Battery under load?
Thread Starter
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From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
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Battery under load?
I post this:
>> FOB not detected checklist <<
whenever a FOB mystery appears on here. The chart asks for the voltage to be checked.
What are the best methods (short of a real load testing tool) to have a car owner load test the battery and read the voltage.
I believe for a manual transmission, simply pushing the start button without depressing the clutch will give the "load" reading. If this is correct, fine if not, then state the procedure. Since I don't do automatics, what is the procedure to get a battery under load on one of those.
Keep it short and sweet as I will further chop it down and add it to my checklist as part of the instructions.
TIA
Elmer
>> FOB not detected checklist <<
whenever a FOB mystery appears on here. The chart asks for the voltage to be checked.
What are the best methods (short of a real load testing tool) to have a car owner load test the battery and read the voltage.
I believe for a manual transmission, simply pushing the start button without depressing the clutch will give the "load" reading. If this is correct, fine if not, then state the procedure. Since I don't do automatics, what is the procedure to get a battery under load on one of those.
Keep it short and sweet as I will further chop it down and add it to my checklist as part of the instructions.
TIA
Elmer
Team Owner
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From: Southern Utah
I'm not sure I understand the question Elmer. The only load that really matters is the starter motor...it is hundreds of amps of load. A bad battery can many times stand up to the load of turning the ignition on, which is perhaps only 10 amps or so.
Pushing the start button without pushing the brake pedal does the same thing in an auto that pushing the button without pushing the clutch does in a stick. It turns on the ignition without running the starter motor.
I would say that in the absence of a real load tester, someone could put a meter directly on the battery and then run the starter motor with the gas pedal held down so that the engine would not start. This would truly give the system voltage while under load. It would really require two people to do this.Does this make sense?
Pushing the start button without pushing the brake pedal does the same thing in an auto that pushing the button without pushing the clutch does in a stick. It turns on the ignition without running the starter motor.
I would say that in the absence of a real load tester, someone could put a meter directly on the battery and then run the starter motor with the gas pedal held down so that the engine would not start. This would truly give the system voltage while under load. It would really require two people to do this.Does this make sense?
Race Director
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From: Las Vegas NV
My multimeter (Fluke 179) as a hold setting that will hold the highest or lowest reading. I just attach it to the battery and start the car. Thats probably as much load as the battery takes.
Team Owner
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From: Southern Utah
This provides more accuracy than having a second person watch the meter also!Correction: definitely more than a load tester...
Thread Starter
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From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
2015 C7 of the Year Finalist
I'm not sure I understand the question Elmer. The only load that really matters is the starter motor...it is hundreds of amps of load. A bad battery can many times stand up to the load of turning the ignition on, which is perhaps only 10 amps or so.
Pushing the start button without pushing the brake pedal does the same thing in an auto that pushing the button without pushing the clutch does in a stick. It turns on the ignition without running the starter motor.
I would say that in the absence of a real load tester, someone could put a meter directly on the battery and then run the starter motor with the gas pedal held down so that the engine would not start. This would truly give the system voltage while under load. It would really require two people to do this.Does this make sense?
Pushing the start button without pushing the brake pedal does the same thing in an auto that pushing the button without pushing the clutch does in a stick. It turns on the ignition without running the starter motor.
I would say that in the absence of a real load tester, someone could put a meter directly on the battery and then run the starter motor with the gas pedal held down so that the engine would not start. This would truly give the system voltage while under load. It would really require two people to do this.Does this make sense?
Team Owner
Joined: Mar 2008
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From: Southern Utah
OK, I understand...I can't see any way to test the battery using the car, if the fob is not recognized. Without a working fob, the DIC will not ever say anything except "no fobs detected"...which of course is the car's way of saying "go away and leave me alone"!
Thread Starter
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From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
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Either bring a load tester to the battery or take the battery to a load tester to prove good/bad on the battery.
ALSO, when the step calls to put the FOB in the slot, the ignition should then come alive and you can see the battery voltage, correct?
Team Owner
Joined: Mar 2008
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From: Southern Utah
Yes, but that means the fob is recognized and also the DIC is not giving voltage under the load of the starter. In fact, even if the entire system is working fine, the DIC can never display the voltage when the battery is under the load of the starter motor.
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Thread Starter
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So, I conclude the instructions are as accurate as they can be and I don't need to edit the information.
Elmer
Melting Slicks
Joined: Jul 2008
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Hate to say it, but you need a good load tester or a shop that will do it for you.
Your battery needs to be fully charged before it is done for the most accurate readings. I'd recommend maybe seeing if your dealer can do it or find a good aftermarket shop that has a quality load tester. (Sun VAT40)
Your battery needs to be fully charged before it is done for the most accurate readings. I'd recommend maybe seeing if your dealer can do it or find a good aftermarket shop that has a quality load tester. (Sun VAT40)
Team Owner
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From: Far NW 'burbs of Chicago
St. Jude Donor '13
I'm not sure I understand the question Elmer. The only load that really matters is the starter motor...it is hundreds of amps of load. A bad battery can many times stand up to the load of turning the ignition on, which is perhaps only 10 amps or so.
Pushing the start button without pushing the brake pedal does the same thing in an auto that pushing the button without pushing the clutch does in a stick. It turns on the ignition without running the starter motor.
I would say that in the absence of a real load tester, someone could put a meter directly on the battery and then run the starter motor with the gas pedal held down so that the engine would not start. This would truly give the system voltage while under load. It would really require two people to do this.Does this make sense?
Pushing the start button without pushing the brake pedal does the same thing in an auto that pushing the button without pushing the clutch does in a stick. It turns on the ignition without running the starter motor.
I would say that in the absence of a real load tester, someone could put a meter directly on the battery and then run the starter motor with the gas pedal held down so that the engine would not start. This would truly give the system voltage while under load. It would really require two people to do this.Does this make sense?
To turn on the ignition without actually starting the engine in a A6, you push and hold the bottom of the switch for about 5 seconds, the car goes into Accessory and then goes into the "Ign On" mode.
Team Owner
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From: Southern Utah
Jim, I'm not sure that the DIC has that many characters... I didn't know that about the A6...thanks for the info and correction... On the M6, it does the same thing as the holding of the ACC position.
I didn't know that about the A6...thanks for the info and correction... On the M6, it does the same thing as the holding of the ACC position.
Thread Starter
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From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
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One Big *** Mistake America! oooorrah!
Team Owner
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From: Far NW 'burbs of Chicago
St. Jude Donor '13
Thread Starter
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From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
2015 C7 of the Year Finalist
Melting Slicks
Joined: Jul 2008
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Likes: 1
Yep! For a limited time only kids, you TOO can have some know nothing kid hook some half assed, poorly calibrated junk up to your car so you know what parts to throw at it! Come on down!
Do you have a dealership you regularly frequent, OP?
Last edited by Pinky...; Jun 18, 2013 at 09:35 PM.