Electric testing
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- Senior Member
- Posts: 1916
- Joined: Mon Sep 20, 2010 11:55 pm
- Bike owned: VFR400
- Location: Blue Mountain NSW Australia
Re: Electric testing
Very interesting, as they say. Made same measurements on my NC30.
Ignition OFF = 0.0 amps,
Ignition ON = 0.3 amps
Same as yours and did an extra one:
Ignition ON and operate brake light = 3.5 amps
A reasonable result ( 2 x 21 Watts / 12 volt = 3.5 amps).
When you connect the alarm with ignition OFF a load current of 10 mA is quite reasonable, should even be less when alarm goes into sleep mode.
What I do not understand is why with ignition ON and alarm connected the current rises to 5.32 amps. Did you have headlights etc. ON at the same time.
Ignition OFF = 0.0 amps,
Ignition ON = 0.3 amps
Same as yours and did an extra one:
Ignition ON and operate brake light = 3.5 amps
A reasonable result ( 2 x 21 Watts / 12 volt = 3.5 amps).
When you connect the alarm with ignition OFF a load current of 10 mA is quite reasonable, should even be less when alarm goes into sleep mode.
What I do not understand is why with ignition ON and alarm connected the current rises to 5.32 amps. Did you have headlights etc. ON at the same time.
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- Senior Member
- Posts: 1916
- Joined: Mon Sep 20, 2010 11:55 pm
- Bike owned: VFR400
- Location: Blue Mountain NSW Australia
Re: Electric testing
Way back at the start you mentioned that the bike had an after market ignition unit. Could you be more specific, manufacturer, model etc.
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- Senior Member
- Posts: 1916
- Joined: Mon Sep 20, 2010 11:55 pm
- Bike owned: VFR400
- Location: Blue Mountain NSW Australia
Re: Electric testing
More questions:
1. when you made measurement with the alarm "disconnected" did you mean the alarm was simply unplugged,
2. was the engine run/stop switch in the RUN position when you made the ignition ON measurement.
1. when you made measurement with the alarm "disconnected" did you mean the alarm was simply unplugged,
2. was the engine run/stop switch in the RUN position when you made the ignition ON measurement.
- bikemonkey
- NWAA Supporter
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- Joined: Tue Dec 27, 2011 12:33 pm
- Bike owned: 92 NC30, 90 VFR750
- Location: Oxfordshire
Re: Electric testing
No, I didn't have anything else turned on at the same time.
I had a look at the ignition unit and took some pictures, it says OKI electronics on the end of it :




Yeah the alarm disconnected measurement was simply the alarm unplugged seeing as the alarm is spliced into the wiring loom I simply unplugged the two plugs from the alarm unit itself.
The kill switch was in the RUN position for all tests.
I had a look at the ignition unit and took some pictures, it says OKI electronics on the end of it :




Yeah the alarm disconnected measurement was simply the alarm unplugged seeing as the alarm is spliced into the wiring loom I simply unplugged the two plugs from the alarm unit itself.
The kill switch was in the RUN position for all tests.
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- Senior Member
- Posts: 1916
- Joined: Mon Sep 20, 2010 11:55 pm
- Bike owned: VFR400
- Location: Blue Mountain NSW Australia
Re: Electric testing
Have I got a great theory for you and a test to try.
To try identify the source of the 5 amp load, measure the current again with alarm plugged in and ignition ON but with the engine run/stop switch in the OFF position. The engine run/stop switch in the OFF position will isolate the ignition unit and the current reading should be around 0.3 amps. If this
To try identify the source of the 5 amp load, measure the current again with alarm plugged in and ignition ON but with the engine run/stop switch in the OFF position. The engine run/stop switch in the OFF position will isolate the ignition unit and the current reading should be around 0.3 amps. If this
- bikemonkey
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- Bike owned: 92 NC30, 90 VFR750
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Re: Electric testing
Got 0.31 amps with the alarm plugged in, ignition on, killswitch OFF.
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- Senior Member
- Posts: 1916
- Joined: Mon Sep 20, 2010 11:55 pm
- Bike owned: VFR400
- Location: Blue Mountain NSW Australia
Re: Electric testing
Here is my theory:
Your alarm has a control circuit that allows power to reach the ignition unit via the normal run/stop switch circuit when all is well. If the alarm detects any illegality it removes the power to the ignition unit by stopping power reaching the engine run/stop switch. Unplugging the alarm during testing obviously has the same effect, no power to the ignition unit no matter which position the engine run/stop switch is in.
During the last series of tests with the ignition ON and alarm unplugged you only the current drawn by the oil and neutral lamps.
When you plugged the alarm in and repeated the test the alarm was now allowing power to reach the ignition unit. You had the engine run/stop switch in the RUN position and the ignition switch in the ON position and the alarm was in the GO state, I assume. The 5 amps reading for this setup IMO is what the ignition unit is drawing from the battery in the non-running state. An OEM ignition unit draws effectively no current unless the engine is running and I suspect considerably less than 5 amps when the engine is running.
As the test you just did confirms the ignition unit as the cause of the 5 amp load, I could imagine that starting the bike and running it at idle until reaching normal water temp, as you say you have done over the months in storage, could result in a flat battery for the next time the bike is started. The charging system at idle does not produce enough power to supply the 5 amps your ignition unit appears to need and charge the battery, in fact, I would expect the battery to be in continual discharge. When you then stop the engine, you now have a battery that has just had a heavy discharge to start the engine and then a continued discharge to keep the engine running. Next time you go to start the bike the battery acts like it is flat because it is.
Great story ah and longer than War and Peace.
If all of then above is true then your aftermarket ignition unit, which I assume came with the bike, needs to be replaced with something that acts more like an OEM unit.
Look forward to your comments.
Your alarm has a control circuit that allows power to reach the ignition unit via the normal run/stop switch circuit when all is well. If the alarm detects any illegality it removes the power to the ignition unit by stopping power reaching the engine run/stop switch. Unplugging the alarm during testing obviously has the same effect, no power to the ignition unit no matter which position the engine run/stop switch is in.
During the last series of tests with the ignition ON and alarm unplugged you only the current drawn by the oil and neutral lamps.
When you plugged the alarm in and repeated the test the alarm was now allowing power to reach the ignition unit. You had the engine run/stop switch in the RUN position and the ignition switch in the ON position and the alarm was in the GO state, I assume. The 5 amps reading for this setup IMO is what the ignition unit is drawing from the battery in the non-running state. An OEM ignition unit draws effectively no current unless the engine is running and I suspect considerably less than 5 amps when the engine is running.
As the test you just did confirms the ignition unit as the cause of the 5 amp load, I could imagine that starting the bike and running it at idle until reaching normal water temp, as you say you have done over the months in storage, could result in a flat battery for the next time the bike is started. The charging system at idle does not produce enough power to supply the 5 amps your ignition unit appears to need and charge the battery, in fact, I would expect the battery to be in continual discharge. When you then stop the engine, you now have a battery that has just had a heavy discharge to start the engine and then a continued discharge to keep the engine running. Next time you go to start the bike the battery acts like it is flat because it is.
Great story ah and longer than War and Peace.
If all of then above is true then your aftermarket ignition unit, which I assume came with the bike, needs to be replaced with something that acts more like an OEM unit.
Look forward to your comments.
- CMSMJ1
- Moderators
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- Bike owned: NC30-No9
- Location: Chesterfield, United Kingdom
Re: Electric testing
^^ Skills.
Great work mate
Great work mate
IMPERATOR REX ANGLORUM
The V4 is the law..
NC30 - No9 - my old mate
The V4 is the law..
NC30 - No9 - my old mate
- bikemonkey
- NWAA Supporter
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- Joined: Tue Dec 27, 2011 12:33 pm
- Bike owned: 92 NC30, 90 VFR750
- Location: Oxfordshire
Re: Electric testing
CMSMJ1 wrote:^^ Skills.
Great work mate

Right so I shall be getting my hands on a hopefully OEM CDI, and when I do I'll be sure to update!
Thanks so much for all your help magg, invaluable, wouldn't have known where to start! Karma coming your way definitely

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- Senior Member
- Posts: 1916
- Joined: Mon Sep 20, 2010 11:55 pm
- Bike owned: VFR400
- Location: Blue Mountain NSW Australia
Re: Electric testing
Happy to help if I have, can you borrow an ignition unit from somewhere, would not want you to outlet a lot of money on a theory only to be proved wrong. Was the OKI ignition unit on the bike when you got it?