Topic: Replacement Regulator/Rectifier CHEAP

[eideteker]

Battery pos to black - 12v with switch off, 0.4v running
Battery neg to green - about half a volt +/- .02v, RPM-dependent

Per the original post, I only have these wires hooked up:

From left to right with the terminals facing you:
1 - Battery (+)
2 - Field
3 - N/A
4 - Ignition
Case - Ground / Battery (-)

The original Honda green wires aren't currently hooked to anything.  After some searching I tried running one of them to the case of the regulator, and the voltage still climbs to 16v.

[TwoTired]

With key switch on and headlight on, place the black voltmeter probe on the black wire supplying power to the regulator, and the red probe on the battery POS terminal.  Report reading.
 Next, under the same conditions, place the black meter probe on the Battery NEG terminal, and the Green wire connection to the Vreg.
Report reading.
Next place black probe on the Battery NEG terminal.  And the red probe on the Battery POS terminal.  Report reading.

Make sure the battery post to battery cable connections are clean and shiny.

[GammaFlat]

After some searching I tried running one of them to the case of the regulator, and the voltage still climbs to 16v.

The factory Honda regulator case does not need to be grounded.  You can let it dangle in the breeze if you like (I wouldn't).  The Ford truck regulator (VR730?) case DOES need to be grounded. 

[eideteker]

With key switch on and headlight on, place the black voltmeter probe on the black wire supplying power to the regulator, and the red probe on the battery POS terminal.  Report reading.
 Next, under the same conditions, place the black meter probe on the Battery NEG terminal, and the Green wire connection to the Vreg.
Report reading.
Next place black probe on the Battery NEG terminal.  And the red probe on the Battery POS terminal.  Report reading.

Make sure the battery post to battery cable connections are clean and shiny.

1. 0.7V
2. 0.09V
3. 11.5V

Post-to-cable connections are shiny beautiful.  After some searching I checked the resistance of the white wire to ground and got about 7 Ohms...is this of any interest?

[eideteker]

After some searching I tried running one of them to the case of the regulator, and the voltage still climbs to 16v.

The factory Honda regulator case does not need to be grounded.  You can let it dangle in the breeze if you like (I wouldn't).  The Ford truck regulator (VR730?) case DOES need to be grounded. 

The VR730 is grounded directly to the negative post.

[TwoTired]

1. 0.7V  I'd like to see 0.5 V. You probably have some old switches in the path.  But, this shouldn't cause 16V.
2. 0.09V This is good)
3. 11.5V I hope this was with everything turned on.

Post-to-cable connections are shiny beautiful.  After some searching I checked the resistance of the white wire to ground and got about 7 Ohms...is this of any interest?

Sure, it tells me you probably have 750.  A 7Ω field coil is normal for that bike.

The next thing to check is to have the engine running and putting that 16v on the battery.
While that is occurring, place the red probe on the Black wire on the regulator, and the Black probe on the white wire on the regulator.
What you should see is big difference in voltage.  In fact, it should be nearly the full battery voltage, indicating the regulator is providing no power to the alternator under these conditions.  If it is still giving full power (0V differential, the vreg is faulty).

Cheers,

[eideteker]

Yes, the 11.5 was with the switch and headlight on.  I have a '73 CB500 - see sig.  Possibly of note - I hooked the old electromechanical regulator back up and it's charging fine (better than before, actually - 12v at idle where it was previously about 10-11v and wouldn't charge until 3000RPM+)...I'm going to return the VR730 for a new one and see if it was faulty from the start.

[TwoTired]

I can't see the sig while writing a response.

FYI, the CB500 is supposed to have 4.9Ω field coil.  But, if it is working, then you probably added some measurement error.  Or you may have some connectors to the alternator field that need attention.

Cheers,

[eideteker]

The next thing to check is to have the engine running and putting that 16v on the battery.
While that is occurring, place the red probe on the Black wire on the regulator, and the Black probe on the white wire on the regulator.
What you should see is big difference in voltage.  In fact, it should be nearly the full battery voltage, indicating the regulator is providing no power to the alternator under these conditions.  If it is still giving full power (0V differential, the vreg is faulty).

Cheers,

I did this and read 0.9v at the regulator while it was pushing 16v to the battery.

I can't see the sig while writing a response.

FYI, the CB500 is supposed to have 4.9Ω field coil.  But, if it is working, then you probably added some measurement error.  Or you may have some connectors to the alternator field that need attention.

Is the new solid-state regulator so sensitive/precise that it can't "work around" some resistance, where the old electromechanical unit was "used" to it?  This part baffles me.  I'm still going to try a new VR730.

[TwoTired]

I did this and read 0.9v at the regulator while it was pushing 16v to the battery.

Then the regulator isn't doing its job.  It should reduce the voltage it passes to the alternator field when the battery goes above 14.5V.

Is the new solid-state regulator so sensitive/precise that it can't "work around" some resistance, where the old electromechanical unit was "used" to it?  This part baffles me.  I'm still going to try a new VR730.

No. I think the VR730 you have got fried somehow.  If you EVER wired it incorrectly.  It was likely damage.  The electromechanical one is far less sensitive to these errors than an electronic one.  I must admit, I've never used a VR730 as I think the stock one work just fine.

Cheers,

[eideteker]

Exchanged the VR730, still overcharging with the new one, put the electromechanical regulator back on and went for a ride.  Either a PO put a 750 field coil in it or something is deeply troubled with the wiring...I don't know.

[BlindJoe]

How hot should these rectifiers ( I have the 3 phase 35 amp Guerte) be getting? Mine is too hot to touch after about 45 secs at idle which doesn't seem right

Thanks

[TwoTired]

How much current is going through it?
Do you have a heat sink on it?
Is you battery fully charged?
Do you have a 100 watt headlight on the bike?

[Pinhead]

Hmm the rectifier on my bike never gets more than "barely warm" to the touch. The heat would be caused by a high amount of current flowing through the rectifier (as TwoTired hinted).

I don't have a heatsink on my rectifier... But am running LED tail light and LED rear turn signals. Head light is 55w halogen and front turn signals are stock.

I don't really think it should get "too hot to touch" unless your battery is bad and the alternator is working like crazy to keep it charged. Or you have a short in the system somewhere.

[Joel]

Will a piece of aluminum bar bent into a C-shape suffice as a heat sink?

[eideteker]

Mine gets too hot to touch, and it's definitely passing heat to the piece of metal it's mounted to as that also gets hot.  I don't know how much of a problem it will be in the long run, I've had mine on for a couple weeks and even riding in 90°+ ambient temps it hasn't crapped out.  They're so cheap maybe I'll pick up another to keep on the bike as a "hot" spare. 

[Joel]

Mine gets too hot to touch, and it's definitely passing heat to the piece of metal it's mounted to as that also gets hot.  I don't know how much of a problem it will be in the long run, I've had mine on for a couple weeks and even riding in 90°+ ambient temps it hasn't crapped out.  They're so cheap maybe I'll pick up another to keep on the bike as a "hot" spare. 

Mine did too in about 10 minutes of riding.  Hot enough with it resting against the inner fender that it melted a spot of the plastic.

[dave500]

im using a boldor one but a bosch regulator,the rectifier is hot but not too hot to touch,i run a 55/60 halogen and normal globes elsewhere,ive removed the globes from the guages i dont ride at night.

[nilsey]

so based on what i've read here i need to order this:

http://www.virtualvillage.com/007809-006.html?utm_source=googlebase&utm_medium=shcomp

and this:

http://www.autozone.com/autozone/parts/Duralast-Voltage-Regulator/_/N-9ci9t?counter=0&filterByKeyWord=vr730&fromString=search&isSearchByPartNumber=true&itemIdentifier=130187_0_0_

or maybe this: http://www.autozone.com/autozone/parts/_/N-9ci9t?counter=2&filterByKeyWord=voltage+regulator&fromString=search&itemIdentifier=130047_0_0


is that about right?

[GammaFlat]

Wow!  That rectifier looks nice.  I don't recall the exact specs of the factory rectifier or those that have been used by members here but it I like it.  It's much "tidier" than the stuff I've cobbled together. 

The VR looks correct but I'd recommend that you consider the factory unit.  They're tough (unlike the rect.) and adjustable.  I have a VR like the one you mention and I'll be testing it but I have a bit of a bias toward the factory unit unlike the rectifier.  The rectifier on the Honda and especially the early ones are more vulnerable to "letting the smoke out" or at least some equivalent.  They're pretty easily "cooked" and the one you found looks great.  If you get the parts and tool to put a compatible connector on it (www.vintageconnections.com), you can have a clean installation.   

[nilsey]

i guess i was leaning toward a solid state regulator because it draws considerably less power than the OEM regulator -- or am i wrong on that?

[TwoTired]

i guess i was leaning toward a solid state regulator because it draws considerably less power than the OEM regulator -- or am i wrong on that?

You are wrong, and I suspect just guessing.

The stock one only draws power when the battery is full and excess power is available.

Cheers,

[nilsey]

actually i was just going by what i read here:

http://forums.sohc4.net/index.php?topic=12465.msg404182#msg404182

Hi Doug/Pinhead
     Another advantage for solid state voltage regulators. The stock Honda electro-mechanical voltage regulator draws about 4.55 watts in the process of measuring the voltage. I doubt that a solid state voltage regulator draws 0.05 watts. So a reduction of about 4.5 watts of normal running power usage. A small help but us CB400F riders can use all the help we can get.
          TomC in Ohio

[TwoTired]

So you are basing your decision on a doubt?
Yes, the stock regulator draws 4.68 ish watts.  (12.8v/35Ω= 0.366 A , 0.366A x12.8v = 4.68W)

Who has actually measured a solid state regulator operating draw?

So then, I will doubt a solid state regulator is much better, (even if it is).  It takes power to run solid state components and it still has to have a voltage divider or reference V on which to base charge state decisions upon.

Btw, just one instrument bulb uses 3 watts.  If your charging system works (or not) based on the existence of one instrument bulb, an electronic regulator isn't going to solve the problem, imo.

Cheers,

[nilsey]

So you are basing your decision on a doubt?

ha ha, no i am trying to gather more information in order to reach a decision, thanks for your help! if i get the SS regulator i'll test it and see what we come up with.