What voltage do you expect to see?
11-06-2023, 04:37 PM
#1
Intermediate
Thread Starter
What voltage do you expect to see?
Looking for some advice.
I have a 2019 Grand Sport with 26,000 miles. I replaced the battery a month ago and have driven it several times since then.
Last Saturday, when I was on the way to an event about 60 miles away, early in the drive I noted the battery voltage was reading 12.7 volts. A few minutes later it was 12.6, then 12.5 and then 12.6. I expect to see something like 13.6 to 14.3 volts if the alternator is charging. I was considering returning to home base. A few minutes later after about 10 miles I saw the voltage increase to 14.6 volts, where it stayed the rest of the trip. Things looked better. On the return trip on an interstate, after starting, the voltage was 14.3 after starting. A few minutes later it was 13.0, where it stayed the rest of the trip.
Something does not seem right here. Alternator? Voltage regulator? Looking for any suggestions/comments before I take a trip and get stranded somewhere.
I have not yet checked the voltage with a volt meter to determine if there is a display problem.
I have a 2019 Grand Sport with 26,000 miles. I replaced the battery a month ago and have driven it several times since then.
Last Saturday, when I was on the way to an event about 60 miles away, early in the drive I noted the battery voltage was reading 12.7 volts. A few minutes later it was 12.6, then 12.5 and then 12.6. I expect to see something like 13.6 to 14.3 volts if the alternator is charging. I was considering returning to home base. A few minutes later after about 10 miles I saw the voltage increase to 14.6 volts, where it stayed the rest of the trip. Things looked better. On the return trip on an interstate, after starting, the voltage was 14.3 after starting. A few minutes later it was 13.0, where it stayed the rest of the trip.
Something does not seem right here. Alternator? Voltage regulator? Looking for any suggestions/comments before I take a trip and get stranded somewhere.
I have not yet checked the voltage with a volt meter to determine if there is a display problem.
Popular Reply
11-06-2023, 05:21 PM
Burning Brakes
I expect to see between 12.6 and 15.2 volts on the DIC. A DVOM on the battery itself should show an almost identical reading. If the car's starting fine, you're probably fine. Especially if you put an AGM in there.
These alternators don't regulate like the old externally regulated stuff you might be more familiar with. They're ECU regulated.
If there is low electrical demand and the state of charge of the battery is within acceptable parameters, the voltage will drop to a low float until it needs to charge, at which point it'll step up to 13 or 14 usually.
Depending on ambient temperature, it's normal to see a 15+ volt charge on an AGM battery. There's a charge of float and charge voltages by battery composition by temperature out there somewhere.
These alternators don't regulate like the old externally regulated stuff you might be more familiar with. They're ECU regulated.
If there is low electrical demand and the state of charge of the battery is within acceptable parameters, the voltage will drop to a low float until it needs to charge, at which point it'll step up to 13 or 14 usually.
Depending on ambient temperature, it's normal to see a 15+ volt charge on an AGM battery. There's a charge of float and charge voltages by battery composition by temperature out there somewhere.
11-06-2023, 05:18 PM
#2
Racer
Check the small black wire on the Negative battery cable. This is a voltage reference for the charging system. It is easily broken or damaged when changing the battery.
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11-06-2023, 05:21 PM
#3
Burning Brakes
I expect to see between 12.6 and 15.2 volts on the DIC. A DVOM on the battery itself should show an almost identical reading. If the car's starting fine, you're probably fine. Especially if you put an AGM in there.
These alternators don't regulate like the old externally regulated stuff you might be more familiar with. They're ECU regulated.
If there is low electrical demand and the state of charge of the battery is within acceptable parameters, the voltage will drop to a low float until it needs to charge, at which point it'll step up to 13 or 14 usually.
Depending on ambient temperature, it's normal to see a 15+ volt charge on an AGM battery. There's a charge of float and charge voltages by battery composition by temperature out there somewhere.
These alternators don't regulate like the old externally regulated stuff you might be more familiar with. They're ECU regulated.
If there is low electrical demand and the state of charge of the battery is within acceptable parameters, the voltage will drop to a low float until it needs to charge, at which point it'll step up to 13 or 14 usually.
Depending on ambient temperature, it's normal to see a 15+ volt charge on an AGM battery. There's a charge of float and charge voltages by battery composition by temperature out there somewhere.
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11-06-2023, 06:11 PM
#4
Intermediate
Thread Starter
11-06-2023, 06:23 PM
#5
Intermediate
Thread Starter
I expect to see between 12.6 and 15.2 volts on the DIC. A DVOM on the battery itself should show an almost identical reading. If the car's starting fine, you're probably fine. Especially if you put an AGM in there.
These alternators don't regulate like the old externally regulated stuff you might be more familiar with. They're ECU regulated.
If there is low electrical demand and the state of charge of the battery is within acceptable parameters, the voltage will drop to a low float until it needs to charge, at which point it'll step up to 13 or 14 usually.
Depending on ambient temperature, it's normal to see a 15+ volt charge on an AGM battery. There's a charge of float and charge voltages by battery composition by temperature out there somewhere.
These alternators don't regulate like the old externally regulated stuff you might be more familiar with. They're ECU regulated.
If there is low electrical demand and the state of charge of the battery is within acceptable parameters, the voltage will drop to a low float until it needs to charge, at which point it'll step up to 13 or 14 usually.
Depending on ambient temperature, it's normal to see a 15+ volt charge on an AGM battery. There's a charge of float and charge voltages by battery composition by temperature out there somewhere.
When I put it on the battery tender, it went green in hour or two, so it was not discharged.
With the old (5 year) battery it was 13.6 to 14.3 constantly.
I will monitor it closely for a while to understand the new normal.
Thanks for the quick response
11-06-2023, 08:25 PM
#6
Melting Slicks
I expect to see between 12.6 and 15.2 volts on the DIC.
If there is low electrical demand and the state of charge of the battery is within acceptable parameters, the voltage will drop to a low float until it needs to charge, at which point it'll step up to 13 or 14 usually.
If there is low electrical demand and the state of charge of the battery is within acceptable parameters, the voltage will drop to a low float until it needs to charge, at which point it'll step up to 13 or 14 usually.
