Inliners International Forums General Discussion Electrical Am I gonna hurt my Optima battery?

Hello everyone, hope your 2016 is treating you all well. Mine started off with a roar, or rather, a lack there of.

1969 c10 with a 292.

She started just fine at home, usual case of morning sickness, choke her a little and nothin outta the ordinary. Still seeing a reading of high 12's to 14 volts on the gauge while shes sitting there at idle, and around 13-14 volts while shes driving. Decided the almost 7 year old walmart lead acid battery finally shat itself when it had less than 10 volts the next morning. It had sat on a charger for about 6 hours and only started the truck one time. Should have had more than 10 volts. bought a good ole Optima red top, "red toptima".

now the voltage hangs around 12 volts at idle, maybe a little less when I have lights and heater and wipers on. yesterday I noticed that it would increase to ~14 when the RPM got to ~1500. Today I noticed the needle just sort of hangs around ~12 volts, and goes a bit below 12 at idle, stoplights, etc. especially when I have lights, heat, and wipers going.

Alternator is maybe 3 or 4 years old, voltage regulator is as well.

Am I having issues? I thought the voltage should never really drop to 12v at idle, let alone below 12v at idle.

Anyone else experience this? All I did was swap in the red toptima.

Im not sure if my alternator is telling me it isnt happy about the new red toptima, or if the walmart battery put so much of a slow hurt on the alternator that it finally gave up.

On a side note, I plan on replacing the positive junction block on the passenger side inner fender. it just looks all old and dirty with all those nice shiny brand new terminals connected to it.

Might it be whats causing my voltage drop? its pretty skanky lookin.

(Edit) Just went out to start her up for work, gauge was reading ~14 volts, and shes sitting idling now at ~13 volts with nothing else on, no lights, radio, wipers, heater, etc. Maybe that's what its supposed to do when you have a good battery? *SMH*

(Edit #2) So yeah, driving along, voltage drops to 12 or a little less than 12 volts with lights and heater, and does not increase with rpm. voltage needle dances just a little when the turn signals are applied. Drove to work then home like this, didnt put it on the charger, this morning the gauge showed ~13 volts before starting and a lil more than 12 while shes idling and warming up. Really starting to suspect the alternator.

Thanks for your time folks!

How many amps is your alternator rated at?
Maybe a bigger one is needed.

sorry for the delay. between work and school its hard to find time. so the alt that was in it was from "oh really" and i believe it to be in the low to mid 50's for amperage. i was able to get a hold of an alt with a lifetime warranty from "the zone" and i believe its 55 for amperage.

i have a 3 groove damper and a 2 groove waterpump pulley, so a stock alternator pulley wont line up, and sits about a quarter inch behind the water pump and damper grooves.

something something life and lemons, something something lemonade.

i hooked it up anyway, belt alignment be damned. she started right up and was showing 14+ volts at idle. so yeah, bad alternator. i dont have the tools to swap pulleys, so i thought id outsmart the alternators and just swap halves out. yeah, no. but shes running and shes charging and im ok with that.


ive run it for about 2 weeks with no alternator. every day i would come home and hook the battery to a 2 amp charger overnight. thats not gonna hurt the battery, is it?

Shouldn't hurt it.

Take a pic of what you're doing with the mounting of the alternator. Pulling the pulley isn't hard and you can "rent" the tool from Autozone for free (just have to buy it and then return it. It's a real service they offer and not just people trying to scam them).

thanks Bauer. ill go out and try to get a decent quality cellphone pic. ran it today and no issues, except the belt is slightly misaligned. shes charging near the high end of 14 volts tho.

this leads me to a question about the voltage regulator. my voltage regulator has a little silver condenser looking thing hooked to it, and the FLAPS have no idea what it is because its not an ignition condenser (breaker points) and its not an AC condenser.

what is that little condenser looking thing and where can i get one? do i even need one? and also, i changed alternators, and the voltage regulator is still fairly new, ~4 years old or so, should i change that out too now that i have a new alternator? *EDIT* <--- a radio capacitor is what i seem to be describing. dont mind me, ill go back to google now.

thanks for your time folks. pics to follow soon.

I went to a 1 wire long ago and haven't looked back. I bought a 120A chrome 1-wire on Ebay for under $100 shipped and have no problems electrically. That's probably less than you spent on your battery.

Here's one for $70: http://www.ebay.com/itm/like/350970868932?ul_noapp=true&chn=ps&lpid=82

I think that's the same one I bought.

umm, do you really trust your voltmeter? if it's an old D'Arsonval (pointer) type, don't. if it's a modern-ish DVM, check it. if it's a quality brand name, eg. Fluke, maybe blind trust is OK. if you paid less than $50 i'd double-check it. if it's old, double-check it.

i do this stuff for a living. 20 years ago, "within a volt" was OK. no longer!

Fluke makes great meters. you can get decent ones under $100. battery life is directly proportional to charge quality... and you need a good meter to test it.

cheap meters can be OK, but I'd check 'em against a drop-dead-known voltage.

i appreciate the tips guys.

you are correct, thats a lot less than what i payed for the battery, and pretty much the exact same amount as the replacement alt i bought at the FLAPS once you figure in the cost of the external voltage regulator.

this should show how the replacement alt pulley does not line up with the rest. it doesnt make noise or seem to slip, im just afraid she might throw the belt. should i be concerned?

She's gonna eat belts that way. Go to Autozone and rent a gear puller. Swap the old pulley on.

On some alternators, once the nut is off the pulley will just fall off. You can use an impact wrench or if you don't have one hold the shaft with an Allen wrench and loosen the nut. Did you get the old alt tested? A slightly loose belt would cause the volt readings you posted. When the new alt is put n the belt gets tightened and majicly the problem is fixed. The test we used is with the engine off try and turn the alt over with the alternator fan, hope this helps. jay 6155

So as the days passed I noticed the factory ammeters needle would dance around. voltage was better than ever before but the dancing ammeter was bugging me. I cleaned all the grounds I could find and applied dielectric grease until I noticed the fastener holding the ground on the voltage regulator just spun freely. I fixed that as best I could and stopped the dancing needle.

that high amp alt that bauer linked would be awesome and allow me to get rid of the external voltage regulator, I just need to find a new 2 groove pulley. the one I have now is kind of old and worn out, and the outer groove has a chip in it so i dont use it. tax time is here again, mines all going into the truck more or less. a new radiator, and 4 matching rims from pull n save are first up, then the rest goes to whats left.

I never bothered to test the old alternator because in my impatience I just went ahead and replaced components that I deemed part of the problem one at a time till the problem stopped. not the most cost efficient way to troubleshoot.

will those high amp ( 100 amp + ) alternators be ok with an optima battery? I'm not an electrical engineer, but I heard you cant dump as much amperage as fast into an AGM as you could with a normal lead acid style battery. is there any truth to this?

Just an update

so I found this pulley on amazon:

2 groove alternator pulley

and it worked like a charm. everything lines up just right and spins as quiet as can be. single groove pulley came off and the 2 groove went right on with no trouble at all. love it when that happens. will try to get a pic of the new setup.