Auto Gen Start Temperature Sensor

[ShapeShifter]

I was looking at THIS THREAD about setting up the auto gen start based on temperature. It told me pretty much all I needed to know about using the temperature based mode (so far, I've only used the auto gen start based on low battery voltage.)

But I have one remaining question, and I wanted to post to that thread, but it's old enough that the forum won't let me revive it and post there. So, I need to start a new thread...

Now, on to the question at hand:

Originally Posted by bullydogs1

if you go into the tech screen, you can see the AGS temp reading. <...snip...> My test with AGS temp reading (the old hair dryer trick) showed it reading like it should...

Just where is the temperature sensor actually located? I see the temperature sensor cable plugged into the AGS module, but it disappears into the wiring harness. Where does it come out? Where does one apply the sophisticated test equipment (hair dryer) to check it out?

[observer]

Shapeshifter,
If you check the temperature sensor in your bedroom you should find the AGS sensor under the same slotted plastic cover.

[ShapeShifter]

Originally Posted by observer

Shapeshifter,
If you check the temperature sensor in your bedroom you should find the AGS sensor under the same slotted plastic cover.

Thanks, I will look at it.

That would be an unfortunate position, as I'm more concerned about the temperatures in the living room area, as that's where the dogs are, in crates. My thought is that I would want to use the AGS to make sure that the living area doesn't get too hot in situations where we might lose shore power, or where we are on limited shore power (15 amps.) We don't leave the dogs alone for very long (longest would be for an hour or two while we are inside a dog show) but that's long enough for the temperature to really climb in some situations. But the more I look at that thread, the more I wonder if it won't do what I want.

One scenario is where we have sufficient shore power to run the A/C, but the breaker on the pedestal trips, or something else happens to cause shore power to be lost (like voltage drops too low and the EMS/Surge cuts off the power.) In that case, I would think I want to set the AGS start temperature to a bit over the A/C thermostat temperature (5 degrees?) While there is shore power, the A/C will keep things cool, and the AGS won't be triggered. But if the shore power goes out, and the temperature starts to rise, then the AGS will kick in and the rig will cool down. But after reading that thread, it would appear that once the temperature drops down below the AGS set point, the generator will shut off again? That doesn't sound like something I would want to happen. I would want to run at least long enough for the A/C to bring the temperature back down to the regular thermostat's set point. Maybe it won't work the way I want in this scenario? Or do I just split the difference and set the normal A/C thermostat temp a little below the ideal temperature, and the AGS temp a little above the ideal temperature?

In the second scenario, we are at a dog show with very limited power (15 or 20 amps.) That is not enough to run an air conditioner. Temperatures may be mild, and no need for A/C. But if the sun then comes out, and starts heating things up, the A/C would be desirable. In that case, I think I could set the AGS temperature a bit below the thermostat temperature. As the temperature rises, the AGS will start, and that will flip the ATS from shore power to generator power. Then, as the temperature continues to climb, the A/C will come on. The generator will stay running until the heat load no longer drives the temperature above the AGS trip point, at which point the AGS will stop the generator. The AGS temperature is set below the A/C temperature, so that the A/C never tries to come on while the generator is not running (which would overload the limited power source.) This scenario seems like it would work?

In a third scenario, we have no power hookups. The AGS is used to start the generator if the battery voltage gets too low (I use this mode routinely) and will also start the generator if the temperature gets too high (have not tried this yet.) When the batteries are charged, or the temperature goes down, the generator stops. This seems to be the primary design intent of the AGS system, and I don't see any issues running in this mode.

The last two scenarios are the common ones for us. We haven't had the first scenario happen to us yet, but I have heard stories where the shore power goes out, and the coach gets very warm.

Any comments on using the AGS this way? Any tips on a better way to set it up to handle the various situations?

[PizzaGuy]

I am not sure but when I was troubleshooting a bad rear Heat Pump, I convinced my self that the temperature sensor for the AGS was located at the Duo Therm Comfort Control Panel at the bottom. I am not sure how I came to this conclusion but somehow I was fairly sure of my results. It had something to do with the sensors at the front and rear of the coach turn on the air conditioners. The one at the duo therm turns on the generator when it senses 70 degrees or what ever the AGS is set to.

[bullydogs1]

Here is how mine works...I set it up on voltage only if we are not plugged in and we are boondocking it. I set it up on temp only when plugged in and I set it down low so that generator will come on within about 20 minutes of power failure (75 degrees) dogs walk the motorhome so the bedroom sensor is OK for me...Note that will a little tenacity, you can fish it up into the living room, but I wouldn't sweat it...the generator will not come on at all with mine whenever plugged into good shore power, regardless of temp., however if shore power cuts out the inverter kicks in and the temp sensor sometimes spikes (like an electric razor watching an old TV) and that will kick off the auto start. (that's OK...better it run than not run if power cuts out)...I disable the temp when on voltage because otherwise the spike might start the generator..I have new everything from Magnum but that doesn't stop the electrical interference spike. Regardless, it does what I want it to do (keep dogs cool).

[observer]

Shapeshifter,
Another thing that I forgot to mention is that the temperature sensors, for the A/C and the AGS, are greatly influenced by the heat in the rear curbside closet. If the rear of you coach is facing South on a sunny day it will be a lot warmer than the rest of the bedroom or the coach.

[ShapeShifter]

Thanks for the input, all. We're heading out this weekend, and while we will have power (only 30 amp, but I don't think we'll need A/C) I will still play around with it and see what I can figure out.

observer: yes, I've noticed that curbside rear shirt closet can be quite warm at times in hot weather, and quite cold in cold weather, but I've never considered the impact on the sensor. Maybe that explains why in cold weather I have to set the bedroom more than 5 degrees cooler than the living room to prevent the bedroom from roasting, while in hot weather I have to set the temperature higher than the living room to prevent freezing? I'll have to try leaving that closet door open and see if that stabilizes the temperatures.

Good information. If anybody still has information to provide, please do.

[ShapeShifter]

Originally Posted by bullydogs1

however if shore power cuts out the inverter kicks in and the temp sensor sometimes spikes

You've mentioned monitoring the temperature a few times, in this thread and the previous one. How are you doing it? I don't see the option on my remote. When I go into the tech menu, I see temperatures and versions, and looking at the temps it only shows the battery, transistors, and FETs (the latter two being internal inverter components.)

Am I looking in the wrong place, or is this something that's only available on newer remotes? My remote is version 1.2.

I want to get Magnum's BMK battery monitor kit, and the upgraded control panel to go with it. The BMK works much like a TriMetric monitor and tallies the total amps in and out of the batteries to determine a true state of charge (rather than inferring it from the voltage.) In combination with the new panel version, it allows you to set the auto gen start to trigger on state of charge, rather than voltage which can temporarily dip with heavy loads (like the water pump) triggering the generator earlier than normal.

If the AGS temperature sensor readout is only in later versions of the control panel, I guess that's another reason to upgrade the remote.

But in other news, even though I can't check the temperature on the remote panel, and I can't really see what's behind that slotted grille in the bedroom, I can see the back of that grille from inside the shirt closet, and there are indeed two sets of flat phone cable going in there. So I'm sure one goes to the thermostat, and the other to the AGS. Thanks for that information!

[itdave]

ShapeShifter,
While working on some other stuff I discovered a whole bunch of telephone cable coiled up under the washer/dryer cabinet. I now realize that this must be the cable that comes from the inverter. If you need to get to it pull the panel off that covers the space under the washer/dryer cabinet. When you look in there you should see a white plastic piece that covers the wiring coming up from the inverter.

[ShapeShifter]

Originally Posted by itdave

ShapeShifter,
While working on some other stuff I discovered a whole bunch of telephone cable coiled up under the washer/dryer cabinet. I now realize that this must be the cable that comes from the inverter. If you need to get to it pull the panel off that covers the space under the washer/dryer cabinet. When you look in there you should see a white plastic piece that covers the wiring coming up from the inverter.

We must have different layouts, because my washer dryer is in front of the bedroom, in the walk-through bath. (Under it is the bedroom furnace.) In that back corner of the bedroom I have shirt closet, with a drawer below. I took out that drawer this morning to peek, and there is a bunch of excess wiring in there (mostly going to the bedroom slide where the TV, power outlets, and CO monitor are) but there is also a bunch of excess phone wire which I also presume is for the temperature sensor(s).

The thought did occur to me to run it farther forward. I will experiment with the AGS functions, and if it seems like something I will use long term, I have considered moving it farther forward. Probably not all the way forward to where the zone 1 sensor is mounted, but maybe to the wall between the bath and kitchen.

[itdave]

Your right about layout my washer/dryer is located in the very back to the left of the wardrobe closet. Because of position of the AC vents and rear temp sensor I ended up unplugging the rear sensor and forcing the rear AC to be controlled by the sensor in the Comfort Control thermostat. Since the thermostat is located in the middle of the coach I have found that I get good temperature control of the rear AC. It seem to me that if you could get the AGS temp probe located near the Comfort Control Thermostat you would have a good sense of the coach average temp.