Battery Q: Cranking AMP test?

This is a litlle OT since it's happening on my daily (2003 Explorer).

Latley the car has been dead (periodically) when I go to start it. It will start with a jump.

Pulled out the voltmeter and the battery checks out (before jumping it) at 12+ volts. After jump starting it I can see that the Alt is working becuase I'm getting 13-14 volts while running.

How do you test for proper cranking AMPs?

 

Carbon pile load tester is the only truly accurate way to test a battery...

 

Who you calling CABRON?

jk



I guess it's just time for a new battery but I would be interetesed in learning more. What is a "carbon pile load test"?

 

Hook it to the battery and turn the big knob to create a load. If the volts gauge starts dropping quickly you probably need a new battery. If it drops a little and holds relatively steady, then you are OK.

 

It's a too damn expensive piece of shop equipment! They are used to load test and calculate amp hours. Also alternator, regulator, starter.

 

Well off to the parts store for new battery.

Thanks guys.

 

It used to be three times the amp/hr. rating of the battery for 15 seconds....the battery should hold 9 volts

Exp. 70 amp/hr battery would be a load of 210 amps for 15 seconds.

They make a simple load tester that uses a coil to supply the load, kind of a one size fits all deal. Milton makes one for 50 bucks or so......Our friends over in China (HF) makes one for 15.