Parasitic drain while driving..?

[danijam]

Hi there - new to the forum but not new to RVing. My husband and I are on our eighth pull behind trailer (three were tent trailers). We bought a new 2023 Winnebago Hike 100, but on our first three hour drive bringing it home from the dealership we began to experience the truck stalling at low idle. The tow vehicle is a 2016 F150 that has towed two other trailers. We immediately replaced the battery and alternator in the truck because we read that could be the problem but it happened again our next trip out. We never leave it plugged in overnight or anything like that. Interested in hearing if anyone else has had a similar problem and what the remedies may be. Voltage on the 7 pin on the trailer is 13.5 and on the truck 7 pin is 14.5. Any thoughts would be greatly appreciated before we head out for a 3,000 mile road trip. Thank you!!

[Skip426]

So if I understand your info correctly , the truck doesn't stall unless the trailer is hooked up .

14.5 V , on the truck pin is high considering a new battery ; should settle to 13.2>13.5 very quickly after trailer disconnect.

13.5 on trailer battery indicates a surface charge , what does it read if disconnected over night with nothing left on in the trailer ?

Charge line from the truck is fuse protected , excessive draw from the trailer systems should blow that fuse.

[danijam]

Originally Posted by Skip426

So if I understand your info correctly , the truck doesn't stall unless the trailer is hooked up .

14.5 V , on the truck pin is high considering a new battery ; should settle to 13.2>13.5 very quickly after trailer disconnect.

13.5 on trailer battery indicates a surface charge , what does it read if disconnected over night with nothing left on in the trailer ?

Charge line from the truck is fuse protected , excessive draw from the trailer systems should blow that fuse.

The truck only stalls at low idle after about 1.5+ hours of pulling the trailer. For example at a red light or in stop/go traffic we have to keep giving it light gas (and simultaneous brake) to keep RPMs up enough to avoid a stall. This happened both before and after the new battery/alternator on the truck.

Haven’t ever run the battery down on the trailer but we might get there on the Oregon Coast trip. We do have a new Lion battery. Also a solar panel and inverter. These are things we’ve never had in previous trailers.

When the truck is running, the mechanic read 3 amps in the trailer 7pin when he climbed under the trailer and used a clamp to measure. The measurement dropped to zero when the truck was turned off.

Not sure if this is helpful additional info… thank you for weighing in!! Seems like a very unusual issue from my research online and talking to the RV technician.

[Toby Dog]

Since the sun is always on why isn't the solar on the trailer charging the battery if you are traveling during daylight hours?
Something is turned off or wired wrong on the trailer side.
How long have you had the trailer?
Another suspect is a blown fuse or a bad relay under the hood in the fuse block.
Battery cutoff switch comes to mind also.

[Richardson2]

Sounds to me like something on the truck side. After towing is the engine temperature elevated? Possibly ignition system problem. I would have a mechanic run a diagnostic check on the engine.

[traveldawg]

You haven't told us if this happens when not pulling get trailer.

I'd suspect something going on with the truck.

Try not using the trucks 12v charge when towing (you have solar). See what happens.

[MtCamper]

I'd have the mechanic pull the charge fuse on the truck and remeasure the amperage going to the trailer. That said, a 3 amp load should not cause stalling at idle. Then I'd have the fuel filter changed on the truck. What happens after a long trip without the trailer? I think you'll find the problem on the truck side.

[Dave Pelletier]

Originally Posted by traveldawg

You haven't told us if this happens when not pulling get trailer.

I'd suspect something going on with the truck.

Try not using the trucks 12v charge when towing (you have solar). See what happens.

Yep; this. just disable the charge line and see what happens - my guess is that there is an unrelated truck problem.

Dave

[MFL]

I agree, may not be trailer issue, but possible ECM issue with truck, which is known to cause low idle/stalling.

[Skip426]

Considering other reported issues with L-ion battery required charge rate ; I'd say disabling the charge line from the truck would be the first thing to try .

[danijam]

Originally Posted by Toby Dog

Since the sun is always on why isn't the solar on the trailer charging the battery if you are traveling during daylight hours?
Something is turned off or wired wrong on the trailer side.
How long have you had the trailer?
Another suspect is a blown fuse or a bad relay under the hood in the fuse block.
Battery cutoff switch comes to mind also.

This is a good thought and along the lines of an idea we're going to test. We bought a 7-pin pig tail for between the truck and trailer. We've disconnected the wire connecting the trailer battery to the truck. All other pins still working. Meaning lights and brake will work, but we'll rely on solar to charge the battery while we travel... our first night out is going to be Sunday and we're driving four hours so we'll try that and I'll report back if that fixes the problem.

[danijam]

Originally Posted by Skip426

Considering other reported issues with L-ion battery required charge rate ; I'd say disabling the charge line from the truck would be the first thing to try .

This is what we're going to try. Good to hear another vote of support for this approach!

[danijam]

Originally Posted by MtCamper

I'd have the mechanic pull the charge fuse on the truck and remeasure the amperage going to the trailer. That said, a 3 amp load should not cause stalling at idle. Then I'd have the fuel filter changed on the truck. What happens after a long trip without the trailer? I think you'll find the problem on the truck side.

It's a good question. Unless the trailer is connected the truck usually only goes short distances. That being said, we did take it three hours to pick up the trailer with no issues. After an hour and a half with the trailer connected that first day, the truck was stalling, and happened again after the second hour and a half when we got home. We replaced the battery, alternator and asked Ford to check everything electrical related tip to tail, which they did. We've cleaned out all the connectors etc...

Next thing to try is that pig tail with the removed connection to the trailer battery... Looks like we're in for one of those 'trouble shooting' holidays, but I guess that adds to the adventure!

[Skip426]

Were all the stalling problems on the same tank of fuel ?