I hate it when your bus systems all gang up on you!!

[gumpy]

So, heading home from our trip today. I'm tooling along a country road where they idiots here in MN had routed major traffic due to a construction project. I notice my "heat" light coming on in the dash cluster. It's about 10:30 am, and the outside temp is around 75 degrees. I thought it a bit odd since I didn't have the air conditioner or heater on at the time. Didn't think too much about it, and changed the rheostat setting to colder so it couldn't be calling for heat and the light stopped coming on. 

About 5 minutes later, not that I was timing it, I hear a static buzz on the CB radio, and instantly, my "Not Gen" light comes on!  All kinds of four letter words rush through my mind, because the last time I saw that light come on while driving, it cost me about $1500 to replace the alternator and regulator.

I find a wide spot on the shoulder and pull over and check to see that the wires on the alternator are not broken and arcing against the case. Nothing seems out of the ordinary. I go back in to check through the hole in the floor, and shut off the bus as I go past. When I get to the back of the bus, I realize there's still a noise that I wasn't expecting. It's not the DD 6V92, though. It's not that loud. It didn't immediately register what I was hearing. Then I realized that I was hearing the generator engine running.

I checked the inverter remote, and sure enough, it was bulk charging. I checked the Tri-metric meter, and it said the batteries were 100% full. Now that's interesting.The batteries are full, and yet the inverter turned on the generator.

I had to stop a minute and figure this one out. I'm driving down the road. The crossover relay is activated, and I've been charging the house batteries off the bus alternator. They're at 100% but my inverter decides to start up the generator. Of course when the inverter kicked in the generator and started bulk charging the batteries at over 28.4 volts, the bus regulator saw the high voltage and said, "Well, the batteries are over my 27.2 volts, so I'll stop charging, which led to the "Not Gen" light coming on.

So, why did my inverter decide to turn on the generator? 

Well, remember I said the heat light started coming on, and about 5 minutes later the "Not Gen" light came on?  It turns out that I forgot to
turn off the house air conditioner thermostat before we started out this morning. I had actually thought about it earlier, but had not asked Teri to turn it off because she had just sat down. I figured I'd ask here the next time she got up for something, and then I forgot. So the thermostat was set to 74 degrees, and when the temp rose above that, it kicked on the air conditioner, which is a basement unit that uses the tunnel for return air. Inside the tunnel is a sensor that senses the temperature of the air going by and uses that to determine if the heat valve should be opened or not to regulate the temperature of the air being blown into the coach by the coach heating and air conditioning systems. When the air conditioner turned on, it started pulling air in past that sensor, and it decided it should regulate some as the rheostat was set to the warmest setting, so it called for heat; hence the "Heat" light in the dash. The inverter doesn't know the batteries are being charged by the alternator, and so after 5 minutes of running the air conditioner, the inverter said, "I have a load that exceeds 15 amps (my setpoint), and it's been there for 5 minutes (another setpoint). I should start up the generator so it doesn't deplete the batteries." So it did. When the inverter kicked in the generator and started the bulk charger, it overwhelmed the bus battery regulator, and it stopped charging; hence the "Not Gen" light.

Basically, all my well engineered bus systems just got together and turned on me today!

Be afraid!  Be very afraid!

craig

[Airbag]

At what point did you stir the tanks. Sorry Apollo 13 joke. 

[gumpy]

My wife swore she heard the bus say, "Good morning, Dave!"

[Stormcloud]

I'm glad you were able to successfully diagnose the problem.
It only goes to prove that you're not 'just another pretty face'....lol.

Have a great day!

Mark

[Jerry32]

That does spook a person tho, I had the same thought when I had just put on solar panel and forgot to disconnect the charge line from the bus. and sudenly going down the road the not gen light came on. Jerry

[Jriddle]

Things like Hello Dave and another name the comes to mind is Hal. Years ago we had a computer system we called Hal. It was an computer automation to run our kilns, that was supposed to learn from its mistakes.

Good luck
John

[Singing Land Cruiser]

Its good you used th Force to figure it out Luke, ah er Craig, M&C