Stella - 1977D survivor, back on the road.

Grounding the battery box serves no purpose. Mikesxs sells a combo rec/reg unit that does not have a black ground wire, so their instruction sheet says to run a black wire from the case to a good ground on the bike. That's a poor design. Every rec/reg or a rectifier by itself, must have a ground connection and the product should come with a black ground wire from the factory.

Never confuse the XS650 with car/trucks electrical parts. Cars and truck electrical parts have always relied on the metal case of a light or other parts to provide the negative ground return to the battery. XS650......................no, can't do that, rubber mounted parts. Each electrical component on an XS650 must have a black ground wire that goes to a common black wire in the harness and/or directly back to the battery negative. No other ground is required. Yamaha does use a metal to metal contact for the turn signals/horn and starter push button switches (from switch housing to the handle bars).
 
MaxPete said:
On my combo reg-rectifier unit - in addition to the black ground wire in the units wiring harness, I actually drilled a hole in one of the cooling fins and used a self-tapping screw to secure a ground wire to it and to a big bolt nearby on the frame.

I was told by someone that the harness ground was not sufficient
and that a separate ground from the chassis of the device to the frame of the bike was also needed.

Pete
Click to expand...
Whoever told you the last statement is wrong. Once you have a proper ground return wire from a device, adding a second ground wire from the chassis will not electrically change anything.
 
TwoManyXS1Bs said:
*whew*, finally found it, RG.
About halfway in.

http://www.xs650.com/threads/first-fire-up-and-strange-noise-developed.45219/

And here:

http://www.xs650.com/threads/over-charging.45875/
Click to expand...
Oh yes, I do recall reading those. A couple of bad things there. He did put the rectifier in an enclosed box, and sounds like his heat sink was just a copper sheet or thin plate. Thin sheets or plates, such as 1/16 " or less should not be used. Much better to have a plate that is 1/8" thick. Then again, maybe he did receive defective rectifiers from China.
 
Hmmmmm....I don't recall for certain but I think that the Mikes combo unit did have a separate black ground wire in its harness AND it was suggested in the instructions to make an additional ground wire from the chassis. Anyhow - I did it and the things works perfectly so.....I guess it did no harm.

Pete
 
DanielBlack said:
Process flaw? Please elaborate.
Click to expand...

Oops, sorry Daniel. I inadvertently assume folks know about this stuff. "Process" is a somewhat collective term for the chain/sequence of manufacturing semiconductors.

http://www.iue.tuwien.ac.at/phd/ceric/node8.html

Unfortunately, not all dies (chips) perform properly, resulting in a batch "yield" of less than 100%. Also unfortunately, not all chip makers thoroughly test their product, and/or toss the rejects onto the "gullible American" marketplace. Let the customer do the Q/A (Quality Analysis).

For these rectifiers, this process would include thermal bonding to whatever heatsinking is provided...
 
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If crappy cheapo rectifiers do turn out to be the problem, maybe a bit better quality unit may be required? This is the one I've been running for several years now with no problem. I put another of the same unit on a local guy's 650 around the same time and it's still OK too.

http://www.ebay.com/itm/35-AMP-3-THREE-PHASE-BRIDGE-RECTIFIER-WIND-/261313978134

fG8Ap7x.jpg
 
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Thank you 5twins.

I just came in from a half-hour driveway charge system test after first double checking wiring, grounds, and rectifier bench readings.

Idling at ~1300 with a couple fans keeping things reasonable.

At start, cold engine, switch off. 12.88v at battery and at rectifier connector. Rectifier 81°F on the epoxy surface.

1 minute. 12.41v at battery, 12.42v at rectifier. 89°

2 minutes. 12.47v at battery, 14.21v max, 12.47v at rectifier. ~10.7v A/C across each of the three phases. 95°

5 minutes. 12.67v at battery, 14.15v max. 101°

10 minutes. 12.62v at battery, 14.09v max. 110°

15 minutes. 12.62v at battery, 14.07v max. 116°

20 minutes. 12.62v at battery, 14.01v max. 122°

25 minutes. 12.60v at battery, 13.92 max. 124°

30 minutes. 12.56v at battery, 13.85v max 125°

So as time goes by, both the idle battery (expected) and max charge voltages (problem?) began to drop.

The rectifier's temp started to settle down around 125°F, still not too hot, telling me the heatsink is doing something. At the end of these 30 minutes the rectifier measures good.

Grounds are good and solid. The matching voltages at the battery lugs and rectifier connector tell me the circuit between the two is clean and solid.

Any thoughts towards where I should focus my attention next?
 
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5twins said:
I've found the charging output will drop off some after the battery has replenished itself. Test the charge output right after electric starting. You might find it back up at that 14.2 output. What I'm saying is, maybe you don't have a problem at all.
Click to expand...
I was reminded that the dropping max charge voltage might not be a problem. Maybe all is well, I think I need to go for a ride. A good long one, but in a local, circuitous route.
 
After a good cool down I restarted her and checked voltages.

The battery had been sitting in the bike after the last round and I hadn't put it on the charger. Back up to 12.88v with the switch off. Cold idle 12.44v. After the valves quieted down I rev'd it for just a quick moment. 14.17v.

Things are looking good so far.
 
That's a good point, I'll get hard numbers next time. For now, I can say they didn't feel particularly warm compared to the epoxy center when I felt it by finger. Maybe 20m in.
 
You're doing very good, thorough work here Daniel. I'm holding my breath for you. I hope you've got this nailed down. I'll tell you one thing , after all you've been through, I'm ready to order a couple back up rectifiers just to have on hand, just in case.
 
A fully charged lead acid battery measures around 12.4 to 12.6 volts. However, if you have just been using a bench charger, the battery voltage may be higher, even up in the 13 volts area. Anything over 12.6 volts is just a surface charge, and is really meaningless. Once you draw some current from the battery, the surface charge disappears, because its a false indication.
Whether a battery measures 12.4 volts or 13.4 volts, tells nothing about it's ability to supply full load amps. The only real measure of a battery is a heavy load test, such as a starter motor.

How do you know if your charging system and battery are both working 100% ?
Bike has sat for 24 hours since last driven.. Measure battery voltage and it's about 12.4 to 12.6 volts. Start the engine using the starter motor, and engine should start immediately. Wait 3 or 4 minutes for the battery to recover from the starter current. Rev the engine to
3000 rpm of greater, and the battery voltage should be 14.1 to 14.5 volts.
 
DanielBlack said:
Thank you RG, but I'm not quite sure what in my recent posts of findings you are responding to.

Pete, I'm on it.
Click to expand...
Too much garage testing, and taking voltage readings every 5 minutes does not provide any real information. Get out of the garage and ride the bike out on the open road. You're focusing too closely on battery readings that will wander around and really mean very little. It just becomes an academic exercise. Too much testing is not what these bikes are meant to do. Every time you start the bike be sure to go for a ride and put on some miles. You need to get away from using a bench charger. As long as you ride 20 or 30 miles, your battery should be fully charged and ready for the next ride.
 

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