Steve Saunders Goldwing Forums banner

Status
Not open for further replies.
1 - 14 of 14 Posts

·
Premium Member
Joined
·
275 Posts
Discussion Starter #1
imported post

Hi guys, bet this is easy for everyone but me.

I have a digital voltmeter tucked deep down where I can see it from the right angle. As the bike sits there now, it reads 12.1 volts.I believe I've seen it as high as 14 before, and certainly down in the 9's.

So, what do these readings mean for me? I'm pretty sure it has to do with battery condition?

Thanks! Just learning some basics here.....
 

·
Premium Member
Joined
·
542 Posts
imported post

Mine runs around 13.5 and change under normal running conditions. If yours runs in the low 12 range or lower you may have a stator issue. Do you have any asessories pulling some volts?
 

·
Premium Member
Joined
·
275 Posts
Discussion Starter #5
imported post

Thanks all......checked into that article, thanks Rudy.

Still wondering, dumb as a post.....what do the numbers mean? They indicate what's in the battery, what's available, what the battery can output? Why does it change from idle or off, to when it's under a load? Doesn't it change at various speeds and as the bike asks for more?

And is there a way I can check the stator, as suggested?

Appreciate your patience, guys.
 

·
Premium Member
Joined
·
542 Posts
imported post

I believe it's the volts coming from the stator. Not 100% sure.
 

·
Premium Member
Joined
·
200 Posts
imported post

Someone with more time right now will probably give a more detailed explanation but here's my quick and dirty one.

Cruising down the highway you should see 13.8 to 14.2 although a couple tenths higher or lower is OK.

As you're cranking the starter it'll be down around 9 to 10.

Setting in traffic with cooling fan running and engine idling you should see around 12.

After the bike sets unused for an hour or more you should see 12.6 if the battery is fully charged.

Q
 

·
Premium Member
Joined
·
542 Posts
imported post

That sounds about right with the way mine runs!
 

·
Monkey with a Football
Joined
·
19,237 Posts
imported post

Ok I have a little more time right now...

Your battery is naturally 2 volts per cell with 6 cells making up a 12 V battery.
To charge a battery you must supply a voltage higher than the 12 volts to get current to flow into the battery. Very similar to a bucket of water that needs the filler to be higher than whatever the water level is to make it rise.

If the voltage is too high then the extra energy is given off as heat since the battery wants to naturally be at 2 volts per cell.

Your battery is just a tank like you read on my page. What fills the battery is your alternator.

Your alternator is similar to a motor that is being forced to turn and as a result converts mechanical energy to electrical energy by turning wire through a magnetic field. Because the wire part is what is being turned, that energy needs to get to the non turning part so it can travel through wires to the battery to charge it. We use brushes inside the alternator to pickup this rotating energy and get it across to the non-turning part of the alternator so we can use it. These brushes wear down with time and while they are wearing down they are shedding bits of them away in the form of carbon dust (and other crap). This dust can get in the way of keeping the brushes in contact with the rotating part (the armature) and cause alternators to vary how much energy is getting transfered.

Also, the slower the alternator turns, the less energy is being put out from it. Sometimes this is less than the rest of the system needs to run itself and sometimes it's more than needed.

The battery, acting like a reservour lake for the energy, fills up when more energy than is needed is produced and loses stored energy when the amount of energy being created by he alternator is less than needed.

The battery charges when you get more flow into it than it is currently holding and discharges when the flow is less than it's current state.

All the while there are demands by the bike for the energy being stored and generated. These demands vary between little ones and large ones. Some demands are constant and others periodical. The starter is a good example of a large periodic demand. The headlight is an example of a large periodic demand. The clock on the dash is an example of a very small regular demand, and so on.

The demands (or loads) are designed to function at specific minimal voltages. Like the starter has a real hard time around 10 volts, as does the ignition system which wants energy at the same time and may not be getting enough. Headlights get very dim around 10 volts also.

So as a rough referenc guide let me put a few things out there voltage wise that I think you may be seeking:

AT:

Below 10 volts, most systems fail to function
10v - The bike may run (if already running) but not start if stopped
11V - Everything will probably work but starting may be iffy.
12V - Everything works as designed, demand wise
13V - Battery charges acceptably
14V - Battery charges very well
Above 14 V Battery will charge and everything work but you may be boiling off battery fluids due to heating the cells with the extra energy
Above 15V you probably have a bad regulator in the system and things will begin to fail due to overvoltage.

Batteries settle to their natural voltage quickly when the supply is removed and the loads pull them down. After that they tend to hold the natural cell voltage as long as the cells can continue to convert the stored chemical energy into electrical energy. This diminishes with age due to the plates in the cell getting smaller from charge and discharge cycles.

Also battery size matters compared to the demands of the system because the smaller plates on a small battery can't convert as long for the same load seen by a larger battery. There are other factors as well but these are the major concept ones for this discussion.

So is it ok to run under 12 Volts? Sure, depending on how long you will be doing it before a charge can restore the system.

But a voltmeter on a bike isn't to monitor the battery voltage. It is to monitor the alternator output voltage, measured at the battery. You expect voltages to drop down when going slow. But you mainly want to learn the normal voltages the alternator produces when going through its paces. It is this abnormal behavior you are really looking for, not a voltage at any random time.

If you are not putting out a normal charging voltage that you know you normally do running 60 mph in 5th gear, it is a cause for observation. Same with idling although not so much but if you idle at 11v normally and you are suddenly seeing 9V, it is worth investingating.

Hope that clarified some of the concepts for you.
 

·
Premium Member
Joined
·
200 Posts
imported post

Just a couple things. The GL1000 doesn't use brushes and I'd be real surprised if the 1500 uses them (but it's possible). Instead they use a permanent magnet brushless alternator. A car alternator has brushes and slip rings so the regulator can vary the current to the rotor in order to control the output. The PM alternator is full on all the time so the external regulator either shunts the excess to ground or disconnects it. In the 1000, one pole is shunted to ground as needed.

Also nominal voltage for a common lead acid battery is 2.1 volts per cell, so 12.6 is what you'll see in a charged and rested battery.

Q
 

·
Monkey with a Football
Joined
·
19,237 Posts
imported post

That will be a relief for all those 1500 owners who have brush related problems then. :cheeky1:
Thanks for the correction on the lead acid voltage. :waving:
 

·
Premium Member
Joined
·
275 Posts
Discussion Starter #12
imported post

I appreciate everyone's help in understanding this. As usual, Rudy is a wealth of information. I do marvel at his knowledge and understandingof technical matters.

Thanks for the time you gave in providing all this information! I have a better understanding, seeing as how it's a sort of early warning system concerning the alternator, and perhaps the battery as well.
 

·
Premium Member
Joined
·
200 Posts
imported post

Damn! Guess I've been out of the motorcycle service business too long. Next thing you know they'll come out with fuel injection and tubeless tires!

Q

Rudy wrote:
That will be a relief for all those 1500 owners who have brush related problems then. :cheeky1:
Thanks for the correction on the lead acid voltage. :waving:
 

·
Monkey with a Football
Joined
·
19,237 Posts
imported post

Q wrote:
Damn! Guess I've been out of the motorcycle service business too long. Next thing you know they'll come out with fuel injection and tubeless tires!

Q

Rudy wrote:
That will be a relief for all those 1500 owners who have brush related problems then. :cheeky1:
Thanks for the correction on the lead acid voltage. :waving:
Don't feel too bad. I had a can of PJ-1 Sperm Oil chain lube with Moly get loose in the garage the other day. I haven't had a chain on a bike for about 35 years.
Did I throw it out? Of course not. :cheeky1:
 
1 - 14 of 14 Posts
Status
Not open for further replies.
Top