need advice on current leakage test

[lawrence21]

got this off the net when looking for info to DIY troubleshoot my scooter's battery problem.

 

"Step 1 - Bike Leakage Current Test

Put the battery back on the bike, but connect only the +VE clamp to the battery, leaving the –VE stud not connected. The battery voltage should measure 12V7 to 13V1 across the stud terminals on top of the battery. Measure the LEAKAGE CURRENT of the bike, by setting the meter to DC AMPS, connect one meter probe to battery -VE terminal, connect the other meter probe to the bike harness -VE battery strap / clamp. The current should be no higher than about 50mA (Ignition OFF). Press the brake lever just to check everything is connected okay - the brake light should light, the meter should read about 1A750. Note: 50mA leakage will take a week to flatten a 9Ahour battery."

 

i have no idea how to use a digital multimeter but managed to borrow one anyway.

 

my problem is with the part in bold. does it matter which of the two multimeter probe (red or black) i use to connect to the battery -ve terminal and to the bike -ve battery clamp? in other words, does it matter if i connect the red probe to the battery -ve terminal and black probe to the bike -ve terminal?

[arthur_chan]

buy n connect up a voltmeter n u can monitor ur battery health everytime u on ur bike. this is for long term. u can't test anything out of testing the battery now, it can only tell u if the battery is weak. n dont tell me u want to carry a multimeter n open ur bike to test on regular basis.

Edited March 24, 2011 by arthur_chan

[arthur_chan]

my problem is with the part in bold. does it matter which of the two multimeter probe (red or black) i use to connect to the battery -ve terminal and to the bike -ve battery clamp? in other words, does it matter if i connect the red probe to the battery -ve terminal and black probe to the bike -ve terminal?

 

if u put red to -ve, black to -ve, u're not connecting to anything, the multimeter is testing itself.

it shouldn't matter if u connect red to +ve or -ve, as long the other end is connected to the opposite end, thus completing a circuit.

[Phang]

It doesn’t matter.

 

Red probe to battery –ve post, black probe to –ve clamp will give you a positive leakage current reading. e.g. [50mA]

 

Black probe to battery –ve post, red probe to –ve clamp will give you a negative leakage current reading. e.g. [-50mA]

 

I measure all my bikes for parasitic drain. In my opinion, 50mA is way too high. I have 2 bikes reading less than 2mA. The worst one was around 20mA and I need to charge it if I don’t ride it for more than a week else the starter will sounds lazy during cranking and fail to start after 2 weeks

[arthur_chan]

Red probe to battery –ve post, black probe to –ve clamp will give you a positive leakage current reading. e.g. [50mA]

 

Black probe to battery –ve post, red probe to –ve clamp will give you a negative leakage current reading. e.g. [-50mA]

 

what's the diff? u're testing the multimeter by connecting the + n - to the same point.

[lawrence21]

if u put red to -ve, black to -ve, u're not connecting to anything, the multimeter is testing itself.

it shouldn't matter if u connect red to +ve or -ve, as long the other end is connected to the opposite end, thus completing a circuit.

 

the multimeter is not testing itself because "Put the battery back on the bike, but connect only the +VE clamp to the battery, leaving the –VE stud not connected.", meaning the circuit is open.

 

The red probe is connected to -ve of the battery terminal and the black probe is connected to the -ve of the bike's -ve battery clamp, the multimeter would thus close the circuit, testing the entire circuit starting from the multimeter red probe -> -ve terminal of the battery -> +ve terminal of batt -> +ve batt clamp of bike -> bike's entire circuit -> -ve batt clamp of bike -> multimeter black probe.

 

umm... am i right?

 

note that this test is to test current leakage, not voltage.

[Phang]

what's the diff? u're testing the multimeter by connecting the + n - to the same point.

 

Arthur, take a coffee/cigarette break. Read the first post again when you come back, especially those in bold letter

[arthur_chan]

the multimeter is not testing itself because "Put the battery back on the bike, but connect only the +VE clamp to the battery, leaving the –VE stud not connected.", meaning the circuit is open.

 

The red probe is connected to -ve of the battery terminal and the black probe is connected to the -ve of the bike's -ve battery clamp, the multimeter would thus close the circuit, testing the entire circuit starting from the multimeter red probe -> -ve terminal of the battery -> +ve terminal of batt -> +ve batt clamp of bike -> bike's entire circuit -> -ve batt clamp of bike -> multimeter black probe.

 

umm... am i right?

 

note that this test is to test current leakage, not voltage.

 

Arthur, take a coffee/cigarette break. Read the first post again when you come back, especially those in bold letter

 

ah, my bad, speed reading too fast.

phang, i didn't notice u put post n clamp, was wondering why -ve to -ve

lawrence, phang's example is right, paiseh for the confusion.

Edited March 24, 2011 by arthur_chan

[Phang]

Old fart read slower so didn't miss the details

[arthur_chan]

i'm old fart, but boss want everything fast fast fast

[Phang]

Tell your boss he can only pick 2 from the followings:-

 

Cheap

Fast

Good

[arthur_chan]

what if he say he want all 3

 

sorry lawrence for OT on ur thread

[lawrence21]

phang: thanks for answering my query and the additional tip on parasitic drain!

 

arthur: no worries, thanks for confirming phang's answer.

[crazydj]

Tell your boss he can only pick 2 from the followings:-

 

Cheap

Fast

Good

 

http://filmindustrybloggers.com/theeditor/files/2009/02/good-triangle.jpg

 

Arthur, i hope your coffee/cigarette break helped.

[kaozie]

ah, my bad, speed reading too fast.

phang, i didn't notice u put post n clamp, was wondering why -ve to -ve

lawrence, phang's example is right, paiseh for the confusion.

 

nothing with speed reading here...

 

he is talking abt amps, where you are talking abt volts...

[arthur_chan]

Arthur, i hope your coffee/cigarette break helped.

no, coffee here is terrible, n i dont smoke

rushing home too.