Battery rated 550 CCA tested at 409 CCA. Problem?

[Donald]

Originally Posted By: Quest
Originally Posted By: HerrStig
Why no meter on modern cars? Cost, and the inability of most people to make sense out of the readings.


Simple! Since most NA automobile operators doesn't even know what an idiot oil light means to them (or oil pressure gauge readings), letting alone a voltmeter/ammeter readings on a car, why should automobile manufacturers spend extra $$$ on automobiles to implement those gauges/meters that owners can't understand/read?

It's a cost-saving measure I admit, but it works both ways (majority owners don't seem to care/indifferent)

Q.


Both my vehicles have gauges for temp/oil/voltage. I also have a mechanical gauge I could use if needed. Oddly my Bobcat has no oil pressure gauge, only an idiot light.

 

[Vikas]

New Subaru no longer has temperature gauge on them!

 

[George7941]

Originally Posted By: JHZR2
Makes good sense.

I=E/R

Assuming voltage is full charge, 12.7V, then 550=12.7/0.023, resistance is 0.023 Ohm.

409=12.7/0.031, so resistance is 0.031 Ohm.

So your battery's internal impedance has grown by 50%. Generally EOL is determined by being at 200% of BOL impedance.

Id say youre good.

Does not mean other things cant kill your battery!


Sorry, JHZR2, your math doesn't add up. CCA is not the short circuit current capability of the battery, rather it is the current the battery can deliver to a starter and still maintain a minimum cranking voltage, generally around 9.5v.

When a battery is generating 550CCA, most of the voltage drop is across the starter and the drop due to internal resistance is only about 3 volts. So, your resistance figures are off by a factor of 4.

 

[GMBoy]

Originally Posted By: JimPghPA
Did their machine adjust the CCA for what it would be at 0 F? If it did that, then your battery is not that bad. But if the 409 amps is what it is doing at 63 F then it is bad.


My thoughts exactly.

 

[George7941]

The Conductance Testers must be automatically compensating for temperature since they measure COLD Cranking Amps, not Cranking Amps.

I own a Conductance Tester, a Midtronics PBT200. I have always taken it for granted that if the Tester rates a battery at 520 CCA then that battery will output 520amps at 0F, even if the testing was done at 100F.

 

[kb27]

I own a Midtronics PBT300 and also Argus 300.
I have a small business changing out car batteries.

Battery EOL is rated at around 70%~75% of spec as I understand it.

So a 550 CCA spec battery at around 412 CCA (75%) would be consider EOL.

As to why the tester says "charge required", it's because it was tested at 12.53V.

When it's charged back to full SoC at 12.66V, the cca will read much higher and gives a more accurate reading.

 

[barlowc]

Thanks to all you guys for the thoughts and information! Though the general consensus seems split as to whether I'm good or whether I should replace the battery. Here's what some different options would run me:

Exide NASCAR Select $61 (after shop coupon and rebate)
Autocraft Gold $84 (after ES123 coupon code at AAP)
Duralast Gold $108 (unless I could get them to match AAP)
Optima Red $153 (after ES123 coupon code at AAP)

The other consideration would be a JCI-manufactured Kirkland battery from Costco which I've used in vehicles in the past and got good Consumer Reports ratings recently.

 

[The_Jeff]

We have the same midtronics tester at the tire shop where I work part-time. We had a miata in with its original 1998 teeny tiny battery. 180 CCA was what it delivered. Yeah it started a little slow. The tester has a "point me at your battery" temp reading gizmo, so, presumably, it does a rough job of compensating for temp. Though a car that had been driven a couple miles might have a warm battery case and cold innards.

Our slips also read out "Your shop name", LOL.

The newer gear reduction starters still work well with fewer amps. When stuff starts turning over slowly you're on the steep part of the battery's death spiral curve.