Silly RV2012 inverter question

[jacwjames]

I had read where some people put there rigs on timers, I was hoping to use the KISS method, so the my wife will be able to monitor/understand so figured having it plugged in to a timer was the way to go.  I bought a 7 day timer and was initially planning to have it turn on once a week maybe for 4 hours.

I need to leave the battery disconnect connected for the charger to work.  

Problem is that if I leave the battery disconnects on the inverter will have a parasitic draw on the batteries. 

If I turn the switch on the inverter off will the charger still work?? 

Only other option would be to get a multiple bank charger and hook directly to batteries.  

 

I've had my rig unplugged for ~a couple weeks and notice that the chassis battery is depleting faster then the house.  When I checked yesterday  via the BMV712 the house was reading 12.66 volt, chassis was 12.58,  So I think topping ir off once per week would work. 

 

[Frank Bergamo]

Turn it off, then check the voltage at the batteries. If it is above 13 volts, it is charging. 

[CAT Stephen]

Jim, 

That depends on your inverter.  What is the make and model of your inverter?

[Tom Wallis]

I'm not sure there's any advantage to a timer. The optimal thing for the batteries is to have the built in multi stage charger on all the time. It will maintain the batteries properly and give them the longest possible life. If it's power consumption that concerns you I don't think charging is the problem. If the batteries drain while the power is off the charger will use more power when it does come on. When my motorhome is plugged in and charging in float mode it uses less than 50 watts of power. If you're using a lot more than that I would look for parasitic loads on the 12v system and or find out if there are other things drawing 120v. Even with the inverter on, if there are no 120v loads the power consumption should be insignificant.

[Ivan K]

My Trace 3012 charges with inverter portion off and I never turn batteries off. 

[Tom Cherry]

Jim,

From the hip.  And you probably have taken this into consideration 

what is the rated contacts of the timer.  My assumption, based on coats, that you are planning on using a 15A 120V non GFCI circuit.  So, you have to set the input or SHORE to the proper source.  Yes, you have a TRACE, but folks with Magums will also want to consider….so this is generic.

Next up.  Battery cut off switch….YES, TO LEAVING ON.  YES…that will mean the Inverter Is in standby mode.  YES, there is a parasitic load on any inverter that is ON…with NO AC.  SO, unplug every appliance and electronic device (microwave, TVs, home entertainment, etc.

Now with the inverter in standby and no AC Shore, measure the parasitic load and calculate the watts lost or amp hours.  Then use a 85% efficiency and see how long you need to leave it on.

MY OTHER sage advice. Turn off the batteries.  Verify no parasitic load on each. On my CAMELOT, the inverter is hard wired via a 300 A fuse, so disconnecting the Negative is the only way to isolate. Somewhere, I recall the TCM & ECM might be fed upstream of the cutoff switch.  The rule of thumb from many folks with extensive electrical knowledge was that you needed 1.75 amps to maintain.  The rule of thumb was…get 2 amps per bank.

Pulse Tech makes gang chargers. Used for boats, stored cars, etc.  there are other brands.  Get a maintainer that also desulfonates.  Hook it up and forget.  

[Gary 05 AMB DST]

I'm going into my third winter in Ohio, something never planned. I winterize it and put it on level pilings at the vertical frame points. Put a 700w oil filled radiator space heater in the living room and have fans constantly blowing air throughout the motorhome. Leave all circuits, 120v, 12v on and keep the Samsung refrigerator on. Set the thermostat on the space heater at upper 30's and let it go all winter. The temperature goes from low 40's at the ceiling and above freezing at the floor. Makes it easier to do any work in the MH, just raise the thermostat or turn on the furnace. My feeling is that everything would always be on, even if I were snowbirding, so there is nothing happening out of the norm. I will not start the diesel engine all winter because I don't want it heating up and expanding then cooling down, too much stress on the engine in my opinion.

Edited December 9, 2022 by Gary 05 AMB DST
better explanation

[jacwjames]

1 hour ago, Gary 05 AMB DST said:

I'm going into my third winter in Ohio, something never planned. I winterize it and put it on level pilings at the vertical frame points. Put a 700w oil filled radiator space heater in the living room and have fans constantly blowing air throughout the motorhome. Leave all circuits, 120v, 12v on and keep the Samsung refrigerator on. Set the thermostat on the space heater at upper 30's and let it go all winter. The temperature goes from low 40's at the ceiling and above freezing at the floor. Makes it easier to do any work in the MH, just raise the thermostat or turn on the furnace. My feeling is that everything would always be on, even if I were snowbirding, so there is nothing happening out of the norm. I will not start the diesel engine all winter because I don't want it heating up and expanding then cooling down, too much stress on the engine in my opinion.

I live in E TN so temps get too extreme but occasionally we will have temps down below zero.  Last year I didn't winterize, first year that I've had a garage to park it in and did do some work on the motorhome.  I let the system heat on and kept a cube heater in the LR area.  I was able to monitor temps via the MicroAir thermostat.  I din't know if I'd be taking a trip so it seemed convenient to just leave it plugged in.   Never had any problems other then pretty high electric bills. 

Being the penny pincher I am I wanted to figure out a way to conserve power.  Last month I did put a Kilowatt monitor on the coach to see what was the power usage leaving the inverter and charger doing it's thing.  It wasn't a lot of power but it does add up. 

So the current plan would be to let the caoch plugged in using a timer, charging the batteries 4 hrs a week (more if necessary)  But if this will shorten the life of the batteries I'll consider getting some sort of battery maintainer. 

 

FWIW, when I went out to the coach to turn on the disconnects and turn off the inverter there is a little printed warning right under the switch that warns that the charger will stay on.  Guess I should have looked at that first. 

 

[96 EVO]

My Magnum 2012 will charge the batteries with the inverter mode turned off.

[Tom Cherry]

28 minutes ago, 96 EVO said:

My Magnum 2012 will charge the batteries with the inverter mode turned off.

YES,

BUT, the inverter is STILL drawing power.  So, when you leave the INVERTER in the CIRCUIT.....it connects to the battery....and there is a drain.  Remove the batteries....and you will see no LOAD.  If you use a good (milliamp) clampon AMMETER, you should be able to read the parasitic drain.  Magnum says.....THERE AIN'T NO FREE LUNCH.  Turn off the INVERTER....and don't charge the batteries....and it will STILL pull power.

I have never felt the need to personally measure that, so I am taking them at their word.

NOW, if you are like one of the other POSTERS that has a concern on another topic about being able to exist on 30 amps....the, YES, you can EITHER turn off the INVERTER.  Now, I THINK that will also KILL the internal ATS so you have NO house appliances.  Again, I don't do this....so maybe someone can experiment with both and let us know...

[jacwjames]

Ok, yesterday I plugged in the coach with everything off except the charger.  Initially it was drawing higher amperage, ~5 amps and charging 14.5 volts, but today it was down to ~1 amp and the batteries on float at 13.4 volts.  I used ~2.6KW for 24 yours, so ~$0.35, so ~$10/month.  I think it will be slightly lower if stays in float charge.  

I am going to leave it plugged in for the next week and see what the total power consumption is.  

[TomV48]

On 12/9/2022 at 4:16 PM, Tom Cherry said:

YES,

BUT, the inverter is STILL drawing power.  So, when you leave the INVERTER in the CIRCUIT.....it connects to the battery....and there is a drain.  Remove the batteries....and you will see no LOAD.  If you use a good (milliamp) clampon AMMETER, you should be able to read the parasitic drain.  Magnum says.....THERE AIN'T NO FREE LUNCH.  Turn off the INVERTER....and don't charge the batteries....and it will STILL pull power.

I have never felt the need to personally measure that, so I am taking them at their word.

NOW, if you are like one of the other POSTERS that has a concern on another topic about being able to exist on 30 amps....the, YES, you can EITHER turn off the INVERTER.  Now, I THINK that will also KILL the internal ATS so you have NO house appliances.  Again, I don't do this....so maybe someone can experiment with both and let us know...

When I am on 15 amp at home, I leave the inverter off.  Both of the pass-through 15 amp circuits that would be fed by the inverter, if not on shore power,  still pass current. So with at least my 17 yr old Magnum 2012 it's no problem to shut inverter off and still use the shore power. At least that way if you lose shore feed the battery will not have a load.

[Tom Cherry]

10 minutes ago, TomV48 said:

When I am on 15 amp at home, I leave the inverter off.  Both of the pass-through 15 amp circuits that would be fed by the inverter, if not on shore power,  still pass current. So with at least my 17 yr old Magnum 2012 it's no problem to shut inverter off and still use the shore power. At least that way if you lose shore feed the battery will not have a load.

Don’t doubt that.  Myself and others have debated the “way it works”.  We were told by Magnum that you had to have the Inverter ON and a reasonable facsimile of a battery hooked up to activate the the internal ATS.  Some thought that was a running change….but we have had members with crappy house batteries that prevented them from having the pass through 120 VAC circuits.

THEN, again directly from Magnum….when you turn off the Magnum from the remote,,,,it is NOT technically OFF.  It is actually  in a  standby mode.  So, it is still pulling power or using current.  Again….not tested that.  But wonder if you actually went outside and killed the power ON THE INVERTER….by doing a Soft Reatart.  It comes back to life.  BUT, it requires you  to push the Power On button again.  I THINK you can start it from the inside remote…..so that seems to indicate that it never turns off, except by pulling the AC on the Main Panel.  And if you do that, that obviously kills the incoming AC…so no main power.  Magnum says that unless you disconnect the batteries, it will remain in “standby” and will have a parasitic load.

[96 EVO]

I do the same as Tom Pratt when I'm parked at home, but on 30A shore.

This time of year I have a dehumidifier running on a timer in there. I leave the inverter turned off so that if I had a power failure, it wouldn't run off batteries.

Inverter off, it passes AC power. Inverter and battery charger off, it passes AC power.

[TomV48]

I think that Tom Cherry is correct.  It is still in a standby mode with inverter off, and I have not tested to see what happens if I tern the charger off too.  I think it is still in a standby status too so probably some parasitic load.    I'm just spoiled that I do not have watch it too close with 600 amps of LIFEPO.

[96 EVO]

Possibly drawing a bit. My intelletec meter is generally showing 1AC amp, but that is with 2 tv's and a audio receiver in standby mode. Likely 1 amp is the lowest it will display.

[Fountdf]

Jim, don't know if you insulated your building when constructed, but I built a 35x50 and insulated with the commercial fiberglass rolls 6 inches thick. Of course I live outside of Atlanta so temps are not as extreme as yours. However, I don't use inside heat until the temps get below 20 degrees for more than 2 days. the slab will keep the inside temp above 35 to 40 without heat. I usually do not have to winterize. But if the temps stay below 20 degrees I will use heat either a heat pump set on its lowest setting or small automatic heater inside the MH. And I usually let the inverter stay on automatic for the batteries, and of course household frig stays on. FWIW. My chassis batteries are not charged by the inverter circuit so I keep a check on them and used a battery Minder with desulfater capability. And I try to remember to use the battery minder on the house batteries about every six months as well. Again FWIW.

[jacwjames]

Fountdf   David, >>>>My garage is insulated but not to the level you did yours.  Wish it was but it is what it is. 

I did build a 23' X 26' work shop inside the garage.  Earlier this year I installed a mini split which easily keeps the shop area warm and I leave the 8' sliding door open it will provide some benefit to the rest of the garage.  

But winterizing my coach is the safest thing to do to make sure I don't have a problem with freezing pipes etc.  Since the coach is winterized I'll charge the batteries as needed to maintain them. 

Now that I've confirmed the charger works without the inverter being on I unplug and see how long the batteries stay up and then set the timer I have to charge as needed. 

[Tom Cherry]

12 hours ago, 96 EVO said:

Possibly drawing a bit. My intelletec meter is generally showing 1AC amp, but that is with 2 tv's and a audio receiver in standby mode. Likely 1 amp is the lowest it will display.

YES….MAYBE…

Again, my understanding.  As long as the inverter is hooked up to your house bank, it is “drawing” power….or is a parasitic load.  That is what keeps it in “standby” and you can NOT turn it off….I assume from the remote.  The “power” button on the inverter is a “momentary contact” switch.  Thus, for it to be “on” there has to used to turn it on, there has to be power on the control board.  That minute standby current is parasitic and it is inconsequential when plugged in.  If your battery disconnect switch kills the circuit between the house and the inverter….then you have no parasitic drain.  BUT Monaco used two different configurations.  Maybe different on older units or different models.  Mine has a 300A fuse which directly connects the house bank to the inverter.  I can turn off the house bank using the HOUSE CUT OFF switch.  But, the house bank runs directly to a two (output) buss or terminal.  One side goes to the 300 A fuse and that goes to the Magnum.  The other goes to the Battery Cut OFF switch.  So, all “house power” is killed, but the inverter is “on standby”.  One needs to look at their prints or go into the RRB and chase cables.  There is no “Monaco always did it this way”.

Your point about what is displaying, if it reads AC, means that the Charger is OFF and the power, coming from the shore, is being measured and passing through the PCB.  Now, that is what the manual says and the remotes have changed.  Typically, with the shore plugged in and charger on….or the default use, the remote will display “DC” voltage.  When there is NO Shore  and the inverter is ON, it will say Inverting and display amps and DC.

When you see “AC”, I think the above is the only time.  YES….the amperage going through is the parasitic draw of the “Standby circuits” as well as the Microwave, which is always ON, unless you unplug it….which I do….  And one amp is the lowest it will display.  Again, Monaco did strange things.  But the ONLY away to totally kill a parasitic load is to be able to disconnect the Magnum from the House Bank….and that depends on how Monaco configured it.  For example….if I turn OFF my House Battery, I lose power to the Magnadyne dash radios’ memory.  BUT some of the Dynasties will allow to use the radio from EITHER House or Chassis….key on or off.  Mine is “key on or accessory” from Chassis….but memory lead is from House.

Isn’t Monaco great in that it keeps us intellectually challenged…..
 

 

[jacwjames]

So it's been about a month since I started this thread.  I did end up getting a digital timer and programmed it to come on ~4 hours on Friday.  I leave the inverter off, the house and chassis battery disconnects on, saleman switch off, and coach plugged into the timer.  

Been a little bit of learning experience but finally confirmed yesterday that it activated and charged the batteries.  Having the Victron display and bluetooth makes it easy to check.  I've been keeping track of the battery voltage anytime I'm out in the garage.  The voltage will say above 94% until the charger comes on to top them off.   Going to continue to monitor the batteries but if it continues to maintain the batteries using this method I don't see any down side.