Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Do not check each wire to ground.  Place a probe into each of the connectors and read the AC voltage from both wires.  You only need the ground AFTER the rectifier as it is DC at that point. 

After checking the two wires in the AC mode of your tester

1 Connect both wires to the rectifier and switch your meter to DC
2 connect the output wires of the rectifier, negative to ground and positive to either the battery or the battery post on the solenoid.
3 take a voltage reading (DC) on your battery with the engine off should be 12.5 or 12.6.
6 start the engine and check the battery voltage at idle
7 bring the RPM's up to full throttle and check the volts again. 

If the battery was in the 12.5 to 12.6 range to start with I would expect to see a voltage around 13.5 or so.  If the battery was low to begin with it may take a while to bring it back up to normal voltage.

If you have a battery charger charge the battery first and make sure it is up to 12.5, 12.6 or so.

jrtrebor wrote:
Am I correct in thinking that you were were alternately measuring each of the two wires across chassis ground.  I'd be interested in what the AC voltage across both wires (no chassis ground) is at idle and full throttle, and with and without the rectifier/regulator (and load) connected.  I hope I'm not covering ground already er...covered.

What I'm after is how the two wires (representing the two coils in parallel) are connected to the rectifier.

manjestic wrote:
Thanks carlb  - This is sometimes part of my problem I don't even know how to correctly hook up and check things.  And yes I was "measuring each of the two wires across ground".  I'll have to put things back together and take a measurement across both of the wires coming from the coils.  The readings given in the photo below were taken with
the battery hooked in the system.  I hadn't checked it that day but when I checked it yesterday it was reading 12.4V.  I'll put it back in the charger and make sure it
has a full charge.
The diagrams that I have found for this rectifier. And the wiring diagram for the tractor that it came off of.  Show or call terminal #1 the Batt + terminal. The wire runs from the
rectifier to the key switch B+ terminal.  Along it's way there it is tapped into and that wire goes thru a main fuse and connects to the Battery + terminal.
Terminal # 2 is called or referred to as the Ign. terminal.  The wire goes from the rectifier to the key switch Ign. terminal.  Along its way there it is tapped into and that wire goes to a small 3 fuse, fuse block.  I hope some of this is making sense
I really appreciate all you guys help with this.  I can do a lot of things. But I can get lost when it comes to this kind of stuff.  As you can imagine with
me taking readings from the coils wires with one probe to ground.  I've simply been trying my best not to burn something up. By doing something stupid.
That I didn't know was stupid to do.  You won't be insulting me by stating simple, (doesn't everyone know this) kind of things.

I must say i have not seen a rectifier with two hot output terminals on it, but it may be more common on tractors than snow blowers.  The light might be fine with the 17.5 volts while that would be too high for maintaining the battery. 

Maybe use term 1 @ 17 volts for the light and term 2 @ 12.5 for batt charging. 

Term one may be limited by a voltage regulator built into the rectifier

carlb wrote:
I think there a few out there, but not many snow blowers have an on board 12v electrical system.  It's almost impossible to find information and any type
of wiring diagrams for the setup I've got.  Actually I haven't found any.  That is why I've been using the Honda HT3810 tractors system as a guide for what I'm doing.
I figure that it doesn't matter whether the system is on a tractor or a snowblower.  But maybe I'm wrong about that.  All I'm hoping to accomplish is to be able to
run my light without draining the battery to the point the I can't use the electric starter to start it the next time out. 
Last year with the 11hp Honda clone and the 3A coil.
I never had a low battery problem unless I had been using the light for a while.  Usually if I did, I would throw a trickle charger on it overnight and things would be fine.
The light is only got a 25 or 35W bulb so I'm not needing that much output from the coil(s) to keep the light running and at the same time be giving the battery a little charge.
I'm going to put the flywheel back on this morning and take another reading from the coil wires.  Meter in VAC mode. With one probe to one wire and the other probe to the other wire. Then I'll make sure that the battery has a full charge. Hook it up in the system and take readings again off the starter solenoid terminal.   With the red wire on terminal #1
and then with it on terminal #2.  Would there be any reason, or would it make any sense to you.  That for some reason terminal #1 needs to be hooked directly to the battery.
And terminal #2 should be hooked to the starter solenoid?  In other words that for some reason both output terminals of the reg/rec need to be hooked to something.
Instead of the why I'm doing it which is to only have only one of the output terminals hooked to something?  I ask because the wiring diagram for the tractor shows the rec/reg hooked up that way.  In my last post I talked a little about how the tractor is wired from the rectifier.

carlb wrote:
Something just occurred to me after thinking about what you said.  The rec/reg I'm using is off that Honda tractor.  It has a few other components that are putting a
draw on the system when it's running.  Like a fuel pump and a electric PTO clutch.  It also has all kinds of safety switches, buzzers, warning lights etc.
So maybe that is why the output from terminal #1 is 17v.  The rec/reg was designed for that output to handle occasional heavy loads lights, etc.
And the output from terminal #2 is a steady 12.5V for just normal load.  Not sure I put that into words to well. 
As I've said before I have to keep reminding myself that this rec/reg was not designed to be used with my engine.
The rec called for my engine is a Shindengen SH586B-12 an the one I'm using is a Shindengen SH561-12
Could be if I had the right one that the output from terminal one would be more in the 14-15V range.
Just speculating.

Alright, put the engine back together and took some readings.
Test 1
Across both wires coming from coil.  Meter set to VAC 
@ idle 9V
@ FT  23V

Battery was charged reading 13.6V and hooked in system
Test 2
Red wire hooked to term #2 on Rec/reg and running to starter Sol.
Meter set to VDC Blk. probe to grnd.  Red probe to battery + post (it's easier to get to).
@ idle 13.0V     w/ lgt. on  12.3V
@ FT  13.3V     w/ lgt. on   13.1V
(This was the first check I ran.  When I ran all the others I ran this one again. And the readings were lower. in the 12.5V range.
Was that the battery voltage dropping some from the original 13.6V charge) ?

Test 3
Moved red wire from term #2 to term. #1
@ idle  12.8V
@ FT   17.8V and it was slowly climbing

Test 4
Removed the red wire from term. #1 and took reading off the bare term.
@ idle 12V
@ FT   38V but it was slowwwwly falling.
(Didn't take this same type of reading off terminal #2)

All the readings seemed fluctuate a little + or -  .2 or more

it is very difficult to get a good reading on a charging system without some type of load or buffer such as a battery or light.  You may be seeing very high voltage with no load but it will normally drop substancially when a load is applied.

I would hook up the light to term 1  and the battery to the term 2 
Then take a reading off both terminals both with the light on and the light off.

Voltage reading at an idle really isn't necessary as it will usually be low.

This is how i would hook it up.  The worst that can happen is you burn out the bulb which i doubt or you undercharge the battery which wont really hurt anything.

If this is the best that you can achive with this regulator that is what i would do. 

You may have to put the battery on a trickle charge after use if the battery gets too low.  If you don't have to use the light you should not have any problems.

Good Luck

carlb -Thanks for the reply.

carlb wrote:

Well, I hooked up term 1 to the starter solenoid.  And term 2 directly to the battery + post. 
Took reading off the battery + post
@ idle 14.6V
@ idle with the light on 13.3V
@ full throttle 14.6v
@ full throttle with the light on 14.3V
That would be a good reading.
I guess for some reason I needed to have both terminals hooked up.  Don't have any idea why that would be. 
But I believe that 14.5V @ FT is an acceptable reading. Yes?
Checked today the light is 35W