Bad battery, or rectifier/regulator ???

[Miles Long]

I hate to add another post to the subject of the charging system, but I've checked out the database ,and did a keyword search. I could not find any specific answers to the questions I have. So here goes.......
I've got a 680 Odessey battery in the bike. It's only been in for 4 years, but during that time I've put a lot of miles on the bike. I've done the "crimp" fix, and also checked out the 3-white wire stator connector. It looks fine, and is packed with dielectric grease.
A couple months ago, before leaving on a trip, I checked the charging voltage at the battery. It was a healthy 14 volts at about 4000 rpm.
Yesterday, after a 100 mile jaunt, I checked out the charging voltage again. Only about 13 volts. With the bike off, the battery was only about 12.2 volts. I trickle-charged it to 12.6, but this morning it was down to 12.3
I have a Clymer manual, and just finished checking the stator at the 3 wire connector. It showed about .7 ohms at each connection, no continuity between any connection and ground, and about 40 volts D.C. output, at 4000 rpm. I'm assuming there is no problem with the stator.
The Clymer manual says there is no way to test an RR, but also states that the "voltage regulator no-load output" should be 14-15 volts.
My questions-
Even with a bad battery, if the charging system is working properly, will a running bike show 14+ volts across the battery terminals??
Why can't the output of the RR be checked, even though the manual says there is no way to test? I pulled apart the separate black and red RR connections (the ones next to the 3 wire stator connector) and checked the DC voltage. It only showed about one volt at the red wire, at 4000 rpm. Has anyone else every measured this voltage? Should it be the full 14-15 volts, or does that figure only apply to voltage across the battery terminals??
Here's hoping that most of you will say that this is just a case of a bad battery . That's an easy fix. I guess I could also take the battery out and have it load-tested at a vendor's shop.
Thanks in advance, Miles

 

[Miles Long]

Sorry, that should read 40 volts A.C. at the stator connections. There is something wrong with this damn keyboard. It doesn't always type what I mean! Miles

 

[MaxMidnight]

I'm curious to know if you have any issues with the bike starting?

If spins as it should then my suggestion would be to stop measuring - it could be that it is your voltmeter that is faulty!

One other point - gel type batteries do need a specific type of charger to bring them back up to optimum charge. If yours isn't of this type then that may be why it doesn't reach full charge.

If you want to check out your charging system then have a look here under the Technical Section

 

[satariel666]

I'm curious to know if you have any issues with the bike starting?

If spins as it should then my suggestion would be to stop measuring - it could be that it is your voltmeter that is faulty!

One other point - gel type batteries do need a specific type of charger to bring them back up to optimum charge. If yours isn't of this type then that may be why it doesn't reach full charge.

If you want to check out your charging system then have a look here under the Technical Section

There are some rumors, some use to claim that gell bateries should be charged with pulse charger. I dont bealive thats tru.

Imagaine that You will need special R/R for that purpose - nobody sells that.
Some vehicles comes out from factory with gel's already instaled.
Do they have a special R/R? Nope.
So by any means we are destroing our gel's while using on the typical vehicle?
IMHO no.

The only advantage of using "gel charger" is that You can recharge them very fast which cant be done with regular charger.

Im using ups gel battery in v-max for 2 years. Only once I was pushed to recharge that battery. At winter and when I was rebuilding my engine and she was weak back there.

 

[Thevmaxrider]

Based on your numbers I am stepping out on a limb and saying you have a stator problem. If my memory serves me correctly, and in this case it is a very RECENT memory, the output should be 70 V AC from the stator. Even though the leg to leg AND leg to ground resistance is good your output sounds about 50% of what it should be. Just sayin'.........

 

[Miles Long]

I'm curious to know if you have any issues with the bike starting?

If spins as it should then my suggestion would be to stop measuring - it could be that it is your voltmeter that is faulty!

One other point - gel type batteries do need a specific type of charger to bring them back up to optimum charge. If yours isn't of this type then that may be why it doesn't reach full charge.

If you want to check out your charging system then have a look here under the Technical Section

Thanks, Steve
The bike is still starting fine, even with the battery reading 12.2-12.3 volts I have two multimeters, they are giving identical readings, so faulty instrumentation is unlikely to be the cause of the readings.
I am planning to purchase one of the AGM-specific chargers - I too have read that AGMS do not take too kindly to trickle-charging. Besides, I should have a higher output charger around the house for the other vehicles.
The Electrosport articles are informative, but the one regarding RRs is still unclear as to what output voltage can be expected if the battery is bad. I will post a question to their "ask an expert" section.
I'll wait for more replies to come in, before purchasing anything other than a charger.

 

[Miles Long]

Based on your numbers I am stepping out on a limb and saying you have a stator problem. If my memory serves me correctly, and in this case it is a very RECENT memory, the output should be 70 V AC from the stator. Even though the leg to leg AND leg to ground resistance is good your output sounds about 50% of what it should be. Just sayin'.........[/QUOTE
Thanks, Jim
70 volts AC, BUT AT WHAT RPM? My stator was showing 40, but just at a fast idle (choke on) If you are sure of that number, I'll try mine again, at higher rpms.

 

[Thevmaxrider]

OOOOOPS, that output is at 5k RPM. Sorry forgot to put that into my post. I think you will find that the voltage doesn't increase much because that should be fairly constant with the amperage output increasing with RPM. Of course I am not an electrical engineer so I may be wrong, will do some research.

 

[Thevmaxrider]

Beings that I am not an electrical engineer, I went and asked one. Best thing is working at a nuclear power plant he is fairly well versed in generator operation. According to him, the voltage output should be fairly constant with little to no fluctuation due to rpm of the rotor. The rpm controls wattage output (or another way to look at it is amperage) only.

 

[MaxMidnight]

Przemek

I was not suggesting that a 'special' R/R is needed and accept that the one on the bike is capable of maintaining a fully charged battery.

However (IMHO) it is advisable to use a device that is designed to re-charge gel type batteries when the charge falls below optimum. I've found that whilst a conventional trickle charger will maintain a fully charged battery it was unable to charge it up to 12.6 volts.

The alternator is not designed to fully restore a depleted battery, but rather to maintain a healthy one.

 

[Thevmaxrider]

The alternator is not designed to fully restore a depleted battery, but rather to maintain a healthy one.

Truer words have never been spoken!!! If your battery is weak or depeleted you should NEVER rely on your charging system to re-charge it. The battery will draw current in parallel to your electrical system which in turn makes your charging system work harder, the worse the charge on the battery to begin with the more it requires to charge back up, hence more heat created in the charging system (those big heat sinks on the R/R are there for a reason:biglaugh. It is always recommended to use a charger to get the battery to its peak, use a trickle charger to maintain peak charge, and use your vehicle's internal charging system to restore energy used to start the vehicle or used during extreme loading of the electrical system.

 

[satariel666]

Przemek

I was not suggesting that a 'special' R/R is needed and accept that the one on the bike is capable of maintaining a fully charged battery.

However (IMHO) it is advisable to use a device that is designed to re-charge gel type batteries when the charge falls below optimum. I've found that whilst a conventional trickle charger will maintain a fully charged battery it was unable to charge it up to 12.6 volts.

The alternator is not designed to fully restore a depleted battery, but rather to maintain a healthy one.

Steve.

I was not sugesting that You were sugesting anything

I agree. You right with maintaining the battery.
In the short way the battery is only for starting the vehicle.
Vehicle gets the power from generator while running.

Its been very controversial topic over the years.

I just wanted to say that according to mine findings, any conventional charger will recharge the gel battery preatty well.

 

[Miles Long]

Truer words have never been spoken!!! If your battery is weak or depeleted you should NEVER rely on your charging system to re-charge it. The battery will draw current in parallel to your electrical system which in turn makes your charging system work harder, the worse the charge on the battery to begin with the more it requires to charge back up, hence more heat created in the charging system (those big heat sinks on the R/R are there for a reason:biglaugh. It is always recommended to use a charger to get the battery to its peak, use a trickle charger to maintain peak charge, and use your vehicle's internal charging system to restore energy used to start the vehicle or used during extreme loading of the electrical system.

Great words of advice from all so far, with everybody agreeing to the above opinion. Keep the cards and letters coming in. So, with the above quote in mind, here's my next step..........
I just borrowed an AGM-friendly charger from a buddy.
What I know for certain is that the battery is not showing a full charge(12.6 volts) The reason hasn't been determined yet - bad stator, bad RR, faulty connections, bad battery, or maybe even an electrical leak (I haven't done a leak-down test yet)
So I'm going to remove the battery from the bike, charge it up overnight,
and then see if it will hold that charge. If it doesn't, it's in the scrap pile.
If it holds the charge, I'll still have it load-tested before re-installing it. Then I'll do a leak-down test.
If the battery does turn out to be bad, and a new one depletes, then obviously I will have to look at the charging system components again.
Doesn't everyone love electrical questions? Nothing seems to stir up more controversy and differences in opinion. Really gets the blood flowing!
Thanks so far to everybody that replied
Miles

 

[Miles Long]

Well folks, it appears my problem is no more.
I charged up the battery with the borrowed charger (2amp setting, for about three hours), until a full charge was indicated. A check across the terminals showed 12.8 volts. After an hour or so it settled back to 12.6
Then I put it back in the bike, but before hooking up the negative cable, I did a "leak-down" test, as outlined in the Clymer manual. It indicated a leak. This is where Lady Luck kicked in - the first circuit I checked (which happened to be one of my own additions - go figure), was the source of the discharge! After fixing up this nasty circuit, the leak-down test came back as good. So this was the cause of the discharging battery, not the charging system, or the battery itself.
So, with a fully charged and rarin' to go battery, naturally the bike fired right up. Now comes the interesting part -
With the bike idling, the voltage across the terminals now again measures 14 +, just where it should be.
So this answers one of my questions. Apparantly, even a well operating charging system will not indicate 14+ volts, IF the battery is in a state of partial discharge. Why? Beats me.
That would be a question for the electrical engineers. My guess would be that it's in the logic of the regulator.
The bottom line is .....for others that might think they have a wonky charging system, based on charging voltage across the battery terminals - before blaming the stator ,RR, connections, etc., - make sure you are working with a healthy, fully-charged battery. And before condeming the battery, do a leak-down test. It's very simple to do.
Cheers, Miles

 

[[email protected]]

Great advice on charging the battery. It is the first step in most electrical flow charts when testing the charging system.

As far as your "leak" test, did you just remove the - cable and put one lead of you meter on the - battery terminal and the other lead of your meter on the wire that connects to the terminal and set to mA and see if it was pulling any amperage?

 

[Miles Long]

Great advice on charging the battery. It is the first step in most electrical flow charts when testing the charging system.

As far as your "leak" test, did you just remove the - cable and put one lead of you meter on the - battery terminal and the other lead of your meter on the wire that connects to the terminal and set to mA and see if it was pulling any amperage?

Mike - Being an accomplished typist (I'm up to 4 words/minute), I'll simply type the directions from the Clymer manual. (Just don't be wondering what I'm doing with my other nine fingers while I do this)
Battery Current Draw (Leakage) Test
1. Turn the main switch off.
2. Remove the rider's seat.
3. Disconnect the electrical lead from the battery negative terminal.
4. Connect an ammeter between the battery negative lead and the negative terminal of the battery ( a diagram shows the negative probe of the meter on the battery post, the positive probe on the battery ground cable)
5. The ammeter should read less than 0.1 mA. A greater reading means a voltage draw exists in the system. The probable causes are:
a. damaged battery
b. short circuit in the system
c. loose, dirty or faulty electrical connections in the wiring harness
6. To isolate the fault to a particular place in the charging system, systematically disconnect individual circuits. If the current draw stops when a particular circuit is disconnected, the fault is in that circuit.

To me, "less than 0.1 mA" seems like an incredibly small leakage amount to be aiming for. Maybe some of the electrical gurus on this forum can shed some light on that, and maybe expand on the test procedure itself.
Cheers, Miles

 

[junglebiker]

I am dealing with a very similar issue. I got my 91 Vmax from a guy who had it for 15 years and took really good care of it. However, he hadn't ridden it much so he decided to sell it. After riding it a few weeks, I found that something wasn't on with the electrical system so took it to the Yamaha dealership - they figured it was the battery and sent me to a guy who they thought had one. After looking at things, he said the rectifyer/regulator was bad and replaced it. A couple of days later, it dies on the open road and I bring it back to be told the battery is shot, the rectifier is fried and the stator is no good. I replace the battery, the rectifier and they rewire the stator, and I am still losing the charge. I guess I have to replace the stator now.

 

[one2dmax]

I should have a few good used OEM Vmax units, A few OEM Venture units (higher output), and can get aftermarket units (good but not as good as OEM). Shoot me an email and I can price one for you.

Sean
[email protected]

 

[shawnlee]

can someone explain how to test the rectifier in very simple terms?

 

[naughtyG]

can someone explain how to test the rectifier in very simple terms?

- Remove the seat
- Put a voltmeter across your battery, set to 15-20V DC range
- Start your engine, rev it to 2000rpm or more
- Measure the voltage across the battery - you should see 14.5V (+-0.5V)
- If you see more than 15V, your Regulator/Rectifier is shot.

If you see less than 13V, let us know. There are a number of reasons for that, but usually it's not the R/R itself.