Ah, Italian bikes

I had a merry time pushing the Quota a quarter of a mile up the A14
today. My, how I laughed.

First the tacho started reading low, then the indicators went, so I
started filtering more carefully on the grounds that I might not have
a headlight any more.

Then the engine cut out. At first I thought that I'd run out of fuel,
I'd done over two hundred miles since the last refuel, but no, the
battery was flat.

It seems that circa £120s' worth of reg rec has gone pop within a
couple of months of being fitted.

We charged the battery at work and I made it home on sidelights this
evening.

Ho hum. I have no idea what's doing this, but I've lost two regulators
in as many months.

 

Pip Luscher was seen penning the following ode to ... whatever:

It uses Honda reg/rects?

 

Using the patented Mavis Beacon "Hunt&Peck" Technique, Pip Luscher

I refer the honourable Gent to the "I" word in his thread title.

HTH.

--
Wicked Uncle Nigel - "Oh Bollocks" said Pooh, having forgotten his lines.

WS* GHPOTHUF#24 APOSTLE#14 DLC#1 COFF#20 BOTAFOT#150 HYPO#0(KoTL) IbW#41
SBS#39 Enfield 500 Curry House Racer "The Basmati Rice Burner",
Honda GL1000K2 (On its hols) Kawasaki ZN1300 Voyager "Oh, Oh, It's so big"
Suzuki TS250 "The Africa Single" Yamaha GTS1000

 

Heh, no. Ducati, surprisingly. At least that explains the astronomical
prices.

It seems I will be de-potting an old one sooner than I thought - I'll
be dammed if I'm buying another.

 

Shawly a reg/rec is a reg/rec? Can't you just bolt any old shit on,
rather than expensive old shit?
--
| ___ Salad Dodger
|/ \
_/_____\_ GL1500SE-V/CBR1100XX-X/CBX1000Z
|_\_____/_| ..78875.../...19923.../..31251.
(>|_|_|<) TPPFATUICG#7 DIAABTCOD#9 YTC#4
|__|_|__| BOTAFOT #70 BOTAFOF #09 two#11
\ |^| / IbW#0 & KotIbW# BotTOS#6 GP#4
\|^|/ ANORAK#17 IbB#4 PM#5 WG*
'^' RBR 2005: Abandoned - Bronze Award.

 

Salad Dodger emerged from their own little world to say

and perhaps relocate it to somewhere where it can cool more efficiently?

 

Salad Dodger wrote

Not quite. The requirements for a 125 and the Wing spring to mind as
examples.

No reason why there shouldn't be similarities in similar bikes but you
could bet your life that if it was acceptable electrically the bolt
holes wouldn't line up.

 

Connectors - they need replacing. The original ones can
only just handle the current and as soon as they get
even slightly dirty/rusty they will cause havoc. Cut
them out and replace them, it's a common fault.

 

Angle grinder.

 

Oh yes this explain astronomical price!

I'm italian and everyone here knows about this price. Ducati is like
ferarri here in italy, very expansive.

REgards

Stefano

 

Aha. Is this in a "doesn't charge the battery" kind of havoc, or a
"blows up the regulator" kind of havoc?

 

It's already out front just above/behind the front wheel. After the
last one, I checked its temperature after a longish run, it was
slightly warm at most. IME most electronics will still work happily up
to finger-sucking hot.

 

I think that you're right, but I'm worried about blowing up the ECU
(despite talking about building my own!)

It's complicated by the fact that there are series, shunt and field
coil regulators, so this has to match.

Also, this alternator is unusual in that it's single phase and quite
high power for a single phase type.

 

More of a "fucks everything" kind of havoc. Depending on which
wires go first, you can get a variety of symptoms from non-charging
battery to blown regulators to duff lights and indicators.

When Ducati designed their old bikes they did it down to the wire
(no pun intended) on things like electrics.

For example, the initial charging system design on the 916 had
a 350 watt single phase alternator. The design basis that Ducati
used for sizing the system would have been:

Low beam OR high beam = 55
Sidelights = 5
Tail and brake lights = 21
Turn signal = 10
Number plate light = 5
instrument bulbs = 2
Fuel pump = 60
Horn = 60
Cooling fan = 60
Electronic ignition = 48
ECU = 24
=========
Total = 350W

Note that the system isn't designed to run both headlights
at once. Also, the fuel pump is based on a clean filter, and
drawing fuel through a clean filter will draw about 2A whereas
trying to do the same through a dirty filter can draw as much
as 10A - clogged fuel filters are a prime source of failed
regulators!

Of course, normal operation doesn't mean everything is switched
on so you more than likely end up with something like:

Low beam OR high beam = 55
Sidelights = 5
Tail and brake lights (off) = 12
Turn signal (off) = 0
Number plate light = 5
instrument bulbs = 2
Fuel pump = 60
Horn (off) = 0
Cooling fan (off) = 0
Electronic ignition = 48
ECU = 24
=========
Total = 211W, leaving 139W available to charge the battery.

It's important to note here that, given the obvious need to charge
the battery, the stator wires will have to pass 29 amps
(350 watts/12 volts) continuously. So I advise you to keep your
bike on a trickle-charger whenever possible to reduce the demands
on your charging system. Also, avoid the temptation to replace your
battery with a low-weight, lower capacity unit. The principal
advantage of using a larger battery is to be able to restart
repeatedly. If you regularly don't ride long enough to recharge
fully between restarts, stay with a larger capacity battery.
A lower amp-hour battery will need to be trickle-charged more often.

For 1999, Ducati redesigned the electrical system, going from the
350 watt design to a 500 watt three-phase system. (Three-phase
alternators have three wires coming out of them, single-phase have
two.) They produce an AC output that has a higher frequency than
the earlier single-phase design so the regulator presumably has to
do less work (i.e. less heat) conditioning the waveform and
converting it to DC. The new alternator also has additional wattage
available to run the lights, fuel pump, ECU and accessories but the
higher output still has to pass through the regulator.

Which leads us to the second problem with the Ducati charging system
....

The wires running from the stator to the regulator are seriously
undersized and their insulation becomes damaged from overheating.

The general rule-of-thumb for sizing wiring is that if it needs to
carry 20 amps use #12 gauge wire; 30 amps needs #10 gauge; 40 amps
needs #8 gauge. Early bikes have 350 watt/29 amp two-wire charging
systems so #10 gauge wire should have been used. 1999 (and later)
three-wire 500 watt alternators produce a little over 40 amps so
#8 gauge wire was needed (but not used.)

So you ought to replace the wiring all the way back to the stator
with a larger gauge.

These wires have to pass high amperage continuously. There's an
electrical phenomenon called I-squared-R loss. That is, if you run
30 amps through a corroded or loose connector or undersized wire
having (say) a 1/2-ohm resistance, the heating effect is 30 X 30 X 1/2,
or 450 watts. That's a lot of continuous heat. This heat just
conducts down the wire, cooking the insulation as it goes.

Just like you can't put your hand on a 450 watt light bulb while
it's lit, you can't expect a plastic connector or electrical
insulation
to survive radiating 450 watts of power either. A corroded or loose
connector always has a higher resistance than the adjacent wires
and it will heat up enough to melt connector plastic parts and adjacent
insulation. That's why it's best to solder the wires directly together
and eliminate connectors entirely.

Generally though, it is the connectors heating up that causing the
insulation and conductors to melt and short out.

Even if the stator wire resistance measurement and the voltage output
checks out OK, the output to the regulator is unreliable because the
insulation between wires (that run in a common sheath) breaks down at
the higher voltage levels at higher RPM.

The undersized stator wires generate the highest heat load at the
points of highest resistance on both ends; connector to the
regulator/rectifier (see above) and at the other end where they
attach to the stator.

HTH.

 

It certainly does. Ta.

 

I was with you all the way up to "worried".
--
| ___ Salad Dodger
|/ \
_/_____\_ GL1500SE-V/CBR1100XX-X/CBX1000Z
|_\_____/_| ..78875.../...19923.../..31251.
(>|_|_|<) TPPFATUICG#7 DIAABTCOD#9 YTC#4
|__|_|__| BOTAFOT #70 BOTAFOF #09 two#11
\ |^| / IbW#0 & KotIbW# BotTOS#6 GP#4
\|^|/ ANORAK#17 IbB#4 PM#5 WG*
'^' RBR 2005: Abandoned - Bronze Award.

 

Excellent reply. Imo, that bit above, at the very least should be in the
FAQ, given it applies to almost every bike and not just Ducati.

 

Have you looked behind the sofa?

 

Have you looked behind the sofa?[/QUOTE]

Err, there's a sideboard...