Power Trac Electrical Monitor

[BobRip]

While I was moving the pumkins a couple of weeks ago, I was driving the PT about 100 yards at most, stopping the engine, unloading for five minutes, driving 100 yards back to the truck, stopping the engine, loading for 5 minutes, and then repeating the process about 25 times (or so it seems). There was a lot of traffic in the area (basically a 7 - 11 parking lot) and I had both 55 watt front lights on, the flashing light, and the fan was running. I was concerned that I was running the battery down as I was exceeding or right on the edge of the 15 amp alternator capacity. I decided to build an electrical monitor. I figured a voltmeter to monitor the battery would give me a pretty good indication of charging/discharging status (above 13.8 you are in good shape, below about 12.5 you are discharging). I purchased a voltmeter from Radio Shack (part # 22-410) and ran wires back to the main negative ground wire that runs from the battery to the engine, and the main positive lead that connects to the starter. This overcomes any issues with voltage drop between the battery and the meter caused by the loads and gives the most accurate reading of the actual battery voltage as well as gives the voltage pretty close to the starter when cranking. Since the meter only pulls 1 mA. I figured it could be left on all of the time.

See attached pictures. It is a 0 to 15 volt voltmeter. It was hard to get this in the picture.

 

[ponytug]

Great customizations! I was admiring all the other mods in the photos as well. I couldn't figure out how I managed to smash my kneecap on the dash the other day, before I thought about the seat tilting up. (Add to do list...)

You might still want to put a switch on it. 1mA adds up over time. If the meter is power separately from the measured line, you could switch it. Worst case, you could use a relay to switch the measure load on and off, when you turn the key.

Harbour freight pretty regularly sells digital volt/amp/ohm/transitor meters for $2.99 I just wait for them to go on sale, and then give them away to friends. They run on a 9V battery, but I am sure you could hack a couple of diodes to get the voltage you need. (They have an in dash meter on sale for $2.99 at the moment.)

While I was moving the pumkins a couple of weeks ago, I was driving the PT about 100 yards at most, stopping the engine, unloading for five minutes, driving 100 yards back to the truck, stopping the engine, loading for 5 minutes, and then repeating the process about 25 times (or so it seems). There was a lot of traffic in the area (basically a 7 - 11 parking lot) and I had both 55 watt front lights on, the flashing light, and the fan was running. I was concerned that I was running the battery down as I was exceeding or right on the edge of the 15 amp alternator capacity. I decided to build an electrical monitor. I figured a voltmeter to monitor the battery would give me a pretty good indication of charging/discharging status (above 13.8 you are in good shape, below about 12.5 you are discharging). I purchased a voltmeter from Radio Shack (part # 22-410) and ran wires back to the main negative ground wire that runs from the battery to the engine, and the main positive lead that connects to the starter. This overcomes any issues with voltage drop between the battery and the meter caused by the loads and gives the most accurate reading of the actual battery voltage as well as gives the voltage pretty close to the starter when cranking. Since the meter only pulls 1 mA. I figured it could be left on all of the time.

See attached pictures. It is a 0 to 15 volt voltmeter. It was hard to get this in the picture.

 

[BobRip]

Great customizations! I was admiring all the other mods in the photos as well. I couldn't figure out how I managed to smash my kneecap on the dash the other day, before I thought about the seat tilting up. (Add to do list...)

You might still want to put a switch on it. 1mA adds up over time. If the meter is power separately from the measured line, you could switch it. Worst case, you could use a relay to switch the measure load on and off, when you turn the key.

Harbour freight pretty regularly sells digital volt/amp/ohm/transitor meters for $2.99 I just wait for them to go on sale, and then give them away to friends. They run on a 9V battery, but I am sure you could hack a couple of diodes to get the voltage you need. (They have an in dash meter on sale for $2.99 at the moment.)

On the 1 Ma. In 400 days the meter will use about 10 ampere hours which is about 20% of the battery capacity. It will probably still start at that level. The battery self discharge will probably be much higher than that.

I like your idea of the Harbor meter. Just lock it on volts. The in dash meter look like a good choice, probably better than the Radio Shack.

No body has asked about the two lights at the bottom of the panel.

 

[ponytug]

OK. I'll bite. Are they your flashing light and backup lights?

I'll also be impressed if your meter only pulls 1mA; if it does, I agree with you there is no problem.

What did you use for the handle on the QA? Does it rotate, or pull? I couldn't quite figure it out from your photos.

Of course, for real money, you could just buy an integrated gauge, but that would spoil the fun, right?

All the best,

Peter

On the 1 Ma. In 400 days the meter will use about 10 ampere hours which is about 20% of the battery capacity. It will probably still start at that level. The battery self discharge will probably be much higher than that.

I like your idea of the Harbor meter. Just lock it on volts. The in dash meter look like a good choice, probably better than the Radio Shack.

No body has asked about the two lights at the bottom of the panel.

 

[BobRip]

OK. I'll bite. Are they your flashing light and backup lights?

I'll also be impressed if your meter only pulls 1mA; if it does, I agree with you there is no problem.

What did you use for the handle on the QA? Does it rotate, or pull? I couldn't quite figure it out from your photos.

Of course, for real money, you could just buy an integrated gauge, but that would spoil the fun, right?

All the best,

Peter

The QA handle pulls up and down. It just extends the old handle. I have attached and here is the link. pictures.http://www.tractorbynet.com/forums/power-trac/93128-quick-attach-control-handle.html

The lights monitor the coolant fan. The amber light on the left comes on when the hydraulic fluid is cold. It monitors the fuse and fan continunity.
The green light on the right comes on once the fluid is warm and the thermostatic switch closes. It verifies that the fan is getting power and the switch has closed. This does not cover every possible failure, but it does cover most of what I have seen (fuse holder failure, spade lug failure and thermostatic switch failure). A current monitor would have been better.

 

[Barryh]

While I was moving the pumkins a couple of weeks ago, I was driving the PT about 100 yards at most, stopping the engine, unloading for five minutes, driving 100 yards back to the truck, stopping the engine, loading for 5 minutes, and then repeating the process about 25 times (or so it seems). There was a lot of traffic in the area (basically a 7 - 11 parking lot) and I had both 55 watt front lights on, the flashing light, and the fan was running. I was concerned that I was running the battery down as I was exceeding or right on the edge of the 15 amp alternator capacity. I decided to build an electrical monitor. I figured a voltmeter to monitor the battery would give me a pretty good indication of charging/discharging status (above 13.8 you are in good shape, below about 12.5 you are discharging). I purchased a voltmeter from Radio Shack (part # 22-410) and ran wires back to the main negative ground wire that runs from the battery to the engine, and the main positive lead that connects to the starter. This overcomes any issues with voltage drop between the battery and the meter caused by the loads and gives the most accurate reading of the actual battery voltage as well as gives the voltage pretty close to the starter when cranking. Since the meter only pulls 1 mA. I figured it could be left on all of the time.

See attached pictures. It is a 0 to 15 volt voltmeter. It was hard to get this in the picture.

Great idea Bob, a much needed accessory on the PT..

 

[ponytug]

Dear Bob,

Great idea!

Do you think that you could use a bicolor LEDs(e.g. radioshack 276-012)? You could use one LED and have it change color (e.g. green to red) when the fan kicks on, by hooking it up to the hot side of the thermostatic switch. When everything is good, you would have ~14V at the switch, when it closes, it would drop somewhat ~12V. With a suitable resistance bridge, the LED would switch states.
I'd have to check what the real voltage drops are at the switch to see if it would work.

Or you could just use a three lead LED and toggle the colors the way you have.

All the best,

Peter

The lights monitor the coolant fan. The amber light on the left comes on when the hydraulic fluid is cold. It monitors the fuse and fan continunity.
The green light on the right comes on once the fluid is warm and the thermostatic switch closes. It verifies that the fan is getting power and the switch has closed. This does not cover every possible failure, but it does cover most of what I have seen (fuse holder failure, spade lug failure and thermostatic switch failure). A current monitor would have been better.

 

[BobRip]

Dear Bob,

Great idea!

Do you think that you could use a bicolor LEDs(e.g. radioshack 276-012)? You could use one LED and have it change color (e.g. green to red) when the fan kicks on, by hooking it up to the hot side of the thermostatic switch. When everything is good, you would have ~14V at the switch, when it closes, it would drop somewhat ~12V. With a suitable resistance bridge, the LED would switch states.
I'd have to check what the real voltage drops are at the switch to see if it would work.

Or you could just use a three lead LED and toggle the colors the way you have.

All the best,

Peter

Peter, it depends on how the LED is internally connected. I suspect (the web site did not show) that there are three leads, one is a common. The way I have the lights connected is:
Amber Light - Wired across the thermal switch.
Green Light - Wired between the fan plus and the engine ground.

The LED probably does not have the right connections for the polarity to work out. There is certainly a way to use an LED, It just may not work the way I did it. You could put in a shunt in parallel with the LED and have that in series with the motor. The LED would light up from the current flow through the motor. This would be a good indication, but the fan would loose about 2 volts and not pull as much air. You could add an operational amplifier or maybe a transistor also, but I did not feel like going that far. I think a current meter would be a really good choice. You can tell a lot about a fan motor by the current it is pulling. There are lot's of options, can you try some? Also if you could find a way to actually measure air flow and monitor that, it would be good, or actually monitor oil temperature.

 

[ponytug]

It's a two lead LED; you can hook it up so that via a suitable resistance network, you get one color or the other, depending upon which circuits are active (Logic HIGH vs LOW). Rather like this one;

When the first circuit goes on, you get green, when just the second goes on, you get red, and when both are one, nothing (unlike the circuit discussed above). Probably getting too fancy.

I came across them trying to get more out of a simple PIC controller (Parallax).

All the best,

Peter

P.S. The in dash voltmeter that I mentioned above is this one;

 

[BobRip]

It's a two lead LED; you can hook it up so that via a suitable resistance network, you get one color or the other, depending upon which circuits are active (Logic HIGH vs LOW). Rather like this one;

When the first circuit goes on, you get green, when just the second goes on, you get red, and when both are one, nothing (unlike the circuit discussed above). Probably getting too fancy.

I came across them trying to get more out of a simple PIC controller (Parallax).

All the best,

Peter

P.S. The in dash voltmeter that I mentioned above is this one;

Peter, thanks for the circuit. You could use 2 separate LED, and not have so many components (2 LED + 2 resistors). Also you will need a 5 volt regulator. No big deal either way.
I saw the meter on Harbor Freight and I think it's a good way to go. If my meter fails, I may convert.

Take care,