2008 hayabusa charging help!

[akanimo]

Friends,
have had charging issues on my 2008 busa for a while now.
I have done the following.
1. checked all connections.
2. Gone through 5 rectifiers and now have bought a brand new coil.

When the bike idles for long and the two fans come on, the voltage accross the battery gradually drops till it eventually gets to about 12.1-12.2v and by this time if you shut down the bike and start, it will not start.

From my haynes manual , i read the following - Generator voltage on a no-load situation when cold should be 70v (alternating) and more at 5000rpm . I really dont understand what this means . Is it that when the bike is idling, it should be 70v and when you rev up to 5000rpm it should give you more voltage . My brand new coil when it idles , it produces 24v and when at 5000rpm its about 90v.

Any suggestions or help will be appreciated .

Thanks .

 

[tranyman]

Are you sure you have a good battery? It should still start your bike if it is at 12v when your bike it turned off.

 

[jphilipson]

Are you sure you have a good battery? It should still start your bike if it is at 12v when your bike it turned off.

Negative, you need "Amps" to start the bike.

At idle, your stator is not putting out a lot of power, it is rated at 400 watts at 5k RPM. I am not sure what it is at idle, but it is WAY lower. The fan uses more power than probably anything else on the bike, hence why it's on it's own 15 Amp fuse. If you are idling for a really long time with the headlight, position lights and fan running, it is going to start draining your battery, and eventually deplete it to the point it will not have enough to start the bike. So, the easy answer to the problem is not to leave your bike idling for a long time. How long are you idling for when this happens? And why are you idling so long?

 

[Lucid]

IF your battery is good, it sounds like your charging system is working. I'd check for a drain somewhere that depleats the battery when the bike is off, then starting and idling finishes the battery off.

BTW if you've run your battery down, EACH time it drains down it holds less and less charge. I don't remember the exact statistics but it's something like 1st time you run it down, it will only charge up to 80% of what it was before. Next time you run it down, 75%, then 65%, and down and down. This is how batteries go bad really quickly so if it's been drained a few times, I'd look there.

 

[akanimo]

sometimes i get into some mind warping traffic go slows where all the fans will come on and the ilks.Not based in the US just to make you understand .
I have a new gell type battery that is strong. Have done a battery leakdown test before and its within specifictions.
On stator power ratings, i dont have the means the measure this, so that was why i asked if anyone has ever measured the voltage from the coil when idling.

 

[jphilipson]

On stator power ratings, i dont have the means the measure this, so that was why i asked if anyone has ever measured the voltage from the coil when idling.

You mean measure it at the stator? There should be three wires coming off the stator. First thing to do is test the impedance and see if all are working with spec. Test all three with a ohmeter and check if one is way out of the park . If so you have a fired section on the stator coil. Not sure what the exact value for this bike should be, but if one is way different than the other two, the stator is shot. And a visual inspection will usually show the damage. Any electrical issues i have had with bikes were either a fried stator or a bad battery.

 

[akanimo]

impedance checked ok between specifications. my main issue is the idling voltage as the brand new one seems to be below spec

 

[micbusathens]

Try another battery.Have had similar issues ....changed 2 rectifiers and finaly was the battery.Measurments with a damaged battery in the circuit give wrong results sometimes.JMO

 

[jphilipson]

impedance checked ok between specifications. my main issue is the idling voltage as the brand new one seems to be below spec

Are you measuring the voltage off the battery terminals at idle? What is the voltage you are showing at idle? If you rev the engine, does it go up or drop? By brand new one, you mean battery? If so, was it fully charged off the bike before you installed it?

 

[akanimo]

brand new battery. no trouble. My question is the voltage across the 3 yellow wires from the stator coil when the bike idles. Suzuki's specs is ambigous- 70V(alternating) and more at 5000 rpm . I dont know if this means 70v at idle and more at 5000rpm OR just more than 70v at 5000rpm.

So i bought a brand new startor coil and made the measurements at idle and it was 24v. Can anyone crosscheck with his own perfectly functioning charging system ? Thanks.

 

[jphilipson]

The resistance across the stator leads should be between .2 and .7 Ohms. The regulated voltage at the battery should be 13.5-15.5 volts at the battery at 5k RPM. The unregulated output from the stator should be 70 volts at 5k RPM, and that should increase a bit as the RPM's go up past that point. To properly test your stator, it should be at 5k RPM. At idle, the voltage will be much lower as you measured. If your system passes the 3 above tests, then your charging system is working properly. If you refer to the charging system troubleshooting section in the manual, if your system passes step 3 (regulated voltage), then the cause of your problem is "faulty battery" or "abnormal driving condition". Since you replaced the battery, then it is most likely the latter. If your fan is constantly on at idle and you are not getting to ride normally (maintaining normal RPM's so the output is enough to charge the battery and run the bike), then your charging system is always at a deficit and your battery will eventually run down. The charging system does not have enough power at idle to run everything else on the bike, and the fan which uses a lot of amps, constantly.

What you should do is install a volt gauge you can use when riding. Then watch your voltage when you ride in the conditions you mentioned (low RPM's, fan on). If the voltage is dropping down to 13-13.5ish or below, then you are no longer generating enough power to run the bike and charge the battery.

 

[akanimo]

really appreciate your candid interest in what i have been going through.

I notice that my riding conditions can be abnormal and i guess the bike wasnt made for such purposes.

Will take a ride and revert again .

Thanks.

 

[AJAY]

brand new battery. no trouble. My question is the voltage across the 3 yellow wires from the stator coil when the bike idles. Suzuki's specs is ambigous- 70V(alternating) and more at 5000 rpm . I dont know if this means 70v at idle and more at 5000rpm OR just more than 70v at 5000rpm.

So i bought a brand new startor coil and made the measurements at idle and it was 24v. Can anyone crosscheck with his own perfectly functioning charging system ? Thanks.

First, jphilison gave you correct advice.

I'm not sure what is "ambiguous". Check the voltage for each of the coils at 5000 rpm. They should each be above 70 VAC. You said you were getting 90 VAC (seems high) on each of the three coils, your resistance is correct, so your alternator is working properly. You should measure between any two of the electrical terminals in the plug when you do this, not from the terminal to ground.

As long as your voltage at idle is above 13V, your battery should be charging (yes, even at idle). The rest voltage of a standard 6 cell lead acid battery (including AGM batteries) is 12.6V, so if you are reading 13VDC at idle, you are charging. Below 12.6V and you are discharging from the battery. Run the idle up to 5000 rpm and your voltage at the battery should be about 13.5 VDC.

Do you have any electrical accessories that you've added, say some underbody lights? Air horn? other electrical gizmos?

Also, verify that your tail light (brake light) is not stuck on. This is actually one of your bigger current draws and a stuck or misadjusted brake light switch has been the cause of many a dead battery.