Inverter on or off?

[PlanBee]

So I stayed at a Walmart and had house batteries drop to 10.8 volts overnight. We had basically nothing on except the Aquahot was running frequently as it was cold out, in the 30F range. I know that was drawing plenty. My wife likes to run the AC fan for the noise, but we did not.

Only other things was maybe 2 cell phone chargers plugged into AC outlets, inverter was on.

Would turning the inverter off help at all?

AGS should have started, but that is something I need to look at because it didn't. Generator wouldn't turn over in the AM, I started the engine and then after a few minutes I started the genny. I didn't use the boost button although I could have, I think I was just interested if the chassis batteries were going to start the main engine.

When overnighting should I be able to run just the fan on the bedroom AC?

Batteries were brand new Interstates last year, 4-6 volt, they are all topped off with water. I did have a issue with house batteries not sending power anywhere one time, but it hasn't re-occurred but I think it might be the relay. Maybe they are not charging well off the alternator, so when I parked they were not topped off.

There sure are a lot of systems on these busses.

[153stars]

I don't think if your batteries should of gone from full charged to to flat overnight with Aqua hot running ,inv., refrig.panel And a few other small draws . I think you have a control center that controls bank charging and genny start in one. If you look that up online or in manual ,get the name of it If that's right and maybe your issue. Rephrase your question maybe . And search for problems like your with it.

[153stars]

If you scroll down this page shows a pic of a control center. From a HR. Not sure what you have exactly. But if you charge your chassis batts fully . Test resting voltage house batts. Run your motor as you retest house batteries and see if get a higher charging voltage to them. You may have to draw some power out of the house batteries the chassis batts have priorty of alternator.
There are white noise machines that are more energy effeciant than a fan ...lol
There are spreadsheets you can plug all your numbers into for power amp draw battery capacity.

[cavie]

Originally Posted by PlanBee

So I stayed at a Walmart and had house batteries drop to 10.8 volts overnight. We had basically nothing on except the Aquahot was running frequently as it was cold out, in the 30F range. I know that was drawing plenty. My wife likes to run the AC fan for the noise, but we did not.

Only other things was maybe 2 cell phone chargers plugged into AC outlets, inverter was on.

Would turning the inverter off help at all?

AGS should have started, but that is something I need to look at because it didn't. Generator wouldn't turn over in the AM, I started the engine and then after a few minutes I started the genny. I didn't use the boost button although I could have, I think I was just interested if the chassis batteries were going to start the main engine.

When overnighting should I be able to run just the fan on the bedroom AC?

Batteries were brand new Interstates last year, 4-6 volt, they are all topped off with water. I did have a issue with house batteries not sending power anywhere one time, but it hasn't re-occurred but I think it might be the relay. Maybe they are not charging well off the alternator, so when I parked they were not topped off.

There sure are a lot of systems on these busses.

Not unless you run the generator.

[jacwjames]

Have you boon docked before, have you been able to go overnight in the past. How new are your batteries, what condition are they, when was the last time you checked the water level?
Leaving the inverter on will result in more of a draw, everything that is plugged will draw a little power which results in a large draw.

We normally top off our batteries before going to bed. We normally turn our inverter off.

[Dom]

Had same exact experience as you, Walmart, inverter on, low batteries next morning. then next time inverter off, and batteries, with furnace, in February ran all night no problem. So inverter off at night

[vito.a]

With your inverter off, you will not have any 110V AC power unless you run the generator or plug the coach into a power pedestal.

I think you need to zero in on if your batteries were fully charged when you parked?

Most of these coaches have an Intellitec Big Boy isolator relay in the rear run box that ties the chassis batteries to the house batteries, but only after the chassis batteries are charged to a minimum voltage. (This relay works the opposite direction when you are plugged in.)
These relays can be problematic. I have rebuilt/replaced them on both of our last two Monaco motor homes.

Some other thoughts:
Did you run any heat producing devices during the evening?
Did you run the microwave?
Are your battery terminals and cables clean?
Could one of your batteries had a bad cell?
What refrigerator do you have and how many amps does it require?
Have you replaced your lights with LEDs?

Link to Intellitec Big Boy relay:
https://www.amazon.com/Intellitec-77.../dp/B077YR1W55
You can also remove it, disassemble and and clean the copper contacts. Be careful, lots of current there.

Hope this helps.

[PlanBee]

I think I do have some issue with charging and or a relay. I had an issue last fall where when I went to the bus there was no power, like the batteries were dead, but just pushing the boost button everything was fine. it did that twice, and I had kept my fluke meter handy for when it did it again so I could diagnose it, but of course it hasn't done it since.

I had checked the charging last fall and everything was getting 14.4 when engine running, or when plugged in and charging, but I think it is intermittent.

All batteries are less than 1 year old and full of water.

I think I will replace relay or clean it up. I have a lot of experience with 12 volt systems, but not the systems on the coaches. The isolators, etc are all new territory.

[RamiDav]

Starting off the evening with the batteries fully charged is a difficult thing to get used
to .

When you park the coach the batteries start being discharged right away , TV
lights and other things . It doesn't take long and they are half discharged .
On top of that it takes a lot longer than we imagine to fully charge them back up .
Running the gen until bed time might be necessary or at least for a couple of hrs
then shutting all the extra stuff off .

The Aquahot draws quite a bit of battery . Each zone has a fan some have 2 plus
each zone has a pump so with 3 zones plus the burner fan that's over 7 elect motors .
That's a lot for the batteries to keep up with .

When allowed we just run the gen that way we are comfortable and we can run
all our stuff all we want .
After all isn't that why we have the gen ?

[153stars]

Originally Posted by RamiDav

Starting off the evening with the batteries fully charged is a difficult thing to get used
to .

When you park the coach the batteries start being discharged right away , TV
lights and other things . It doesn't take long and they are half discharged .
On top of that it takes a lot longer than we imagine to fully charge them back up .
Running the gen until bed time might be necessary or at least for a couple of hrs
then shutting all the extra stuff off .

The Aquahot draws quite a bit of battery . Each zone has a fan some have 2 plus
each zone has a pump so with 3 zones plus the burner fan that's over 7 elect motors .
That's a lot for the batteries to keep up with .

When allowed we just run the gen that way we are comfortable and we can run
all our stuff all we want .
After all isn't that why we have the gen ?

He also pointed out his AGS didn't start his genset for him .You have far more experience than I do with his system.Assuming his tank was over 1/4 And AGS was active. Root cause would lean towards control system . Is this is the system that controls alternator and 120v battery priority? If intermittent that can be a pain to get a handle on.
His batteries may have been full charged before shutting down his rig.
He wanted to get his house batteries recharged so started genny. I'm curious if the engine would started charging them back up as well. If big boy would have got control power to pull in.

[PlanBee]

I drove approximately 480 miles from my home that day in a little over 7 hours. I'm sure the batteries were all fully charged when I left home. I never looked at voltage when I pulled into Walmart.

I have all LED lights inside, a few were on until we went to bed within an hour, no TV, radio or anything else were on. Just the inverter was on, a few phone chargers in 120VAC outlets and the heat from the aquahot.

Probably went to bed at 10:30, was up at 7:30.

Fuel was over half tank. And even if it was low wouldn't the genny try to start, I know I have had it running until it quit under 1/4 tank. Does it run until out of fuel, or is it tied to gauge and shuts off based on that and not actually running dry. I thought it just ran dry when the pickup was higher than the level in the tank.

Now that I'm thinking of it on the way home from that trip I ran genny last 2 hours before stopping for the night. Everything else was the same, heat etc. and I had no issue with low voltage in the AM.

SO much stuff on these coaches I don't even know if I have a problem or not, I just thought I would be able to stay overnight with next to nothing running without a battery issue.

[twinboat]

I'v haven't seen any fuel gauge controlled generator shutdowns.

They all just run out of fuel because the tank pickup pipe is set higher in the tank. When the pickup pipe is exposed to air, the fuel stops flowing and the engine runs out.

[96 Wideglide]

I found they had wired my AGS module wrong, and the sensing voltage wire was coming from the chassis batteries rather than the house batteries ! So, although I had AGS set to start when batteries reached 11.9V, the generator wasn't planning on "trying" to start, till the chassis batteries dropped to 11.9V.
If you would like, I can have a look and let you know the wire color, and position on the AGS module, so you can check that. It's a simple fix to run a new wire to a house battery power source.

[vito.a]

First you need to see if the AGS is even set up to turn on and at what voltage. Check your Magnum remote menus.