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2005 Escalade 6.0L 2WD, 2007 Jeep Grand Cherokee Limited CRD
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3,723 Posts
Discussion Starter #1
I've been having a problem with the battery voltage on my '94 Deville. The voltage would spike above 16, then go back down for a while, then spike back up. I blew a pair of Silverstar headlamp highbeam bulbs last night, so I had to replace those! :wtf:
I figured it was the voltage regulator in the alternator going bad, so I replaced the alternator with a new one. Now I am still having the same problem! :suspect: When this happened with the original alternator, the DIC would display "Battery Voltage High". Now it will display that as well as an occasional "Battery No Charge" message. So I'm not sure if there's a loose connection causing that, but what would be causing the battery volts to be too high?
I'm not sure what to do now? I'm thinking the battery is bad??? It's only a month old though. I read in the service manual about the battery cable connection to the starter could be a cause of intermittent voltage problem. I had installed a new starter yesterday, so I'm thinking of checking to make sure the cable is tight.
Anything else I should look into? :worship:
 

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2005 Escalade 6.0L 2WD, 2007 Jeep Grand Cherokee Limited CRD
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3,723 Posts
Discussion Starter #3
yeah, but if it fried a $36 pair of headlight bulbs, I'm sure it would do the same to several hundred dollar amps!
I think I figured out what the problem is. The bolt that holds the positive battery cable on seems to have messed up the threads in the battery a bit, so it's not contacting very good some of the time. I'm not sure how to fix the threads on the battery. They're not bad, but they don't seem to be grabbing enough of the bolt threads. Any ideas?????
 

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2005 Escalade 6.0L 2WD, 2007 Jeep Grand Cherokee Limited CRD
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3,723 Posts
Discussion Starter #5
I've fixed the problem. The battery sense wire going to the starter had a bad connection. So I rewired it with new wire and connector and it has worked great for over 1,000 miles since! :bouncy:
 

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2002 DHS
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16 Posts
I've fixed the problem. The battery sense wire going to the starter had a bad connection. So I rewired it with new wire and connector and it has worked great for over 1,000 miles since! :bouncy:
Hey I have a 2002 cadillac deville 76000 miles did that return your voltage to normal settings? How do I check that wire to my starter?
 

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2005 Escalade 6.0L 2WD, 2007 Jeep Grand Cherokee Limited CRD
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3,723 Posts
Discussion Starter #7
Hey I have a 2002 cadillac deville 76000 miles did that return your voltage to normal settings? How do I check that wire to my starter?
Hi, yes, after fixing that wire, I had no more voltage issues. As for your Deville, that has a completely different engine. I'm not sure where the wiring goes on that. I do know that the starter on your car is under the intake manifold. I would investigate the alternator and other wiring before trying to get at the starter.
 

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2002 DHS
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16 Posts
Hi, yes, after fixing that wire, I had no more voltage issues. As for your Deville, that has a completely different engine. I'm not sure where the wiring goes on that. I do know that the starter on your car is under the intake manifold. I would investigate the alternator and other wiring before trying to get at the starter.
Yes , I have tried tried checking alternator and it is going up to 15.volts 15.1 tops my battery wont stay more then 12.5 volts I think my battery is dead (suflated)
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,043 Posts
My 2002 Seville regularly runs at 14.8 during the initial after-start recharge cycle. Normally, about 14.2 - 14.4 on the road.

A fully charged "12 volt" battery reads 12.5 or 12.6 volts at rest. Vehicle electrical system voltage can read as high as 15 or 15.2 during maximum charge rates.

battery charge table.jpg


Google "lead acid automobile battery charging" and do some studying.
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,043 Posts
"Battery" - a box with two or more cells connected in series. A lead-acid cell produces 2.1 Volts at full charge. Our car batteries have 6 cells connected together.

No, a battery will only "charge" to 12.6 volts. That's the max reading you should see on the DIC message board or on a multimeter with the battery disconnected from anything for a half hour. Reconnect the battery, start the engine and voltage climbs to 14.5 - 15.2 or so and, as the battery comes back to full charge the system voltage should drop down to 14.5 or a bit less. 13 - 13.4 volts is the system voltage with a battery minder connected and plugged in.


Your earlier "sulfated' question - Battery electrolyte is made up of distilled water and sulfuric acid to a specified specific gravity number. Specific gravity varies with charge state. It's very low at full discharge, highest at full charge.(Read some of the info in my previous link) The electrolyte in a discharged battery is almost pure water; the sulfuric acid is deposited on the lead battery cell plates as lead sulfate jelly which is driven back into solution as the battery charges. If left discharged the jelly crystallizes ("sulfation") and will NOT go back into solution: The battery is ruined.

Open the link provided and do some study - it's all in there. For the first 4 years of my 30 year navy submarine career I was a main power electrician in a diesel/electric submarine. Lotsa BIG batteries - 256 cells, 1 ton each cell. USS PIPER (SS 409). Our 12 volt car batteries have 6 cells in series = 12.6 Volts. A pair of diesel sub batteries in series can discharge over 500 volts at over 10,000 Amperes. Raw power.
 

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2002 DHS
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16 Posts
Hi, yes, after fixing that wire, I had no more voltage issues. As for your Deville, that has a completely different engine. I'm not sure where the wiring goes on that. I do know that the starter on your car is under the intake manifold. I would investigate the alternator and other wiring before trying to get at the starter.
Hey , UPDATE! Both new battery and alternator is running better now, so the battery was dying.
 
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