What should a good battery voltage be?

sounds exactly the same as my problems. i however went the opposite way and got a battery first instead of the reg/rec. all the figure you have quoted are roughly the same as mine. I cleaned all the contacts up on the reg/rec and sprayed them with wd40. cable tied them together so they couldn't come apart and mine has had no trouble starting since, however the voltage readings haven't changed. Can you let me know what you come up with to sort you problem.

cheers

andy

[yorkie_chris]

All well and good talking about battery acid testers etc. but aren't the SV batteries supposed to be sealed units?

In my experience with car batteries, all battery hydrometers are good for is distributing acid all over your toolbox, after telling you the batterys goosed just like you thought in the first place!

Well, I took martin_SV's suggestion and tried the tests with a known good battery (car battery) and the results were identical (minus a couple of hundredths of a volt, probably due to the jumper leads). The car battery registered 12.6V with the ignition off. When connected to the car with the engine running it registered 14V, whereas on the bike it only registered 12.1V with the engine running. While the car battery was connected to the bike and the bike engine running I disconnected the bike's starter solenoid to see if that was drawing any current but it had no effect on voltage. With the bike battery re-installed I then measured the current draw on the battery under various conditions: 1) ignition off - no current, 2) ignition on, low beam on - 7A, 3) ignition on, high-beam on - 9A, engine running and low beam - 7A, engine running and high-beam - 9A. Needless to say my meter wires got quite hot during this time. Still not sure if these results are normal, but the only things not replaced now are the stator and the wiring. I have checked all the fuses but is there anything else I can test in the electrical system?

What stands out to me from your most recent tests are the current readings. Getting the same (negative) current readings even when the motor is running then clearly for some reason the power from the alternator is not getting through. I cant say I know why this should be but clearly this is why you're battery is running down after a day or so usage. Is there any way your new reg regulator has been wired in incorrectly? I imagine not as I guess there's a mutli connector brick utilised. That my only guess at the moment. The only other point of comment is the fact that you did manage to get a more normal "on charge" voltage (14.1v)when you were using a known good battery. If you remember my comments about high internal resistance in an otherwise apparently within spec battery. As other have said subsititution is often the easiest approach. The final test i could sugest is to check whether you get a positive current flow to battery with engine runnign at 4-5k when using your known good battery. ie the car batt.
Good luck!!!

Something to add as Just read your post again, re: are these results normal?
No!, The engine running currents should be positive.
B) the values obtained ie -7a and -9a engine stoipped are probably about correct, they equate to a draw of 84 and 108 watts respectively ( watts =VxA. Not sure whether both filaments light when on main beam but if yes then again this sounds vaguely right. but not exactly as hlight bulb filaments are 55+55 if I recall correctly.
Don't give up!!

HTH Martin

Actually, the 14V reading was only when the car battery was connected to the car charging system (so the car is charging the car battery fine, but the bike does not charge the car battery when its connected). When connected to the bike, the car battery never got above 12.3V while running at 5k RPM. Neither was there ever a positive current flow to the battery using either the bike or the car battery (I measured the current to both). As mentioned before the alternator test showed good voltage from all 3 wire pairs and the connectors to the R/R are the standard block type. Also, I now have 3 R/R units that all exhibit the same behavior when connected. Looking at the wiring diagram I see that the only components between the alternator wires and the battery are the R/R and the starter relay. According to the diagram the relay has a fuse and a feed to the starter solenoid. I'm not 100% sure but I think this is the junction box under the right side of the seat that has a green plastic cover over it. It's certainly the only place I can find a fuse that isn't in the fuse box. The fuse itself looks good but maybe there's something else going on in that box that is causing a high resistance and causing the low voltage at the battery. I would think that if that circuit was open (i.e. blown fuse or broken wire) that the battery voltage would show no sign of increasing with RPM. Since I'm getting an increase from 12.1V (@ idle) to 12.3V (@ 5k) I'm assuming that some current must be getting through the relay. Now... how to test the relay...

BTW. I have high-powered bulbs installed so that would account for the higher current draw.

sounds exactly the same as my problem. i got a new battery first and then a reg/rec. My battery reads 13.6 when fully charged, drops to 10.5 when starting, and gets back to 12.3 ideling and if I rev it to ~5000 rpm it will get back to 12.5. If I unplug my headlight fuse I will get 12.8v at an idle and rev up to 13v. Both of my reg/reqs behave the same. I tested the alternator and it pumps 60v ac at ~4500 rpms under no load. I have tested the continuity on all of the wires I can get my hands on and sprayed cleaner on all the connectors. I wonder about that starter relay as well . . . please let me know what you come up with,

brennan

OK. Here's the latest test results... I checked the continuity through the starter relay (red wire from harness going into the R/R) to the +ve battery connector (battery disconnected) and it showed 0.2 ohms, which is good, so I think we can rule out the starter relay. Then I went back to testing the stator coils and I think I may have found something. I tested the coils by measuring the resistance across each of the yellow wires (3 combos) and found that the resistance was outside of range at 0.8 ohms (specs say 0.2 - 0.7 ohms) but the biggest revelation was that the test for continuity between each of the 3 wires and earth also showed a resistance of 0.8 ohms whereas the specs say that this should be infinite! I'm now fairly certain it must be the stator assembly although I am puzzled why the no-load test on the coils shows good voltage (65V at 5k RPM).

[Spanner Man]

Morning all.
It sounds as if you have located the problem, though I believe at my suggestion you have tested for earthing of the alternator before. It is possible that if you did the test with the engine cold your meter would show infinite resistance, but the alternator coils are breaking down when hot.

I have seen plenty of alternators that have the specified AC output, but wont charge due to an earth leakage. Frustrating things electrical components.

Cheers.

I'm a Mechanical Engineer so am on shakey ground here but could you "mega" the stator coils to confirm any insulation breakdown?

I assume that you would need to disconect the alternator from the bike entirly

I'm sure a sparky will come along and confirm this one way or another