing a **voltage monitor LED** in the cabin to visually confirm battery health while towing. If the LED dims or flickers, it’s time to stop and recharge.

Good advice - I have not seen a battery drain issue flat towing my 2025 Lariat AWD Hybrid

 

[Steve Wolf]

I have a charge line going to the appropriate place under the hood . On two different trips the charge line fuse was blown a 10 amp. Fuse and then a 15 amp fuse also blew. The charge line is only #14 wire . What size fuse should I use! The start battery ends up dead at the conclusion of distances from 225 to 400 miles any help would be much appreciated on this subject the charge line I think carries 13 to 14 volts the vehicle is a 2024 lariat hybrid.

Kind of sounds like you're getting replies from bots or ai. Dumb ai.

Google "how do I use a meter to find a short circuit" and learn that.

I would start by putting a meter between the disconnected charging line at the vehicle's post and ground. Set the meter to show a short. Work backwards on your charging line until you see where it is shorting to ground. Wiggle here and there until the meter wails and you've found the fault.

If nothing, take the plug apart and see if the wiring in the plug is messed up.

If there is no fault, if the charge line is fine from the motorhome plug to the battery post, then you have an issue with your motorhome charge line. If you have a Winnebago, get the wiring diagram and start tracing back from there.

I bet the charge line that was installed between the motorhome and the post has worn through and is shorting to ground. The plug is also a major candidate for a short.

 

[processwrench]

the issue isn't having the charge line its that the OP is blowing 10 and 15 amp fuses, thats 180watts! my entire brake controller is fused for 15 amps. somewhere you have a major draw. All that charge line should be doing is trickle charging the battery. Maybe somehow the brake controller is actually drawing from the charge line and not the TOAD battery

 

[Yetiman]

Earlier this year, I set my Maverick up for flat towing using my 2018 Coachman Class A. Coachman did not run a 12v wire to the 7 pin on the back of the RV. I had to add that. I ran a 12ga fused wire from the battery with a 20amp fuse to the 7 pin. My brake system (RVI Brakeshadow) uses a 20amp inline fuse. When the engine is running at idle, I get 14.3v at the 7 pin. It is probably a little more when I'm actually driving and running higher rpms. If it were me, and if it was easy, I would replace the 14ga wire with 12ga and go with a 20amp fuse, but I personally wouldn't feel like it's too much of stretch to just bump up the fuse to a 20amp and see how it goes.

You definitely don't want the braking system to not work because you drained out the very small 12v Maverick battery.

As another poster noted, it's important to stop at 6 hours and run the engine for a while. 6 hours of RV driving is my limit anyway.

Good Luck.

 

[Scenicgene]

I tow my 2024 Mav XLT behind my MH. I installed A charge line kit I bought from Etrailer that feeds from the MH plug. I think the kit has a diode in the line but I installed per instructions and have no problems with the battery. I like buying towing stuff from Etrailer because they have decent tech support if your stuff isn’t working properly.

 

[processwrench]

The brake controller in the TOAD should be connected to the TOAD 12v battery. As Yetiman said above the brake controller itself can draw 20 amp or more intermittently. HOWEVER the 12v charge line from the motorhome is to top off the battery, not to run the brake controller, it doesn't or shouldn't need to supply more than 5 to 10 amps to do so, that's why a 14ga wire is plenty big enough for this. The fact that somehow this is pulling 15+amps indicates a problem.

 

[Scenicgene]

If you’re blowing fuses make sure you’re going to the positive post under the hood instead of a ground. The labeling around the jumping points are a little confusing at first glance

 

[MakinDoForNow]

I tow my 2024 Mav XLT behind my MH. I installed A charge line kit I bought from Etrailer that feeds from the MH plug. I think the kit has a diode in the line but I installed per instructions and have no problems with the battery. I like buying towing stuff from Etrailer because they have decent tech support if your stuff isn’t working properly.

I installed a 7 pin relay from Curt to power the trailer lights and to charge the auxillary battery the wire from the battery to the 7 pin was fused with 30amps......
ETA: if your RV battery is 12.6-12.8 volts and your toad battery is 11 volts or less what will be the amps to equalize the two. Batteries. Be absolutely sure you have the proper diode?

 

[MikeC]

Are you using a DC charger or just a direct line? You should have a current limiting DC charger to charge the battery in the Maverick while flat towing. The line itself would then be sized for the charger you are using.

 

[Platinum2]

To prevent battery drain and ensure proper engine lubrication while flat towing your **2024 Ford Maverick Lariat Hybrid**, Ford recommends a specific maintenance routine during long-distance towing:

Periodic Engine Start Procedure While Flat Towing

To **protect the hybrid system and lubricate internal components**, follow this routine **every 6 hours of towing or every 300 miles**, whichever comes first:

#### Step-by-Step Instructions:
1. **Stop the tow vehicle** in a safe location.
2. **Start the Maverick Hybrid** (press brake and push Start).
3. **Shift through gears**:
- Move the rotary dial from **Park → Neutral → Drive → Low**, then back to **Neutral**.
4. **Let the engine run for 5 minutes**.
- This circulates fluids and maintains lubrication in the hybrid transmission.
5. **Re-enable Neutral Tow Mode**:
- Use the steering wheel controls to go to:
- *Settings* → *Vehicle Settings* → *Neutral Tow*
- Hold **OK** to confirm.
6. **Turn off the ignition**, but **leave the key fob inside** the vehicle.

> **Important**: If you skip this step, you risk damaging the hybrid transmission due to lack of lubrication.

---

### Battery Maintenance Tips

To avoid 12V battery drain during towing:

- **Install a Battery Charge Line Kit**:
- Connects your RV’s 7-pin connector to the Maverick’s battery.
- Keeps the battery charged while towing.
- **Use a supplemental braking system** with low power draw (e.g., Blue Ox Patriot or RVi Brake).
- **Avoid leaving accessories on** (interior lights, infotainment, etc.).
- **Check battery voltage periodically** with a plug-in voltmeter.

---

### Pro Tip
Some owners also recommend installing a **voltage monitor LED** in the cabin to visually confirm battery health while towing. If the LED dims or flickers, it’s time to stop and recharge.

What a pain in the ass.

 

[Dave O]

What a pain in the ass.

My 2025 Maverick Lariat AWD Hybrid is one of the easiest and best vehicles I’ve ever flat towed towed and I’ve towed many - I currently flat tow my 2025 Maverick and have my 2004 Jeep Wrangler TJ set up to flat tow…

 

[Platinum2]

Geez....I'd hate to see the requirements for all the others then....

 

[Dave O]

Flat Towing is so much better than trailering or using a tow dolly which requires more maintenance and dealing with storing extra equipment at the campsite

Sponsored