Battery or Alternator Issue? Or Both?

itselvis

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Hi to all!

I have a 2016 Honda Civic Touring and I use a Uniden R3 Radar Detector to display the battery voltage as my car is running.
Before I drive of course it is in Park mode I'm getting 14.2V, when I start to get on the road when I shift the car to drive, I notice the voltage drop gradually quickly around to the 12's and sometimes it goes up and down depending on how I am driving. I also notice when I accelerate it appears that the voltage goes down and when I release the gas letting inertia go, you see the voltage come back up, then when I get to a stop light I usually see the voltage drops down, sometimes I seen it as low as 11.8v. Or one time I was backing up (reverse) and I saw it shoot down to 11.5v. Just know that mainly my car runs between 12.1v-12.6v on normal city speed limits. I also notice that the voltage stays good when I'm driving in cooler weather and it seems like the car runs better, but during the day time I get the ups and downs...
I'm very close to 60K miles, I still have the original battery when I bought the car in January 2016.

So I'm curious if this is a normal thing the car does or is there something really wrong.
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shoegazer

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Well the battery is a known weak link in our cars. But Autozone will test your battery and alternator for free.
 

calonzo

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Hi to all!

I have a 2016 Honda Civic Touring and I use a Uniden R3 Radar Detector to display the battery voltage as my car is running.
Before I drive of course it is in Park mode I'm getting 14.2V, when I start to get on the road when I shift the car to drive, I notice the voltage drop gradually quickly around to the 12's and sometimes it goes up and down depending on how I am driving. I also notice when I accelerate it appears that the voltage goes down and when I release the gas letting inertia go, you see the voltage come back up, then when I get to a stop light I usually see the voltage drops down, sometimes I seen it as low as 11.8v. Or one time I was backing up (reverse) and I saw it shoot down to 11.5v. Just know that mainly my car runs between 12.1v-12.6v on normal city speed limits. I also notice that the voltage stays good when I'm driving in cooler weather and it seems like the car runs better, but during the day time I get the ups and downs...
I'm very close to 60K miles, I still have the original battery when I bought the car in January 2016.

So I'm curious if this is a normal thing the car does or is there something really wrong.
If you are running the A/C, the electric cooling fans are probably going on and off causing the drops.
 

red06

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I believe these cars have an electric load detector which controls the charging system. If the load is high the alternator puts out 14.4; if very little load it puts out 12.3 or thereabouts.
 


Mikeybc

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I believe these cars have an electric load detector which controls the charging system. If the load is high the alternator puts out 14.4; if very little load it puts out 12.3 or thereabouts.
I think this is the case, All part of the effort to reduce fuel consumption and engine load...there's no point in trying to cram 14 volts into a battery that doesn't need it. I know General Motors use this type of charging system.
 

PowerPerLiter

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Yes it uses sensor outputs to variably apply voltage/amperage. Sounds completely normal.
 
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itselvis

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Thanks for everyone's input!

However I feel like like my pedal is more responsive when I have higher voltage however when it drops, its like I have to kinda step on it harder to get the car goin quick..
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