Flickering charge light

[Camn]

A nice and educational drawing, specially and personally made for us viewers. My humble thanks. Still, for us non-electricians it is not so easy… just the charge light itself for example… I had to have it explained to me. The minus pole of the battery is not connected to the other side of the bulb wire as it is with every other pilot light on V11. There is the plus on both sides of charge light wire – but still a potential difference (different voltage), which makes the wire inside the bulb glow if the difference is big enough… If I did understand everything right. When my charging light started to have individual behavior last summer I just barbarically changed the Ducati regulator and that’s it. No trouble after that

[docc]

A nice and educational drawing, specially and personally made for us viewers. My humble thanks. Still, for us non-electricians it is not so easy… just the charge light itself for example… I had to have it explained to me. The minus pole of the battery is not connected to the other side of the bulb wire as it is with every other pilot light on V11. There is the plus on both sides of charge light wire – but still a potential difference (different voltage), which makes the wire inside the bulb glow if the difference is big enough… If I did understand everything right. When my charging light started to have individual behavior last summer I just barbarically changed the Ducati regulator and that’s it. No trouble after that

In that case, I definitely don't understand what the regulator's white wire does (?)

[Camn]

I must be wrong then…. I found an earlier document of Kiwi Roy; there is an 'IFR 730A Mosfet (Q3)', which turns the charging light on and off: “as the engine revs, negative pulses from D6/D7 oppose the reference voltage and force Q3 to turn off extinguishing the warning light.”

[lemppari]

A very tempting idea would be to change the regulator to the version that dispenses with the charge light circuit altogether. One would have to change the connectors, though. Hmmmmmm............

[Kiwi_Roy]

A better option is to upgrade the regulator to one directly connected to the battery as per a modern Guzzi
I now now have an Electrosport ESR-10

Hubert,
I must confess I'm mathmaticaly challenged but the current flow into a cell once it has achieved full Voltage is a function of applied Voltage over cell resistance. (

If the reg thinks the battery is low it never gets a break.

The actual current is limited by what the alternator will produce, spikes exceeding 30 Amps which may account for the way the fuse holder overheats.

The regulator just thinks the battery is low because of too much Voltage drop through less than perfect contacts, in fact it may be overcharged.

 

If you have a better theory as to why so many Ducati Energias fail, I'm all ears.

[luhbo]

No need for beeing a math champ. You can do most of the typical sparky business with Ohm's law, in this case I'd try P=U*U/R and compare P at 13.8V with P at 14.5V. The resulting 1.1 won't make any difference for a regulator, the more as we have to talk about power dissipation only.

 

Battery questions you can have answered here: http://www.batteryfaq.org/

Look it up and you'll find that cell resistance is all but constant. So

...current flow into a cell once it has achieved full Voltage is a function of applied Voltage over cell resistance. (

is to easy I'd say.

 

BTW, do you still promote your compensation diodes to get the voltage over 14.5V, to avoid undercharged batteries?

 

Hubert

[Kiwi_Roy]

As you say the math is not that complex, it's finding the figures to work with. A quick search for "Motorcycle Battery Internal Resistance" came up empty.

When I say it's

Actually the instantaneous charge current is limited to whatever the alternator can produce, somewhere over 40 I think.

The Ducati Energia cannot restrict the current it just decides whether to fire the SCR or not.

 

I think when the regulator Voltage was set at 13.8V Guzzi were allowing for the Voltage drop (~0.5)  to give a charge Voltage ~14.3.

They sense the battery Voltage after the headlight relay because it's open when the key is off, the regulator draws quite a few milliamps which would flatten the battery over several days.

 

If headlight relays are added direct from the battery you lose the benefit of the Voltage drop so now the battery instead of reaching over 14.2 only charges to 13.8

The Voltage can be boosted back up by changing the trim resistor or adding some voltage drop in series with the black wire, a diode will add 0.6, a resistor in series is another option.

 

Another way of boosting the headlight is to add a single relay downstream of the existing one with N/C to one filament N/O to the other, this leaves the Volt drop in place.

 

There are several ways the Ducati Energia could be re-wired  but I prefer to upgrade the regulator with a more modern design wired direct to the battery.

[luhbo]

They're not so hard to find. The picture below is taken from the battery faq, for instance. It often helps to search for pictures btw, Google is better with pix than with letters.

 

 

Resistance is not explicitely shown, anyway it's easy to calculate from U and I with the shown curves.

 

I didn't give any formulas leading to 24 or 48 Amps. The mentioned relation of P1 / P2 works without any resistance at all. You'll end up with 14,5²/13,8². I also edited my previous posting to make the quote a bit clearer.

 

Hubert

[Kiwi_Roy]

We are getting too far off topic, I deleted my last post

[czakky]

I was lost days ago....

[docc]

. . .  Steady 12.75 when not running. Idle without lights was the same, but at times undulating between 12,5 and 12,9. Switching the lights on dipped the voltage appr. 0,2 Volts, undulation as well. Steady 13,9 V at 3000 rpm, 14,2 at 4000 and up with lights on . . .

Those look like good charging voltages for the alternator and regulator, but a battery that is not functioning properly. Or simply loose or bad connections.

[lemppari]

Most likely a combination of both. Yesterday the tacho started To act, the needle dropped To Zero at idle, then worked ok To 3 thou, then jumped up and Down, only To stabilize again at 5 thou. I then went through all relay connectors and look and behold, it has been accurate since. For all I know, the battery may well be the Original one from -02 and way past its' prime.

[lemppari]

Just went through every connection coming from or going to the generator and voltage regulator. We are leaving for Central Europe tomorrow, so I'll have plenty of time to watch the gen light while riding the autobahn on our way to Italy.

[Kiwi_Roy]

The tach acting erratic tells me the reference Voltage to the regulator is also being effected (they use the same red/black wire from the headlight relay)

 

Keep an eye on the headlight, and the tacho, if with another bike ride behind so they can spot any flickering.

Make a dummy relay pin and check the relay base contacts are gripping the pins or they haven't slipped out the back.

 

This could explain the charge light

Loose contact in the headlight relay or bad relay results in low Voltage at the regulator reference (Black Wire) so the regulator thinks the battery is low and turns on charge light. Meanwhile the battery is possibly getting overcharged.

 

If you get stuck take a hot wire from one of the switched fuses and run it forward to the male pin of the regulator black/white pair (leave the plug half in) This will ensure the reg sees the battery Voltage and back feed the tacho.

 

I was looking at a bike last night, no tach, no headlight, it had a bad headlight relay, although you could hear it click it would only make intermittent contact, we also found one of the coil wires (ECU Relay) had slipped out the rear making intermittent contact.

[lemppari]

Riding down from Kokkola to Helsinki, I had some oncoming motorcyclists flashing their headlights, so that might probably have been why. Come to think of it, I had a no tach, no headlight and might have been no blinkers scenario the first summer after having bought the bike. That time there was no flickering gen light, only stone dead lights and tacho. After a connections clean-up all systems were go. All the relays are still original, so it wouldn't hurt to change them as well.

 

So it's down south to Braunschweig or maybe Röttenbach to get some. Funny though that I didn't even remember the first incident.