LS1-450

iTrader: (33)

Battery = Optima 8022-091 CA:910 CCA:720, installed for 15 months.
Alternator = stock w/ 2.25" pulley

Car has Sony Xploid coupled to an Alpine F-240 AMP & Alarm. Checked remote wire & is off when radio is off. However, measured .0003 volts through remote wire consistantly w/power off.

Problem:
Radio won't hold memory now for several months. Most recently, starter wouldn't turn over (battery @ 11.9 volts). Lights are good @ night; no diming @ night regardless of power users.

Car is often not driven for one or two weeks @ a time. During this period is when the radio memory settings are erased.

Starter tested good.

Could it be that the combination of the alarm, radio memory, ECU memory, & faint trickle through the remote wire are draining the battery & have done so for long enough that the battery is bad? Will only charge to 12.3 volts. Don't know how long the 12.3 charge lasts w/ no load because I haven't checked it yet.

What voltage does a fully charged battery read? Should I invest in a trickle charger to solve the problem?

Is it possible that the alternator is providing a borderline charge to the battery? What should the output of the alternator be w/ just car running & then w/ car running + lights, radio, AC, cooling fan?

Any other suggestions? Sorry for the long post. Want to resolve it once. Am thinking maybe a 160 AMP alternator & a trickle charger once a new battery is installed. Would like confirmation from those who know. Thank-you.

technical

How many amps are passing through the system while the key is off? Put your meter inline with the disconnected black battery cable and check the current drain (key off, doors closed, etc.).

LS1-450

iTrader: (33)

It reads zero. I checked the voltage drop through the wiring to the starter also. When the battery is @ 12.3 volts, the power @ the starter motor is 12.07 volts. There is also a kill switch wired through a relay (smaller gauge wire). The voltage @ the starter solenoid through the relay is 11.98v when the battery is 12.3 volts. Am considering this normal voltage drop through these wires. Can anyone confirm this?

The in-line meter test checks all except an armed alarm (alarm won't set without black battery cable connected). Is there a way to check battery load with the alarm armed?

What's the voltage of a new battery 13.5-14v.?

technical

The cable is connected via the meter then the circuit is complete. I use claw ends, but you can probably rig something up if you don't have any.

New battery voltage is usually 12-12.5v

Judging from the voltage drop you measured at the starter it sounds a bit fishy. How do the ends of the cable look? corroded?

LS1-450

iTrader: (33)

I used meter leads w/ the pointers. The alarm didn't go off as it normally would. So, something is different about connecting through the meter via the lead pointers. Was able to read full voltage, but, no alarm & no current.

Re-read the voltage @ the starter. Voltage is .01 to .015 less @ the starter motor prior to turning the key. Once the key is "on", voltage drops .3 to .4 volts (from 12.33v to 11.99v). Previously had read the votage only after the key was "on". This is why the voltage drop was greater.

So basically I have to find a way to connect through the meter while making the alarm go off when connected. If under these conditions there is current, then the low battery over time would be explained.

Maybe it's just a tired battery. I did find belt dust on the alternator indicating that it had slipped or had been slipping @ some point. Maybe under the right conditions, the battery doesn't get a full charge. That coupled to the voltage drop with key "on" could be enough to keep the car from starting.

The NAPA guy told me a battery reading 11.9v is considered a dead battery for what it's worth.

Am gonna check the battery voltage in the AM & try & turn the starter motor with whatever power is available. Will try somehow to connect through the meter & make the alarm go off. I think the leads are too small for this to happen. As stated, I can read full voltage by connecting through the meter from the black wire to the negative battery terminal, just no current.

technical

11.9 isn't really a dead battery. The true test is a load test. Volts don't start a car, amps do. I would get the alternator checked too. Your original post seemed to point to a bad alarm, but it is very possible that the alternator is weak.

DaddySS

Does the car start after sitting for a short time but not if it sits for days or does it not start at all?

LS1-450

iTrader: (33)

Sometimes after stopping for gas or something it wouldn't start, but, would after a while. Other times it would do this after sitting for a few days. Most recently, it wouldn't start for 15 minutes @ the gas staion. The next morning, it wouldn't start again, so I stored it for Winter & to work on the issue. That was a month ago.

What has been found so far is that the battery was low when initially checked (low 11's.), the starter tested good @ NAPA, the wire voltages are as stated above, & I'm about to go check the battery for leak down while connected over night w/o alarm.

After thinking about when the no starting has ocurred & from the comments here, it seems as though the battery isn't getting a full charge. The last time (@ the gas station) the heater had been running, the radio was on, & maybe the cooling fan. After checking the battery this morning & again after it sits overnight with the alarm on, will check the alternator with stuff running.

Everyone please keep the comments & suggestions coming. They are quite helpful.

2K2WS6TA

iTrader: (2)

How is the alarm/amp powered is the power hooked up to the bat positive with a ring terminal, you could be not getting good enough contact between the bat terminal and the positive connector (this applies to a side post battery)
Are the pos & neg cables new or used, if used check for corrosion

LS1-450

iTrader: (33)

Thanks for the comments. The AMP is hooked up through a ring connector directly to the battery & there is no corrosion.

Voltage checks from alarm no alarm tests were good, thankfully. Went from 12.33v down to 12.28v in about 15 hours without alarm. With alarm armed, went from 12.28 down to 12.21 in 24 hours. Seems like we're narrowed down to an insufficient alternator charge. Will be checking that next, after re-installing the starter.

Thanks again everyone for posting. If it turns out to be other than the alternator, I'll re-post. Otherwise, I think we're there.

Happy Thanksgiving

LS1-450

iTrader: (33)

technical, DaddySS, & 2K2WS6TA,

Don't know if any of you visit this area. Apparently, I posted in the wrong place & it was moved here. Anyway, it was the alternator. When I checked just the voltage, it was 11.3v while the car was running & nothing else turned on. Am gonna take it to NAPA for an AMP test before buying an 160 amp alternator from Afterthought.

Thanks again for the comments.