Alternator Problems with Casita

[Ron in Wyo]

Just bought a used 2002 Casita Sprite Deluxe 17 foot. The owner before me said that when he towed the trailer with the 12 volt refrigerator on would cause the alternator to go bad. I towed it 900 plus miles with the refrigerator off, and my alternator on my 2013 GMC pickup is not working properly. Has anyone had any alternator problems ?

Thank Ron

[cpaharley2008]

You GMC is under warranty, ask the dealer the cause. I see little connection between the 2 other than coincidence.

[Donna D.]

Hi Ron to FiberglassRV, we're glad you're here

I don't see any revelance between a refrigerator that's not running on 12volt and an alternator either. But, the alternator should charge the battery under tow, if properly wired/hooked up.

Others will be along shortly with other suggestions

[MarkyVasquez]

The power wire on the TV plug should have a fuse. If there was a large current draw or if there is a short, the fuse would blow before the alternator. The alternator should be heavy duty if you bought the TV with the tow package. The fuse is usually rated at 20 to 30 amps. Unless the TV plug power was wired direct without a fuse, the fuse was bypassed or a larger rated fuse was installed the trailer should not burn the alternator. Even if the fridge is on.

[RogerDat]

If the hot wire to the trailer plug is too small of gauge it can make the alternator work harder to try and charge the trailer battery. Or run the fridge for that matter.

Still considering that an alternator runs all your TV lights, the blower on the AC/Heater, rear defrost, wipers, with reserve enough to still run your power windows and stero it should not "fail" from charging your trailer battery unless as Marky points out there is no fuse on the line to the trailer and a short.

[MarkyVasquez]

The trailer also has a fuse for the fridge. The fuse will protect unless it was bypassed or replaced with the wrong fuse. If nothing has been tampered, the alternator just went bad.

If you have a meter or a friend with a meter you can check the trailer current draw. You have to know how to connect the meter to test for current. The circuit is broken and the meter is placed inline. Do not connect the meter across the circuit red to pos and black to neg the way we measure voltage, this will blow the meter fuse or even damage the meter. Disconnect the power wire and connect the meter inline. There are several videos on YouTube on measuring current.

[RogerDat]

Originally Posted by MarkyVasquez

....
If you have a meter or a friend with a meter you can check the trailer current draw. You have to know how to connect the meter to test for current....

Excellent! Looks like we have a new member with electrical skills.
Electrical problems can be a bear to solve, and do tend to come up a lot so having a new member with some knowledge in the field is always welcome.

[Ron in Wyo]

Originally Posted by RogerDat

Excellent! Looks like we have a new member with electrical skills.
Electrical problems can be a bear to solve, and do tend to come up a lot so having a new member with some knowledge in the field is always welcome.

I do have a meter and electrical skills, will do some testing when get a free moment. Thanks for all the advice
Ron

[Bob Miller]

GM "Usually" connects the trailer DC power feed wire to something called the #2 stud in the underhood fuse box. Both of my GM so equipped had a 30 amp fuse built into the box just for that use.

GM-Delco alternators are usually considered bullet proof, I would install 120 amp versions on Toyota Motorhomes and they would last forever

[Brian B-P]

Originally Posted by RogerDat

If the hot wire to the trailer plug is too small of gauge it can make the alternator work harder to try and charge the trailer battery.

The alternator - or more precisely the regulator which may be built into the alternator - doesn't know or care about the trailer. It will not change behaviour in response to the state of charge of the trailer battery. The trailer is just another thing attached to the vehicle taking power, and as long as it doesn't take too much current I agree with the statements already posted that it can't hurt anything.

[RogerDat]

Originally Posted by Brian B-P

The alternator - or more precisely the regulator which may be built into the alternator - doesn't know or care about the trailer. It will not change behaviour in response to the state of charge of the trailer battery. The trailer is just another thing attached to the vehicle taking power, and as long as it doesn't take too much current I agree with the statements already posted that it can't hurt anything.

If it can not get a full charge to the trailer battery I was thinking there would be a constant draw. Making the alternator and regulator work at a greater portion of rated capacity than normal for a longer period of time. Possibly causing a marginal alternator component to fail.

I tend to think it was not related to the trailer, as do you. If it was trailer I would expect a dead short in trailer to blow a fuse and was trying to think of why trailer could make a difference over the duration of the trip but still not blow a fuse.

Circut breaker? I once had an RV battery that had a positive wire smoking, and the alternator very hot to the touch. Battery was damaged in that case and circut breaker kept resetting. Caught it on the way out of the park because of the smell of hot plastic insulation. Pretty sure my alternator would not have stood that load for a long trip.

More extreme than what I was suggesting but same idea.

[Bob Miller]

Non one has mentioned the output rating for the alternator that failed. If the TV included the tow kit option it should be at least 100 amps rated.

As I mentioned earlier, I used to mount 120 amp GM Delco 3 wire alternators in Toyota motorhomes and, in that environment, they were more than happy to charge two or three batteries, run the refrigerator on 12VDC and what ever else the vehicle needed going down the road, and they ran cool with that load.

GM provides a 30 amp fuse on Stud #2 for the charging line on vehicles with the 7 wire HD trailer kit, and that should be long-gone before the alternator gets more than warm. If someone is running an altenator to trailer charging line without a protective fuse basically, they get what they deserve.