1989 Ford Econoline E250 Class B motorhome battery overcharging

This link should help you to easily evaluate what appears to be a faulty voltage regulator:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-10.html#post1973613

On many Ford alternators, these are easy to replace.

If someone could help me it would be greatly appreciated. I have just had an alternator replaced on my '89 Econoline E250 motorhome. Two days after I had the work done, I woke up to a dead and I mean dead battery. The batery is an Optima red top gel cell, and was under warranty, so I swapped it out for a new one. A few hours later I had to make a 3 hour drive, and when I got to my destination, I found out that the battery had blown one of its relief caps and spewed electrolyte all over the compartment, most likely from overcharging the whole time I was driving. So, this morning, I replaced the battery a second time, since the one that blew barely had enough power to start the engine. I also replaced the voltage regulator, and all seems well, at least as far as my dash gauge says.

I think I have two problems: One was a blown VR, which probably had something to do with the alt change, and two, I may have a short somewhere that drained the original battery down to nothing in the first place.

Is it possible that they are related? I just finished the VR and battery install, and I am letting her sit for a few hours, to see if there will be a drain on the battery charge, so I won't know for sure until then, but I suspect that something bad happened at the sop and now I have a real big problem on my hands.

Has anyone ever seen this dual overcharge/drain scenario, and if so, are there any ideas out there on how to remedy it?

Thanks, and I hope to hear from someone soon. I am traveling and I am waaay too far from home to be having a problem like this crop up.

Just saw your post TX and I'll look over the thread. I did replace the VR already, although all I could get was an analog one. I will check it out and see if it's working properly asap.

Do you have any idea about the drain on the bat? I'm nt sure if I have two separate problems or not, but it sure looks like it to me.

Be sure to use abrasive cloth and clean the wire and connector going from the alternator to the under hood fuse box, after disconnecting the negative battery cable. Also, clean the ground near the under hood fuse box. On all of these connections, apply dielectric grease.

Make sure the voltage regulator is the correct one--I have my doubts.

I did clean the ground from alt to frame and will go after the fuse box asap. The VR is the correct one, per Autozone. The vehicle originally came with an analog VR, so it isn't a problem, but I figure upgrading to the electronic one wold be a good idea.

I saw something somewhere about connecting a ground strap from the negative post to the frame possibly correcting the problem. I was going to get a piece of 8 ga. Wire and do that too. I figure another ground can't hurt anything.

Thoroughly examine the battery cables for internal corrosion. Clean all grounds and apply dielectric grease. Over the years, I've noticed substantial corrosion on the connection that goes to the top of the alternator. This is the wire going from the alternator to the mega fuse at the end of the under hood fuse box. Take abrasive cloth and clean the connection thoroughly.

What's the regulated battery voltage, when you test it with your multimeter? Are there fans or other major drains on the battery, since it is a motor home?

When we checked it at the store it was right around optimum (14.2v). But a funny thing happened there too. The store's testing gauge started smoking about 30 seconds into the test. However, this was before the VR was swapped out. I have not checked with the new VR in, since I have to run to the store for a battery for my V-meter, but I think it's safe to assume that the alt is pumping out correct voltage.

Sorry, didn't finish my thought.

I think the alt overloaded the store's gauge, since the old VR wasn't working, but it was still putting out about 14.2v when the gauge overheated.

If the regulated voltage was OK, why did you replace the VR?

Because the alt is overcharging my battery. It literally blew one of the vent ports off the batt yesterday, and sprayed electrolyte all over the compartment. If it isn't the VR, what else could it be?

I mean, the VR is supposed to regulate the voltage and current flow to the battery and shut the alt down when necessary, at least to my understanding. And it wasn't doing that. The battery just kept getting a continuous charge, whether it needed it or not.

This is almost an unheard of situation. Something is fundamentally wrong. Make sure the alternator and voltage regulator are the correct ones for your vehicle. The alternator and voltage regulator need to be the correct ones to work with your ECM. Here's where I'm coming from:

Check Alternator FR (Field Response) Signal. Have alternator inspected, if idle speed fluctuates with electrical load. The FR signal communicates to the ECM how "hard" the alternator is working to meet the electrical demands of the car, including the battery and any loads which aren't monitored by the ELD (Electrical Load). This square-wave signal varies in pulse width, according to the load on the alternator. The ECM places, approximately, 5 reference volts on the wire. The voltage regulator will drop this signal to approximately 1.2 volts, in proportion to alternator load. The ECM compares the electrical load (ELD) signal with the FR (Charging Rate) signal from the alternator and uses that information to set the idle speed and turn the alternator on and off. This helps fuel economy.

This is an involved "dance" that takes place. Everything needs to be in synch. Hope this helps. Double-check that the alternator and voltage regulator are correct. After that, check out the ECM.

Ok so in other words it has to go into the shop again, because I have no way of finding out any of this information when I'm 2000 miles from my regular mechanic. Unbelievable...

OK, I'm assuming that what you think needs to be done requires testing benches, scopes, etc. I'm just going to take her to an auto electrician on Monday. Thanks a lot and I appreciate all your info. It wasn't what I wanted to hear, but I needed to know this stuff so I can get her back home to Texas.

This link will help you isolate battery drain:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-3.html#post241804

I don't know what else I can add.

After you find out what is wrong, give us a report. I'd take it to Ford.

Thanks. I'm just going to take her in and have them perform the surgery. The alternator problem has been an ongoing problem for awhile now, and now I think the shop that's done all the work has screwed up something else. This is actually the 5th or 6th alt they have thrown at her. The first 4 they couldn't dial in properly, and as soon as they installed them they blew. The 5th one lasted about 6 months, and now this. I just can't believe a shop that has been in business for 30 years can't get an alternator, and a relatively primitive one at that, right. Now I'm probably looking at a thousand dollar repair bill on top of what they charged me for the original work. At least they haven't charged me for all their screwups, but this is disheartening, to say the least.

I use this old girl to live in when I work all over the country, and she's never given me an ounce of trouble until these guys got their hands on her.

Sorry for the grousing. This has been a very trying experience. Thanks again for the info.

I don't know if taking any info to Ford will help. She's 21 years old now, and she's a van converted into a class B motorhome by a company that no longer exists, so I doubt they would know or even care about the problem.

When I do find out what the deal is, I'll make sure to get back to you folks and let you know what happened. I have a bad feeling it may be terminal though. If the system is getting over-amped, I figure the harness is probably burning up, and the problems from now on will be continual.

Again, I'd take it to Ford, who best understands the vehicle, and get it done right. From what you said, this other outfit has not been able to solve the problem in many attempts.