Charge voltage

[30yearoldjunk]

Check the other vehicles on your place. Could be your meter is off.

[Duane Ausherman]

George, where did you get the idea that the original mechanical regulator was set for 13.8 VDC? I am here to tell you that that isn't correct. They were set all over the place. We adjusted them to 14.0 to 14.2 depending upon the owners riding habits.

Even this test of the charge voltage can show a false positive. Suppose that the battery is old and fully charged up it may still not be able to properly turn the bike over.

The term "fully charged" has little meaning, as when it is new it can be thought of as 100%. As time goes on, the capacity degades fairly well in a straight line. A battery can be "fully charged" but only has 10% of its original capacity.

Once the resulting capacity gets down to a certain level, it just won't do the job. The appearance to the owner is that it went bad overnight. In actuality the total capacity was failing lower and lower all of the time, but wasn't noticed until it fell below the threshold.

I think that there are a lot of "old wives tales" around batteries that easily mislead many.

One that comes to mind is the rule "Never put a battery on concrete, as it will discharge it." How much leakage do you really think happens through the case? Not much. Even if that were true, don't you think that all of those highly conductive battery boxes made of steel would drain it faster than the slightly conductive concrete?

When presented with this logical arguement, I always hear, "My daddy told me that, so it must be true." Oh well.

[Major Softie]

One that comes to mind is the rule "Never put a battery on concrete, as it will discharge it." How much leakage do you really think happens through the case? Not much. Even if that were true, don't you think that all of those highly conductive battery boxes made of steel would drain it faster than the slightly conductive concrete?

When presented with this logical arguement, I always hear, "My daddy told me that, so it must be true." Oh well.

I've always wondered about that one, and where it came from. Even as very a young teenager (when I first heard it), what relatively meager electrical knowledge I had told me that this didn't seem to make any sense.

[George Ryals]

Duane, Chuey's question was what charging voltage should he have to be "in the ball park" not ,would his battery turn the bike over.

Every unmodified airhead voltage regulator(6)I have tested on my bike has regulated to 13.8 volts, maximum. I guess I should have added "battery in good condition" and fully charged to get a fair test your charging system.

[Duane Ausherman]

Every unmodified airhead voltage regulator(6)I have tested on my bike has regulated to 13.8 volts, maximum.

We found the same thing, but some were down to 13.5. Putting in the word "maximum" changes things quite a bit.

With a fully charged up battery, once it has been started with the electric starter, the battery is no longer charged. Running it at mid range will charge it up fairly quickly. By watching the needle on an analog meter will show when it just isn't going to reach a higher number.

Just because a digital meter gives the reading with decimals, doesn't make it more accurate. You are just happier to have more significant digits and therefore believe the reading.

I like using a digital in parallel with the analog meter. A digital meter won't show odd changes the same way an analog meter will.

[lrz]

Slightly OT, if I may.

Duane-first, I hope you're feeling better & getting some answers/info about your health.

With a fully charged up battery, once it has been started with the electric starter, the battery is no longer charged. Running it at mid range will charge it up fairly quickly. By watching the needle on an analog meter will show when it just isn't going to reach a higher number.

Re: the voltmeter & battery charge; I just installed a new battery in my work van. The previous, and original(2003) battery would have the dash voltmeter showing above 14v after startup, right at 14 while running. The new battery never shows 14, let alone above.

My immediate thought was that this battery, w/ much higher CCA, simply wasn't losing that much at startup and therefore was not requiring much of a re-charge. Your last post seems to corroborate this. (?) I do wonder, though, why I'm not hitting 14v at all.

[George Ryals]

Duane, I use a very large analog voltmeter, one tenth of a volt is easily measured.

[Duane Ausherman]

George, you have one of the good ones and I am jealous. In school we had a very old voltmeter mounted in an oak case that must have had a 9 inch dial. It was nicely damped and a wonder to use. I doubt I could afford one now.

Irz, I would put a meter on the battery itself to make sure that you have around the usual 14 volts. You really can't trust one of those built in meters. Who knows where they take off the leads for the meter. Who knows if the meter is even accurate.

That said, I would expect the new battery to have similar characteristics as the old one. Your engine takes the same amount of energy to start it as it used to, so that is a constant. If this new battery is the same physical size as the old one, then it stores about the same amount of energy.

It is more likely that the new connections to the new battery are the difference.

Higher CCA (cold cranking amps) may be better, or worse, depending upon what a person wants most. A battery with higher CCA just means that it has thinner plates. Which is another way of saying that it has a greater surface area. That means that it can discharge at a greater rate. It has huge downsides too, as there is no free lunch.

Assuming that the new battery is the same physical size as the old one. The plates are thinner and the material will wear off faster. They will be more prone to warping, as they can get hot faster. This risks an internal short, which is a common failure mode in any lead acid battery. More warping can cause more of the crud that collects on the surface to fall off. That stuff falls down to the bottom and builds up to eventually cause more trouble.

All of this info is very old, so modern technology could well obviate some of it. In other words, I haven't learned a thing in a long time.

[Chuey]

So your voltage regulator checks out?
How are your diode board grounds?

I am going to try to learn what to do to check the voltage regulator. All connections mentioned are in excellent condition. I made my own solid mounts for the diode board. I added a Rob Frankham grounding harness. The slip rings are bright and shiny. The brushes have plenty of life left. The battery is brand new and was fully charged.

Chuey

[Chuey]

What is the procedure for checking the Voltage regulator? I made mine look all sharp and newish but know nothing of how to check it.

Chuey