Electrical woes part 2

[Dads_FJ]

I recall a thread on an old FJ forum where someone determined his overcharging was due to corrosion of an electrical connection, I believe it was near the rear of the engine but I cannot recall that.  Anyway, there was a voltage drop across this connection (wiring harness plug), thus giving the regulator a false battery low condition and the charging system would overcharge as a result.  Anyone recall this?

[fintip]

John, I don't know a ton about regulator/rectifiers, but is there really 'smart' circuitry that lets it know if the battery is low or not, and prevents it from sending more current if it's full?

Now that I type it out, that sounds like it would make sense, I just didn't realize that level of complexity was built into the design.

And now that I've typed all of this out and read the thread responses again, it seems like this is exactly what Randy and David are referring to as the reason this burned plug can be such a big deal.

As far as asking about running it before I've replaced the regulator... I'm trying to decide if I should wait for Randy to get stock in again or not. Even if I need to just get one from somewhere else, it will be probably a week before it gets to me, and this bike is my only form of transportation. I've been without a ride for over a week now, and that's made life pretty hard.

So the question is, how bad is the abuse of a few days of overcharging? The other battery has lasted this long, and if the lights dimming/brightening was the first symptom, that was maybe two months before it killed the battery (though it may have progressively gotten worse?).

And if it is bad enough that I shouldn't consider it--what about disconnecting the charging system from the battery and charging the battery at home overnight every night? Would the battery get me through the day ok without being charged if it were fresh every morning off of a trickle charger?

Any other ideas?

[rktmanfj]

My last AGM battery survived 8 years of overcharging before it finally died.   

[Dads_FJ]

John, I don't know a ton about regulator/rectifiers, but is there really 'smart' circuitry that lets it know if the battery is low or not, and prevents it from sending more current if it's full?

Now that I type it out, that sounds like it would make sense, I just didn't realize that level of complexity was built into the design.

And now that I've typed all of this out and read the thread responses again, it seems like this is exactly what Randy and David are referring to as the reason this burned plug can be such a big deal.

As far as asking about running it before I've replaced the regulator... I'm trying to decide if I should wait for Randy to get stock in again or not. Even if I need to just get one from somewhere else, it will be probably a week before it gets to me, and this bike is my only form of transportation. I've been without a ride for over a week now, and that's made life pretty hard.

So the question is, how bad is the abuse of a few days of overcharging? The other battery has lasted this long, and if the lights dimming/brightening was the first symptom, that was maybe two months before it killed the battery (though it may have progressively gotten worse?).

And if it is bad enough that I shouldn't consider it--what about disconnecting the charging system from the battery and charging the battery at home overnight every night? Would the battery get me through the day ok without being charged if it were fresh every morning off of a trickle charger?

Any other ideas?

I wouldn't really call it smart circuitry, but in layman's terms the regulator monitors voltage (input) and controls (by output) the alternator's output voltage.  The rectifier's only function is to convert the alternators AC output to DC using diodes.  If the input voltage is low (by any means including a low battery OR voltage drop across a connector...), it will just do it's job and signal the alternator to step it up.  Not sure how long it would take to do damage to your battery, but it sounds like Not a lib has some experience with this... Oxidized/corroded connectors are not uncommon on our FJ's, including mine! 

[SlowOldGuy]

Kyle,
I'm going to type this real slow.

Before you make 47 alternate "What if?" plans, go check that alternator connector before you get all wrapped around the axle on needing a new regulator.

I have the RPM/RT regulator in mine.  I'll send you my old one which was working perfectly.  I only changed it as PM.

DavidR.

[fintip]

Notalib, could you give more details?

David, will check it first thing when I see it later today (have it at friend's house to work on, no place or tools here). I'll send a PM if the connector seems fine.

Is there any visible sign of damage that confirms if a regulator is bad?

[SlowOldGuy]

The regulator is probably bad if you see absolutely NO fluctuation in the charging voltage as you rev the engine.  That would probably indicate that it has failed to maximum output.

The charging voltage should vary slightly from an idle voltage of no less than about 12.5 volts (depending on idle speed) to something like 14.5 volts at 3000 RPM and above.  Anything over 15 volts is BAD.

DavidR.

[rktmanfj]

Notalib, could you give more details?

It's right here... disregard the obsolete s/n.     

http://www.fjowners.com/index.php?topic=2456.5

[fintip]

So like I said, I got 18 volts--I can automatically assume it's bad, right?

If I'm looking at the correct plug, it seems to be fine. This bike has been an indoors bike most of its life, for whatever that's worth (I know the history of all three owners before myself on it).

notalib, how can you be sure you're overcharging? 8 years is outrageous for any battery, much less one subject to overcharging.

My new battery is a DEKA brand (x2 power or something, but it's just another face of DEKA), which are supposed to be good.

David, I'm holding out to see if I can find another used one at a mechanic's shop who has a bunch of old bikes. Seeing as installing one requires some soldering, I'll probably try and get someone else to do it--I don't have much experience soldering, and a bad soldering job might be ok in some applications, but a heavily vibrating bike isn't one of them.

Thanks for the offer, though, I may take you up on it. This forum's generosity never ceases to amaze.

[rktmanfj]

notalib, how can you be sure you're overcharging? 8 years is outrageous for any battery, much less one subject to overcharging.

Aside from the symptoms described in Reply #6 of the afrementioned thread?

I have a VOM, and know how to use it.      

FWIW, I still think you have a hot wire that's worn through the insulation, intermittently contacting the frame when you turn the front wheel (in addition to the 18v problem.

[fintip]

I know, sounds like a great theory, and an easy diagnosis from a distance... but not much is touching the steering column, and what is looks great... So I don't know what to tell you. Just work with one problem at a time.