WTH is going on with this charging system? I know...discusse
 

d before but I can't seem to find out what the problem is.

2000 model.
New battery.
Used rectifier/regultor that supposedly was tested by E-bay seller with impeccable rating.
Stator output is 70+Volts AC.
Charging at 13.5 +/- at idle, but voltage drops to below 13 at 5000 rpm. (per testing instructions.)

Prior to new battery and changing out the rec/reg, this system was charging at 13.0 +/- mostly - at idle and to below 12 during rpm increase. This is on a friends bike and I am at wits end. I have searched through the forums but have not found this particularly selection of symptoms. No leakage above allowed amounts so grounding doesn't seem an issue.

My meter is a standard digital VOM with mA but no 'diode check' plan on trying the test light in series with power source but if anyone has any other ideas on how to test the rec/reg I would gladly entertain any thought, up to and including voodoo.

Thanks.

Do you have a charging fault now, or is it just that you're wondering what's happening when the voltage level drops?
If you have no fault, then there's nowt to worry about, as long as the battery is sufficiently charging don't fuss over the numbers.
If you are having trouble with the electrics, is it that the battery discharges whilst in use, (insufficient charge), or does it discharge whilst not used, (current leakage)?
Even if you don't trust your meter's accuracy it doesn't matter, what you really need to look for is that the battery voltage rises by at least a volt when the motor is running compared to when stopped, in all circumstances.
Standard SV reg/rec units are poor quality*, better to replace with one from a Kawasaki or a Honda, these will have a sixth wire that isn't present on the Suzuki one, it's a voltage sensor which gives a more 'real world' picture of system voltage than just sensing charging level at the battery.

*Which is strange as the ones found on all Kwaks and most Hondas are made by the same company, Shindingen, which makes the Suzuki ones, I imagine that they are made to the spec Suzuki request, whatever, they often don't live long, and don't work that well during their life.

Your new RR is toast, your charging system should be putting out 14+ volts at anything above an idle.

The charging system isn't doing it for sure, but it could be the alternator windings that are at fault. Disconnect the alternator from the RR and test the resistances:

between all three wires in pairs, should be a few ohms
between each wire and ground, should be open circuit

If this is okay, start the motor and measure the AC voltage across each of the pairs of wires, I think at 5000rpm it should be over 75V (or whatever the manual says). If this is also okay the the alternator is fine.

Like Sid says, as long as the voltage goes up 2-3V when the motor is on, you should be fine, it could be your meter. Does the manual have a test table for the RR?

This also may help:

http://www.bikeguru.fsnet.co.uk/alternator.html

Yep.
 

I'm really leaning towards both of the rectifier/regulators being bad. The stator coil resistance tests out okay and with output being greater than 75volts AC @5000 rpm.

Thanks alot for your input!

Have you tested this on your own SV? My SV puts out 13-13.8V, have never seen it above 14V. I thought the RR was defect as well, replaced it with a new one and the charging voltage was the same...

Er, are you having problems with the battery going flat? You haven't said so above. Have you got an alarm or something that is still connected? The odds of having two duff RRs is pretty small, they are quite reliable but obviously some do fail. Also remember that the battery has internal resisitance and the effect of this is greater at higher current. Apart from the voltage dropping as the revs go up, anything else wrong?

I have exactly the same symptons as scarredpelt, sometimes the battery stays charged during use, sometimes it will flatten itself (the lights have to be on for it to do this).

I have tried a secondhand RR and it was slightly better, but not great.

Talking to my Dad (who is an electronics engineer) I have come to the same conclusion as Sid Squid - the standard Suzuki RR is crap.

I am going to get a proper one off a Honda or something and see what happens.....

Sorry guys, I know ya'all must love your SV but for some reason, I just don't feel as comfortable on one as I do scraping the pegs on my Goldwing. 8)

The bike belongs to a friend. He hasn't had any real trouble from the bike since he got it at the dealership he used to work at. (Honda) They had put in a new battery, the wrong one incidentally, and it worked great for about 2 years. It isn't a daily rider, and he has made quite a few modifications to it. The mods really shouldn't have had that much affect on the electrical system but there were some changes to the signals, and at one time he had some kind of jury rigged twin headlight system that has since been replaced with the stock one.

About a month ago now he had to bump start it in the parking lot at work to get it home. When I tested his voltage, it read 12.5 volts. During the load of starting, the voltage dropped to below 3 volts. Seemed pretty obvious to me that it was a battery problem and we replaced it; but not before jump starting the bike to test the charging system.

For those of you who don't know, a bad battery can really screw up a good charging system and can cause incorrect readings. So when I got the voltage drop during the 5000 rpm test I was really sure that the battey was bad. When my friend replaced the battery I wasn't there when he tested it, but he said that the system never got higher than 13.87 and immediately dropped on the 5000 rpm to low 12's volt range. That's when we got the salvaged RR and hooked it up with some voltage improvement but not enough for even government work.

To reiterate:
Battery leakdown test is within specs. <1 mA (.3mA is what I read.)
Battery holds to above 11 volts during start up load. (new)
Stator coil voltage output is above 70 volts AC and resistance across windings and to ground is withing specs.
Voltage charge at idle is between 13.2 and 13.8 regardless of electrical load. (i.e. High Beam, horn and brake light active.)
Voltage charge at 5000 rpm is below 13 volts regardless of load.
All charging readings are from the 'new' RR but are slightly improved over the old one. (tenths of volts)

So me buckos, where to now?

There is a 4-page PDF of charging system fault-finding at www.electrexusa.com look under tech support (link on the left), I briefly skimmed this but didn't tell me much. Have you ruled out grotty connections? Poor connections between the battery and the charging system + and -? Since replacing the battery has it gone flat again, or have trouble being charged? The first battery was definitely scrap if the voltage dropped that far on starting, but at the moment, is there still a problem? As well as the alternator/RR producing more juice for charging at higher revs, the ignition system is also gobbling it up at a greater rate, and I reckon there will be a bigger internal voltage loss in the battery cos of the higher current. Only other thing you can do, apart from ride it and see if the battery goes flat, is try to get hold of an ammeter to measure the charging current. I don't know what this would be but it will almost certianly be over the 10A that most multimeters measure (alternator will be 250W or so I think).

Er, does this help?