Overcharging. What to check next??

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Budgetmoparman

Budgetmoparman

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A little background about the vehicle. It is an 86 dodge truck that the previous owner had all cobbled together. I have converted to a 1 wire HEI distributor, eliminating the balast resistor. I just installed a brand new ignition switch (old one fried because of shitty wiring from previous owner). New alternator. New voltage regulator. I replaced a few of the wires thru the bulkhead when I put the ignition switch in. Battery has been tested and is good. Ohm reading from ground to VR housing is 0. Battery voltage is 12.47 engine not running. Voltage from battery to VR plug is 12.40 without engine running. Ohms for both field wires from alt to VR is 0. Some reason it is still charging at 14.95v. What else can I check? Did I check something wrong?
 
check voltage regular ground. Add a ground wire from it to the battery
 
I went through the same thing on my 86 W250. New alternator, regulator, hei distributor. Aftermarket gauge set and voltmeter would fluctuate between 15 and 16bolts. Added a ground wire to regulator, put a heavy duty ground cable from battery to engine and put new ends on cables. It still runs at 14.5 volts but the needle is steady now. I'm using a big 1200 amp battery out of a Cat 920. Gauge idles at 13.5 volts and goes to 14.5 at anything over idle speed. Hasn't seemed to cause any problems with the wiring or battery so I kinda stopped worrying about it. Hope this helps
 
Budgetmoparman said:
A little background about the vehicle. It is an 86 dodge truck that the previous owner had all cobbled together. I have converted to a 1 wire HEI distributor, eliminating the balast resistor. I just installed a brand new ignition switch (old one fried because of shitty wiring from previous owner). New alternator. New voltage regulator. I replaced a few of the wires thru the bulkhead when I put the ignition switch in. Battery has been tested and is good. Ohm reading from ground to VR housing is 0. Battery voltage is 12.47 engine not running. Voltage from battery to VR plug is 12.40 without engine running. Ohms for both field wires from alt to VR is 0. Some reason it is still charging at 14.95v. What else can I check? Did I check something wrong?
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How long did you let it run for?A cold battery is a low-charged battery.
Battery voltage at 12.47 seems a bit low.I would charge the battery up for a few hours or until it reads closer to 13.2v, make sure it is warm, and retest it.
The usual full charge on a warm car battery is 2.2 v per cell, so 6 cells is 13.2 , and I always look for a charging voltage that is a minimum of 1.5 volts higher than the battery rest voltage.So that would be 14.7v.This with a fully warmed up system and with the headlights on bright and the heater-fan blowing on hi.
I think 14.95 is nearly bang-on in this case.I have seen lots of GMs charge at 15.2v

You might want to check for an off-draw.
 
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AJ/FormS said:
How long did you let it run for?A cold battery is a low-charged battery.
Battery voltage at 12.47 seems a bit low.I would charge the battery up for a few hours or until it reads closer to 13.2v, make sure it is warm, and retest it.
The usual full charge on a warm car battery is 2.2 v per cell, so 6 cells is 13.2 , and I always look for a charging voltage that is a minimum of 1.5 volts higher than the battery rest voltage.So that would be 14.7v.This with a fully warmed up system and with the headlights on bright and the heater-fan blowing on hi.
I think 14.95 is nearly bang-on in this case.I have seen lots of GMs charge at 15.2v

You might want to check for an off-draw.
Click to expand...
So if it charges to 13-13.5v it should be ok? I thought it was overcharging the battery. It was not at running temp when I did the tests. I will try taking it for a drive and then doing some tests.
 
Sounds like you're fine. Is the top of the battery ever way after a long drive?
 
I put the charger on the battery for a few hours this morning and then took the truck for a drive so everything was warmed up. At cruise speed it is still charging 15.06v without any electronics turned on. With the lights on and heater wide open it drops to 14.97v. With the engine off the battery is at 14.10v. Is this something to worry about or are those numbers ok? I don't want to fry any more wiring or ruin my good optima battery. The battery doesn't feel warm but it wasn't a really long drive.
 
Budgetmoparman said:
Some reason it is still charging at 14.95v. What else can I check? Did I check something wrong?
Click to expand...

14.95 is only 2.5 volts DC per battery cell. That is not unusually high. I would consider that on the high side of normal for charging the battery, but NOT HIGH.

It is up to you, if it were mine, I would leave it be
 
I think your battery may have problems. A 14.10 rest voltage seems high. Is there any chance it is frozen? Or sulfated? Measure the voltage again to verify it is at or near 14.Leave the voltmeter installed and then with the engine off, turn the brights on, for 15 seconds and watch the voltmeter. Then turn the lights off and continue to watch the voltage.
The voltage should no drop to less than 10.5 and should recover to about 1/2 volt less than the voltage at the start of the test. If it fails either test, Ima thinking it's days are numbered.
At this point if you have a temperature-compensated battery-hygrometer, it's time to go find it.You would be looking for fl,.................. oh wait, you said Optima? That is "dry-cell" technology, and it runs a slightly higher rest voltage.Sorry to confuse you, but yeah, my Optima runs around 14 volts as well.
The test is still valid, but I agree with Pawned, in post #9
 
AJ/FormS said:
I think your battery may have problems. A 14.10 rest voltage seems high. Is there any chance it is frozen? Or sulfated? Measure the voltage again to verify it is at or near 14.Leave the voltmeter installed and then with the engine off, turn the brights on, for 15 seconds and watch the voltmeter. Then turn the lights off and continue to watch the voltage.
The voltage should no drop to less than 10.5 and should recover to about 1/2 volt less than the voltage at the start of the test. If it fails either test, Ima thinking it's days are numbered.
At this point if you have a temperature-compensated battery-hygrometer, it's time to go find it.You would be looking for fl,.................. oh wait, you said Optima? That is "dry-cell" technology, and it runs a slightly higher rest voltage.Sorry to confuse you, but yeah, my Optima runs around 14 volts as well.
The test is still valid, but I agree with Pawned, in post #9
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I did this test this morning after the truck sat over night. Resting voltage was at 12.92v, with high beams on it dropped to 12.22v, it recovered back to 12.80v. I would guess the battery is good. I suppose I will just run it for a while and monitor it to make sure the battery and wiring aren't getting hot. If I have any issues I will be back with more questions. Thanks for all of the help.
 
Budgetmoparman said:
I did this test this morning after the truck sat over night. Resting voltage was at 12.92v, with high beams on it dropped to 12.22v, it recovered back to 12.80v. I would guess the battery is good. I suppose I will just run it for a while and monitor it to make sure the battery and wiring aren't getting hot. If I have any issues I will be back with more questions. Thanks for all of the help.
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Technically, with a stable load on the battery, the higher the voltage the lower the current will be. Not a whole lot, mind you, but it will be lower current flow than if the battery was at 10volts.
If it were me I would not worry too much about the wires overheating, if they are not now
 
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