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Charging Mystery

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Manfred

Manfred

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Joined
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Location
La Vernia, TX
First Name
Stuart
Last Name
Brogden
My 1985 Honda VF700S failed to start recently after I stopped for gas after 25 miles. Was able to charge the battery and get home. The battery is a 5 year-old AGM. I check reg/rect and stator for resistance and they both checked out. I ran a dynamic test on the stator and it produced two readings of 56.6 and one of 58.6 at 3,000 rpm. At slightly high idle (1,400 rpm) 24. 5v, 24.5v and 25.5v. The reg/rect the battery voltage is 14.4 at idle and 13.6 at 5,000 rpm.

Fellas at the V-bike muscle forum tell me I should see 14.4 at 5,000 rpm and I should replace the reg/rect with a $170 MOSFET part. I do not want to spend that kind of money.

Another replacement supplier, Rick's, says voltage readings should be between 13.5 and 14.4 or 14.5 at 5,000 rpm. My bike is within this range.

Do y'all think the reg/rect is suspect?
 
I think the simplest solution is the most likely: the battery is on its way out.

There are other options to the "$170 MOSFET" part. I have put MOSFET reg/rect on my bikes ... I just remembered I have another one to put in my Scrambler! .. anyway, I get a '07-08 Kawasaki ZX6R take-off part, so far the most I have paid on eBay has been $26 and it makes a rock solid 14.4-14.6V from idle to 12K and is cool to the touch while doing it. I picked this unit because it has a wiring pigtail that you can splice into your factory wiring cut off of the OEM R/R, assuming you have a R/R with wiring hanging off and not an integrated plug.

That said, yeah 13.6V should be enough. A really good battery may charge to 13.0V so if you are able to run 13.6V then it should fully charge the battery just fine. If I were you I'd charge the battery on a battery tender type charger overnight and then check the voltage at the terminals before you turn anything on. I bet it's well below 13V when charged. Once you verify that, take the battery out and have it tested at an auto parts store. They'll tell you it's dead and you buy a new one for $50 and Bob's your uncle. None of the AGM batteries in any of my motorcycles have lasted 5 whole years.

FWIW the fact that your R/R's voltage is lower at 5K than it is at idle probably indicates it's generating excessive heat, hotter conductors have higher resistance so they drop more voltage. Eventually this will result in failure of the R/R or more likely the stator wiring. So I'd still make a plan to replace that one with something new, or a ZX6R part if you like to solder and fab brackets and you're cheap.
 
Many thanks! A local auto-parts store did a load test on my battery and it passed. I'm not convinced that is a slam-dunk on an AGM battery this old. Can you give a link to that ZX6R take-off part you mentioned?
 
mr72 said:
Here's one:
www.ebay.com

07-08 Kawasaki Ninja ZX6R ZX-6R Rectifier Voltage Regulator | eBay

Model : Ninja ZX6R. 2005-2006 ZX6R 636. 2007-2008 ZX6R. 2009-2012 ZX6R. 1998-2002 ZX6R. 2003-2004 ZX6R 636. Kawasaki Motorcycle Parts. Make : Kawasaki.
www.ebay.com

And here's my write-up of the install on my Bonneville:
www.triumphrat.net

ZX-6R Regulator Rectifier install

www.triumphrat.net www.triumphrat.net

I'm about to do the same thing on my Scrambler.
Click to expand...
That stock reg/rect from the Kaw is not a MOSFET device, is it? Not sure, based on your opening comments on your blog. No concerns with an old used part? It's 20 years newer than the one on my bike. :rofl:
 
The Shindigen p/n on the actual original part is for a MOSFET part. Not known for an "OEM" aftermarket replacement part. You spend $30 and take your chances I guess. I have bought three of them and they are all MOSFET parts. If they don't overheat, no reason they wouldn't last basically forever.
 
Honda rectifiers are filled with weak sauce...not even smoke.
My VT1100 lost two stators before I saw the light and swapped in a MOSFET regulator.
Charging system was full of awesome sauce thereafter.
 
Just to be clear. The one you provided a link to on eBay is a MOSFET part?
 
I bought a this on eBay. Thanks for your counsel and the write-up! I have more wires on the Sabre than you do on the Triumph, but I think I'll be able to sort it out.
2007 2008 Kawasaki ZX6 ZX6R Voltage Regulator Rectifier FH016AA

2007 2008 Kawasaki ZX6 ZX6R Voltage Regulator Rectifier FH016AA
 
Boulder Ed said:
Sounds like a small nightmare to me :-) I hate electrical issues.
Click to expand...

I'll swap you the tank cleaning and carb issues on my scooter for whatever electrical issues you have. Different strokes I guess. Electrical stuff is easy. It obeys ordinary predictable physics that you can learn when you're 13. For my scooter, you have to be a clairvoyant who speaks both Italian and Hindi with a time machine to go get parts with.
 
mr72 said:
The Shindigen p/n on the actual original part is for a MOSFET part. Not known for an "OEM" aftermarket replacement part. You spend $30 and take your chances I guess. I have bought three of them and they are all MOSFET parts. If they don't overheat, no reason they wouldn't last basically forever.
Click to expand...

Here's the diagram showing my reg/rect wiring. Turns out I have the same number of wires - a pair gets tied together past the connector on my bike. The solid green wire runs to the spark unit; the red/white wire runs to the starter relay. How do you think I should connect the wires from the Kaw device?
 

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mr72 said:
The Shindigen p/n on the actual original part is for a MOSFET part. Not known for an "OEM" aftermarket replacement part. You spend $30 and take your chances I guess. I have bought three of them and they are all MOSFET parts. If they don't overheat, no reason they wouldn't last basically forever.
Click to expand...
Does this make sense? Found it on a Honda site:

1) Remove old regulator and rectifier
2) Mount new reg/rect behind the battery box where original rectifier was
mounted. Make sure the unit has a solid ground at the mounting point. Also make
sure wires are not kinked or crushed where they exit the unit.
3) Cut off and tape up connector or wires from harness that connected to original
rectifier. You will not be connecting your new regulator/rectifier to the wires
from your old rectifier.
4) Connect three yellow from the new reg/rect to the three wires coming from the
stator coming from the bottom of the motor. Note: there is a fourth wire coming
from the stator that is light green w/red stripe. It has a different type of insulation
than the other three wires. This is the neutral light switch wire and needs to be
plugged back into the harness.
5) Connect red/white striped wire from unit to battery positive, and connect green
wire from unit to battery negative.
 
The picture from the wiring diagram doesn't show where those wires go, so I am not sure. You can sort it out though.

From my notes in the Triumphrat post, this is how I worked out the wiring on the ZX reg.

The ZX-6R reg/rect has six wires:
Black with blue stripe: +VDC --> connect to whatever is +12VDC power on your original wiring (likely the red/white?)
Black with white stripe: GROUND -> connect to whatever was ground on your original wiring (likely green? according to the other Honda forum instructionss)
small black wire: not used, just tie it off
Three fat black wires: connect each to one of the yellow wires from your stator

Again, you can do this one of a few different ways:

1. depending on your original and replacement connectors, if the pins inside them are identical (meaning the actual metallic pin, not the whole housing or arrangement of pins), then you can pop the pins out of the connectors and swap the pins of the replacement part into the connector housing from the original part, arranged in the correct way. This is highly unlikely. But remotely possible.

2. Cut the connector off of the new reg/rect near the connector to give you the max length of wires. Then chop the pigtail off of the original reg/rect. Splice/solder/heat-shrink the new reg/rect wires onto the original pigtail, then just plug it in. This is the simplest and easiest way to do it, and maintains compatibility with the original wiring in case you or a future owner have to replace the reg/rect again in a couple of decades.

3. do what I did described in that Triumphrat post, which is really only warranted if you are doing this mod on a Bonneville. It's a uniquely Triumph problem and solution, I because the factory connector on a Bonnie is crammed inside the headlight housing, and the original location of the reg/rect is under the headlight on the fork triple. I was relocating the reg/rect to under the tank and therefore I could reduce the wiring by over two feet by cutting it and re-wrapping it. If I was re-using the stock part location, I would have done #2. And BTW that's probably what I'll do on my Scrambler.
 
Thanks again. I read your article on the Triumph and the thing that had me confused is that the stock reg/rect runs a line to a spark unit; the Ninja device does not.

I talked with folk on the V4 Muscle Bike forum and they told me I could follow the guidance on the Honda site that I pasted above - abandon the stock wire and run the two Ninja wires to the battery, with a fuse on the hot wire. I don't understand why the spark unit would continue to work without input from the reg/rect. I also wonder if the hot wire from the Ninja device could run to the starter relay, which is already equipped with a fuse.

My reg/rect sits under the seat, right behind the battery.
 
I had a thought - I ran a dynamic test on the stator, with the reg/rect disconnected from that. The bike ran fine - checking AC voltage on the stator. Appears the reg/rect does not provide anything to the spark unit.
 
Manfred said:
I had a thought - I ran a dynamic test on the stator, with the reg/rect disconnected from that. The bike ran fine - checking AC voltage on the stator. Appears the reg/rect does not provide anything to the spark unit.
Click to expand...

Could be there's some kind of starter relay logic happening to reduce load during starting and the signal from the reg/rect works with that. IDK. I'd have to see the entire wiring diagram in order to even guess.

Note, there's that one wire that does come from the ZX reg/rect that I just tie off on my bikes. Who knows what that's for. I discovered these particular reg/rect devices by just combing the internet for info on which motorcycles come from the factory with a MOSFET regulator, then filtering down on those with a pigtail wiring rather than an integrated plug like the Shindigen ones. I'm sure there are others, I just found one that met my requirements and was the right price, now I put one on everything I own.
 
The folks on the V4 Muscle Bike forum tell me not to worry about it. Here's the complete diagram.
 

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The small black wire is a sensor wire - again, one that the V4 Muscle Bike folk say is not needed.
 
mr72 said:
Could be there's some kind of starter relay logic happening to reduce load during starting and the signal from the reg/rect works with that. IDK. I'd have to see the entire wiring diagram in order to even guess.

Note, there's that one wire that does come from the ZX reg/rect that I just tie off on my bikes. Who knows what that's for. I discovered these particular reg/rect devices by just combing the internet for info on which motorcycles come from the factory with a MOSFET regulator, then filtering down on those with a pigtail wiring rather than an integrated plug like the Shindigen ones. I'm sure there are others, I just found one that met my requirements and was the right price, now I put one on everything I own.
Click to expand...

My Ninja part should be here Wednesday. Question: does it have three wires one each connector, one connector to the stator, the other to the 12v side? Never mind; I re-read your Triumph article and the question is answered there. Thanks again!
 
Last edited:
Ninja part works GREAT! Battery is being charged at 13.9-14.1 at 4,000 - 5,000 rpm after bike is warm. Bike seems to be running better than ever! Thanks again for your help!
 
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