Dual inverter setup with 2 battery banks 12v system

[Oregonconversion]

 Does anyone have a dual inverter set up in their bus? 2 separate battery banks. I currently have a single 2000 W Xantrex  inverter installed.( rv2012gs )  I just acquired a xantrex freedom 458  model 20 inverter/charger (also 2000 watts).  Both of these inverters have single AC input but dual AC outputs whitch  is nice.

Basically I'm trying to figure out how to power everything while Boondocking!  I currently have a battery bank set up of 8 Trojan 105 batteries and a bank set up of 4 Trojan L16 batteries.  One bank for each inverter.  Each bank is just over 800 amp hours.  Ideally,  with my Yamaha ef3000isb  generator I should get   6800 working watts at once...  until my batteries go dead.  Which is why I would use the  inverters for such things as microwave, hot water heater, hot plate,  bathroom heater and outlet?

One thing I'm trying to calculate is the number of amps that will be used for charging the batteries with the inverters.   If the batteries are dead it could be up to 100 on the freedom and 140 on the other one.  But, does into the charger give as many amps as it can when  The amps are going some where else such as a heater?

[gumpy]

You only have so many amps available from generator or shore. It's available for either the charger or the loads. Will depend on may things, such as your inverters/chargers, generator, shore connection, batteries, etc.

This seems like overkill to the max. I run 8 T105s with a 4000 watt inverter.  I can't imagine why you would want 4 L16s in there also, plus a generator!

Using battery power to make hot water and heat the coach is impractical. Same with using it for air conditioning. Your batteries just won't carry it very long.

If you're planning to boondock, look at LP for heat and hot water. Use the batteries wisely, for lighting and outlets. Short term loads such as the microwave and electric hot plate are ok if used sparingly.

[brmax]

I would think yes, and add some may have different outputs;

1st and selectable possibly, depending on the type of battery as gel or typical wet and any other specialty options the charger recognizes.

2 maybe additional based output is on battery heat measured so to  keep optimum care in life cycles.

3 some could have a percent priority assigned towards either use or charge and signal some how.

great question and will keep an ear up for more tips you bring up
thanks!

Floyd

[bigred]

Yep:Any kind of resistance load is hard on batteries ie electric heat ,clothes dryer water heaters electric hot plates or ranges .As stated before ,i would in vest in propane for the water heater and heat and let the inverter handle the lights ,the refer and the coffee maker.For instance a 120v 1500w water heater will draw 14 amps !!

[Oregonconversion]

 I'm only going to be using it one night a week I'm guessing.   So I'm hoping that 800 amp hours of battery for each  inverter set up will make do for hot water heater and fridge.

I guess I just have to figure out how many  Watch in solar panels I will need to charge up the batteries within a weeks time.  Got a love Oregon winters 😝

[Oonrahnjay]

I'm only going to be using it one night a week I'm guessing.   So I'm hoping that 800 amp hours of battery for each  inverter set up will make do for hot water heater and fridge.

I guess I just have to figure out how many  Watch in solar panels I will need to charge up the batteries within a weeks time.  Got a love Oregon winters 😝 

     OK, if you call it 400 amp hours (1/2 of 800 so as to not pull down more than 50% of charge) at a nominal 12V you get 4800 watt/hours.  If your fridge takes an average of 100 (YMMV) watts per hour (it will cycle on and off but you gotta guess somewhere), the mean you're using 1200 watt/hours if your "one night per week" 12 hours; that leaves you with 3600 watt/hours.  You'll lose some to efficiency losses (again YMMV), but if you're running a 1500 watt water heater, in theory, you could run the water heater (again, you're looking at cycles though -- unless you're running taps full time, you'll have water for dishwashing, showers, handwashing, etc. -- for about 2 hours.  Not considering the efficiency losses, or power for lights, coffee maker in the AM, a thermostat if you're running propane heat, you'd have about 1200 watt/hours left --BUT all those small uses would probably add up to that 1200 watt/hours.
      So, yeah, 800 amp/hours in a battery bank would probably give you fridge (if it's a small fridge and you don't open it much or put a lot of warm stuff in it) and water heater, plus a small margin for lights, etc. and efficiency losses.  But it's going to be pretty barely enough.  Of course, you have two of those battery banks, so you're probably OK, but just small things (sweetie pie wants to watch TV for a couple of hours, check her email, warm a snack up in the microwave) will put you really close to using all your stored power.  If you need heat, even if it's propane, you're looking at fan power draw, too, and that's going to put you at least *really close* or -- probably -- OVER.  To not go over, I'm guessing you're going to have to be careful about power use, power shedding (running one big user at the time, let us know how "honey, you can't watch 'Dancing With The Stars' or use your computer for half an hour while the water heats up" works for you), watching your gauges, etc.  I'd be ready to piss off the neighbors (and The Boss) with the noise maker, if you need it.  And that's strictly a 12-hour night. 
      My take on it is you'll be OK if you're careful and everything goes OK, but I don't think you're looking at a lot of reserve. 

      And don't ask me about solar -- that s**t is voodoo and you're gonna have to get somebody else to run numbers on that. 

[Iceni John]

Nah, Bruce, solar's really not that complicated.   Almost everything I've learnt about it is from the collective wisdom and experience of the Northern Arizona Wind & Sun forum  -  there's several solar Cliffords there!

If you do go the solar route, 2kW of PV panels will nicely charge eight golfcart batteries at about a 13% charge rate, the most that FLA batteries normally will take.   I do however think that your intended loads are simply unrealistic.   There are folk fulltiming with a lot less PV than I have, and they're managing just fine.   Their secret is that they use electricity selectively, having it as just one part of their overall power portfolio.   Unless you have a 20kW generator (and some buses do!), you simply need to make adjustments to your lifestyle  -  thinking that you can subsist offgrid with 1600Ah of batteries and a small generator in the same manner as if living in a grid-connected house is guaranteed to result in major disappointment and frustration.

At the very least, buy yourself a Kill-A-Watt meter and see exactly how much power each appliance uses, then draw up a realistic usage scenario based on your ability to keep your batteries charged each day and to never let them drop below 50% SOC.

Good luck, John

[Oregonconversion]

 You have to remember that just because something is rated at so many amps or watts, doesn't mean that it is consistent.  Everything including the hot water heater, heaters, refrigerator, etc. it's going to be cycling on and off depending on their  environment temperature and needs.  Every time the  heater cycles off, which is going to be at least a fraction of the time;  battery charging goes into effect from my generator. Up to 23 amps.

[Oregonconversion]

My fridge is 1.5 amps. Water heater on an hour per twist timer.

[Oonrahnjay]

You have to remember that just because something is rated at so many amps or watts, doesn't mean that it is consistent.  Everything including the hot water heater, heaters, refrigerator, etc. it's going to be cycling on and off depending on their  environment temperature and needs.  Every time the  heater cycles off, which is going to be at least a fraction of the time;  battery charging goes into effect from my generator. Up to 23 amps.   

     I'm thinkin I don't understand your setup (not that I can really follow whut all them little electrictrons is doin anyway).  If you're running your generator, you're pulling the power direct to run your heater and if you're not pulling power from the batteries, they don't need charging.  I thought you were talking about running from the batteries so you wouldn't have to use the generator.  Or not?   

[TomC]

When I originally bought my 2,500 Trace inverter, I could have also bought a second one and stacked it to get 5,000 watts. The gal selling me the inverter asked if I had a Diesel generator. I said yes-she said if you go over 2,500 watts, just run the generator.
I don't believe in carrying all those batteries and the weight you have to haul around. I have 2-31's for starting the engines, 2-8D AGM deep cycle for house 12v and the inverter. The inverter can run everything except my 3 roof top A/C's.
Having a lot of batteries-think of them like tanks of electricity. If you have a lot of batteries-yes you can go many hours, or possibly days without running the generator. But then when you do want to charge the batteries, you have to run the generator much longer to get full charge, compared to running the generator 2 hours in the morning and 2 hours at night (like I do). Everything is a compromise and trade off. Good Luck, TomC

[daddysgirl]

I've got a Xantrex 3000W inverter that is powered by 4 31's...the 31's are charged by the PD4590 electrical system (it monitors the level of charge and provides what the batteries need automatically). I also have another converter/charger now connected to nothing, because I don't need it to charge the house.
The fridge can be gas and/or electric, heater, water heater, and stove all propane. The 4590 also has breakers for AC, and connections for any DC items I decide to integrate into the 2016 update.

In the 8 years since dad passed, I have NEVER used the inverter. I'm either plugged in or running the generator...14k watt. I upgraded last year from 30 to 50 A.

Honestly, because I haven't done the power consumption equations and I don't like to be restricted when I want all 3 roof airs, the TV and the microwave, I have been reluctant to plug into the inverter.
I appreciate the post, because it's something I need to do.

[Oregonconversion]

Sorry I forgot to mention I plan on running the gender the full time I am there. But only using it one or 2 nights a week.

[luvrbus]

Sorry I forgot to mention I plan on running the gender the full time I am there. But only using it one or 2 nights a week. 

If you lived somewhere besides Oregon,solar would be a good option for you,not much sunshine in Oregon in the winter though so solar would be a waste of time and money run the generator 

[Oregonconversion]

 Solar does work in Oregon,  but unfortunately I don't have a large enough array to provide heat in the winter. So running the generator is my only option at the moment.  I'm hoping I can get away with only burning about 3 gallons of gas per night.