Charging Sys Woes...but no light

[msova]

74 Spider (california model)

Hey all. been troubleshooting my charging system mostly due to a battery that went dead a few months back, and an over-the-counter alternator needing replacement (lifetime warranty repacement! woo hoo!!) Put the new alternator on but I think i still need a new battery even after having it charged.

Through all of these issues, I have not had the charge light come on or glow at all. It DOES come on with the ignition so the bulb is not out. I've upgraded from the original external regulated model to a later style 55amp internally regulated following procedure for doing so (including unhooked wires 85 and 30 at the charge light relay and hooked them together...this supposedly makes the light work properly). Do I have something wrong? The spaded wire at the back of the alternator is on the D+ spade...not the other spade.

Not that I don't mind not having to deal with that constant glow that so many experience!...

Thanks

[So Cal Mark]

have you attached a voltmeter to the batt or alt to check output?

[msova]

Yes. Been troubleshooting some electrical things and some low voltage readings were part of that. How low does the voltage need to be before the light comes on? Below 12v or waaaaaay low like under 10v or something? Before the new alternator my lowest reading was about 11.7v with everything on at idle (lights, wipers, heater, radiator fan, etc). AT 3K it was about 12.4v

I would think its supposed to start to glow once it is in the low 12v range????

[fiat218]

a instance glow means what? other then not charging !! i mean i am aware of that sign, what if it all charging and so forth and the lite stays on? then what? is it just one of these FIAT THINGYS lol that u just live with hahahaah

[baltobernie]

What is your voltage reading now, with all accessories ON and engine above 1500 RPM?

[msova]

Thanks Bernie! That last paragraph was about the most help I've gotten on this issue! (i.e.- no real guidelines for exactly what voltage should be with which accessories on at what idle).

FWIW: I have done the "brown wire fix" some time ago, and plan adding doing headlight relays (taking power from alternator).

This all started when I noticed my wipers were exremely slow when the heater fan was on (after complete r&r about a year ago afterwhich they worked incredibly fast if you can believe that!). I cleaned the fuse holder/box (again!), re-inspected the wiper ground and other connections, and now they work good when the heater is on, but still slow with the headlights on (if the glass is dry they pretty much stop half way up!). By themselves, the wipers are still FAST!!!!!

Then the radiator fan started staying on (not enough voltage to run at proper rpm). had this issue about 2.5 years ago and new alternator fixed it. So, since my alternator is free lifetime replacement, I did that. Things are better but I think I still should get a new battery. Even after having it charged (about a 20 minute charge at O'reilly auto), once a battery has gone completely discharged as this one did a few months ago....well, they're never really the same right? I would have though the new alt would have solved all this but maybe the battery is still draining the system or something?

BTW< my 74 and some other early models does use a relay for the charge light (its located just aft and above the original fender mounted voltage regulator). Not sure of its function but surely it fits into your excellent explanation somewhere (it is bypassed since I upgraded to the internally regulated alternator since the later style grounds directly to the light). I just don't get why I've not seen the infamous "glow" that so many folk experience since I've been having voltage issues.

...just when I thought I had the car sold!

Thanks

[baltobernie]

I revised the post when I realized that your car is one of those with the relay; didn't want to confuse the issue. You may not "get the glow" with your setup.

I read somewhere that lead-acid batteries (even "deep cycle" marine models) last thousands of cycles if discharged to 80% of their capacity (in other words, taken 20% out), but only hundreds of cycles if discharged to 60%, and can be ruined with a single complete discharge. The battery can even "go backwards" if discharged enough. So I'd replace that suspect battery on a nice, dry, warm afternoon in my driveway - rather than risk Murphy's wrath.

[msova]

Good info about the batteries....isn't it sort of a known factor that trying to troubleshoot charging system problems with a suspect battery just makes the job harder?

Is it possible that even with a new alternator, the battery is draining the system somewhat. Not sure exactly what percentage it was discharged....turning the key did nothing......probably at least below 60% if not all the way!

[manoa matt]

If you measure voltage at your battery with everything off it should be about 12.5 volts. With the key in the on position test the voltage at the main power supply to the alternator, it should be about 12 to 12.5 volts. With the car on and idling below 1100rmp the alternator should be putting out around 13.5 to 14 volts. Most alternators have what is known as a cut in speed, which means it will not start to charge the battery untill it reaches the cut in speed usually around 1100 rpms. At idle the alternator will not charge the battery, above 1100 rpms it will charge the battery.

If you have a battery that is discharging it could be several things. First check the ground connection at the battery and where it attaches to the body. If you have a bad ground, the alternator will "try" to charge the battery, and all tests will show that the alternator is working, sending power to the battery via the positive cable. But if you don't have a good ground from the negative terminal to the body then the battery won't accept the charge.

Dust, dirt, oil, and spilled battery fluid on the surface of the battery housing will also cause it to discharge.

Even at a 50% discharged rate, the battery will still be good. Check your electrolite level in the battery. If its low add only steam distilled water to bring it up to the proper level then charge the battery and it should be fine. You can buy a simple 4 ball turkey baster type battery tester that will tell you the discharge rate of your battery.

[msova]

Thanks Matt for that more detailed info on voltages, etc.

Well...turns out that autozone had me and their system and low and behold I had a good chunk of pro rated warranty on this battery! So, including a new neg. ground cable and the battery...and a few other tidbits, I got outta there for just under thirty bucks! Not bad for an $80 battery!

So things seem back to normal....still need to do the headlight relays! I guess I'll just live with not ever seeing the indicator light glow! I'll just listen for the fan never kicking off as that has been the tell tale sign the last two times an alternator has gone bad!

thanks all!

[msova]

Is the brown wire fix mod suppsed to be a fused wire? I don't think so....mine's not. And 10ga wire is ok right? Thats what I used and someone mentioned 8ga wire in another thread or elsewhere.

I was just looking at some nice really thick (much more copper than typical wire) 10ga wire in the car audio section of best buy (by fostgate) and thought about redoing it.....it's go a built in fuseholder and I guess I'd just cut it off.

[mbouse]

do not fuse the brown wire mod..waste of time. the existing wire is not fused, so fusing the additional wire will do no good.

10 gauge is great for the brown wire mod.

http://flumichigan.italiancarclub.com/T ... urgery.pdf