Regulator/Rectifier Upgrade

[LongDistance]

I've been frustrated with the charge rate of my Honda CM400. I even replaced the RR with a NOS OEM unit with no change. 15.5V is the top end of spec and I've been running 15.3+ most of the time. The wiring checks good with no voltage drops anywhere except a .02V one on the Black sense wire to the RR. After searching for a couple of weeks for a cure I decided to experiment with using a FH020AA Mosfet RR after reading thru this http://www.rc51forums.com/forums/showthread.php?t=6540 Found this one for a good price after checking the local boneyard for a used one http://www.ebay.com/itm/YAMAHA-SHINDENGEN-FH020AA-REGULATOR-W-CONNECTORS-REPLACES-FH012AA-/360635395542?pt=Motorcycles_Parts_Accessories&hash=item53f78b6dd6&vxp=mtr
Regulator got here and I've got the harness made so I can install tomorrow. I noticed that the wires coming out of the stator are 16 gauge but the RR wires are 18 gauge. I'm using 16 gauge going into the Mosfet RR.
New RR installed and roadtested. I'm a happy camper
Battery is new MotoBatt MB12U, charged on battery tender, sat for 1 hour to stabilze, 15-30 second load of running lights prior to each test
RED is the OEM regulator GREEN is the Mosfet regulator FH020AA
Started and running at 1200 rpm cold 14.8V....14.25V
Rode @5 miles in town charging at 14.1 to 15.5V....13.7V to 14.1V
Rode @5 miles freeway speed charging 13.5V to 15.3V....13.7 to 14.1V
Idle when done with headlight on 12.9 to 13.8V....14.0V
Battery voltage after parked 13.5V.... 13.2V
15 sec load w/o headlight 13.0V....12.8V
1 hour parked 13.1V....12.57V
These results say this is a good upgrade for stabile charge voltages and eliminating the excessively high charge rate found on the OEM regulator. Now to get it permanently mounted. The hole spacing is larger so I have to figure that out.

 

[mydlyfkryzis]

Honda would never fix your regulator. they all tended to be in the top of the spec. 15.0 volt +/- 0.5 is the spec. 15.5 is within spec.

The thing is, it's not the contruction of the regulator that makes a difference in that voltage. It's where it is designed to shunt. Honda always stuck to the higher end. Theoretically, Honda could of made the same regulator 14.5 Volt, by using slightly different voltage dividing resistors in the device.

A mosfet can be doing 15.5 volts if the resistors controlling it set it for that.

Mosfet run a little cooler, but for shunt type regulators, unless the heat is actually damaging something, it really doesn't matter. efficiency is not the goal when you are just loading the alternator to a ground source anyway.

Permanent magnet alternators are not regulated output like a field excited alternator. they put out everything they can. You regulate them by adding load. So if the lights are off, the regulator adds load when the voltage climbs by just shorting the output of the alternator to ground, in a controlled way.

So there is no real efficiency, in the sense that the alternator will reduce the hp load on the bike. You are essentially saving heat.

There are regulators that control the output of PM alternators by restricting the flow of electric out of the alternator. The problem with them is the AC voltage, without a load, climbs up higher. With a low electrical load, and high RPM's, the higher voltage can break down the resistance of the insulation on the stator. In theory, the voltage can go to infinity without any load, but in treality, there is always some load, even if it is inductance or capacitance to ground. the volts can get high though.

I have the Kohler CLone type regulator, that is keeping things to 14.5 so far. Good enough.

 

[crazypj]

I have NEVER had an issue with CB/CM 400 twin regulator/rectifier.
They were so good I fitted them to load of different Suzuki's, Yamah and a few Kawasaki's (even a couple of other Honda's)
I still buy them when they come up on 'feepay'
The CB/CM400 has a really good charging system, fit a higher wattage headlight bulb ;D

 

[mydlyfkryzis]

At 1200 RPM, my CB360 isn't even doing 12.7 volts. It's dragging the battery down. The regulator doesn't even do anything till 14.4 volts. Wish the CB360 had output like the 400, 14.8 volts at idle? Sheesh...That's a great system.

If I idled for 15 minutes, the battery would be dead and the idle gone...

 

[Bert Jan]

At 1200 RPM, my CB360 isn't even doing 12.7 volts. It's dragging the battery down. The regulator doesn't even do anything till 14.4 volts. Wish the CB360 had output like the 400, 14.8 volts at idle? Sheesh...That's a great system.

If I idled for 15 minutes, the battery would be dead and the idle gone...

Karma. You should not idle a bike. BRRAAAAPPPPP

 

[crazypj]

I fitted a CM400 reg/rect to Brendon's bike Saturday, 13.6v at idle, 14.52v @5,000 (also fitted LED headlight bulb for less draw)
Reg/rect is wired direct to stator and battery, I'm sure that helps with voltage losses