Battery Voltage Question

[Trendkill 10+ year member]

I just got the first piece of my system installed, a Pioneer 880PRS. I was messing around with it and discovered that it had a battery voltage meter. When I'm driving around it fluctuates in the 13's, sometimes 14's. When the engine is off, it's in the 11's. Does this seem normal or should it be more steady? Keep in mind I'm just running 4 speakers off Head Unit power.

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[SPL140.2 5,000+ posts]

what does the dmm say when the engine is off? compare the dmm to the head unit.

 

[Trendkill 10+ year member]

Do you mean use a digital multimeter to test if the head unit is displaying the same?

I wasn't really concerned about the accuracy, I just assumed it was correct (although I suppose t wouldn't hurt to test that anyway). I'm wondering if those values make sense for a vehicle, or if it sounds like I need a new battery. I really don't have a clue as to how my voltage should look.

 

[SPL140.2 5,000+ posts]

yeah take the multimeter to the front battery when the engine is off and write down the reading than compare it to the head units reading.

 

[audioholic 5,000+ posts]

Do you mean use a digital multimeter to test if the head unit is displaying the same?
I wasn't really concerned about the accuracy, I just assumed it was correct (although I suppose t wouldn't hurt to test that anyway). I'm wondering if those values make sense for a vehicle, or if it sounds like I need a new battery. I really don't have a clue as to how my voltage should look.

A new batt should read approx 12.8 volts with the engine off, and system voltage should jump up to about 14.4volts with the engine on (supplied by the alternator).
With that meager of a system, it sounds like you have an issue somewhere. Your voltage shouldn't be moving around that much with such a small drain from the stereo, nor should the batt read below 12volts with the engine off. Make sure none of the cells in the batt have gone dry.

 

[phyphoestilic 5,000+ posts]

A new batt should read approx 12.8 volts with the engine off, and system voltage should jump up to about 14.4volts with the engine on (supplied by the alternator).
With that meager of a system, it sounds like you have an issue somewhere. Your voltage shouldn't be moving around that much with such a small drain from the stereo, nor should the batt read below 12volts with the engine off. Make sure none of the cells in the batt have gone dry.

I agree with this. The only reason i can see it going down to 11v with the engine off, would be if u are/have been blasting music and just been draining from the battery. Depending on the car the output of the alt could be anywhere from 13.5-14.4v w/ the car on. So it seems to me the alternator is working correctly at least. Could u tell us if u have a deep cycle battery? (yellow top for example) or just a regular starter battery.

 

[Trendkill 10+ year member]

Regular battery

 

[05gliguy 10+ year member]

I have a pioneer 9800bt and it also has a voltage meter and mine is about three to four tenths off than the dmm (with the dmm reading the higher voltage). So maybe this helps...

 

[audioholic 5,000+ posts]

I have a pioneer 9800bt and it also has a voltage meter and mine is about three to four tenths off than the dmm (with the dmm reading the higher voltage). So maybe this helps...

The difference wouldn't be a function of the head, its a function of how much resistance is in between the baterry and the pioneer. It will change from vehicle to vehicle.

 

[phyphoestilic 5,000+ posts]

Regular battery

Better test with a DMM at the actual battery. Cuse a non deep cycle battery dropping to 11v is never good since they weren't designed to actually drop that low.