Load testing a battery when cold vs hot:

[The_Jeff]

Originally Posted By: johnachak
A) It does matter the temperature the measurement is taken at
B) CCA's are for when the engine is off. You need the full 500 to start the car.


They spec plenty of headroom/ cushion/ whatever you want to call it when they spec the battery. Just because 500 are available doesn't mean they'll be used. Also the CCA rating is for 30 seconds continuous, a generous cushion there as well.

Look at this 1.2 kW starter, that's 100 amps, or actually probably more like 120 if the volts dip to 10 during cranking.

 

[hemitom]

No , 500cca is more than enough for starting I used to start a 440 cubic in engine with this size of battery. which is probably four times bigger than his honda engine. 300 cca would be more than enough to start this car

 

[Carnoobie]

Well OEM is 410CCA, and couple people with my car have been running 750CCA batteries and starts up right away even in -30. More CCA definitely wouldnt hurt but only 500CCA is the max at stores here.

I think the kind of oil has more to do with the battery no? dont forget I went from using one of the thinnest oils (Mobil 1 5w30) to Castrol High Mileage GTX 5w30, rated as the thickest High Mileage oil out there. In those 2 winters running Mobil 1 syn, I never ever got a slow crank last winter when running Mobil 1. Even in -24 and plugged in, it fired up right away.

The reason why I switched to High Mileage for good is because of the addictives found in High Mileage oils over Syn. I am a believer that High Mileage oils will benefit an older engine than a Syn would. I was told they will make the engine last longer (not sure how true this is).

And also, I did just get my seals replaced from oil leakage (and was running Mobil 1 at the time), and scared to death of another so im not wanting to take a chance running Syn again. No way im paying for that big job again! Not saying the syn oil is what caused it, but I think with 160K km, and new seals, I shouldnt use Mobil 1 syn anymore.

Do I want to run Mobil 1 Syn again? Of course I do, for the fact I never got slow cranking when using it. But I just cant take the chance and think at this point High Mileage oil is better for me.

 

[Vikas]

If you *really* want to check out your battery and starter, disconnect the fuel pump fuse and start cranking and watching the voltage. Don't go crazy on the starter but few seconds (5?) of cranking and if the voltage is staying well above 10V, your battery is fine.

 

[mechtech2]

Originally Posted By: Carnoobie
Originally Posted By: mechtech2
Of course it matters cold/hot.
That is why cold cranking amps and hot cranking amps are given on all batteries.


I mean for testing the starters draw, does it matter if done hot or cold? One Mech says it does not, otehr says it does.


Resistance goes up when hot for most materials/metals, except carbon. [note the heat shields on starters on V8 Chevys of old]. So starter draw should be greater when hot. How much? Never figured it out, but 20% is fair. Also note engine oil is thicker when cold, and thinner when hot. This will offset the starter's gains/losses somewhat.

 

[Carnoobie]

Did load test just now with the load tester, hit the switch for about 7 secs, car completely cold.

10.5V, says on the meter weak!

 

[Carnoobie]

Can anyone comment? Is 10.5V good or bad? The 10.5V said weak on the load tester gauge.

 

[hemitom]

With the battery electrolyte at minus 12 c and a load test down for 15 seconds minimum voltage should be 8.9 volts

 

[hemitom]

sorry should be done for 15 seconds.

 

[Carnoobie]

really 15secs? I was told no more than 10secs but if its 15secs then ill redo it.

 

[mechtech2]

Load testers are adjustable. Your readings will vary greatly by the load put on the battery.

 

[Carnoobie]

Well mechtech my tester does not have any adjustments. Just has a load switch on and off so i hit on and held for 10secs.

A mech still swears its the battery and to replace it.

The past few days have been normal starts. From this morning cold start.