No start! 83 GS1100G! Horrible wiring!

[Guest]

Hello all. I'm new to the site and in desperate need of advice...

Let me give the basics. This is a 83 GS1100G. I'm located right outside of Washington DC. The issue I'm having is the Voltage drops to zero (when measuring at the battery) when starting. The bike has a new beefy SH775 R/R, new stator, new battery, new starter, and starter motor. Fuses are all good. Am I missing anything? Is there a troubleshooting process to narrow this down? Please help, its beautiful outside and I get deployed in a month!

[tom203]

Does it crank over when the battery "voltage goes to zero"? Are you sure your voltmeter is ok ? New starter motor- "new" as in rebuilt or like real expensive brand new?

[JTGS850GL]

Did you do an initial charge on the battery? Not likely a problem with the bike's charging system that would cause a battery to go to zero volts if the battery was fully charged. At least not without a whole lot of drama taking place.

[posplayr]

As stated, if the battery drops to zero with no smoke then the battery is dead. It has very high internal impedance.

[JTGS850GL]

As stated, if the battery drops to zero with no smoke then the battery is dead. It has very high internal impedance.

You did mean a very low internal Z. Typical lead acid batteries have an internal resistance of something along the lines of a few hundred milliohms.

[amarshall]

Does it crank over when the battery "voltage goes to zero"? Are you sure your voltmeter is ok ? New starter motor- "new" as in rebuilt or like real expensive brand new?

It gives the first turn of the crank and each following crank is weaker. When the battery was brand spanking new (two weeks ago) it would drop to about 6 VDC. Ok, the starter motor wasn't 'new' but it works.

[amarshall]

Oh Drama is one thing this baby is full of... I had a hunch to dig into to headlight harness... good lord what a rats nest! I'm going with something in this harness is shorting. Its actually about to storm so I'm trying to throw the cover back on but I'll tell y'all what I find.

[posplayr]

You did mean a very low internal Z. Typical lead acid batteries have an internal resistance of something along the lines of a few hundred milliohms.

The general guidelines of the Quick test are, with key on the voltage goes from about 12.8 to 12.2 volts for a good battery (10 amps drops 0.6V). So for purposes of discussion the typical lead acid battery has an internal resistance of about 0.6 ohms . Use the application in the link below to confirm these values.

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/dcex6.html

Part of understanding the notion of internal resistance is that it is not constant. It is directly related to "state of charge" (SOC).

http://en.wikipedia.org/wiki/State_of_charge

Internal resistance is used as a direct indicator of state of charge. If the battery is "down", internal resistance is higher and the voltage drops more when you pull a known current. If SOC is higher and internal resistance is lower then the terminal voltage drops less.


My comment follow this theory; the larger the voltage drop the higher the internal resistance.

[posplayr]

It gives the first turn of the crank and each following crank is weaker. When the battery was brand spanking new (two weeks ago) it would drop to about 6 VDC. Ok, the starter motor wasn't 'new' but it works.

It sounds like you have a short in your starter and you are excessively drawing down your battery. The only way to bring it back is with a charger as the charging system is really not capable of bring it back fast enough.

[tom203]

"...Ok, the starter motor wasn't 'new' but it works."

probably doesn't work well. Sounds like an error in the rebuild process- assuming your starter solenoid is not fried (yet). As posplayr said, the starter is likely shorting out internally. Remove and take to auto parts store and let them test it under load.

[JTGS850GL]

The general guidelines of the Quick test are, with key on the voltage goes from about 12.8 to 12.2 volts for a good battery (10 amps drops 0.6V). So for purposes of discussion the typical lead acid battery has an internal resistance of about 0.6 ohms . Use the application in the link below to confirm these values.

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/dcex6.html

Part of understanding the notion of internal resistance is that it is not constant. It is directly related to "state of charge" (SOC).

http://en.wikipedia.org/wiki/State_of_charge

Internal resistance is used as a direct indicator of state of charge. If the battery is "down", internal resistance is higher and the voltage drops more when you pull a known current. If SOC is higher and internal resistance is lower then the terminal voltage drops less.


My comment follow this theory; the larger the voltage drop the higher the internal resistance.

I'm pretty well versed in how power supplies work.

I was referring to the nominal internal resistance of a CHARGED battery. I though you were stating that a lead acid battery normally has a high internal impendence. That's why I was questioning your statement of the impedance of a lead acid battery being very high. After rereading your post it does make sense that you were referring to his dead battery having a high Rint. Sorry for the confusion.

[posplayr]

I'm pretty well versed in how power supplies work.

I was referring to the nominal internal resistance of a CHARGED battery. I though you were stating that a lead acid battery normally has a high internal impendence. That's why I was questioning your statement of the impedance of a lead acid battery being very high. After rereading your post it does make sense that you were referring to his dead battery having a high Rint. Sorry for the confusion.

Sorry, If I was not clear in the beginning. I just immediately interpret a voltage drop on the battery (without smoke i.e. design currents) with high internal battery resistance and therefore reduced state of charge;

[JTGS850GL]

Agreed. The only way you could have a zero reading on the battery when trying to start the engine is with an almost or completely discharged battery.