Battery drain while bike is on.

[Smellii]

Ok. So I took my bike out today for my longest run and first time on the freeway. (a freggin blast!) Ran it solid for a couple hours trying to get to the point needing my reserve tank so I can determine gas milage and miles per tank ect.. Anyway, I started the day on a full battery cuz I charged it overnight and only cranked it once (1 sec of start button) to start off my ride. After two hours my bike had almost no charge when I started it back up after getting gas. From this I deduce I have a major drain while the bike is running but not while it sits. Battery doesn't have drain while it sits. I tested per stator papers and it tested fine. I have a multimeter but don't know how to use it to test various components for drain. How can I test them while the bike is on? Is this even possible?

Thanks in advance.

[BassCliff]

Hi,

Here's a quick test.

If it's not auto-ranging, set your multimeter to at least 20v DC.

Start your bike.

Put your multimeter leads across the battery (red to positive, black to negative).

What is the voltage at idle? What is the voltage at 4000 or 5000 rpm?


Thank you for your indulgence,

BassCliff

[Smellii]

Thanks, Basscliff.

Off: 12.00
Idle: 11.32
4000 rpm: 11.74

Interesting. I did this test a week or two ago and it registered 12+ at 4k rpm (Don't remember exact number).

[Smellii]

Going to go through stator papers again....

[Steve]

Your bike will ALWAYS use electricity while running, that's what keeps the fires lit in the combustion chambers.

The trick is to have a functioning charging system to replenish what is used.

BassCliff has given the basic tests, more-detailed ones are outlined in the Stator Papers.

Basically, measure the voltage of the battery before turning the bike on, you should see over 12.5 volts. With the key ON and the bike not running, you should still see about 12, maybe as low as 11.5, but the higher, the better. While cranking, you should see at least 10 volts, or you won't have enough to fire the coils. These quick tests will give a basic evaluation of BATTERY CONDITION.

Once the engine is running, your voltage could be about anything, depending on the state of your charging system, but should be at least 12 volts at idle. As you increase engine speed a little, you should see the voltage rise. By the time you get to 2500 RPM, you should be seeing 14 volts, maybe a bit more. By the time you get to 3000 RPM, the regulator should be dumping any excess, so voltage might actually drop one or two tenths of a volt, and should remain there through the rest of the engine speed range. These quick tests will give a basic evaluation of CHARGING ABILITY.

From your description, I am guessing that you will not be seeing very large numbers while the engine is running.

EDIT: I see you posted some results while I was typing. Those are DEFINITELY low numbers, so break out the meter and get to work.

.

[Smellii]

@Steve: Just completed the tests you mentioned.

Off: 12.15
Key only: 11.50
Cranking: 6.00-7.00
Idle: 11.72
2500 rpm: 12.10
3000 rpm: 11.85

Going through stator papers flow chart now. Have a quick question in the mean time, however. If the voltage between 2500 and 3000 rpm drops does that indicate my rr is good and my stator is bad given all the other numbers are so bad?

[koolaid_kid]

Not necessarily. Next you need to test the AC output of your 3 stator wires. That will help pinpoint root cause.

[BassCliff]

Hi,

Yes, with those symptoms my first suspect would be the stator. Here's a quick test guide for the stator.

Stator Test

If the voltage drops as you rev the motor, that means there is resistance in the r/r output circuit. Make sure all of your electrical connections are clean, ground connections, inside the fuse box, blinker stalks, all the connections in the headlight bucket, everything. It is common practice to take the ground wire from the r/r unit and connect it directly to the negative terminal of the battery. (If I had a dollar for every time I've typed that in this forum....)

You may also want to peruse these guides from my little website.

Stator Replacement

Regulator/Rectifier Replacement

Plus there's lots more information collected in the Electrical Odds and Ends section of my little website.

Thank you for your indulgence,

BassCliff

[Smellii]

Got as far as I could through the flowchart but have some questions so I can finish up:

1: My multimeter will read a negative voltage if it thinks I have the black and red accidently swapped so for Phase A row 3 "Idle...black multimeter lead to + battery teminal and red multimeter lead to red RR output wire..." I got a -.24V. The negative threw me off so I wasn't sure which way to proceed on the flowchart. Unsure I proceeded down to test more stuff. (I'm assuming it's ok because voltage is going in the correct direction as far as I understand)

2: Testing voltage on all three yellow (all black in my case) stator wires I got 88, 84, and 83. They weren't exactly the same but I assume close enough? In any case they were well above 60 so I think I'm ok there.

3: I'm ready to start Phase C of the flowchart. Regarding this statement:

"Disconnect the RR from the bike. Switch the multimeter to the diode test position. Connect the RED multimeter lead to the RED positive output wire of the RR. Connect the BLACK multimeter-lead to one of the yellow wires. Check the reading. Repeat this procedure for the two other yellow wires."

Firstly, can I leave the ground of the RR connected to the bike (it's really hard to get to). Also, when connecting to the yellow wires; yellow wires from what?

Thanks.

[Smellii]

Also, not sure if this applies here but it seems my tail light is always on. When I initiate the brakes I can see the blip (momentary studder) in the bulb as if the brake light switch properly engaged but there is no change in brightness because it's already on. Could this be contributing to my drainage/charging problem?

[koolaid_kid]

1. The negative reading only means you have the leads switched. You made the correct assumption.
2. Excellent. As I stated in my prior post, a failure to charge does not necessarily mean the stator is bad. Yours checked good. Congrats on not going into parts replacement mode.
3. One of the stator input wires on the R/R. Your color may vary. You can keep the ground connected, it is not involved in this test.

[koolaid_kid]

Your taillight is on all the time. It is a separate unrelated issue, and I strongly suggest you stay focused on the charging issue first.
My stator went out last year. I replaced it and the R/R at the same time. It still did not charge. It turns out the "T" where the R/R connects to the original wiring harness had broken. I wired it straight to the battery (fused of course) and now it charges. Just an example of why you should find root cause before purchasing any parts.

[Smellii]

@ koolaid_kid

1:Actually I tripple-checked my connections. They were exactly correct and still read negative. What if it read "0" volts on a multimeter that didn't have this feature. Would a "0" volts indicate a successful test in this case?

2: I'm poor so I couldn't go into replacement mode even if I wanted to. haha

3: Thanks testing now.....

[Smellii]

Ok. Narrowed it down to my R/R. Performed the diode test and got absolutely no continuity from the red R/R output wire to either of the three other R/R input wires. I'm going to check my connections anyway but based on this result I've confirmed at least the R/R is toast, correct?

[cowboyup3371]

I would say that taillight being always on AND BRIGHT is actually caused by one of you brake switches so yea, I'd fix that real quick to rule it out. Then get back to retesting things. Unplug the rear brake switch and see if the light goes out or not. If not, you'll need to adjust the front switch; if it does, your rear is probably the issue.

Once that is done, start testing again.