Ducati Monster Motorcycle Forum banner
1 - 20 of 24 Posts

·
Registered
Joined
·
393 Posts
Discussion Starter · #1 ·
I just replaced my voltage regulator and my battery.

I checked it out a couple days ago after I got in from a ride, and I only got 12.1 V. I put my battery charger on at 2 amps, and it read 55% charge on the battery. However, it charged up to 100% in about 5-10 minutes. This may be a completely unrelated thing, but it doesn't make a lot of sense to me seeing as a full 16 amp-hour battery charge would take 8 hours at 2 amps, and a higher charge takes longer to increase, right? (So at 50%, it would take more than half of a full charge, which would be more than 4 hours?) ???

Either way my main concern is my bike charging the battery right by herself.


Yesterday I rode for about 20 miles, let her sit for about 3 hours and when I tried to start her again, she was giving me crap. On the other hand, it was raining pretty good and she sat those 3 hours in the rain. Even after I got her started she didn't want to idle without dying. I let her warm up a few minutes on choke, but even after I got going it took a couple miles before she started behaving.

I only suspect this is electrical because I noticed that revving the engine up made the indicator lights considerably brighter. I'll check the battery out tonight. Is it possible I've got a bad alternator or could the rain have caused these symptoms?
 

·
Banned
Joined
·
897 Posts
Did you check your ground? A bad connection there would give you the symptoms you're describing.
 

·
Registered
Joined
·
6,266 Posts
Id be more inclined to think the regulator is bad. You can check the connection of the yellow wires coming out of the left side cover. Ive seen this conection overheat and cause a failure as well.
 

·
Registered
Joined
·
6,266 Posts
Ddan said:
Ya, but he said he already replaced it.
Although rare Ive had one bad "new" out of the package regulator.

You can check the output of the Alt, by checking it with a DVOM set on AC voltage.
 

·
Registered
Joined
·
393 Posts
Discussion Starter · #7 ·
ducman851 said:
Although rare Ive had one bad "new" out of the package regulator.

You can check the output of the Alt, by checking it with a DVOM set on AC voltage.
Whoa, good idea on the alternator, i hadn't thought of that. Is there a way to test the regulator?

Ddan said:
Did you check your ground? A bad connection there would give you the symptoms you're describing.
Do you mean the ground wire off the battery? Or the ground off the Regulator? I'm guessing off the regulator...
 

·
Banned
Joined
·
897 Posts
howie said:
http://www.electrosport.com/electrosport_fault_finding.html

Also, don't forget to load test your battery and check your battery connections.
That will tell you everything you need to know about testing the regulator.

You can test the alternator output at the battery with the bike running.

The ground I was refering to is tha main ground on the engine.
 

·
Registered
Joined
·
393 Posts
Discussion Starter · #9 ·
So where is the main ground on the engine then? Im checking it out tonight and the battery charger will only go up to 12.2 V with the battery in the bike, so I just removed it and it now seems to be charging like it should. I hope the battery hasn't been hit too hard by leaving it not all the way charged for so long. ::)

I also just followed the fault finding steps to test the old regulator that I replaced.

Uh... anyone need a perfectly good used regulator?

Remind me to make the shop specifically test parts before they tell me they need replacing. On the other hand I'm happy I didn't shell out $200 for something I didn't need instead of the $100
 

·
Registered
Joined
·
393 Posts
Discussion Starter · #10 ·
Also while traversing muddy off-road terrain to go play paintball (wasn't by choice until I figured I was too far out to go back) I got caught up in the moment and left the key in. My battery was completely drained and sat for about 4 hours of paintballing. I got it jumped, then went back home and put the battery up on the charger.

Would this have been enough to ruin a new battery?

[edit] Alright alright, screw that crap about the battery, I checked the alternator and its outputting 16 volts. Thats so bad! When I get more time I'll do more thorough testing, but 16 V seems jacked up. At least I seem to have found the problem. I hope a new alt isn't too expensive...
 

·
Registered
Joined
·
8,324 Posts
Ddan said:
WHat are they supposed to put out?
13.5-14.5V regulated at about 2500rpm. I wonder where he's checking it?
 

·
Banned
Joined
·
897 Posts
ducpainter said:
13.5-14.5V regulated at about 2500rpm. I wonder where he's checking it?
I guess that was really my question, but I do wonder what the unregulated voltage would be. I would think not all that much more than regulated, but I have no clue.
 

·
Registered
Joined
·
393 Posts
Discussion Starter · #14 ·
I was under the impression that it should be 50 V AC

[edit] Or is it necessary to disconnect the RR first before testing the alternator voltage.... dang I missed that step. I guess that would make sense
 

·
Registered
Joined
·
8,324 Posts
Aguacate said:
I was under the impression that it should be 50 V AC

[edit] Or is it necessary to disconnect the RR first before testing the alternator voltage.... dang I missed that step. I guess that would make sense
So is it really OK?
 

·
Registered
Joined
·
393 Posts
Discussion Starter · #16 ·
Dont know yet, I was gonna test it again once I got home from work, but then I decided to wait until the morning since it was late (my neighborhood is pretty quiet). All I know is what I read from the fault-finding diagram and it says to test the alternator with the RR unplugged. I'm guessing the target voltage of about 50 is the no-load voltage, and it may or may not be affected very much by being loaded. We'll see in a bit
 

·
Registered
Joined
·
6,266 Posts
Aguacate said:
Dont know yet, I was gonna test it again once I got home from work, but then I decided to wait until the morning since it was late (my neighborhood is pretty quiet). All I know is what I read from the fault-finding diagram and it says to test the alternator with the RR unplugged. I'm guessing the target voltage of about 50 is the no-load voltage, and it may or may not be affected very much by being loaded. We'll see in a bit
50 is about what I look for when checking them, rememeber to check all 3 legs (wires) with each other
 

·
Registered
Joined
·
393 Posts
Discussion Starter · #18 ·
OK, so the alternator is good. I'm getting about 45 V between each pair and I don't even think that was at the suggested 5000 RPM. All the tests on the regulator pass. I checked the grounds and the connections everywhere, and everything checks out.

And yet the RR is only putting out 3.5 V. To test this I unplugged its output from the bike and tested in between the green and red wires. If anything the unloaded voltage should be higher than what it puts out once connected, right? This is driving me mad.

Even though the RR test passed I guess it's possible what ducman said, that I just got a bad one out of the package. I hope Electrosport is good at RMAs.
 
1 - 20 of 24 Posts
Top