Outback Flexpower off-grid setup

ramsaymp · October 2021

So long, crazy, complicated story short I moved onto a property recently and the lovely lady next door who had rights to our electricity decided to cut us off so now we're in the dark. Fortunately one of the previous owners planed ahead for the very situation and installed a full solar system. Unfortunately through property ownership disputes etc. . the batteries all disappeared and the system was shut down. Now I have to pleasure of getting things up and running again.

All the equipment seems to be intact and in working order. I haven't calculated the solar array yet but there are 40 panels that get full sun most of the day. I also have a honda 2000w generator to supplement for cloudy winter days.

SO my question is, I just need to mount and connect the charge controller, get some batteries and fire it up right? To run 48V I was going to get either 16 12v 100ah AGM batteries or I've been looking at the Renogy 12v 200ah batteries and just getting 8. Does anyone have any experience with these? My thoughts were fewer batteries fewer connections, less cable, less voltage drop and easier install with the same storage capacity?? Storage is not really an issue. Money IS an issue so I need to be careful. The reason I'm going with AGM's is I am the only one who will maintain the system and if I'm gone for 2 months and no one maintains the batteries all with go to hell. If we need more storage capacity I can add another string in a couple of months when we have some more money.

My other question is how do I connect the generator to the system? Can I plug it into the inverter to feed the panel without batteries? This would be helpful at least for a few days. Going forward I assume I will use it morning and evenings to keep the batteries at an optimal level.

I am totally open to and would appreciate any feedback or suggestions!

Image: https://us.v-cdn.net/6024911/uploads/editor/ht/wvdcd7y9bqqo.gif

https://www.solar-electric.com/outback-flexpower-inverter-system-fp1-vfxr3648a-01.html?gclid=CjwKCAjw8KmLBhB8EiwAQbqNoAZVsLRgRcKj2tpEhZaUPMKxO9TZu3EEBP5c2u54t_GMjCkjoOqZfhoCPiMQAvD_BwE

mike95490 · October 2021

I'd suggest AGM 6V, 200ah golf cart batteries . You are not paying the premium price for renogy , and properly constructed jumpers have little actual effect. 8, 6v batteries in series would give you 48V @ 200ah

ramsaymp · October 2021

So having done some more research I decided to go with 16 6V 210ah batteries for 48v 420 ah total. I get the same capacity for half the price and if I screw then up it’s a less money down the drain.

wellbuilt · October 2021

I just use Flood lead acid battery’s from sams club they seam to last 5 years or so the cost 100$ each with tax and core charge

wellbuilt · October 2021

If you look on line out back has a quick start guide to get you going .

You will need to program your mate and charge controller .
My system is 5 years old +- and it needed some up dates there should be a SIM card to load the up grade to and it slides in the top of the mate .

To start turn power breaker on , then hit inveter button on top left mate turn The unit on
Then hit ac out put top left breaker second from the top , turn the breaker panel main on .

The fm80 needs to be powered up first with the breaker bottom left , then turn on the solar panels bottom left
little black box on top rite is the battery Monitor , there is a breaker bottom left for it .
If you don’t have the manual you will need one ,mine is 3” thick .
You mate code should be 141 so you can change charging parameters in the mate and charge controler .

You will need to program you battery size , genarator size , and amount of power the charger will take from the generator , , amount of solar
You can program the fm80 on its key pad I use 54v float , 58.5 summer 59.5 winter when there is little sun
EQ is 62v
The inverter charge dose not use temperature Compensation for EQ so you need to bump the number up manually

wellbuilt · October 2021

One other thing your genarator is small, the charger will charge at 1900 watts you will need to change a setting in the mate so the charger pulls 1500 watts +

ramsaymp · October 2021

Thanks for the advise. Yea I grabbed batteries from Costco yesterday. Literally everyone they had. $115 a piece. I have a little work to do on the room and build battery shelves first. I'll probably start wiring things up tomorrow and see how it goes.

As for the generator. . . I've read the rule of thumb is to double the inverter output for the generator size. I guess this makes sense since it will be charging the batteries and running the house. Should I just ditch the 2000w and get a 6 or 7000w?

ramsaymp · October 2021

What size cable are you using between the batteries?

wellbuilt · October 2021

You will need a vented battery box
here is mine .

When the battery’s are in absorb they give off
A lot of gassing
there is a small fan made to work with your fm 80 it is power by the fm80 and can be set to turn on at absorb voltage automatically and it turns off on the charger goes to float
the small wire on the gray box in the controler
is the point to attach the fan wires .
My fan is on the white pipe on the other side of the lid .
My wires came from a place on line I think they are 2/0
Notice I have a fuse block on top of the battery in the pic on both strings ,this is a good idea
buy a extra fuse so you have it .
Make sure your battery lugs fit the wires I bought mine a little to small and had to drill them out .
My house runs on 2/300 watts day in day out I have a Honda 2800 watt inverter / charger I use 3400 to 5000 wh a day .
What I did is hook up a larger cheep generator to the generator in put , on the invert box on top the unit it has Pretty dirty power , then on my ac grid power input I have my Honda 2800 with clean power .
If I’m need a lot of power I use the larger generator ( I have never used it )
On a regular day I start charging with my 2800 Honda 7am in a hour or so I’m in absorb and the charging drops off
so I have more power .

A 2200 watt generator can work but you need to set the generator size and amount of power used in the mate .
In the winter my panels can be iced up for 10 weeks my Honda uses 5 gallons of fuel a week .

Running a large generator uses a lot of fuel .

Image: https://us.v-cdn.net/6024911/uploads/editor/0e/7z2ckjsue9d5.jpeg

ramsaymp · October 2021

Thanks for all the info! I like the way you built your battery box. I got the system up and running today with no issues so far. Batteries charged up and have been on float for a few hours now. The little shed the batteries are in has plenty of ventilation to the outside. I went with 2/0 wire as well. May be over kill but whatever. I will look into the fan once I sort out my next set of issues as well as the settings on the mate.

The AC out on the inverter is wired to a 30amp breaker in the panel beside it which then heats up that panel and feeds another subpanel. This doesn't seem right to me. Correct me if I'm wrong here but I think the AC out should feed a 100amp subpanel which than feeds my other 2 subpanels and on to all my loads. The AC in on the inverter should be wired to the 30amp breaker with a transfer switch connected to my generator. In my mind this makes sense and the wiring diagram on the product sheet seems to confirm.

wellbuilt · October 2021

This seams to have some thing to do with grid power , grid would be feed to the in put and if grid go’s out you would hit the transfer switch to charge with genarator .
I think you had grid and inverter power at one time and they Probably have the loads set up so they can turn high load items off when running on battery.

My ac out put go’s to a 200 amp service panel the hot lead is 6g and powers L1 and L2 with a jumper .
The 200 amp main breaker is just a switch to turn of the panel .

I have 40 breakers 20amp and 15 amp breakers .

Image: https://us.v-cdn.net/6024911/uploads/editor/ue/kpb2mhlc8vnu.jpeg

Google this title one thru 4 has a bunch of information .
In put is where your genarator hooks in
out put go’s to your ac panel .
The system has a built in transfer switch .
When you turn on (ac ) on the mate top right on the key pad yellow lite
this will sense your genarator , go into the mate under inverter charger and set charging .

The inverter will qualify the powerand start charging .
You should see this on the mate main screen .
If the power isn’t stable the inverter won’t start to charge .
Your Honda should work but if you over power the generator with load the inverter will stop charging and invert power then switch back to charging when the genarator can handle the load.

Sooooo you don’t need a transfer switch , there is ac by pass it the3rd breaker on the left .
This by passes all inverting and charging and the ac panel will run on genarator only .
It is easy to set your charging Perimeters in the fm 80.
Go to charge on your screen on the fm 80 you will see float , absorb ,eq you code is 141 on the fm80 to get in to change settings .

If you have fla golf cart battery’s your settings should be float 54 absorb 58.5 summer now I would push that to 59.5 for winter . EQ 60.7
I had no help with setting from The battery manufacturer .

A few things to know
there should be a battery temp sender in the center of the battery bank that go’s to the inverter not the fm80 .
With out this the battery’s will not get charged to full when it gets cold .

Your EQ charging on your inverter is not temperature compensated for some reason so in the winter when the battery’s are cold you need to raise the voltage to 62v or more depending on how cold it is .
You need to get into the mate and add the generator watts and how much power you want to use for charging 1500watt should be good .
You allso need to put in your battery amp hours so420 ah for your battery’s
You should check your sg as soon as possible , all battery’s should read 1.275 plus when charged at the end of the day , if some are low you can use a small 6 volt charger to bring them up to full charge just run on generator with bypass on
Ps if you are not 100% sure what a setting dose and what value it should be don’t change it 😖

Photowhit · October 2021

ramsaymp said:

$115 a piece.

Keep your recite! I think they have a very liberal core battery policy, ask them. Go around to lawn mower shops and pick up old/dead lawn tractor batteries for $5 each, exchange for the $16-20 core fee.

Advice, DON'T use gif's for static photos!

ramsaymp · October 2021

I guess I am still confused on how to physically connect the generator. Do I run a wire from the AC input breaker to a Male plug and run a cord to the gen? Or I can wire a regular outlet and use a Male to male plug?

BB. · October 2021

Can you tell us what model of Outback AC inverter you have?

For connecting the genset--Some inverters have an AC input (or even two, one for grid power and a second AC2 for genset)...

Some inverters simply pass AC2 to ACout, others "mix" AC2+ACout, And the inverters can be an inverter-charger. Inverters that have AC input generally have their own internal AC Transfer switch/relay and make for a simple installation.

And there is the option to have one or two separate AC transfer switch which allows the genset to power your AC loads directly and bypass your AC inverter module.... This is usually done when something has failed (solar charging, AC inverter, etc.) and you just want to get AC power to your home while getting parts/working on the solar/inverter system.

Officially, never use a Male/Male cord... That is known as a "suicide cord". The male blades can be "hot" and electrocute somebody--Plus it can create a situation where somebody plugs a genset AC out into an existing AC power system (grid, inverter AC out) and smoke the genset/inverter/injure a lineman or electrician (or worse).

Generally, you have a "male plug" in a wall box that connects to an AC transfer switch (with normal male/female cord set backt to genset). The transfer switch ensures that the genset is never exposed to a "hot" AC line, and that the Genset power is never applied to where it is not supposed to go (AC output of inverter, etc.).

For wire AWG size on battery banks... Use the NEC tables (assuming in North America). Here is a simplified table that gives you a quick and dirty AWG sizing:

https://lugsdirect.com/WireCurrentAmpacitiesNEC-Table-301-16.htm

Remember that for NEC, normal residential circuit breakers/fuses/wiring is designed for 80% continuous loads... I.e., a fuse/breaker will not trip at 80% or below of rated current, and will trip at 100% or above of rated current--In between is a "gray" zone where breaker/fuse may or may not trip over time.

So, for things like charging your battery bank... Batteries can take full charging current for hours at a time (10% rate of charge from 50% to 100% State of Charge can take upwards of 5 hours to complete)... So for those charging circuits, take the max continuous current and multiply by (1/0.80 or) 1.25x for branch wiring/breaker wiring (i.e., 20 amps * 1.25 = 25 amp minimum rated wiring+breaker) to save you the hassles of false trips and overheated wiring.

I gather with your neighbor filed with the county, there never was an easement for power (water/sewer/phone/cable/utility/driveway) access from the "road" to your property? In some cases, if you have open and notoriously accessed utility power for many years, you may have a constructive easement you can enforce (time for lawyer$ to be involved?).

-Bill

706jim · October 2021

Nobody has commented on the size of your array. 40 panels HAS to be overkill for a single charge controller.

wellbuilt · October 2021

I was wondering about the 40 panels 🤷‍♂️ But I did not get around to asking about that 😜

wellbuilt · October 2021

My system has a 6g wire running 100 feet +- the wire is wired to the inverter like in the pic above , in the generator shed I have a box with the 6g wire coming in and a 10 /2 with ground running to a 20 amp locking plug .
The plug is just plugged into the genarator 🤷‍♂️ I’m not sure if this is the best way to do it .
There is a breaker A/C in that leaves the genarator lead with no power for sure but I’ve never tested the plug to see if it is live ?

I may just do that this weekend ?

ramsaymp · October 2021

Thanks everyone for the feedback. Its been hugely helpful. My system is up and running. I connected the AC out to my main panel hot with a jumper to heat the whole panel and now my subpanels are all working good. Thanks Wellbuilt.

BB. I have the VFX3648. I wired the AC in to a 30amp breaker box which goes to a 20a male plug in the wall. Maybe overkill with the extra breaker but I wanted to be safe. The issue I have now is my generator is too small (2000w honda) If I turn off inverter charging in the mate I can run my house off the generator. With inverter charging on it seems to way overload the generator and kick the breaker. Any recommendations on a generator? I'm thinking 6kw to 7kw gas.

If I turn inverter charging On in the mate and shutoff the AC out will it then direct 2000w to charging the battery bank? I'm concerned that with a week of no sun my brand new batteries won't receive a full charge off the panels.

Most of this system was already in place when I started this project. I have 40 panels on the roof but upon further investigation only 30 are connected. The other string of 10 were never hooked up. Once the rain clears I'll pull up a panel or 2 and get some specs. There are 2 different panels all of which were bought used 3 or so years ago.

BB. · October 2021

I am no expert, but looking at the manual, it appears that your Inverter probably does not "energize" the AC input terminals (there was a Grid Tied version--But not yours?).

Can you program the AC inverter--It appears that you can program the max AC input current from 2 amps to 60 amps (I think).

https://www.outbackpower.com/downloads/documents/n_series/FX_series_Install.pdf (page 51 pdf or page 48 paper)

There is a way of using newer AC inverter-chargers as "generator support"...

https://forum.solar-electric.com/discussion/17098/demonstration-of-generator-support/p1

I don't know about your model (the manual does not have much information on the internal capabilities of the inverter--Such as the ability to supply 2,000 Watts AC out, with 1,000 Watts of generator in and 1,000 Watts from battery bank at the same time--Basically generator support).

Your genset:

1,600 Watts continuous * 0.8 derating = 1,280 Watts "comfortable" continuous power
1,280 Watts / 120 VAC = 10.7 Amp AC draw

Try setting your AC input to ~10 amps and see what happens... At the very least, it will limit the AC current from the genset and let you recharge the battery bank with the capabilities of the EU2000i... At best, the inverter will run AC loads and charge the battery bank at the same time (and very best--Steer genset power between battery bank and AC loads).

Rate of charge for a "happy" battery bank... 10% nominal, and 5% minimum highly suggested (10-13% for full time off grid--recommended). If you have a 400 AH @ 48 volt battery bank (minimum bank suggested for a 4 kWatt AC inverter operating near full output on a 48 Volt FLA battery bank).

400 AH * 0.05 rate of charge = 20 amps minimum
400 AH * 0.10 rate of charge = 40 amps nominal
20 amps * 58 volts charging * 1/0.8 charging eff = 1,450 Watt (VA) genset loading @ 5% rate of charge
40 amps * 58 volts charging * 1/0.8 charging eff = 2,900 Watt (VA) genset loading @ 10% rate of charge

With a genset, charging to 20% rate of charge (on occasion) is an option too.

So size of genset really depends your battery bank size--Which depends on how much energy you want to pull from the bank.

For a standard genst--You want to load them at roughly 50%-80% of rated output (for non-commercial gensets). For gasoline (propane, natural gas) gensets, more or less their fuel flow (gallons per hour) levels off at ~50% of rated fuel flow at 50% to 0% of power draw/AC loading.

For inverter-generators--You can run them (fairly fuel efficient) down to 25% of rated output... So you don't want to "oversize" the genset and run it at much less than 50% of rated load for hours on end Bulk/Absorb charging the battery bank. Inverter-generators at down to 25% is sort of OK--But inverter-generators tend to be expensive and in the smaller Watt range...

An alternative which can work well--Try and program the inverter to run at limited AC input draw and use the eu2000i for a stretch of cloudy weather--Quiet and fuel efficient for soft charging of batteries (high current, hot batteries, gassing are all hard on FLA batteries)... And get your larger genset (3,000-7,000 Watt or whatever) for the larger/cheaper non-inverter-generator when more power is needed (deeper discharge, running shop loads, filling water cistern, etc.)--And as a backup for the eu2000i when/if needed.

You might try FLA batteries for your first bank (keep first/training bank small and cheap). Once you have run for a few years (adjusting bank size as needed)--Then get your "better" AGM batteries (which do supply surge current better--But tend not to have as long as life as a similarly priced FLA high quality battery bank).

I did not see how much solar array you have(?). For example on a 400 AH @ 48 volt battery bank, based on rate of charge:

400 AH * 58 volts charging * 1/0.77 panel+controller derating * 0.05 rate of charge = 1,506 Watt array minimum
400 AH * 58 volts charging * 1/0.77 panel+controller derating * 0.10 rate of charge = 3,013 Watt array nominal
400 AH * 58 volts charging * 1/0.77 panel+controller derating * 0.13 rate of charge = 3,917 Watt array "typical" cost effective maximum

There is also sizing the array based on your daily loads and location (hours of sun per day, by season).

-Bill

wellbuilt · October 2021

As bill said you can adjust the amount of power the inverter will use for charging and pass thru the rest for loads.
This is in your mate , it will ask how big the generator is then it will ask how much power you want to use for charging .
There are other questions you need to answer in system set up .

You inverter /charger only puts out 1900watts max charging I use a 2800watt Honda inverter generator .

My charger uses 1900 watts then my house loads are 2/300 watts so I have a little head room .

I charge in the morning for 11/2 hours before every one is up using power .

When I hit absorb the charger draws less power .

I charge on 5 gallons a week +- a 7000watt unit will cost you in fuel .

I think you would be fine on your little Honda to start

wellbuilt · October 2021

I don’t know if I mentioned this but my system freaked out over some up dates that I never installed.

The system had a mind of its own .

I did the 3 missing updates and it was back to working 100%
My fm80 would not hold a absorb charge it would turn off at 1 hour absorb ? Very weird
I think you should default to factory settings and reprogram the mate to your battery amp hours
Generator size , power used by genarator for charging .

There are more things but I set my system up 3 years ago I have not Seen the screen recently

Surfpath · October 2021

You said, “I haven't calculated the solar array yet but there are [30 or] 40 panels that get full sun most of the day. I also have a honda 2000w generator to supplement”

With the potential of so many panels I think you’ll be surprised at how little you’ll need your generator. I run a 375 amp hour bank also using an Outback flex power 1. I too thought I’d need a big generator for cloudy days and bought an expensive 3kw Yamaha inverter generator. Big mistake. I didn’t need it, and it mysteriously blew up after just a few uses. I’ll try to find the link to that thread and post it here.

The FP1 FM80 has the potential for something like 3,800 watts of panel at 48v. That’s a pretty high charging rate for your 400amp hr bank. What are your loads and is your battery bank designed for 2-3 days of no or low sun? Maybe you can just use the genny to run loads, like the fridge, directly during cloudy days? Do you really need a whole house generator?

Outback Flexpower off-grid setup

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