Ignition power consumption

steph

steph

Hero member
Location
Torgny, Belgium
Some of you would have an idea of an (electronic) ignition system's power consumption ?
I would say between 1 and 2 Amps at maximum r.p.m. but never made a metering.

Cheers,
St?phane

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It shouldn?t make any difference what ignition is fitted should it?
The HT coils are what consume power. The electronic unit for my Ignitech uses a few milliamps. The HT coils a couple of amps from memory.
 
It shouldn?t make any difference what ignition is fitted should it?
Click to expand...
The ignition unit will determine how long to switch on the current to the coil(s) - most use some sort of control circuit to limit this - which is why you can use small coils instead of the beefy items that were designed to run with points ignition which has no such control. Dwell time will therefore affect overall power consumption.  Typically it will be of the order of milliseconds. The Ignitech may have some sort of dwell trim feature too which will further complicate things.  So it's not just an amps x volts equation!
 
with the Ignitech system you do have the ability to adjust the dwell time of the coils in their software settings or you can leave the setting set on "auto" and let the unit work it out itself.
If you get the setting wrong you can fry the coils so auto would work best for the majority of people

 
Steph said:
Some of you would have an idea of an (electronic) ignition system's power consumption ?
I would say between 1 and 2 Amps at maximum r.p.m. but never made a metering.
Click to expand...

Once built a twin spark system for a Beemer air-head based on old Laverda/Bosch BTZ boxes ('cos the bits were laying around).  Worked extremely well but consumed a whopping 7A over 5000rpm!

After swapping to Ignitech, the consumption dropped to 0.7A, allowing Oliver to do an entire weekend of track sessions on a single charge of his little 5Ah battery.

piet
 
Thanks for your comments.

sfcpiet said:
Once built a twin spark system for a Beemer air-head based on old Laverda/Bosch BTZ boxes ('cos the bits were laying around).  Worked extremely well but consumed a whopping 7A over 5000rpm! After swapping to Ignitech, the consumption dropped to 0.7A, allowing Oliver to do an entire weekend of track sessions on a single charge of his little 5Ah battery.
Click to expand...

As I understand current consumption can widely vary depending on the ignition "black box" used ..  :D

I am using ZDG3 box (Sachse) with the big old Bosch coils (750 twin).

Last ZDG3.2 version seems (?) to have been improved in terms of coils current management because minimum recommended conductors cross-section dropped from 0,75 mm2 to 0,5 mm2.

Better to make accurate measurement.

Cheers,
St?phane
 
recommended conductors cross-section dropped from 0,75 mm2 to 0,5 mm2
Click to expand...

Yes, but don't forget that even if the current flows for a short time to the coil, the inrush current will be high - and you don't want to lose voltage to maximise the available spark energy.  So although the heating effect on the wire might not be a problem due to the short current 'on' time, volt drop might be.  I'd suggest using 1mm2 cable unless you are very confident about your terminations & connectors not deteriorating over time.  A 4 ohm coil only needs 3 amps at 12v under steady state conditions....but an ignition circuit is far from a steady state!
 
Rob said:
I'd suggest using 1mm2 cable unless you are very confident about your terminations & connectors not deteriorating over time.  A 4 ohm coil only needs 3 amps at 12v under steady state conditions....but an ignition circuit is far from a steady state!
Click to expand...

Thanks for your interesting comment Rob.

I would add that beyond theoretical currents laws considerations all those heavy vibrations our beloved bikes produce and transmit to electrical components and terminal joints suggests to use stronger cables ?

I used to use old 2 mm2 wires.
Modern thinwall cables are much stronger and I was indeed thinking reducing them to 1 mm2 (for ignition).

Cheers,
St?phane
 
Just reviving this old topic as I am looking for another related info.

Anyone would know the big Bosch ignition coil (750 twin) dwell time (or better the dwell chart) ?

I was not able to get it from the Bosch website.

Thanks
St?phane
 
Interesting question, St?phane!  I'm wondering why you want this information?  Are you setting up an electronic ignition system?
 
OK.  Don't know what you're running, but the default Ignitech settings are usually OK....think they increase dwell for low rpm(cranking to start) to give a fat spark and then reduce to avoid overheating.  If you're using something else, then I'd expect 5ms would be a typical safe value for a standard 12v HT coil. 
 
Rob said:
OK.  Don't know what you're running, but the default Ignitech settings are usually OK.
Click to expand...

depends on what brand of coil you run, we find we need to adjust the coil dwell settings in the Ignitech software for Dyna mini series and Nology Pro-Fire coils for example
neat unit the Ignitech set up, we run 0.6 ohm coils on the race bike with no issues but stay with the 3 ohm coils for street bikes

only downside on the Ignitech system is their test circuit settings, only get one single spark when testing ignition circuit, on the old IIS ignition systems, John had a great set up where in test mode, the system would start firing all plugs and continue to fire the plugs in steps of 1,000 rpm right through to 10,000 rpm and then revert back to 1,000 rpm and start again, was a great way to stress out the HT circuit especially by cutting off the electrode on the Spark plugs themselves to increase the plug gap thus making everything work harder


 
Steph said:
Just reviving this old topic as I am looking for another related info.

Anyone would know the big Bosch ignition coil (750 twin) dwell time (or better the dwell chart) ?

I was not able to get it from the Bosch website.

Thanks
St?phane
Click to expand...

Look at the ignition cam lobe.
 
He has a Sachse unit installed so is either Optical or Hall Effect depending on when it was bought but neither have cam lobe profiles on them
Optical is a straight cut out in the rotor plate similar to the DMC unit and Hall Effect is two opposing pole magnets that turn the trigger off and on as they pass

as Cam stated, dwell settings are controlled by the ignition software that is pre-loaded in the Sachse box
AFAIK
 
redax5 said:
as Cam stated, dwell settings are controlled by the ignition software that is pre-loaded in the Sachse box
AFAIK
Click to expand...

Old topic .. but interesting info.

Marco Patzer (from Sachse) came back to me (some time ago, sorry for the delay) with the dwell time information for the ZDG3 ignition module.
-> 3.5ms (fixed).

As Red wrote, smart electronic systems, like the Ignitech one, will adjust the dwell time to ensure that enough magnetic field is built up for a good (ignition coil) charge.
Modern coils draw about 4-6 Amps while the points are closed (for Marx) :)
So all data needed here to do the maths.
 
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