Massive (Intermittent) Electrical Failure

[Dr Gil]

This is the same story that started out with my tachometer quitting intermittently (see the thread HERE). The problem has since worsened.

 

Two weeks ago I trailered my '02 Le Mans down to my "local" dealership 250 miles away. It has left me stranded on the roadside on my morning commute. The battery had drained to the point that I suspect it no longer had the juice to run the fuel injection.

 

The dealership (Moto Meccanica) completely checked the grounds, the charging system, the battery and for any shorts in the wiring. Nothing. Everything was as it should be. The only suggestion they could make was that I was running too many accessories for the bike (it is wired for heated grips, 12V outlet and GPS mount but none have been used for quite some period of time).

 

I trailered the bike back home last weekend, fully charged the battery and rode off to work on Monday morning. It again died 10 miles into the ride (after loosing the tach again). It had a completely dead battery. I took the battery out and had it tested and it is fine...just drained.

 

I am a dunce about electrics. For the life of me I can't imagine what would drain a battery so quickly other than a bad ground. The only difference in when it was tested in sunny, hot Santa Rosa and my morning commute (in the past the tach would quit on my morning commute and then "heal" up during the day and was fine going home) is the weather. The mornings here on the coast are damp and cool. Could something moisture related cause this sort of drain?

 

Today I plan to disconnect all my accessories and take a spray bottle of water to different areas of the bike and see if I can recreate the problem.

 

I'm also thinking of installing a voltmeter (any recommendations?) on it to see if I can get a better information about exactly when this drain is occurring.

 

I'm stumped and without a bike until I get this worked out.

[Cliff]

Something that drains the battery so quickly has to be generating some heat.

[Kiwi Dave]

Something that drains the battery so quickly has to be generating some heat.

 

I agree, and I suspect it might be draining back into the alternator due to a faulty rectifier.

 

Try lashing in an ammeter, but make sure you don't include the large cable that goes to the starter motor, just the others. Use heavy wire, and locate the ammeter where you can keep an eye on it.

 

You should see several amps on normal charge, any massive discharge from the battery will show up as "negative" current, i.e. the needle will go the wrong way.

 

If you don't see any discharge from the battery, but it still dies, I would replace the battery. It may have internal shorts. Does the battery get really hot when it discharges?

[Guest Phil_P]

My first thought would be the battery, despite you saying it tested ok. When you tested it, did you really load it up during the test, or just put a meter between the terminals? My original Guzzi AGM battery seemed ok, and would even provide a couple of starts, but would die soon after. I don't know if duff relays could cause a current drain, but if you still have standard Siemens relays on the bike, bin them in favour of something better (which isn't difficult).

[Greg Field]

One question:

 

Did you lose the dash lights in addtion to the tach?

[Dr Gil]

Cliff...I agree there should be heat.

 

Dave...this sort of electrical work is probably beyond me but if I can't sort this out with "easy answers" I may well drag it down to a local electrical shop and put your ammeter idea to them.

 

Phil...I have now tested the battery twice. Once on the bike and once out. We loaded up the battery for the "out of the bike" test. I replaced the battery about 2 months ago with an Odyssey. While testing the battery out of the bike I also tested the old, original MG battery. It was quite weak. Also I have replaced all the relays on the bike within the last year with those made by that fellow in New Zealand.

 

Greg...I don't loose the dash lights when I loose the tach. At one point a few weeks ago, before the bike started dying but after I started loosing the tach on my morning commute I noticed the tach pulsing about 2K in time with my turn indicators.

 

I removed all my accessories yesterday, topped off the battery and covered my commute route (middle of the day, dry) both ways without incident. I then parked it in the driveway, running and using a squirt bottle started soaking different areas of the bike. I used two full bottles of water on it (even under the seat) and could not get the tach to fail.

 

Something my brother-in-law (Dan Kalal) suggested got me thinking. What are the variables between the testing done at the dealership where everything tests ok and my morning commute where the bike dies. The thing I've pinned on is the moisture. Two mechanics now have told me they don't think that would do it. Another thing Daniel suggested might be weight on the seat. My weight might be causing contact or pressure on something to cause it to fail or short. I'm going in and give that a better look today. Both my 12V outlet and my GPS power cord were tied in directly to the battery with their terminals sticking up and excess wiring tucked into (tidy) corners. I'll give them both a closer look and see if I can find any indication that one of them was the culprit. I hope it turns out to be something as simple as this.

 

Fingers crossed.

[BrianG]

A EFI system uses quite a bit of electricity. I would not jump to the conclusion that you are overdrawing the system.

 

I would look to the charge side first. This sounds like a typical dead/dying voltage regulator/rectifier. Just attach a volt meter across the battery terminals with the battery freshly charged. You should see 12.2 - 12.8v across the battery disconnected, and connected but with the ignition switch "off". With the switch "on" you should see over 10v unless there is a short somewhere.

 

Start the bike and you should see 12v+ and rev to 3000rpm and you should see over 13.5v Preferably up to 14.5v but not over.

 

If you see less than 13.5v at 3000RPM it is likely the voltage regulator/rectifier.

 

If you see some other abnormality post it up and I'll direct the rest of the diagnosis....

[dlaing]

Greg...I don't loose the dash lights when I loose the tach. At one point a few weeks ago, before the bike started dying but after I started loosing the tach on my morning commute I noticed the tach pulsing about 2K in time with my turn indicators.

If you lose the headlight (Low or high, not the 10W dip light) when the tach goes out, followed by charging problems, it most likely indicates that the starter or headlight relay is going bad.

Motoguzznix mentioned this in the other thread.

Next time it happens put your hand in front of the headlight and see if is lit.

Also, check if horn works.

If both are out, than you need relays.

You can get the best amp rated relays here, for cheap:

http://www.dpguzzi.com/relay.htm

[mdude]

I might be out on a limb on this one, but my completely identical problem a month ago was solved by simply fondling everyting in the electric system that could be fondled. I think... Bike runs perfect now.

 

It could be moisture but...

 

In hindsight, the only thing I found that actually could be described as a fault, was a suspect rear bulb and rear light connectors (Rossopuro tail and light) that had become suspiciously close to one another. Its quite possible that they touched when engine ran and vibrated. Also, the local Ducati technician mentioned to me that he seemed to remember that the rear light assembly had been cause to similar problems in the past on italobikes.

[Murray]

Just out of cuirosity have you tired disconnecting the heated grips? Pull the fuse is the easiest these will be heavly wired and capable of drawing the sort of current you are talking about.

[BRENTTODD]

I only work on cars but I would check to see if your alternator is making ac current and battery is running out of the right voltage I've seen this stump a lot of car guys

[motoguzznix]

Remove all your additionnal electrics from the bike!

This is always the first things to suspect!

 

 

If the fault still exists, I would suspect the voltge regulator.

[RichPugh]

As mentioned, check to see when your tach is intermittently also out with the headlamp and brakelamp. That would be a simple typical starter relay. The electrical current for the charging system runs back through that relay. If the relay sticks, it never sends a signal for the voltage regulator to recharge the battery and thus the battery runs til it dies. I had the EXACT same problem with my bike when I bought it.

 

Bike would not crank, I'd charge the battery, it would start once, no headlamp, no tach, no brakelamp (parking lamp was ok), would die running and not restart. Turned out to be a starter relay. Upgraded to all new 5 pin relays, trickle charged the original battery - OK now.

[kiwidave]

I love the help everyone has been giving you. Just put a voltage meter on the battery and see if the battery is being charged. Check at idle and then rev the engine to 3000 rpm. Should read about 14.5 volts.

[docc]

I love the help everyone has been giving you. Just put a voltage meter on the battery and see if the battery is being charged. Check at idle and then rev the engine to 3000 rpm. Should read about 14.5 volts.

That is good advice!

 

Not sure how it might go back ten years, but these common issues with the V11 are timeless.