Battery

[Therman]

I have a brand new battery that show 12.8 volts but when craked it only puts out 10.4. whats wrong.

 

[Will Bark]

Re: Battery

Could be dirty battery connections on each end of the cables or corrosion internal in the cables.

 

[Therman]

Re: Battery

The connections are new but i have the voltmater on each post of the battery so would a bad cable affect the voltage.

 

[JB]

Re: Battery

Nothing is wrong. The starter draws so much current that internal impedance drops the other 2 volts or so. That is normal.

 

[metriccrescentwrench]

Re: Battery

Could be dirty battery connections on each end of the cables or corrosion internal in the cables.

NO, that's not going to have any effect on a voltmeter reading taken right at the battery posts.

I have a brand new battery that show 12.8 volts but when craked it only puts out 10.4. whats wrong.

No battery is going to show the open circuit voltage when there's a load on it, that's because of the internal resistance of the battery. I can't remember off the top of my head what voltage drop is normal when cranking, but you'll ALWAYS get a lower reading at the battery when cranking.

 

[boobie]

Re: Battery

The spec used to be 9.8 volts across the batttery when cranking.

 

[Therman]

Re: Battery

Ok, good to know thanks.