Current Drain (Parasitic Draw)

Ex3t3r

Ex3t3r

Club Member
Left my bike for 2 weeks parked up and on the day I planned a ride out the previous night thought I would
check the battery for charge and found out it was virtually dead, so charged it over night all is now good,
so this leads me to the question in hand do I have a 'Parasitic Electrical Draw'?

I have fitted no after market electrical accessories it is completely stock, there is a Youtube tutorial for
testing if their is a specific electrical drain issue (see below) but my H-D manual does not cover this issue
so I at the moment I have no way of knowing the acceptable milliamp draw threshold, I have carried out
a leakage test as described in the tutorial below and it is showing OL (Open Line) on my multimeter = CONFUSED!

I tested the charging system and all is well but as my bike has no fuses and only circuit breakers would this prevent
me from finding this potential current draw/leakage?

Would appreciate any constructive comments/ideas on this issue.

Model: 1991 FLHS EVO

Link: h##ps://www.youtube.com/watch?v=V_kM1kP1I38&list=FLPLz6NOG8t7kFgM8VErVnyg&index=3


Replace the ## for tt in the URL
 
Last edited:
All Batteries self discharge. Wet/Flooded Batteries can lose about 3% of their capacity per month and AGM batteries are better at 1% per month. The discharge is temperature dependant and the length of storage, The hotter the Temp. the faster the discharge rate. The above example was at a Temp. of 77 degrees F.
There is plenty of information on the Net regarding this. Click HERE for one I have picked out.
I forgot to add that the older the Battery there is a chance of Sulfation on the Battery Plates which will affect the ability of the battery to store and hold a charge.
Pat.
 
Last edited:
From memory, one of the most common culprits is the regulator/rectifier. It needs to be very well earthed, and many riders install an extra earth lead as a precaution.
 
softail898 said:
All Batteries self discharge. Wet/Flooded Batteries can lose about 3% of their capacity per month and AGM batteries are better at 1% per month. The discharge is temperature dependant and the length of storage, The hotter the Temp. the faster the discharge rate. The above example was at a Temp. of 77 degrees F.
There is plenty of information on the Net regarding this. Click HERE for one I have picked out.
I forgot to add that the older the Battery there is a chance of Sulfation on the Battery Plates which will affect the ability of the battery to store and hold a charge.
Pat.
Click to expand...
New battery only 6 months old, bike is kept in a cool storage so even on a hot day temp is approx 15C/59F but will take on-board kevscrivener suggestion and fit another earth. But to my original question with the help of a multimeter can I identify to source of the current leak?
 
What setting is your Multi Meter on? OL reading stands for “Overload”. The Meter is seeing a higher Amperage than the Meter is set for. Post a pic. of the Meter with the setting you are using.
 
Wiring diagram here - https://serviceinfo.harley-davidson...92#a25c7420-c0a2-4856-9814-0c92811e01d7!!1!14

Looking at the diagram there is nothing that ought to be drawing power with the ignition off except maybe the regulator but that shouldn't be more than a few milliamps that wouldn't flatten a battery in 2 weeks.

I didn't watch the video. To do a parasitic test you remove the positive wire from the battery and insert the ammeter to then complete the circuit. You do not turn on the ignition nor attempt to start the engine.

Start with meter on highest current reading and then reduce to lower one if not seeing a reading.

Batteries do self charge. I have one here sitting on the bench and it is holding its charge very well.
 
softail898 said:
What setting is your Multi Meter on? OL reading stands for “Overload”. The Meter is seeing a higher Amperage than the Meter is set for. Post a pic. of the Meter with the setting you are using.
Click to expand...
OL = Open Line (meaning no circuit present) Hoping to borrow a better Multimeter to verify my old multimeter readings to see if I get a different reading
 
Ex3t3r said:
New battery only 6 months old, bike is kept in a cool storage so even on a hot day temp is approx 15C/59F but will take on-board kevscrivener suggestion and fit another earth. But to my original question with the help of a multimeter can I identify to source of the current leak?
Click to expand...
Yes you can but you must set the Meter to the required setting. Show us a pic. of the Meter.
 
Andy from Sandy said:
Wiring diagram here - https://serviceinfo.harley-davidson...92#a25c7420-c0a2-4856-9814-0c92811e01d7!!1!14

Looking at the diagram there is nothing that ought to be drawing power with the ignition off except maybe the regulator but that shouldn't be more than a few milliamps that wouldn't flatten a battery in 2 weeks.

I didn't watch the video. To do a parasitic test you remove the positive wire from the battery and insert the ammeter to then complete the circuit. You do not turn on the ignition nor attempt to start the engine.

Start with meter on highest current reading and then reduce to lower one if not seeing a reading.

Batteries do self charge. I have one here sitting on the bench and it is holding its charge very well.
Click to expand...
All the video tutorials I have seen they all state you remove the negative lead from the battery connect to black multimeter lead (negative probe) and the red probe lead to battery negative terminal/post in DC Amp test mode first then change to DC milliamp mode to determine the amp draw present and if the draw is above a certain limit then I need to find the source of the leak, but as my H-D manual does not cover this testing procedure I do not know what is a permissible amperage leak!

Screenshot.jpg
 
softail898 said:
Did you get a reading when in DC Amp mode? If so what was it?
Click to expand...
No, but I am using a very cheap Chinese multimeter and I cannot be sure I am getting accurate or reliable readings, a friend is letting me borrow his Fluke multimeter soon so I will carry out the tests again and get back to you with screen shots for you to examine
 
Sorry I was wrong on the lead to remove from the battery purely from the point of view on safety, as you should always remove the lead that is the ground wire first. In the case of Harleys it is the negative terminal coloured black.
 
You must log in or register to reply here.
Back
Top