6volt or 12 volt?

[Jon Pegler]

I run a 450 with the Ducati electronica electronic ignition system , but have the rest of the electrical system working at 12 volts.
I may have enough parts for a conversion for your 450.
I'm in West London if you want to get in contact.

Jon

[DewCatTea-Bob]

Here is an excerpt from the document under development regarding the question of conversion:

Converting from 6-volts to 12-volts:

The back-story...

The conversion to 12 volts is a purely individual choice. Originality, functionality and reliability are all considerations for the Ducati single owner. The switch to 12-volts is usually predicated by these common desires:

Brighter lighting

Electronic ignition

Electrical system reliability

Electrical component availability


Many people associate the conversion to 12-volts as gaining a more powerful electrical system which in almost all cases is true. But just to be fair let’s review electrical power. It’s not that 6-volt systems are any less powerful than 12-volt systems, that’s a common misconception. Power, which is measured in a unit called “watts”, is defined as the product of Voltage (in Volts) multiplied by Current (in Amps.) A 60 watt 6-volt alternator is capable then of supplying 10 amps (6-volts x 10 amps = 60 watts.). A 12-volt alternator that supplies 5 amps also delivers 60 watts (12-volts x 5 amps = 60 watts.) In this comparison both the 12-volt and the 6-volt alternator are equally powerful.

Ducati supplied motorcycles with 40 and 60 watt alternators in a 6-volt configuration which were sufficient to the task of supplying the needs of the motorcycle as they were outfitted from the factory.. Keep in mind though that the headlights which are the major consumer of electrical power on a Ducati single were on the order of 25 watt units which are not bright by modern standards. If you desire brighter lighting you need to install either a more powerful (more wattage) headlight beam or a more efficient headlamp beam (same wattage but brighter light.)

Given a stock 6-volt system you could try to find a 25-watt Halogen beam which is a more efficient technology and emits more light than incandescent beams for the same amount of power. But finding 6-volt incandescent replacement beams is difficult enough, much less trying to locate a halogen light bulb that fits the headlight bucket perfectly. Also, neither incandescent or halogen 25 watt bulbs will supply anywhere near the light output of any type of 50 watt or better light bulb.

The more common solution then is to install a modern 12-volt sealed beam of around 55 to 60 watts (either incandescent or Halogen.) The problem however is that you need both 12-volts to power the headlight and also more electrical power (watts) than the motorcycle’s alternator in stock form can generate.

You might ask why you can not put a 55-watt beam on a Ducati single with a stock 60-watt alternator. The reason is that there are other electrical consumers (also known as 'loads') on your motorcycle’s electrical system that also want a portion of that limited available electrical power, such as the brake/running light and the ignition system. So the full alternator power output is not completely at the headlight’s disposal. Also you would need to find either a 6-volt 55-watt beam or convert your 60-watt alternator to 12-volts.

A power increase results from either putting in a more powerful alternator or in some cases recovering power from the existing alternator that may be wasted (see “How to capture more power from twin wire lead alternators” elsewhere in this guide.) So in effect more power is gained by:

1) changing to a new alternator that supplies more voltage without sacrificing amperage,

2) changing to a new alternator that supplies more amperage at the same voltage,

3) changing to an new alternator that supplies both more (higher) voltage and more amperage, or

4) modifying the existing alternator (if possible) to supply more amperage (similar to list item number 2.)

Item number 3 will be ignored here as it is covered in the section “How to capture more power from twin lead alternators” and this discussion is about converting from a 6-volt system to a 12-volt electrical system.

A 12-volt conversion requires that all the electrical loads such as the headlamp bulb, taillight bulb, horn, coil, regulator/rectifier and instrument bulbs be replaced from 6-volt units to 12-volt units. The wires and switches can stay the same. Any fuses in the system will have to be re-evaluated as to its amperage rating.

A 12-volt conversion offers more options with regards to commercially available electronic ignition systems, though a commercial 6-volt electronic system is available.

The next question might be “how much power do I need?” The answer is to create a simple power budget that will detail how much power you are likely to require. Here is an example:

1) Headlight: est. 55 watts

2) Brake/running lamps est. 7 to 10 watts

3 Turn signals: est. 3 watts, intermittent consumption.

4) Ignition system est. 10 watts, depends heavily on the ignition system

5) Horn: est. 5 watts, though rarely ever consuming power.

6) Accessories (heated grips, heated vest, GPS system, etc.): On a Ducati single??? Get real!

7) battery charging: This should be negligible in a healthy electrical system.

In this example about a 75 watt alternator is minimally needed, and a 100-watt alternator would be robust.

The alternator produces watts of power, and all the electrical loads of the bike consume watts of power. So at the end of the day the alternator has to outproduce (in wattage) all the wattage of your motorcycle's electrical loads combined.

[Have you ever noticed a light bulb go dim when you switch something else on, and then the light bulb regains brightness when that switch is returned to the off position? This happens because the power source is being asked to deliver more wattage than all the combined loads are asking for. Turning the switch off removes a portion of the combined loads and the power source is better able to supply the demands of the remaining loads including the light bulb.]

Your two choices then are to install a 12-volt alternator or modify you existing 6-volt alternator to produce 12-volts.

Regarding alternator conversions: Keep in mind though that owing to the laws of physics your 6-volt 40-watt alternator will by default remain a 40-watt alternator at 12-volts. Instead of supplying 6-volts DC at 10 amps it will supply 12-volts DC at 5-amps unless you have an rectifier that only captures half the power of the alternator’s sine wave. If your system has no rectifier (an AC system) there is no way to convert to 12-volts and all the power generated is already being used.

Jim

____ I've finally taken the time to read-through all the above (during a time when I felt clear of mind enough to fully grasp what all is being stated)...
__ I must say that if I-myself had been the one who wrote it all, I'd now feel the need to do some editing on it, as it's not all totally in line with that which I believe to be completely correct.
As it is, it's possibly good enough for those who know next to nothing on the subject, or who care not to become fully understanding of all the more involved complexities.
If you -(the reader) consider yourself to fall into either of those groups, then you ought need not read any of that which I'm about to add.....

____ First, (so far as I know) there's actually no such thing as either a "6-volt" or "12-volt" (or ANY constant preset voltage) 'alternator' ! ... They are only 'RATED' as such ! _ As their actual voltage-output is highly dependent on the particular load-total (which they're connected to), and also the RPM which they are running at. _ Thus their actual-voltage must vary between zer0 & up towards 90-volts, (all depending on whatever particular cicumstances).
__ Second, the rated wattage, be it "40" or "60" (or whatever amount of) watts, of any particular alternator, is actually just a (somewhat hopeful) average-rating,, where the rating-source who figured the particular 'rating', worked-out a (possibly optimistic) average-RPM for a point where the alt.output actually could really be at the 'rated' wattage-output. _ Thus it's likely most of the time that alternators are only capable of lesser amounts than that which they've been rated at,, and, (except while under racing-RPMs), soldom put out more wattage than they're rated for, although certainly possible (at the expense of likely overheating past expected specs).
__ Now since alternators spend a good deal of time producing less wattage-power (and even possibly less voltage) than they were 'rated' for, it's then fairly important that the battery store any excess alt.output during the (likely fewer) times when RPMs exceed that predetermined average RPM-point (which the rater-source had worked-out to get the expected alt.wattage-rating).
So thus the bottom-line here is that ya can't expect to obtain an alternator's rated-wattage (for use by the electrical-system) if ya spend too much time running below the (unspecified) average-RPM that the alternator had been prefigured to be ran at (averagely) !
And thus as well, the battery makes wattage-loads such as horn & turn-signals, fairly irrelevant !
Finally, it's mainly the battery itself (and/or a very-good aftermarket-type voltage-regulator), which is totally responsible for a system's 6 or 12 volt working-voltage, (NOT the alternator's rated-voltage) !

____ That's all I have to add, (for now).


Balanced-Cheers,
-Bob

[JimF]

There is a lone 6-volt elecronic ignition product for Ducati singles that I am aware of, but at least there is one.

It is offered by Kirby Rowbotham based in the UK:

http://www.kirbyrowbotham.com/ignitions.php?page=5

[Jordan]

i am sure it will help starting the 450!
Steve

I've always found electronic ignition makes starting easier.

Jordan

[Bevel bob]

My 250 narrow case came to me with non functioning electrics, a 60 watt 6v-2 yellow wire alt, a 12v battery, a modern (Podronic)rectifier under the seat and no charge. As most of my riding is in country back roads and to classic Bike events I decided to fit a better 35watt headlight and a Pazon electronic ignition booster, no indicators as my bike resembles a Mach1/M3 and looks are an issue.A simple un-earthing and linking mod to. the stator coils got the charge working,Bulbs ,coil and horn are 12v. The bike is used regularly with the headlight on, I keep the revs up to protect the big end (no plodding) and have no problems with electrics. The points need minimal attention now as the booster does the work,Its simple to work on and do timing statically (booster has a points break light built in and is fitted high on the front down tube mostly concealed by the tank on the primary side which helpfully is where the timing disc is mounted) .The capacitor is not needed.The Pazon is polarity matched and cheap to buy.Anything more complicated gives me a headache.

[MotoMike]

Maybe someone installed the podtronics and didn't realize the ground needed to be lifted. that pazon box seems like a nice piece of gear. I like the static timing light being part of the system.

[Bevel bob]

Thats right mike, the shop that built the bike from a wreck had little understanding of anything other than basic stuff. the Pazon unit looks a bit suspect on the watersealing so i used a little mastic ,the wiring with the unit is also lightweight but has been ok. My system works well but of course relies on the orriginal alt being servicable,but thats easy to test.As i am still using the orriginal Ducati loom (!!) i have installed a flying hotwire connection for the ignition system that can be connected to the battery if a problem occurs on the road.With the Pod settup the charge bypasses the Ducati old wiring.

[DewCatTea-Bob]

____ Just a note that this actually-new thread I've started is where I've moved (at least for now) all the original/related posts to, from Steve's originally-named/created thread.

Temporary-Cheers,
-Bob