Battery Voltages - what is good vs. bad?

[Checkswrecks]

Skoots-

The starter value is a clue, as that energy has an easier path to ground somewhere. Pop the wires off the starter and use the ohm meter across it and each to the starter case. Compare that to the salvage starter &/or Dons'. I'm going to guess they aren't even in the same ball park.

Bob

 

[SkooterG]

What is the 'solenoid'? Just a relay to keep the high amps from running through the starter switch? Anybody know where it is on the FJR?

Edit: Some quality time with the service manual and I believe I have answered my own question. SM shows a 'starter relay' that is just aft of the battery.

 

[beemerdons]

Wolfhound, vectervp1, BadCatBurk, Spudmanz, Big-D, charismaticmegafauna, Tucson Joe, & the rest of Arizona FJR Forum:

Would you FJR guys please call me at 602-722-0427 and let me know what Saturday we can get together; to go over to the Snottsdale Mansion of this sniveling *****, so we can install his spare salvage starter and not have to hear about his PERIOD!

 

[beemerdons]

On a positive note: GregM, Honey; if you need to borrow "Miss Lucy Liu" for a months transportation, then just help yourself!

With Kelvin-Florence this Sunday, Four Peaks next Sunday and Death Valley Daze the following Sunday: I am tied up riding the BMW F650GS offroad every weekend for the next month. Lucy will just be sitting in my Chandler garage going nowhere!

When you wake up at noon today give me a call at 602-722-0427; I'll pick you up in my work truck and you can take Lucy!!!

 

[Fred W]

Ok, so I tried some different readings, can anybody tell me what they mean?
I measured voltages while cranking. Engine always started after about a second, though cranking was slow. This was on a cold engine. I wish engine wouldn't have started so quickly so I could have gotten a longer Voltmeter reading.

+ battery terminal and ground to frame, 3 different trys. Readings between 6 and 7 volts.

+ battery terminal and ground to - terminal, 3 different trys. Readings between 7 and 8 volts.

+ terminal of starter and grounded to frame, 2 trys. Reading of .6 -.7 volts.

So these cranking readings are lower than the 10v I got yesterday. Is the approximate 1v difference between ground to frame and battery enough to show a problem with my ground cable? Or is that normal?

And what about the paltry .6v reading at the starter? Is that right?

Oh, btw. I hope to install my salvage starter sometime in the future. But this bike is my everyday transportation and according to the SM it's a big job. Airbox and throttlebodies need to be removed. Hopefully I can get to it in the next few weeks. Unless I HAVE to get to is sooner.

Skooter,

The relatively small difference between the voltage reading at the battery referenced to the frame and referenced to the battery terminal says that isn't your (main) problem. I'd rather the difference was less, but in this case it doesn't seem to be the main issue.

The fact that you are reading only .6V at the starter says the problem is back toward the battery from the starter (not inside the starter). My speculation at this point is that your starter solenoid relay is bad. Yes, the starter relay is just a big relay to allow control of the large current required by the starter motor. It should have almost no resistance and should therefore not have much voltage dropped across it. In your case it is dropping from 8V to .6V.

You could test this theory by measuring the voltage at the starter motor again while briefly using a stout piece of wire to short across the two larger terminals of the starter relay with the key off. Note: It will throw sparks as soon as you make the (temporary) connection and the starter will start to turn the engine over, but the bike will not start with the key off. If the voltage is now ~7-8V at the starter, and the engine turns over relatively quickly, then the relay is your problem. If it is still just .6V at the starter and turns slowly then the relay isn't the culprit and there is something wrong with the wiring that is dropping that voltage.

 

[road runner]

Skooter,

Try this test. It's easier and quicker than a voltage drop test. It checks the condition of the circuit being tested between test meter leads.

- place pos. meter lead on batt. pos. term,

- place neg meter lead on starter pos. term.

- crank over and observe reading.

This will read the voltage that is trying to go around your entire pos. circuit so it should be very low if all is OK, (1 volt or less, ideally 0 volts)

- then do the same on neg. side

- place neg. meter lead on batt. neg term,

- place pos. lead on starter case.

- crank over and observe reading.

This reading should also be very low (ideally o volts).

If you get little or no volts on both tests then it's either your battery or starter. From what you already said I don't think it's your battery. I think it could be your starter, because if it is shorting it will pull the voltage way down, like you already stated in one of your tests. I would still do these tests to confirm.

If one of these tests shows higher voltage, then start at the battery and do the same test on every wire and connection between the battery and the starter on that circit. For example, on the pos. side test from batt. to solenoid, then across solenoid, then from solenoid to starter stud. You can even isolate it to a bad wire end by testing between the stud and wire end. And don't worry about which test lead goes were, because if it is backward then the meter will just read neg.(-) volts. Just remember any high volt reading is bad.

A wise man once told me " an intermittent electrical problem can be caused by one of three things.

1- connections,

2- connections,

3- or connections " :huh:

This is not 100% true, but about 99%.

Good luck and keep us posted.

A.C.

edit;

I would do both neg. and pos. sides to get an idea of what a good reading is, because it is unlikelly that both sides will be bad. If they are both good then they will both be low and close to each other.

Also I would try unpluging the ECM while doing test so it doesn't start or flood. I don't know if it will still crank over with ECM unplugd, but I would try.

 

[SkooterG]

A.C. Thanks for the advice. My DMM's leads aren't long enough to go from battery to starter, but maybe I can find some wire around here to assist with that.

Here's where I am:

After the last posted test results, I began to wonder if the battery was part of the problem. According to Ionbeam's and 3dogs' posts, my battery cranking voltage was low.

See those posts HERE (Ionbeam's) and HERE (3dogs). They were both very helpful.

So I followed 3dogs advice and disconnected the 15a fuel injection fuse so I could get more cranking w/o start-up. The fuse is right next to the starter solenoid behind the battery and was easy to get to. Even so, I could only get about 3 seconds of cranking. But that was enough. Voltages during cranking between the battery terminals was between 6 and 7 volts. So now I was back to suspecting battery trouble.

I took the battery out and returned it to the store I bought it. I found out it had a 1 year warranty. (Battery is only 5 months old) Well, they load tested it and pronounced it in excellent shape. Some weird kind of load tester that said it pulled 170 CCA even though battery is only rated at 130. Just to be sure, on the way home I stopped at a BMW m/c shop where I know some folks and they load tested it also and gave it a clean bill of health.

So, my battery is good. But something is really going wrong. I still think it's the starter, but will try some of your and others (Thanks FredW) ideas and tests. The other day I did try putting a jumper cable from the + battery to the + starter terminal (bypassing stater relay and all cables). Starter barely turned over. Meaning it's the starter, or that the connections with the jumper cable 'clips' weren't good enough to provide the necessary current.

Thanks again for taking the time to give some good advice.

 

[Capt. Bob]

Skoot,

The brushes wear down with use and the springs weaken. That leads to arcing on the commutator and results in burnt spots. All cases of hard (slowed )starter speed. The voltage draw down though sounds like a bad field in the armature.

That my guess.

 

[road runner]

Skoot,The brushes wear down with use and the springs weaken. That leads to arcing on the commutator and results in burnt spots. All cases of hard (slowed )starter speed. The voltage draw down though sounds like a bad field in the armature.

That my guess.

+1

Sounds like something is wrong with the starter, and it's pulling the voltage down.

 

[Fred W]

The other day I did try putting a jumper cable from the + battery to the + starter terminal (bypassing stater relay and all cables). Starter barely turned over. Meaning it's the starter, or that the connections with the jumper cable 'clips' weren't good enough to provide the necessary current.

OK, that is essentially the test I was advocating and it sounds like you've ruled out the starter relay. It really is beginning to smell like the starter motor is the culprit. But I am surprised about a couple of things. One is the .6V measured at the starter when cranking. That means the rest of the wiring and connections are dropping the remainder of the battery's supply voltage. In that case, the motor is must be nearly a dead short, and you must be pulling a butt load of current out of the battery. If the motor is shorted I'm surprised it will turn the engine over at all. Strange.

But if the battery is good and you use a good jumper cable to bypass the relay and all of the wiring and it still won't spin right, it almost has to be the starter. I haven't looked yet, but I bet swapping the starter motor out will be fun, fun, fun.

 

[SkooterG]

Well, before I put the battery back in again, I tried the jumper cable routine again. Starter barely turned over, and after a short time SMOKE came out of the negative jumper cable where it was attached to the engine case. Looked like smoke was coming from where cable and hand clip join. BTW, these are low quality jumper cables my g/f had from an emergency kit. Low gauge wire. Still, I thought they would be ideal for m/c application. WTF?!?! After a phone call with Ionbeam, the consensus was bad starter causing a high current/low voltage condition.

Oh and Fred, I tried measuring that starter terminal voltage again now that I can crank for a while w/o start. This time it read in the 4v-5v range, not that silly .6-.7v. Much more inline with what would be expected.

So now I am done with this for a while until I can schedule a 'starter swap' into my schedule. Probably in two or three weeks. I expect it to be a major PITA as according to SM, airbox AND throttlebodies need to be removed.

Thanks ALL!!!

Help is much appreciated!!

 

[odot]

All this from the great and almighty......................skooterG.....

...go figure.

 

[dcarver]

Kickstarter bikes rock, SkooterG...

 

[beemerdons]

Wolfhound, vectervp1, BadCat and my other FJR Phoenicians: Please help me comprehend this: "...until I can schedule a 'starter swap' into my schedule." What the ****, over! In the last few years have you ever known his schedule to be anything other than the following! His 'schedule' consists of the trash truck outside waking him up, he then wanders down to the Pinnacle Peak General Store where either GSJane, BeemerDonS or you guys buy his breakfast, he then goes to the gym to "work out" - which means he sits at the juice bar and ogles the Snottsdale "COUGARS" and then he rolls on home.

He then watches his soap operas, followed by his nap and then the evening is spent on the Internet. I'd kill for his schedule!

 

[odot]

I was under the impression that skooterG was one of them dudes that split atoms in his spare time......

 

[Capt. Bob]

I was under the impression that skooterG was one of them dudes that split atoms in his spare time......

He would, if he had any. :blink:

Atoms that is.

 

[odot]

You saying that we should leave him with a skid of butter and a crack whore?

 

[Capt. Bob]

You saying that we should leave him with a skid of butter and a crack whore?

As far as I can tell, the melding of butter and crack defies no current known laws of physics and...

If her name is "Electron" so much the better :dribble:

Alas, this thread is deteriorating quickly ^_^

 

[odot]

Ever seen the movie "last tango in paris" there, cap?

 

[zorkler]

Put your face by the starter and start the bike 3 times is there any kind of strange odor comeing from the starter ? If so explain.