Trimetric Meter

**Caver** · 05-30-2004, 08:24 PM

I've just completed the installation of a Trimetric 2020 meter to monitor the battery status when I am boondocking and running off solar. These are the current values for the interior lights and some of the 12v appliances:

load Amps
Phantom Load 0.12 gas detector, solar charge controller, and Trimetric
Porch 1.04 #912
Overhead one 1.48 1 x #1141
Overhead two 2.92 2 x #1141
Overhead three 4.35 3 x #1141
Overhead four 5.75 4 x #1141
Bathroom light 2.1
Fan speed 1 1.13
Fan speed 2 1.55
Fan speed 3 2.03
Refrigerator 10.62
Refrigerator fan 0.41
Bathroom fan 0.36

These were measured at a nominal 12.7 volts. I used the 100A 100 mv shunt. It's nice to see what's going on and keep track of AHs used. Now to wire up some extra 12v connectors and go camping.

Ray

**Bill** · 05-30-2004, 09:06 PM

That's a nice piece of equipment, Ray, I envy you. I agree that it is nice to know what is happening to your battery. I installed an inexpensive 20-0-20 ammeter for just that purpose. Doesn't do amp-hours, of course.

Thanks for the info.

Bill

RockyMtnRay · 05-30-2004, 09:11 PM

Thanks for providing those amperage numbers, Ray!!! I've long been wondering what each of the overhead lamps was pulling. The other number I've long wondered about is how much current the furnace pulls...my guess is somewhere around 5 to 8 amps. Realize it's sizzlin' hot on the east coast now but when you can get a chance to run the furnace, sure would appreciate having that number.

**Bill** · 05-31-2004, 08:25 AM

Ray(s) -

The Suburban website is one of the classic example of bad site design, but at one point I rummmaged around long enough to find that the furnace blower is supposed to take 2.8 amps, and the ignitor takes 0.1 amps. Don't know how much the electronics adds, but it shouldn't be much. It will be interesting to see what the Trimetric says.

Bill

RockyMtnRay · 05-31-2004, 09:51 AM

Quote:

Ray(s) -

The Suburban website is one of the classic example of bad site design, but at one point I rummmaged around long enough to find that the blower is supposed to take 2.8 amps, and the ignitor takes 0.1 amps. Don't know how much the electronics adds, but it shouldn't be much. It will be interesting to see what the Trimetric says.

Bill

There's also a significant load from the gas valve solenoid and associated circuitry (not just the ignitor)...when the thermostat quits calling for heat and the gas valve closes, I always notice a definite jump in system voltage (like several tenths of a volt). The change in system voltage when the flame shuts off, particularly when the battery is getting low, is enough to produce a clearly audible increase in the furnace's fan speed and and a noticeable brightness increase in the interior lighting.

I eagerly await the Trmetric numbers on the furnace...particularly with and without the gas valve being open.

05-31-2004, 01:27 PM

I too am curious to see the numbers on the furnace. The tiny battery that is stock with the TM doesn't have a prayer in late fall here in the northeast, but it is nice to know.

Camperboy

**Caver** · 05-31-2004, 06:08 PM

I hope to have some readings for the furnace soon. I'll be sure to try to capture the current of the solenoid and starter in addition to the blower motor.

Below are two photos of the meter and installation. I wanted to have the meter at a convenient height to read and operate it so I decided to soft mount it with Velcro. The challenges of a folding trailer are worth the tradeoff.

I used a standard CAT5 connector for the meter since that was easy to mount in the standard quad outlet with the phone and 4 Anderson PowerPoles. This way I can use an extension cable and use the meter externally when the TM is closed.

The PowerPoles are standard 12v 30A connectors that I use for my ham radio equipment. I'm running a separate cable from the battery to these four 12v connectors.

Ray

RockyMtnRay · 06-01-2004, 10:00 AM

Using Cat5 cabling is most ingenious. Do you also use Cat5 cable from the battery and/or ammeter shunt to the back of this Cat5 terminal?

**Caver** · 06-01-2004, 10:52 AM

Ray, I used stranded hookup wire from the shunt at the battery to the CAT5 connector. Of the four wires two were 20 gauge and the other two 22 Gauge. 22 Gauge is easier to crimp into the female CAT5 connector.

I prefer to use stranded wire in the RV due to the vibration. Normal CAT5 wire is single strand. I cut a commercial cable into two pieces to connect the meter. I was pleased that it used stranded wire.

I'm always reluctant to use a connector for something other than its intended purpose. You would not want to plug a standard network adapter into this connector or it could damage the NIC. Likewise it would not be a good idea to plug the meter into an actual network.

Having the meter plug in allows it to be removed and tucked out of the way when you're running off AC. However, it does need to remain plugged in to track AHs or % capacity.

Ray

RockyMtnRay · 06-02-2004, 07:44 AM

Quote:

Ray, I used stranded hookup wire from the shunt at the battery to the CAT5 connector. Of the four wires two were 20 gauge and the other two 22 Gauge. 22 Gauge is easier to crimp into the female CAT5 connector.

I prefer to use stranded wire in the RV due to the vibration. Normal CAT5 wire is single strand. I cut a commercial cable into two pieces to connect the meter. I was pleased that it used stranded wire.

I'm always reluctant to use a connector for something other than its intended purpose. You would not want to plug a standard network adapter into this connector or it could damage the NIC. Likewise it would not be a good idea to plug the meter into an actual network.

Having the meter plug in allows it to be removed and tucked out of the way when you're running off AC. However, it does need to remain plugged in to track AHs or % capacity.

Ray

Great thinking. I'd forgotten that Cat5 cabling uses single strand and not the more flexible, vibration resistant multi-strand (haven't done any connector crimping for a year or so)...but now that you mention it I had a Homeresque DOH!! moment. Sure is great to have another really knowledgeable techie contributing to this forum!

I'm contemplating whipping up my own digital ammeter to measure current in/out of the battery...bought the parts (digital voltmeter display, shunt, necessary voltage controller, etc.) last summer with the intent of installing same in the dash of my Jeep so that I could keep track of current going to the trailer while traveling. But never got around to doing the circuit layup...and then traded the Jeep for a Tundra which has no place in the dash for such a display. If I do get a "RoundTuit" for this project this summer, I would have the same issue you faced...how to bring the relatively low voltage difference signal off the shunt forward about 12 feet to the ammeter. Stranded and/or shielded cable oughta do the trick.

Not particularly interested in cumulative AHs but do have a periodic curiousity about the current flow at any given moment, particularly how much the panels are putting out at various times.