Battery Won't Hold Charge... PLEASE HELP

I have a 1985 FJ600 and i just got done doing a ton of work to it. bike runs and rides wonderfully. i bought a brand new battery and it ran great and then after a few days to a week died. i thought it may be the battery because it had a weak load and luckily i had a warranty on it and was able to get a new one. same thing a few days to a week the battery was dead.

obviously the problem isn't the battery it is something with it not charging.

i was wondering if anybody could give me some advice with how i would go about troubleshooting it and figuring out what the problem is before i go buying new parts of what i think it is and wasting my money.

thanks for your help and time,

-Harlan

 

Why not put a voltmeter on it while its running and see if its putting out any voltage, then, check for a closed circuit when it's not running.

 

Start out with checking your generator brushes.
Then check the rotor to test for shorting.
Follow this up with making sure the connector to the regulator/rectifier has not vibrated loose, and shorted/melted.
Finally. Test the regulator to make sure it is still in working condition.

Ghost

 

Put a Meter on the POSITIVE Battery Terminal.
It should read +14.2 -to- 14.5 Volts at 2,000 rpm and above.

Pop the Cover off the Alternator.
Measure the Brushes inside the Cover.
10mm or less = Replace.

Clean the Orbit Circles the Brushes make contact to the Rotor with an Old-style Typewriter Eraser.
http://www.amazon.com/Venus-Circular-Ty ... B003KEFV02

 

Thank you everybody for your help, i will be testing it out soon!

 

Hey Quinton
Seeing as you are going to do the testing why not do a tutorial. Snap some pics as you trouble shoot with a little write up, it might be a valuable tool for the next guy with a similar problem.
At least update us with what you found and how you fixed it.

Good luck.

 

Yep I plan on filming the whole process and making an instructional video.

If you want to check it out I've already made a video on rebuilding the Mikuni carburateors when I fixed them in the fall, here's the link.

http://m.youtube.com/watch?feature=plpp&v=MdfH_kodoSU

Also feel free to check out my family's YouTube channel at www.youtube.com/mreinsmith. We have anything from projects on our cars to our bikes up there.

Stay tuned for the troubleshooting video!

-Harlan (Quinton)

 

I've added a cheap volt-meter as a permanent tool to my XJ.
It really helped in solving some electrical issues I had when I got the bike. Eventually my (main) problem was a bad fusebox and some minor corrosion issues. And, as I'm expecting to have a bad alternator soon, I can see when it stops charging, as this bike does not seem to have a charge warning light.

 

The Alternator shouldn't fail until there some high miles on the bike.

The BRUSHES wear-out.

You should see +14.5V to the Battery at 2000 rpm's and above.

I like the Voltmeter.
Nice touch.

 

I might write a how-to on this very subject. The very best way to check a charging system in whole is with amps. It allows you to see the amount of power and direction. It won't help you pinpoint any one fault, but it will tell you the overall health of the system. You will still need to do all the other basic troubleshooting if this fails.


Basic theory: amps will flow away from the battery when being discharged, amps will flow to the battery when being charged. A digital voltmeter can display this as negative or postive number.


Example for most bikes:

1) You start with a DIGITAL voltmeter that can do pass-through amp measuring. A beefy 20-30amp able meter will be needed.

2) You remove your main fuse and replace either side of the fuse with a meter probe.


3) Turn the key on. You should see a negative amp reading. If you see a postive value then you should reverse the probes. The idea is that you want to see the draw on your battery.


4) Start the engine. When you rev the bike you should see the amp reading go from a negative number to a postive one. This lets you see the amps going into the battery. The second it switches to 0 amps is your break even point. Thats when the bike has enough power to run, but not charge. In most cases you won't see it charging until its above idle speed.

 

The Genuine YAMAHA Workshop Manual says measure VOLTS.

At the Battery.
The Battery should show +12Volts.
Dip to +11~11.2 when the Starter is engaged.
Gradually increase back toward +12Volts while warming-up.
Increase beyond +12Volts as the engine's rpm's increase.
Reach +14.2 Volts as rpm's near 2,000.
Maintain +14.2 ~ 14.5 Volts at 2,000 rpm's and above.
Above +14.8 - Defective Regulator. Replace.

 

A defective regulator can also drain the battery . Bad diodes in there will drain a good battery overnight. Unplug the regulator and see if the battery still drains.

 

79xs, while your write up works in theory, Yamaha's volt measurement that Rick provides is the best way to determine the charger function for the following reasons:

1. Amp meters are more expensive than volt meters.
2. Amp meters have to be in the flow of current to measure it, meaning that they are limited by the current measured and actually act as a (small) load. Current can go to infinity (fuses help this situation). Voltmeters measure potential energy, so they don't actually pass any of the load through them. If you get a short in your electrical system, the voltmeter won't be affected.
3. Batteries chemistry dictates that the open circuit voltage (OCV) will be between 12 and 13V from 0 to 100% State of Charge (SOC). Therefore, any voltage greater than its OCV=f(SOC) will cause current to flow toward the battery.
4. The rectifier/regulator (RR) is designed to keep the voltage at 14.5V, thus always charging the battery as long as there is enough power to support that voltage, and the resulting load current (since P = IV). If it can't, the voltage drops.

Amp meters are great if you want to closely telemeter the performance of a complicated electrical system, or want to add more load to the electrical system and want to know exactly what margin you have at a particular rpm. But for monitoring general health, especially while riding, a voltmeter tells you everything you need to know.

 

If you use a amp meter that example will work the same way with a dead cell in your battery !

 

If by "work" you mean that you'll still read current going into the battery. But in that example, the electrical system isn't healthy, and the current alone won't tell you that, but the voltage can if the RR can't get to 14.5V when it's supposed to.

Current going in to the battery is proportional to the voltage difference between its OCV = f(SOC) (12-13V), and the Voltage at the terminal (OCV - 14.8V as f(rpm)). If a cell has failed, the OCV drops, and you'll get even more current flow into the battery. But it isn't stored as chemical energy, it'll just generate heat. The charging system could drop in output, but still flow current to the battery, since it's OCV dropped.

Current could tell you something was wrong IF your RR could still get the voltage up to spec, but the current margin was smaller than it should be for a given rpm. But that would require CLOSE monitoring.

 

You are right, I understand what you are saying. What I should have really said is that it's something to check at the same time as volts. Maybe it's not as useful on solid-state voltage regulators since there is no adjustment. I always used the amps reading when adjusting old mechanical voltage regulators. In most cases I will have one meter doing amps and one doing voltage. Yes, in truth the voltage should never be able to get above the battery level if it's not able to charge. I guess in that case it would be an overcharge/boil over instead of a discharge.

Also Polock, In this example it's taken for granted that the battery is healthy.

To each their own. Lets not high-jack his thread. We got a good convo going though.. =)

 

The 550 Seca comes with one; and it's reasonably accurate (I said "reasonably" and it IS more accurate than the fuel gauge.)

The needle generally sits in the area between 14V and the red block. (Except when the turn signals are on, and I'm idling at a light with the headlight modulator engaged. Then it does a very interesting little dance.)



Back to the OP's issue: it's probably wiring or a connection problem before I'd suspect anything of being actually worn out, if 8.5K miles is accurate. What sort of condition is the fusebox in?

If that bike still uses a brush-type alternator, then by all means have a peek at the brushes. But the problem is more likely a connection somewhere.

 

89.9 Miles ??

That thing work?

Or does it get hauled-around on a trailer.

 

The dues you pay for being a Biker in the "Get's-bitter-cold North" ... is buying yourself a New Battery every season.

Even bringing the Battery indoors and keeping it on a decent Battery Tender from December to April won't keep the poor thing from losing its reserve.

I enjoy picking-up the New Battery at Sears,, bringing it home and ruining a pair of Jeans with Acid splatter filling the cells.

 

No, it says 9974 or somesuch now; the pic was taken right after I installed the new speedo.

I don't own a trailer.

I generally get about 4 ~ 5 seasons out of a decent battery.