Hooking up combination voltmeter / ammeter

[ST Gui]

Years back I put an electronic ignition in my 750-4 which was based on the Hall effect. There were two magnets attached to a circuit board that spun over one or two pickup coils to trigger the spark.

It worked very well. But you might be concerned that if there were some kind of imbalance were induced to that spinning board there could be a catastrophic failure.

And you'd be right. I carried the points and condenser with me - just in case. But the failure occurred in my drive way, and the manufacturer sent me a new v2.0 unit that worked beyond my selling the bike.

 

[Jim Van]

John:

Yea, it's that simple - just run the wire through the current loop. And it comes with an extension wire - it doesn't look shielded to me, tho. If it didn't come with the extension, or if it's too short, you could make your own, it's just three wires.

​

 

[Jim Van]

Years back I put an electronic ignition in my 750-4 which was based on the Hall effect. There were two magnets attached to a circuit board that spun over one or two pickup coils to trigger the spark.

It worked very well. But you might be concerned that if there were some kind of imbalance were induced to that spinning board there could be a catastrophic failure.

And you'd be right. I carried the points and condenser with me - just in case. But the failure occurred in my drive way, and the manufacturer sent me a new v2.0 unit that worked beyond my selling the bike.

Dyna Ignitions use Hall Effect sensors, BTW. The sensor(s) are stationary and the magnet spins.

When I installed the Rostra cruise on my ST1100, I made a homebrew speed sensor using a Hall Effect device - the sensor, 1 resistor & 1 capacitor mounted on a PC board. I encased it in epoxy to waterproof it. Then I fabbed 3 plates ( mounted where a ABS ring would have be mounted on the rear wheel ) and mounted a piece of nylon threaded rod on each plate drilled to accept a small magnet. It's amazing how far that little magnet can be from the sensor to trigger it. Been working fine for about 5 years now.

Maybe I'll post a pic to satisfy John.

 

[W7AX-Lee]

Maybe it could be put inside one of the top compartments. You won't be looking at it that much while riding anyway.

 

[k2mpw]

Anything "simple" from China can become a "what the hell did I do" project in a hurry. On the bench, that product may work fine but put it in the environment that is a motorcycle and you may have a whole new experiment! Good luck.

 

[ST Gui]

Dyna Ignitions

Apologies to the OP for the hijack but sometimes I can't help myself.

I remember Dyna back when but don't remember who made my kit which was on sale before Dyna. Their stuff is Star Trek tech compared to what I bought which looked like something out of Job's garage. I pretty much ignored Dyna because I now had electronic ignition. Should have waited but...

It's amazing how far that little magnet can be from the sensor to trigger it.

Regular or rare earth magnet? I doubt my EI had rare earth magnets. You could measure the gap with one blade of a feeler gauge.

 

[aSTerix]

I run a lot of accessories (including an amateur radio transceiver) on the bike

Can I ask where/how you mounted your antenna and what make (I'm assuming dual 2m/70cm ?)

 

[popefelix]

Can I ask where/how you mounted your antenna and what make (I'm assuming dual 2m/70cm ?)

Sure! There's a board bolted to the tail over the passenger handles (using the same bolt holes and longer bolts). The antenna is a Comet SBB-5, and it is mounted there using a straight NMO bracket. I took some pictures and put them on my Insta: https://www.instagram.com/p/B-rx6K6HGDj/

 

[jrp]

John:

Yea, it's that simple - just run the wire through the current loop. And it comes with an extension wire - it doesn't look shielded to me, tho. If it didn't come with the extension, or if it's too short, you could make your own, it's just three wires.

​

I'm going to mount it in a plastic waterproof project box along with a voltmeter. The ammeter is $5 cheaper from this vendor:

Amazon.com

In the picture below, the display is reading 5.4 amps going out from the battery. The extra dot to the right of the 4 indicates that the current direction is flowing from the battery (i.e. your battery is being drained). If the battery has a net charge going to it, the dot to the right is not displayed. When I did this test, I had the bike stripped down and the only lights connected were those in the taillight assembly (LEDs) and the instrument cluster. The fuel pump was also disconnected. I just turned on the ignition and it read 5.4 amps. The display read 0.1 with the ignition off. I have not yet tested the accuracy. There is also a button on the circuit board that lets you reset the display for zero current (which I have not yet done). I wrapped some closed cell foam around the wire so that the sensor wouldn't flop around. The extension is plenty long enough.

 

[aSTerix]

So I bought a panel mount voltmeter / ammeter to put on my ST1100 (98). I run a lot of accessories (including an amateur radio transceiver) on the bike, and I want to make sure that I'm not draining the battery when I'm using stuff. Mounting it wasn't hard, but I'm at a loss as to where to connect it. I'd really like to monitor the total current draw on the bike (including things like fuel pump and headlights), but the ammeter can't handle more than 15A, and I don't want to burn the thing out every time I start the bike.

The ammeter wants to be connected in parallel with the "hot" wire going to the load, so I was figuring on using one of those "tap" connectors from the auto parts store and attaching it to something. But I don't know what. If I hook it up to the wire coming off the battery, is the meter going to see the starter current as well as everything else?

If you would like to run a RIg on your bike and considering the low amperage shunt (15A) perhaps place the shunt in the ground return of your rig. That way if the shunt burns out you will only lose your Rig ! It will be handy to monitor Rig efficiency although won't tell you anything about the battery ! (personally I would get a non intrusive current measuring sensor that has higher rating and place it on the battery)

Usually the Rig ends up being at the end of the wiring system and being a high current draw it means a lot of voltage drop. You might consider two things:

(1) Put a switch on your voltmeter pickup and give it two inputs, one at the battery and one at the input to the Rig, that way you can monitor the rig voltage which could be very useful
(2) Consider moving your Alternator voltage sense wire to be connected at the Rig, this means the Alternator will produce charge dependant on the sensed voltage at the Rig, when the Rig is not being used this voltage will be close to the rest of the system and when your transmitting it will result in a boost output from Alternator (because the voltage drop in the wiring to that sense point will trigger the Alternator to kick in sooner).

73 K2JE

 

[jrp]

I'm going to mount it in a plastic waterproof project box along with a voltmeter. The ammeter is $5 cheaper from this vendor:

Amazon.com

In the picture below, the display is reading 5.4 amps going out from the battery. The extra dot to the right of the 4 indicates that the current direction is flowing from the battery (i.e. your battery is being drained). If the battery has a net charge going to it, the dot to the right is not displayed. When I did this test, I had the bike stripped down and the only lights connected were those in the taillight assembly (LEDs) and the instrument cluster. The fuel pump was also disconnected. I just turned on the ignition and it read 5.4 amps. The display read 0.1 with the ignition off. I have not yet tested the accuracy. There is also a button on the circuit board that lets you reset the display for zero current (which I have not yet done). I wrapped some closed cell foam around the wire so that the sensor wouldn't flop around. The extension is plenty long enough.

I did some testing with two different loads (both at 12v). One was with 45 watts (2.75A) and the other was 90 watts (7.5A).

The meter read 2.6A with the 45 watt load and 7.3A with the 90 watt load.

Definitely not a precision instrument, but for $19 I think it should suit my purposes.

Jeff

EDIT: The testing was done with the longer cable.

 

[John OoSTerhuis]

Nice job, Jeff, where are you mounting the display?

John

 

[jrp]

Nice job, Jeff, where are you mounting the display?

John

I am initially going to mount it in a plastic project box attached to the handlebar, along with a voltmeter and a temperature gauge. I'll post pictures after I'm done.

 

[John OoSTerhuis]

I am initially going to mount it in a plastic project box attached to the handlebar, along with a voltmeter and a temperature gauge. I'll post pictures after I'm done.

I take it you’re not going to use the voltage feature... is the toggle access a problem?

OK, I’ve got one on order so I’ll soon see...

John

 

[jrp]

I take it you’re not going to use the voltage feature... is the toggle access a problem?

OK, I’ve got one on order so I’ll soon see...

John

You can set it to to display A alone, V alone, or alternating display between A&V. But there is an annoying (to me) flash when it switches between A & V, so I opted for a separate V meter.

 

[John OoSTerhuis]

Just saw this in the Q&A section:

Yes, there are three display settings: Amps only, Volts only, and volts and amps alternating display. (there is also a fourth calibration position) The settings selection is made by a small push switch on the back of the meter which cycles through the settings in order so if you are going to panel mount the meter you need to leave access to the rear or, as I did, solder a switch in parallel (and then mount the new switch in an accessible position)

Somebody will have to show me how to add the switch.

John

 

[jrp]

Just saw this in the Q&A section:

Somebody will have to show me how to add the switch.

John

John,

I tried to solder a switch in parallel and ended up melting the plastic part of the switch, ruining the switch and necessitating the purchase of a second ammeter. It must have a real small solder window and I'm not even an amateur at soldering surface mounted components. Since I just plan to leave it displaying amps, I don't need ready access to the switch.

Jeff

 

[Larry Fine]

Somebody will have to show me how to add the switch.

You mean what is parallel, or which board terminals?

 

[Larry Fine]

I tried to solder a switch in parallel and ended up melting the plastic part of the switch (had to buy a second ammeter). It must have a real small solder window and I'm not even an amateur at soldering surface mounted components. Since I just plan to leave it displaying amps, I don't need ready access to the switch.

Can you get to the other side of the PC board?

You can only read load current and not charging current, right?

 

[jrp]

Can you get to the other side of the PC board?

You can only read load current and not charging current, right?

I don't know if I can get to the other side. I will check to see if it is possible.

It reads current both ways. If the current is flowing into the battery (i.e. charging) there is a dot that is lit in the lower right hand corner of the display.