High Voltage

[kooblekidz]

I've got an 84 345 with a 454. I was having alternator problems and had a lincoln regulator put on and then had it rebuilt. I was doing ok for awhile and then had a new battery isolator put on. It seemed that from that point forward I was overcharging, sometimes as high as 16+ volts. I contacted Lestek, (manufacturer of the alternator) and they tell me that the Lincoln regulator was a bandaid and that I should get one of theirs. Would that do it? I'm not up to speed on auto electronics and need some advice!
Eric, fulltiming, currently in Palmetto FL.

[74Argosy24MH]

Go to a junk yard and get the brackets to put on a Delco alternator. If they have a good 105 amp alternator get that, if not any parts store will have one. The regulator is built in, they are everywhere, and are very reliable.

John

[markdoane]

If you elect to get a Delco alternator, be sure to a a '3-wire' model with remote voltage sensing. This is more than a DIY job if you have limited electrical knowlege. You need to be able to sense the voltage at the batteries 'past' the isolator or you will be undercharging the batteries due to voltage drop through the diodes.

[74Argosy24MH]

It's not that bad of a job. Run the charge wire to the isolator, the 2 regulator wires to any wire that is hot with the ignition switch on.

John

[Lido&Linda]

What kind of alternator does the mid 80's p30 chevy come with stock?100 amp?

[TomW]

Originally posted by Lido&Linda
What kind of alternator does the mid 80's p30 chevy come with stock?100 amp?

My 1984 C20 has a 90 amp alternator

[87MH]

Lestek's were installed by Airstream on their mid 80's coaches.

I think mine is a 105 amp also.

[RonJudi]

A regulator senses the voltage and applies the correct field current to keep the output were it needs to be. Modern Battery chemistry is about 14.5 V in the Winter and a little less in the summer. A modern Altenator with a life time warranty from O Reillys is about $6o but if it has a built in regulator it does not regulate on the output of the isolater but on the output of the alternator terminal. If your output was too low then your results would be logical. The voltage drop of a silcon juntion in your isolater is 0.7V so you should see the output of the isolater 0.7 volts lower than that of the Alternator Many rigs did not use a built in regulator for this reason. Instead they used an external regulator so a sense lead could be placed at the battery using a small seperate wire and still provide what it takes to get 14.2V at normal temperature at the battery. Always use a digital voltmeter to get your readings as the old analog type historically is inaccurate after a few years. The early Delcos like the Motorolas from which they were derived (Motorola holds the Patent) all had seperate regulators and thus you can place the sense lead downstream of the isolator. One exception especially in the early days, some of the early Alternators did can regulate at a higher point ( E.G. 14.2 plus 0.7 or 14.9V) thus allowing for known voltage drop. If you can find a good Delco or other with about 100 Amp and a companion regulator then I would use it. The mechanical installation and mount is the hard part. GOOD NEWS: Your regulator is not doing a good job or the sense lead is connected to wrong point in system. Locate it and make sure it is TIGHTLY connected to the positive terminal on battery. That may be all that is wrong. Otherwise a regulator that belongs to the same union as the alternator might need to be found. In that case the regulator change is the answer as suggested. Ron

[kooblekidz]

Thanks everyone, the consensus at the RV Tech course I'm currently taking agrees with Ron, that it is likely the regulator. I am going to order a Lestek, which is compatible with the alternator and expect to see immediate good results. I'll keep you posted.
Eric