Living on House Batteries

[Dale Barham]

2001 Patriot Thunder.  We have 2 fairly new chassis batteries and 4 almost new Trojan 105 house batteries.  We are full-timing and normally plugged in to 50 amp shore power, but are now boondocking for a few days and have questions about the draw on our coach batteries. 

We found that with everything turned off (Refrig on LP, no lights, nothing plugged in to 12v, but still have basic indicator lights and functions) we use 3 - 4 amps.  Lights use only an amp or two, occasional water pump.  When we use the inverter, DirecTV box comes on along with TV & stereo indicator (off) lights,  microwave clock panel, etc. and we are using 10 amps.  Turn the TV ON and it is another 3 amps.  Does this all sound reasonable?  Now for our operating questions:

1.  If the house batteries (and chassis) are fully charged (would that be around 13.5v?), how long should our 4 Trojan batteries last if we are NOT using the inverter for AC power (using apparently 4-6 amps)?  We have not even been running our HydroHot.  Assume night, with no solar trickle.

2.  If we want to then watch TV, should we be able to turn on the inverter and watch for, say, an hour or so?

3.  What is the lower limit for the coach batteries - we are getting down to 12.4v very quickly, and don't want to drain the batteries.

4.  On the ProSine panel next to the CMP-20 over the door, I know we need to have it on CHARGE for the batteries to charge from 50 Amp OR Generator, but does the Inverter button need to be on standby also?  And will the solar panel charge the batteries with the ProSine panel OFF?

Any tricks or tips for living on house battery power only would be appreciated.

Thank you!

Dale & Sue Barham
Currently Mesa, AZ, on the move

[Jerry Emert]

I also have 4 6v batteries for the house side.  When dry camping I've found that our batteries will last pretty much all evening with the inverter on and watching two TVs plus normal lights and stuff.  But, I will usually run the genny from 8-10 at night to top off when I think of it just to be safe.  Then TV watching goes on to 0100-0200.  I run the genny from about 0700-0900 then not until evening.  I also have the genny set to auto start if batteries go down to 11.9 volts.  That has happened once in the middle of the night when I forgot to switch the Norcold to gas.  Yes I have the norcold on the inverter plug so it runs off the inverter when I'm driving. 
Jerry

[David T. Richelderfer]

Your power draw examples look similar to ours.  We have six 6v golf-cart style batteries from Les Schwab's that are about 4 years from new and for about 2 years have had a Xantrex Freedom 3000w inverter.  Your inverter is a Xantrex Prosine 1800w or 2000w, I assume?

We always have our inverter ON.  Overnight we like to run the bedroom TV and our batteries will usually not last the night.  The batteries run-down enough by 3:00 to 4:00 am for the Auto Gen Start (AGS) to kick on the onboard diesel generator.  Therefore, we purchased a Honda EU3000is portable generator to run overnight to keep the batteries up and power the TV, lights, fridge on 110v, etc., and prevent the onboard diesel generator from starting.  The Honda generator is electric key-start and has a 3.6-gallon gasoline tank.  The Honda will just idle along all night and will run on a single fill for upwards of 20 hours.  We cannot hear the Honda generator when it's chained and padlocked to the pickup's tailgate when running.  Honda generators are known for being quiet; ours is advertised at under 60 decibels!  If it looks like rain, then I slide the generator under the pickup's tonneau cover out of the weather and still chained and padlocked to prevent it from being stolen.

We used to dry camp quite often, not so much these days.  But on our several-day trips from home to our Yuma, AZ digs and back, we dry camp most of those overnights and have also used the Honda generator at RV parks and campgrounds when their power is out, which isn't often.  We are set-up for comfort, I guess.  lol

[Bill Sprague]

You can't use voltage as a measurement of battery life unless there is a zero load and a battery has rested for about a half hour.   In other words, you have to remove it, put it on the ground and wait.  That obviously does not fit the RV lifestyle.  The systems in a motorhome are only best guess estimates.   Serious off grid homeowners use meters that measure amps in and out to provide a higher accuracy.  Stock Beavers don't have those.

Deep cycling a battery only means you are going to have to buy new ones sooner rather than later. 

The best way to dry camp a Beaver (without a roof full of solar panels) is to run the genset in the morning and evening for about an hour and a half each.  Batteries won't charge fast so it takes that much to keep them operating in their upper half.  Don't try for a full charge because the last 10% takes a long time.  Save full charging for when you are plugged in.

The control panels are made so you can set up for auto genset start.  Keep the settings toward the higher voltage range and it will keep your batteries in the top 50% range for long life.  The lower setting are for applications like ambulances where they choose to sacrifice battery life. 

[Dale Barham]

Thanks, all.  Bill, I think you explained what we need to do - run the generator regularly to keep the batteries charged.  That leads to the next question, how do you set up the generator to automatically start (AGS)?  Can it be programmed or do we need to buy something to make that happen?

I will research on this.  Appreciate the responses and think we have a better understanding now.

[Bill Sprague]

Our '04 had a Xantrex inverter control panel above the entry door.  The AGS was programmed and controlled from there.  The trick was understanding the instructions!

Onan does make an add on component.  I don't know how it works. 

Frankly, the AGS really did little.  Twice I had a little electric heater plugged in when the shore power went out.  It didn't take long to bring the batteries down to force a genstart.   In an otherwise quiet moment it scared the crap out of the sleeping dog!

[Dale Barham]

Great story, though!  We are still thinking like we did when we had our 1999 class C - we could take the kids and camp for 3-4 days just using limited lights and water pump, and a few other 12v things.  The answers to this post seem to tell the story that we need to run our generator - something we have never been inclined to do.   

We'll now check our ProSine Manual instead of the Onan manual for AGS programming.  We're planning on the Beaver Club at the FMCA Western Region Rally in Indio.  Hope we have lots of new friends (!) to help us along.  Thanks, Bill!  Will see you at Ft. Flaggler if not before.  Not going to miss the pulled pork this time!

[Bill Sprague]

.... Thanks, Bill!  Will see you at Ft. Flaggler if not before.  Not going to miss the pulled pork this time!

You want pulled pork, beef brisket, Dutch oven biscuits, ribs, deep fried turkey, a crab feed?  I'm learning Cioppino too.  We smoked a turkey in the Chuck Wagon for thanksgiving at my son's house.  There were NO leftovers.

See you in June!

[Gerald Farris]

Dale,
The 2001 Thunder did not come with an AGS. So you do not have one unless the previous owner added one.

Gerald

[D. Wendal Attig]

Gerald,
Should my 2002 have an AGS I can program in my Prosine 2.0?
D. Wendal

[David T. Richelderfer]

The Prosine 2.0 manual I accessed online did not indicate anything AGS... that I could see.

[Gerald Farris]

D.
The 2002 Patriot that was equipped with a Prosine inverter did not come with an AGS. So you do not have one unless it was added by a previous owner.

Gerald

[Ron Baisley]

I now have 4 160 watt Solar panels I also have 4 AGM - 6 volt batteries the batteries were almost $500.00 a piece. They charge quicker and hold the charge longer. They are maintenance free. I can even run my microwave off Solar. And in the winter if I’m not in the rig ,I don’t worry about winterizing the RV I turn my Furnace on 50 degrees and let my Solar and Batteries keeps everything from freezing. The AGM Batteries make a world of difference. To me it was and is worth the price. Ron

[William Jordan]

We have 6 - 6 volt batteries and run the inverter 24/7 your draws are about right. As noted measuring voltage while your drawing amps esp 8+ amps a well charged battery can easily drop to the mid 11 volt range. More with more draw  The Auto start measure of this voltage in not a good way to determine startup, unless it’s set for long draw .. like below 11.5 for several hours. Just dropping to 11.5 for a few minutes  is normal and if not programmed properly will start the genset.
We installed a trimetric monitor to measure amps in and amps out giving us a accurate assessment of battery life and have never come close to needing a generator run in the overnight. 4 6 volts should have 400 amps +\- of which you can use 50% so 200 amps .. multiply your normal draw times the hours in use .. don’t exceed 200.
A generator run of 1-2 hours at dinner and 2 hours in the am should get you easily by. We don’t schedule generator runs we just turn it on and off manually. We have since added 800 watts of solar and still do a short a.m. generator run to quick charge and then  let the solar bring them up to 102 % .. no more evening runs unless we need the convection or air.