Battery not staying charged

Biggredd2069

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I have a 68 Newport 383. Fresh rebuild, FItech fuel injection. Battery and alternator are a year old. I've had so many problems with this car I don't really know when the problem actually arose. I fix one thing and another breaks. I'm on an endless trajectory now. I've been having to keep my car on a trickle charger and seems like now the alternator might not be charging my battery? The battery gets about 6 or 8 good starts then magically I'll be driving it and I'll see the stereo go nuts and I know moments later my engine is gonna die. The fitech can't handle a low battery. the guy who rebuilt my engine is on the far side of town and keeps trying to deflect and just give me suggestions on what to do next. I paid him not to have this issue. getting so damn frustrated at this car I sometimes just want to start a convenient fire. Just want to enjoy it and not be scared its gonna stall or die on me constantly. Should I take the alternator out and take it to be tested only to be told its fine and then chase something else someone is gonna tell me is fine but isn't? my car died 20 feet from my house today. I jumped it and got it in my driveway and had 11.75 volts on the meter. The other day my tester was showing 12.5 after charging and the fitech computer only showed 10.4 but still started just fine.
 

LocuMob

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Have you checked the battery itself? Charged it to a good charge and monitored what happened? Or checked the output from the alternator with the car running? Started the car and unhooked the ground from the battery, see if the car still runs? Free ways to try and determine what the issue is instead of throwing parts at it? I can't remember if you have an amp for your stereo or not, but adding power sicking add ons won't help your cause. Upgraded alternator AND upgraded wiring is the only proper way to go about doing that. Good luck.
 

Biggredd2069

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I've taken the battery back to the auto store twice to have it checked. they say it checks out. I can try removing the negative, will that verify the alternator? concerned my fitech system might not like that though. I do have an amp but I wasn't really using much volume at the time, if any at all.
 

LocuMob

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I've taken the battery back to the auto store twice to have it checked. they say it checks out. I can try removing the negative, will that verify the alternator? concerned my fitech system might not like that though. I do have an amp but I wasn't really using much volume at the time, if any at all.
Forgot about the efi, not sure if it would like it or not, but you are looking for the output from the alternator, it will only take a minute to check. If it's putting out the correct amount of power, it shouldn't make a difference. After the battery starts the car the alternator takes over and charges the battery up and powers all the electronics.
 

Biggredd2069

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So if the car dies after pulling the negative then possible the alternator is not hooked up right and/or not working properly? I'll try that first thing in morning after I get the battery charged back up.
 

LocuMob

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So if the car dies after pulling the negative then possible the alternator is not hooked up right and/or not working properly? I'll try that first thing in morning after I get the battery charged back up.
If it dies right away, definitely. Check the connections and go from there.
 

Newport 66

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Have you tested the voltage regulator? Is the ignition converted to electronic, I would assume it has been since you've gone to FI. If so you need to upgrade to a solid state regulator.
 

Biggredd2069

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I have a pertronix ignition. I did upgrade the regulator too. I could test it again, it's about a year old.
 

Davea Lux

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Start the car and check the voltage at the battery with a voltmeter, you should get a steady 13.2 volts or a little higher
I have a pertronix ignition. I did upgrade the regulator too. I could test it again, it's about a year old.

Do not disconnect the battery cables with an electronic regulator, that will usually fry the regulator instantly.

Dave
 

Biggredd2069

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I have no choice but to charge it back up overnight. If I start it I'll likely have a good charge on the Volt meter. If I can't disconnect the battery what am I testing to check continuous charging?
 

Davea Lux

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I have no choice but to charge it back up overnight. If I start it I'll likely have a good charge on the Volt meter. If I can't disconnect the battery what am I testing to check continuous charging?

If you have an electronic regulator, that is a very bad idea. Use the voltmeter instead. If the car is running it should hold steady voltage if the charging circuit is working. If the charging circuit is not working the voltage will start to drop, turn on lights and note the voltage when you start checking, if the charging circuit is dead it will start to drop pretty fast.

Dave
 

Biggredd2069

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When I tested the other day it wasn't dropping steadily. I measured 12.05 on the battery direct and 10.6
20200717_135702.jpg
20200717_135702.jpg
on the fitech computer but it wasn't steadily and obviously dropping. How long should I test for? Here is what I was showing the other day at the same time
20200717_135715.jpg
 

Davea Lux

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You can test the alternator independent of the regulator by running a test lead from the battery positive terminal to the field post on the single pass alternator, unhook the lead on the alternator field and hook up the test lead. This will energize the alternator in full charge mode if it is working and you should start to pull about 14.5 volts or more at the battery using your voltmeter. If you get a charge this way, you know the alternator and the ammeter are both working and your regulator is likely dead. If you have an alternator with two field posts installed, unhook both the those connections and hook up the test lead as before and hook the remaining terminal to a good ground.

Dave
 

Davea Lux

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The other possibility is that you have added a lot of load with the new stereo and the Fitech injection. Your should also run a continuity test on the ammeter as it could also be toasted and open. All amperage goes thru the ammeter on '69 and older mopars and the ammeters were famous for getting fried. The are several posts on this site about how to run a partial or full ammeter bypass to decrease or eliminate the load on the ammeter.

Dave
 

FURYGT

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Your battery looks to small. I am not home and remember whether the correct size is group 26, 27 or 28.

What is the amp rating of the alternator?

The FI system has a constant draw from the battery and as you found out shuts down when the voltage drops below 12 volts.
 

CBODY67

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Standard was Grp 24, Grp 27 was optional, back then. What amps is the alternator?

What is the voltage for the battery itself, both cables removed? With both the cables attached, but engine not running? With the engine at hot base idle? With the engine at about 1500rpm?

Check BOTH the cables for resistance/continuity, too! They can look fine on the outside, but can have a hidden issue under the insulation. Which is where I found an issue on one of my cars. When the stereo started to buzz, I knew to put the car in "N" and rev the motor before it died. This was on a carb'd car. Discovered a voltage loss in the ground cable, which was intermittent, when some things didn't work. Replaced the cable and all was well. fwiw

Is your VOM sensitive enough to check for parasitic draws?

IF you have an aftermarket radio with a clock in it, it's getting power all the time, for the clock function and station memory. What about the amp for the sound system?

IF you had an unmolested car with a rebuilt engine and an aftermarket efi system, that's ONE thing. With an aftermarket sound system, that can put it into the same class as a modern car with all of the electronics they have. Which is probably why your tech might be not desiring to get involved! Chasing electrical things can take a good bit of time, which is $$$$ you might not desire to spend, as it is usually "by the hour" rather than a flat-rate charge. Unless he's attuned to these things, best for him to not get involved, by observation.

Got to be methodical, rather than hit/miss in looking at these things! Might end up chasing them through the bulkhead connector, too. CLEAN battery cable ends and posts are essential for good charging system performance. Looking good is not enough, they MUST be spotlessly clean and tight.

Keep us posted,
CBODY67
 

Biggredd2069

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Think charging is bad clearly. Put trickle charger on for 24 hours and here is the voltage test I did.
Posts on 13.10
Posts off 13.10
right after cold start 12.39 volts
After 5 minutes idle 12.33
Rev to 1500 goes to 12.3
Shut engine off it jumped to 12.75
Should I take the alternator in to get tested?
 

Davea Lux

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Think charging is bad clearly. Put trickle charger on for 24 hours and here is the voltage test I did.
Posts on 13.10
Posts off 13.10
right after cold start 12.39 volts
After 5 minutes idle 12.33
Rev to 1500 goes to 12.3
Shut engine off it jumped to 12.75
Should I take the alternator in to get tested?

You are clearly not getting a charge, if you are not comfortable running the test above, then take it off and have it tested.

Dave
 

CBODY67

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Might be a failed diode? What size/amps is the alternator?

CBODY67
 
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