Inverter

[minpintft]

If the RV is not hooked to shore power how long will the inverter run the residential refrigerator? Thinking of a future trip which will involve boondocking and don’t want to run the generator non stop.

[nosticks]

Till the battery is dead. Underway, your alternator will charge your battery. Boon docking, depends on your power usage and that's a question that can not be answered with any accuracy here.

[TurnerFam]

agreed, so many folks ask this same question, but it's not one anyone else can answer but you. YOUR situation and how your use it and how you 'camp' and your expectations and how much 'stuff' you put in it and how often your open the door and how 'low' your set the temperature and whether you want the ice maker to make ice.... etc, etc... you get the idea.

what is your make and model of RV?
what type of fridge do you have?
how many batteries for the House do you have?
what make and model Inverter do you have?
do you have an AGS(automatic generator starter)?
do you have a battery charge/level readout?

you'll not be needing to ever run your generator 24/7 'just because' you have a residential fridge, if that's indeed what you have. most any manufacturer is going to provide at least two 6v deep charge House batteries, even if just for the fridge. Your inverter will take the 12v battery output and turn it into 120v outlet power for the fridge, and even possibly other outlets in your RV. Your generator will charge the batteries when off-grid, but how often and for how long truly is subjective to your situation at the time. None of us have an 'exact' amount of time that a generator runs... it will depend on the usage. Everyone is different. Plus, some of us turn our fridge 'up', or even 'off', during the night.

[Miramar Owner]

As others have said there is a lot of unknowns but I can tell you of my experience. I have a 2016 Miramar with an 1800 watt inverter and had 2-6 volt deep cycle batteries. I would turn the generator off at 10:00 pm and the low battery warning would begin beeping at 5:00 am.

I had the AutoGenStart set to not run from 10:00 pm to 7:00 am so I couldn't make it through the night. I replaced the 2 batteries that came with the coach with 4-6 volt 235AH batteries. I haven't had a problem since.

You could also shut off the fridge just before going to bed and it should remain cold enough through the night. A couple hours of running the generator should bring the batteries back to normal.

[DanChateau33SW]

2015 Chateau 33SW on the F-550 chassis.

I have been having troubles with more than about 30 minutes on the inverter with the fridge, so have been wondering the same thing for a couple of months. The batteries were new in 2017, 2 under the step in the battery compartment, and a 3rd added in the storage compartment with the inverter. I did notice the other day that 2 of the batteries are starting batteries and the 3rd is a deep cycle, all 12V. Could the starting batteries be causing part of the issue? It's pretty frustrating that the inverter starts alarming very soon after switching from shore power to battery.

[TurnerFam]

Originally Posted by DanChateau33SW

2015 Chateau 33SW on the F-550 chassis.

I have been having troubles with more than about 30 minutes on the inverter with the fridge, so have been wondering the same thing for a couple of months. The batteries were new in 2017, 2 under the step in the battery compartment, and a 3rd added in the storage compartment with the inverter. I did notice the other day that 2 of the batteries are starting batteries and the 3rd is a deep cycle, all 12V. Could the starting batteries be causing part of the issue? It's pretty frustrating that the inverter starts alarming very soon after switching from shore power to battery.

doubtful, since only the one battery is for the House, or thru the Inverter... the starting batteries are for the vehicle/coach only, nothing to do with the inverter or running the 'fridge'...

12v batteries aren't the best for 'deep charge' usage, which is what you need for slow consistent drain on the batteries from inverter usage. Two 6v deep cycle would work much better, longer. Most of the larger coaches have a least 4 of these, and most all have residential fridges, but most smaller coaches only provide 2 6v batteries on a smaller 'fridge only' inverter.

[jpmihalk]

Originally Posted by DanChateau33SW

2015 Chateau 33SW on the F-550 chassis.

I have been having troubles with more than about 30 minutes on the inverter with the fridge, so have been wondering the same thing for a couple of months. The batteries were new in 2017, 2 under the step in the battery compartment, and a 3rd added in the storage compartment with the inverter. I did notice the other day that 2 of the batteries are starting batteries and the 3rd is a deep cycle, all 12V. Could the starting batteries be causing part of the issue? It's pretty frustrating that the inverter starts alarming very soon after switching from shore power to battery.

Sounds like the wrong type of batteries are being used for the wrong application. Your starting (chassis) battery should be a 12V starting battery, but the house batteries should be deep cycle (either 6V or 12V.) You may want to consider replacing the house batteries with good deep cycle batteries, and move the starting battery to the chassis battery wiring. If they are sealed lead acid batteries, you may also want to check their water levels and top them off (cover the plates) every so often with distilled water. Constant charging tends to wreck SLA batteries as the fluid boils off and the level goes down, uncovering the lead plates and making them less effective. If you choose to replace them, I would recommend AGM (absorbed glass mat) deep cycle batteries as they are pretty much no maintenance batteries.

[DanChateau33SW]

I should clarify that the starter batteries I ma referencing are not the chassis batteries. They are coach batteries, connected to the 12V coach side. A 3rd deep cycle was added, presumably because there wasn't enough run time with the 2 that were installed.

[DanChateau33SW]

Originally Posted by jpmihalk

Sounds like the wrong type of batteries are being used for the wrong application. Your starting (chassis) battery should be a 12V starting battery, but the house batteries should be deep cycle (either 6V or 12V.) You may want to consider replacing the house batteries with good deep cycle batteries, and move the starting battery to the chassis battery wiring. If they are sealed lead acid batteries, you may also want to check their water levels and top them off (cover the plates) every so often with distilled water. Constant charging tends to wreck SLA batteries as the fluid boils off and the level goes down, uncovering the lead plates and making them less effective. If you choose to replace them, I would recommend AGM (absorbed glass mat) deep cycle batteries as they are pretty much no maintenance batteries.

Thanks for the reply.

I was thinking they installed the wrong application of batteries also. If I change out the 2 batteries to 6V and still have the 12V deep cycle, am I going to have any problems? Seems that I wouldn't want to mismatch the system like that.

I would definitely go with AGM if/when I replace them. You get better aH and less maintenance. I was thinking also o fbuying pure lead batteries for more run time. Thoughts?

[Chance]

Dan, if you install two new 6-Volt batteries they will be connected in series to provide the same 12-Volts, so that in itself isn’t the biggest problem. In my opinion you don’t want to connect AGMs and flooded together because they have different charging requirements.

In the long run you’d probably be happier with 4 new batteries. Your existing deep cycle battery may not be that great already. If you go with AGM, check converter to see if you can switch charge setting from flooded to AGM.

By the way, I like AGM batteries, but I’m not sure you get more amp-hours compared to flooded for the same size or weight. That’s not to say they are not worth the slight reduction in capacity — they have other advantages.

[jpmihalk]

If they are under the steps, there may not be enough room for additional batteries. And yes, don’t mix battery types (SLA and AGM) or they will all perform poorly as charging is different for each.

[DanChateau33SW]

Thanks All. Sounds like our batteries are not at the top of their game any more. When not running the inverter, they seem to last quite a while just running the radio, lights, and the water pump though.

[Edk]

Originally Posted by DanChateau33SW

2015 Chateau 33SW on the F-550 chassis.

I have been having troubles with more than about 30 minutes on the inverter with the fridge, so have been wondering the same thing for a couple of months. The batteries were new in 2017, 2 under the step in the battery compartment, and a 3rd added in the storage compartment with the inverter. I did notice the other day that 2 of the batteries are starting batteries and the 3rd is a deep cycle, all 12V. Could the starting batteries be causing part of the issue? It's pretty frustrating that the inverter starts alarming very soon after switching from shore power to battery.

Dan, a couple of things you got to be aware of 1st most important if that 3rd battery is flooded lead acid it most definitely should be in a ventilated compartment. When charging it off gases corrosive and possible flammable gases. With your inverter mounted in the same compartment could cause severe consequences. Also a properly designed battery bank should be, 1) all batteries same amp hrs, and 2) same age, and 3) all deep cycle 6 or 12 volt if not, charging and discharging will not work correctly.
Edk

[16ACE27]

Your inverter may be screaming after about half an hour due to low voltage detection caused by an excessive voltage drop from your batteries to the inverter. Check those connections for corrosion and the wires to the inverter to make sure they are sized properly for the current draw and length of run.

[DanChateau33SW]

Originally Posted by Edk

Dan, a couple of things you got to be aware of 1st most important if that 3rd battery is flooded lead acid it most definitely should be in a ventilated compartment. When charging it off gases corrosive and possible flammable gases. With your inverter mounted in the same compartment could cause severe consequences. Also a properly designed battery bank should be, 1) all batteries same amp hrs, and 2) same age, and 3) all deep cycle 6 or 12 volt if not, charging and discharging will not work correctly.
Edk

Thanks Ed. The battery box does have a vent to the outside of the compartment. We bought the MH in January, and just took our first trip this past weekend. I haven't checked the water level in the batteries yet, but will be sure to do that this week.

They are different batteries, and I agree that the will have different charging requirements and discharge rates. No doubt, the "starter" batteries under the step will draw down before the deep cycle in the compartment, but it won't be far behind once the other 2 are dead.

[DanChateau33SW]

Originally Posted by Tfryman

Your inverter may be screaming after about half an hour due to low voltage detection caused by an excessive voltage drop from your batteries to the inverter. Check those connections for corrosion and the wires to the inverter to make sure they are sized properly for the current draw and length of run.

Thanks Ted & Melinda. The terminals are all clean, battery cables are appropriately sized, and the inverter is only a couple of feet away - I'd say less than 4 feet, maybe a 5 foot cable run.

I think I am going to start with replacing the batteries, but will also add a solar array to help with keeping them charged - probably start with 400W. I am going to star another thread about solar because I have several questions regarding how to connect and if the coach charger being on at the same time is going to cause any problems.

[DanChateau33SW]

Checked water and connections in the batteries tonight. 4 of the 6 terminals we loose. Tightened them and testing the fridge on inverter for the last hour or so. Batteries are holding steady at 12.1V. The fridge was starting from being if the last few days, so that's with the compressor running constantly. I think we are in good shape as far as batteries go. Thanks for the help and advice.

[engrprof]

Newby, and not sure how to post so here goes. Will the aria 3901 microwave and induction stove top run off the magnum inverter? I think it's a MODIFIED sine wave inverter. Thanks, engrprof

[TurnerFam]

yes, they should, if they are plugged into a 120v outlet, as I'm sure they are. You'll have to watch the cooktop which can bring down the battery levels very quickly, though.