Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Grrr!!

[moto748]

Day before yesterday jumped on bike to go to work, and found the battery flat(ish). That familiar rotation of the rev counter needle...
Although it's normally used every day, it hadn't been used for a few days cos I'd been ill. So off came fairing, out came spanners, and battery is removed and put on Optimate. Change out of leathers and drive to work (late).
I noticed when I took the battery off that the leads were quite loose. So I thought, with a bit of luck, that'll be the prob, and once it's re-charged it'll be OK.

That evening the battery looks fine on the Optimate. Put it on the bike, and it fires up no prob.

Ride to work and back yesterday, no probs.

This morning, battery flat(ish) again. Oh dear. So now of course I'm thinking reg/rect. Or wiring thereto.
Despite the fact that a new one was only fitting in the summer, a couple of thousand miles ago, tops...

I don't normally have any difficulty in keeping the battery charged with the pattern of use that I have, so I don't think it's a question of needing to ride further, or autumn setting in, or anything like that.
It's at moments like this that I wonder why I put off buying that multi-meter....

Anyway, I'm going to get a meter tonight, and check rectified output when I replace the battery. I'll also take the opportunity to remove the battery tray and check the famous yellow wire connectors (already replaced the stock connector with something more durable, though).

If it is the rect/reg, I'll be well ****ed off. And it'll be an Electrex item next!

Have I overlooked anything obvious? I should add that the battery is OE Ducati and as new as the rect/reg.


2001 MY 748 (3-phase alternator)

[Edited on 24-9-2004 by moto748]

[moto748]

Hmm. Still not sure whether to blame battery or rectifier (surely one of the two?).

Bought a meter, check battery; a bit low (11.5-12V, can't remember exactly). Charged battery overnight, checked in morning, 13V no probs. Fitted to bike, fired up OK. Checked rectified output, 14.2V no prob. Rode it to work for a couple of days, then it wouldn't start Wed am. Checked battery: 12V, not quite enough to turn it over, obviously. Didn't have time to put battery on charge again. but grabbed car and headed for work. Didn't get home until tonight, re-checked battery prior to re-charging, and 9.5V only!

Now I'd thought before that the prob was one of two things: either an intermittent fault with the rect (starts off giving 14.2V, but breaks down when hot), or the battery (it's the "gel" type) failing to hold charge.

I thought before that the first solution was by far the most likely, bearing in mind that both battery and rect are nearly new.
But having seen the reading across the battery tonight, I'm wondering if I've traduced the rect unfairly: could it be a duff battery after all? I kinda hope it is, of only because a battery's cheaper than a rectifier, not to mention more available "off the shelf".

By the way, I removed the battery tray, and examined the yellow wires and connections: all looked fine. I even took the rect unit off the heat-sink, to look for any signs of cracks/distortion in the back of the casing that could indicate a failure (I've seen this before). All was fine.

My current thinking (DYSWIDT? ) is to charge it overnight Friday, and ride out to get a replacement battery on Sat am.

Any comments welcomed.

[Edited on 30-9-2004 by moto748]

[bostrom998]

Had a similar prob getting off Channel tunnel in May. Battery less than a year old and just wouldn't do the biz despite having run OK earlier in the day. Managed to find a new one (after not letting engine stop and risk not working again for 4 whole hours, this included two "hot" fill ups ..thank God I had a spare set of keys...) and all has been fine.
I know it sounds silly but I reckon you should always change battery min every two years or best every year.

Someone will no doubt be able to point to one of Shazaam's posts where he recommends thicker gauge wires etc and I'm sure that's a good idea, but you can't beat a new battery!

[keefer]

i would of thought that the optimate would tell you if the battery was not holding a charge ?
but charge it up leave it off the bike over night then check the voltige if its gone down its got to be the battery

[Edited on 30-9-2004 by keefer]

[moto748]

Thanks guys.

I don't always really trust Optimates, though, but I think keefer's suggestion of charging it and leaving it off the bike is a sensible one.

I've just taken it off and put it on charge. Although the Optimate only shows "half-discharged", the meter only reads 9.7V across the terminals. That sounds very low to me; I reckon it's clapped.

I'll see how it looks in the morning, then leave it until tomorrow evening and see how it does.

[DAVE HARRIS]

A fully charged battery left for a few hours to settle should read 12.6 volts, any less indicates a battery fault.
for example if one cell is completely dead only 10.5 volts will show on the voltmeter, check again after 24 hours if the voltage has dropped further say from 12.3 volts to 12 volts it strongly suggests a battery fault.

the best way to check a starting fault is to attatch the voltmeter to the battery and attempt to crank the engine you should see a minimum of 9 volts whilst the engine is turning and idealy around 9.5-10.5 volts with ambient temperatures around 20 degrees c.

Batteries generate electricity thorough an iron exchange from the plates to the acid, this process is temperature dependant. as the ambient temperature drops the total current availiable to start the vehicle is reduced and eventually a fully charged battery at around -30 degrees c will only just light a small bulb.

I would suspect the battery first as ambient temperatures have dropped around 10 degrees in thae last month and this will have had a affect on the batteries ability to supply the required amount of current.

also we have seen many gell type and sealed batteries fail recently at work having worked all summer perfectly( I run a car repair workshop)

Also check the connections at the earth cable to frame, the contact at the rear of the starter motor for a voltage drop when cranking as even a small resistence will reduce the current supply at the starter.(to check voltage drop at the earth connect the multmeter one side to the earth(-) terminal on the battery and the other to the engine cases and crank the engine you should see virtually no voltage. to check the starter positive feed carry out the same check from the battery(+) terminal and the starter main contact on the starter motor again there should a negligable voltage shown when cranking if thier is a noticeable voltage shown on the (+) side it could be worn starter solenoid contacts or a bad connection at battery solenoid or the starter itself).

long winded but I hope this helps

dave

[moto748]

weeksy>

I don't expect the disconnected battery to read 14V, or even necessarily 13V, but I do expect it to be over 12V.

Dave Harris> Thanks, that's very helpful. more or less tallies with what I was thinking. I'll do the checks you suggest tonight.

In fact this morning , although the Optimate was still on the "half-charged" light, the meter reading was 13V. I disconnected it from the charger, and will re-check tonight.

[moto748]

And Dave, I don't know if you live in a northern tundra, but down here in the semi-tropical West country, it's still pretty damn mild!

[moto748]

This morning I took the bike for a visitation at Dr. Louigi Moto, known to some of you on these pages.

I charged the battery overnight on Thursday, not Friday, so it could be left disconnected for a day or two. It was OK this morning and the bike fired up no prob at all. Rode over to the good Doctor's (say about 15-20 miles), taking a meter with me. Check the voltage on arrival: all fine. 12.4V on idle lights on. 12.7V on idle lights off, 14-14.2V at 3500rpm lights on.

That looks spot-on to me!

We both agreed that the most likely source of the prob is not the bike at all, but our old friend, the alarm.

The alarm has been giving trouble; in fact, the alarm fitter was supposed to replace the unit last week. I'll be chasing him up at once. Although the alarm doesn't stop me using the bike, all is clearly not well with it. When I hit the zapper, the indicators flash, but the alarm only gives a whimper, instead of the normal "beep". As Louigi said, it's entirely possible that an internal short in the alarm unit is draining current from the bike. After all, the voltage dropped to under 10V after a couple of days when connected on the bike, but only dropped a fraction when charged and disconnected from the bike. Back home from my run out, the reading is now a healthy 13V again.

So who ever said Ducati rect/regs and batteries where unreliable?


Good news is, if this is the case, I'll cost me nowt.
Tha way forward seems to be to get a new alarm unit fitted ASAP next week (this'll be done under warranty), and then see if I still have a problem.

Hopefully, not!

Of course I knew all along that the alarm was a bit dodgy, but because of past experience with batteries and rect/regs, I'd (wrongly?) dismissed it as a cause.

[Edited on 2-10-2004 by moto748]