altenator problems

[Chris F20 maniac]

ok guys a newbie question for ya.

my altenator doesnt quite seem powerfull enough, so im thinking about getting it rewound.

if i get my altenator rewound to produce more than it does now, do need to redo my wiring?

and is it worth getting the altenator rewound or should i try to find a more powerfull one that will fit?

thanks guys

[chimpboy]

It's usually cheaper and not really any harder to just get another one that will fit from a wreckers.

I don't know what yours looks like but the usually have pretty standard dimensions. Try looking at something from a camry or magna or whatever is common and has plenty of electrical stuff to run.

The usual process is you find something that has the same mounting setup and the same relative position of pulley to mountings.

I'm afraid I don't even know what an F20 is, is it a Daihatsu?

You can also have a look at this website, see what else has sometihng similar in layout to your current alternator. Or maybe someone on here will know what fits.

Jason

[murcod]

I recently changed the one on my Feroza. Even if you find one that bolts in you'll have to change the electrical plug for the ignition wiring; plus I had to change the pulley and get it machined down to get the belt alignment right.

But for $60 the price was right. Mine was off a Camry and outputs 70 Amp compared to the standard 50. The new one also has remote voltage sensing (for the internal voltage reg) which is a lot better.

Running a new heavy duty cable from your alt output to the battery is a good idea. Just make sure you fuse it.

[Area54]

How much stuff are you running off the rig chris? I'm still running the standard one off my old 12R, with radios, spots, rocklights and reversing lights (but not on all the time) and no batt charging problems. Your voltage regulator might be on the fritz.

post it up in the daihatsu section, more info to go in there.

[Chris F20 maniac]

I'm afraid I don't even know what an F20 is, is it a Daihatsu?

yeah its a daihatsu made in 77'

well im running a reversing spottie and two 100w ones on the front plus the radio and all the normal lights but of course not all at the same time.

the problem was that the charge light was on and it wasn't charging, so i took the altenator out and cleaned it up with a bit of WD40 and washed out the inside of it as well with WD40 and cleaned up all the connections as well, put it back in the car, hooked up all the belts and charged up my car battery over night.

in the morning i droped the battery back in, kicked the old girl over and it was all working fine and charge light didn't come on again.

so that seems to have fixed the problem of it not working.

but when i run the standard headlights at night i can notice the headlights brighten up when i rev the engine and then they dull down when the car goes back to idle.

so im thinking that the solution for this is to get a higher output one or make the curent one output more amps.

this voltage regulator you speak of where is it locatad in the car?
and are they expensive to replace?

[Area54]

I'll have to look now

they are about 50 bucks, but make sure you get the adjustable one, not the solid state.

I rebuilt my alternator at home, but best left to the specialists if you can't tackle electrical work.

Anyways, the regulator will regulate the voltage and the charging current - within limits - but it sounds like the volt output might be a bit low. Do you have access to a multimeter to measure the voltage of the battery, with motor off, then running without electrical load (lights, fan etc) then running with electrical load (lights on, fan on etc)? These things I would be checking first to give you a basic idea of the state of the battery and the ability of the reg to compensate for loads placed on the system. The lights dimming on lower revs indicates the voltage is dropping, the reg should be compensating for this to a degree.

[Area54]

Voltage reg is on the drivers side, mounted on the fender wall near the end of the brake master cylinder.

[Chris F20 maniac]

cool thanks man.

ill get out my multi meter tonight and test all that stuff out and see what conclusion i come to.

cheers

[Chris F20 maniac]

ok i found the voltage regulator!

it was this little black box that said voltage regulator on it

so i took off the top and had a look and it was like brand new inside and nothing seemed to be broken so i put it back together. then i cleaned out the connection for it cause that looked like it was full of dirt and stuff.

started the car and it seemed to be a bit better so i turned on high beams and the spotties and they wern't really dimming at all. after running all the lights for a while then they started to dim at idle.

so im yet to test with the multi meter but i think its the battery that is letting me down.

[elgordomuygrande]

Hey Chris, Do you have actual measurements, It doesnt sound like the battery though. Did you check the field coil wiring of the alternator and if the characteristics of the regulator are within specs? I tweaked mine to prescribed regulated Voltage and a lot of electric problems suddenly dissapeared, including the dimming lights at idle

Ron

[chimpboy]

It's normal for an alternator to provide a bit less current at idle because it's spinning slower. If it's dropping too low then it could be a problem, but just having the headlights dim a little bit at idle doesn't actually signify a problem in itself.

Is it the original alternator?

Anyway, the measurements Area54 suggested are a good start - voltage with engine off, voltage with no load at idle, voltage with no load when revving, voltage with load at idle, voltage with load when revving.

Just write them all down and it starts to form a picture.

[Area54]

The inside of the reg will look clean as it's a fully sealed unit with rubber seal. What you can't see is the distance between the contacts, and how this distance will alter the voltage/current from the alternator. The arms holding the contacts can be bent, but do not touch them until you have some solid specs from the tests mentioned.

If you over adjust them, you can overcharge the battery, resulting in boiling the electrolyte away, under charging - well the situation is fairly self explanatory.

[elgordomuygrande]

T
If you over adjust them, you can overcharge the battery, resulting in boiling the electrolyte away, under charging - well the situation is fairly self explanatory.

Chris, when you're up to adjusting the regulator, I'll send you the procedure and specs from the manual.

[Chris F20 maniac]

cool thanks guys!

ill take some readings tonight

cheers

[Chris F20 maniac]

ok so ive done some readings on the battery. and here they are

car off - 11.9V
car at idle - 13V
parking lights - 12.8V (idle)
headlights low beam - 12V (idle)
headlights high beam - 11.5V (idle)
headlights (highbeam) and spotties - 11V (idle)
headlights (highbeam) and spotties - 11.5V (3000 RPM)

not quite sure what to make of these

what do you guys think?

[murcod]

How old is your battery? The voltage is low to start with (with nothing on should be at least 12.5v)

[murcod]

Didn't have much time to type a response yesterday.... In short I had a similar problem in my Feroza. With high beam on and thermos running my alt was struggling to keep the engine running- battery was quickly dropping to 11V at idle.

Since then I've upgraded the alt to a higher output one plus I've uprated the battery to a higher CCA one (280 vs 460CCA.) Even with the uprated alt the old battery still dropped to 11v at idle; combined with a new battery the problem is gone. If I now sit with it idling for a very long period I'm sure it would still drop under full load, but the new battery is able to cope with the drain at idle for a lot longer period. My old battery was tested and was way down on capacity.

Alternators need to be turning over at a decent amount of revs to get the full rated output. So simply fitting a higher rated alt may not fix the problem. By the sound of what you've written your battery isn't too healthy to start with.

If you do get a new alt then fit an internally IC regulated one with remote sensing. Then you can get rid of the old mechanical regulator.

[Chris F20 maniac]

cool

what im thinking of doing is getting a good battery and adjusting the regulator, and then seeing what happens.

cause im sure that i fried my battery the night i drove home from toolangi just on battery power till she wouldn't go no more. then got towed the rest of the way!

[murcod]

Yes, that would be a good start. If that doesn't improve things then look at replacing the alternator.

Check all your wiring and terminals when you do the battery and make sure they are all in good condition.

[Chris F20 maniac]

well ive got the new deep cycle yellow top optima battery in and the new altenator and ive adjusted the voltage regulator. it might still need a little tweaking but its working better than before at last!

[DamTriton]

Yes, that would be a good start. If that doesn't improve things then look at replacing the alternator.

Check all your wiring and terminals when you do the battery and make sure they are all in good condition.

Might only need a new set of brushes in the alternator. They do wear, and can get a bit of resistance through not having the right pressure applied to them against the armature. This can cause low output from the alternator, eventually destroying the battery through using only the "bottom half" of the battery's charge. (your test results)

Brushes should be only $10 or so, and maybe another $20-30 to have an auto-leccie solder them in for you.

A new batery is definitely on the cards after the fix.

[murcod]

Given that my EFI Feroza had only a 50 Amp alternator fitted , I'd hate to think what an F20 has standard!?

I got the second hand 70 Amp alt for $50- so even $10 for new brushes goes a long way towards an uprated one from the wreckers.