Slow Cranking - Starter AMP Draw

Posted By: solarguy

Slow Cranking - Starter AMP Draw - 07/22/12 05:51 PM

I'm troubleshooting a recent slow cranking speed situation and am looking for Starter amp draw numbers. Car has 340, Turbo-Start mopar resto yellow cap battery, DB electrical mini starter, Heavy duty battery cables, clean terminals. Battery and starter are about 18 months old.

With my d/c amp probe clamped around the positive cable and cranking with a remote starter switch, I am measuring 235-248 amps. That seems high off the top of my head but I actually have no data plate to compare it against. Before I go have the battery load tested, does anyone have any "Normal" amp draw numbers.

Thanks

Posted By: 540DUSTER

Re: Slow Cranking - Starter AMP Draw - 07/22/12 06:21 PM

I am not sure about amp draw,but your numbers don't sound that high.Had a slow cranking starter once,and it turned out that the long bolts that hold the casting together were loose.Got em tight and starter cranked good.I think the bolts are 1/4".When tight it must have grounded the starter better.

Posted By: RapidRobert

Re: Slow Cranking - Starter AMP Draw - 07/22/12 08:02 PM

Quote:

a recent slow cranking speed situation

Starters are weird electrical devices as in the slower they turn the more amps it draws which depletes the batt which means less current available to the starter so it goes even slower yet & this compounds in a matter of split seconds so a high amp starter draw could be from a bad battery. If you're sure your large cable ends/terminals are clean I'd slow charge the battery overnight then have it load tested or faster yet borrow a known good batt & toss it in

Posted By: solarguy

Re: Slow Cranking - Starter AMP Draw - 07/22/12 08:12 PM

I just got back from load testing the battery, print out shows 13.23 volts and 183 CCA

, looks like 18 mth old resto battery is gone.

I'm curious though why I was reading 235 or so amps and the load test shows only 183. I guess variable in load between their tester and my engine load??

Posted By: Supercuda

Re: Slow Cranking - Starter AMP Draw - 07/22/12 10:42 PM

Current is determined by the load. Sounds like the starter is a bigger load than the load tester in this case. that or your meter is reading off.

Posted By: markz528

Re: Slow Cranking - Starter AMP Draw - 07/23/12 04:53 AM

The current means little without knowing the voltage. What is the battery voltage when you are cranking it?

If the voltage is reasonable, measure the voltage from the negative battery post to the engine block to make sure you don't have a ground problem - - don't want much of a voltage drop there.

You would also want to measure the voltage at the starter and compare to the battery when cranking to make sure you don't have a bad connection in that circuit also.

I would not trust the battery test the store did. Measuring voltage and current when cranking is the best way to know, just make sure the battery is fully charged when doing the test.