over charging.

cruzin

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I put a dc meter on the bike just one of those from ebay sent in from china. It seems to hold close to my multimeter. My voltage seems to run around 14.2 or so. Isn’t that a volt or so high?
I checked the alternator had .6 on the leads. If I just turn the key on the volts meter comes on and tells me my battery has 13.6 vdc sometimes. Today it was a strange thing, I started up the bike and volts gage showed 13.3 at idle I idled it a while the revved it up just a bit and volts showed 14.2 or so on gage and stayed up in the 14's any thought on this.
I have stock alternator vr-115 and 3 phase rectifier. I ohm out the rectifier same as I checked alternator. the diodes are fine. I just checked the ac output of the alternator and it was 15 or so volts at idle and went to high 40's or 50 when I ran the rpms up to 4000 or so.
Any thoughts as to whats going on? thanks
 
14.2 volts while running at anything much above idle is ideal.
Your charge voltage needs to be about 1.5 volts above what the battery voltage should be. 12 volt batteries run about 13.5 or so when fully charged. It needs the extra voltage to overcome the batteries internal resistance.
At idle the rotor isn't spinning fast enough to have the alternator put out it's max. Atidle it puts out enough to counter the draw of the rotor and ignition. This gives you a reading of about battery voltage.
Once up around 1800 to 2000 rpms it reaches high enough rpms to do it's job. At this point the reg starts to control the output to keep the voltage at the 14.2 volts. It shouldn't go higher at any rpms.
If the voltage gets much higher, like 15 volts or so it is getting into the range of overcharging. At this voltage running the headlight will help keep the charge voltage down a bit. upgrading the headlight to a Halogen bulb headlight will help even more. It draws a bit more current.
if your bike keeps the voltage up at the 14.2 range I would recommend the halogen bulb headlight. Much brighter, more light helps you see better as well as be seen better.
Leo
 
well I guess I wont be so concerned about the 14v. Ive been using those cheap 3 phase rectifiers and with the radio shack stores closing I found a store in Saginaw mi still open and bought 4 of them. Im on my 3rd rectifier so I guess I keep expecting to have another problem with the quality of them lasting. I started to wire up a pair of the radio shack ones last night and will have them ready. to put into the system. thanks guys. Hope the weather has been better out west for ya 2m.
 
... Ive been using those cheap 3 phase rectifiers...
... Im on my 3rd rectifier so I guess I keep expecting to have another problem with the quality of them lasting...

Fully understand and agree. Once burned, ...etc.

... Hope the weather has been better out west for ya 2m.

It's been great last few days. We have what folks call "different" weather.

If you don't like it, tomorrow it'll be different...
 
the first one only lasted a few start up. It was smoking from the start, the second one did not last a week, The ones i was using were the 2 for 6 bucks shipped from china. I think 25 or 30 amp. After the first one fried ordered a 50amp one. It still seems to be working ok. But like I said I did track down some radio shack ones. I liked the ones that were 3 phase but I can live with these. I probably just got a bad batch when I bought my first ones. If yours is working good I would not worry to much if you been running it that long.
 
cruzin what kind of heat sink are you using? And you are using a thermal paste/grease?
 
3"x5" x.25 chunk of copper with thermal paste. The first one started smoking around the positive terminal within moments after I first fired it up. The second one started low output within a few days of putting it in. And I was not riding it like a daily rider. I had just got the bike together and checking things out. I think I just got a pair of bad ones from the same seller. The last one I changed to has not been a problem so far. I was just curious about seeing 14.2 and 14.3 voltage on my gauge.
 
Recently I have been reading up on regulators and what is normal behavior with the charge system. The mystery I cannot get my head around is the role of the regulator in relation to overcharging.

I have an 81' SH and have replaced the rectifier/regulator with a DIY version that controls at 14.2V as opposed to 14.5V for the stock system. I run a 35W H4 bulb which lights as soon as the engine is running. My battery always seems to be fully charged and the electric start runs nicely. I have a voltmeter fitted to the handlebars and find that when ever I am above 1500-2000rpm the voltage stays constant at 14.1-14.3V, but most of the time it is 14.2V.

Does this mean I am overcharging my battery or is the 14.2V the consequence of the electrics/headlight constantly draining power?

If I were to disconnect the headlight would, or should, I see a different behavior from the regulator? With the lower power drain will the regulator drop the charge voltage when the battery is fully charged like an intelligent battery charger does?

Just how will I see signs of overcharging?

I would appreciate hearing any ideas/views - Thank you,.
 
Oboy, a simple question. ........not.

Regulator manufactures set the voltage point, and can vary across types.
The regulator does its thing based on the voltage it sees. If it's downstream from other current drawing devices, it could be seeing a low voltage, and overcharge to compensate.

The battery voltage is known only to the battery, unless the voltmeter is tied direct to it.

Otherwise, the voltmeter will report voltage at its connection point.

Voltage drops across wiring and connectors add to this mess.

An interesting trivia item. In the general (civil) aviation world, folks were curious why panel lighting called for 14v bulbs, but wingtip and tail lighting called for 12v bulbs. The voltage drops in the long wiring to those remote zones created the strange bulb callouts...
 
The mystery I cannot get my head around is the role of the regulator in relation to overcharging.
...
Does this mean I am overcharging my battery or is the 14.2V the consequence of the electrics/headlight constantly draining power?
...
If I were to disconnect the headlight would, or should, I see a different behavior from the regulator?
...
Just how will I see signs of overcharging?
The regulator has two jobs -- line regulation and load regulation. We're only concerned with load regulation here, What load regulation means is regardless of the current draw of the load the output voltage stays the same. The more it stays the same (and faster it stays the same) the better the regulator. As a consequence nothing you connect or disconnect should affect the voltage at the output of the regulator, up to the load rating of the regulator.

The battery is a separate issue. It's designed to see 14v or so all the time, so there's no problem there.
 
Even though I have the earlier charging system ('78), it puts out pretty much the same as yours. I have the DIY reg and rec as well. You didn't mention it but my voltage drops off by a few tenths after about 5 miles of riding, I'm assuming after the battery has been replenished. I start out seeing 14.2 or 3 right after (electric) starting then that eventually drops to the high 13's or right around 14. Even if kick starting, I get the higher output for a while at first. I assume this is replenishing the battery's loss from being parked for a few days or a week.

All of the above is running with the headlight on. I have a 55/60 halogen. The only L.E.D. I run is the tail/brake light. My model also has a (now) functioning headlight on/off switch. If I turn the headlight on and off at idle, I see a pretty big change on the voltmeter, a good half volt. Running down the road, turning the headlight on and off seems to have little, if any effect on the voltage output. I guess the charging output is able to deal with it no problem.

I assume my small drop in output voltage after running a few miles is normal. It's always been like this, even when I still had the original mechanical regulator. I figure that's what a regulator is supposed to do, regulate, lol.
 
Thank you Guys. Can I then conclude that the 14.2V as set by my regulator is just not high enough to cause overcharging damage? Hence my battery is happy to sit connected to a 14.2V supply for several hours while riding.

I have noticed an issue with my DIY regulator recently with occasional voltage fluctuations to lower voltages so today I am rebuilding with a new Fiat regulator. Hopefully I will get to test it this weekend unless I am too sore following my kidney stone treatment in hospital tomorrow.
 
In my search for regulators I have seen preset values from 13.8V up to 15V. I also saw a couple that can be custom set with a little dial - probably a little variable resistor (the old style regulators could also be adjusted). When I ride in the cold my present regulator favors 14.3V and 14.1V in the hot weather.
 
my battery is happy to sit connected to a 14.2V supply for several hours while riding.
They all are. Read some theoretical article about lead/acid batteries to see why they can sit at 14+ v but revert to their nominal voltage when the charging is removed. I know litle to nothing about batteries but I know all I need to know :)

Regarding the not exact 14.2 v, there are tolerances, including with the battery. If you were really into it you could find out the biggest difference that's acceptable, with a little research. Trying to hit 14.2 exactly would be kind of nuts. Choosing 14.2 to start with might be too, depending on how you got there.
 
I noticed the slightly higher output in cold temps on mine too. Again, I'm thinking it's just another normal occurrence. I also noticed the different set points on various units. I have an actual VR115 on my bike but I have also set up and tested some equivalents (NAPA VR1010, Ace VR1760). All seem to have slightly different set points. They're all close, within a couple tenths of a volt, but they do differ.
 
As a regulator heats up, its internal resistors increase in resistance, and that changes its internal voltage reference value.

Well designed regulators have some sort of temperature compensation, built into the internal voltage reference circuit, as a thermistor with the reference zener diode circuitry.

http://www.xs650.com/threads/stella-1977d-survivor-back-on-the-road.47329/page-27#post-499073

Note thermistor "R2" in the Delco documents.
http://www.xs650.com/threads/xs650-...-and-regulator-units.48291/page-2#post-489612

If you're experiencing disturbing charging voltage swings between cold and hot operation, you could spritz a little water mist on the suspect regulator, to cool it off, and see what charging voltage results. If significant, or unsettling, may want to pursue another brand/type of regulator, or redesign the mounting, enclosure, airflow, to enhance its cooling.

It's been a long time, memory challenges, but I seem to recall that you want reduced charging current (hence voltage) when the battery warms up, because its chemistry is more efficient at temperature, and to avoid boil-over...
 
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I run volt meters and have seen differences of more than half a volt between stock solid circuit regulators in direct swap outs. (electrical parts testing)
IMHO anything above about 13.5 and below 15 is "acceptable".
 
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