Off-Grid system advice

General Talk

Moderators: OutBack Moderator Team, OutBack

Off-Grid system advice

Postby andyporter on Tue Sep 12, 2017 5:41 pm

I have a small off-grid system with a 3kw array, mx60 charge controller, fx inverter, and (16) 6V Rolls lead acid batteries. The batteries are beginning to sulphate. I know I need to do a better job equalizing and maintaining them.

Any suggestions on best practices to do this aside from monthly equalizing and fluid topping?

We are interested in getting a propane generator to auto start when the batteries are discharged to a certain point.

Does anyone have suggestions or recommendations on doing this properly and/or specific generators that will work well for our configuration?

Also, does the mx 60 have an auto start setting that could kick on the generator? (Searched the manual unsuccessfully for this answer)

Thanks for your help!
andyporter
Junior Member
 
Posts: 2
Joined: Tue Sep 12, 2017 4:05 pm
Location: www.envinity.com
My RE system: Outback VFX 3648 Inverter
Outback MX 60 charge controller
Outback Mate
(16) 4000 series Rolls Surrette S-530 6V battery bank (48V)
(12) Amerisolar 250W modules.

Re: Off-Grid system advice

Postby Mike Curran on Tue Sep 12, 2017 7:44 pm

Hi - In addition to periodic equalizations, your batteries need to regularly (daily, if possible) receive an absorb charge cycle, which is sort of a "mini-equalization" - lower voltage than equalization, around 59 volts for a 48 volt system, and for a longer period of time, until all the amp-hours you've taken out of your battery is returned. This may not be possible with the small size of your array relative to your battery size, and being off-grid. I imagine that's why you're considering adding a generator.

All that said, I cannot recommend a generator to use - no experience with VFX's, and very little with generators. But I understand they aren't as picky with power quality as the "G" series inverter/chargers are.

The key to auto-starting your generator is the auxiliary relay built in to your VFX. It will provide 12 volts DC under various programmable scenarios. In the auxiliary menu on your Mate(ADV/FX/PG2/PG3/AUX) you can set it up using the GENALERT function, which allows you to set the low battery voltage when you want a generator to start, and various other settings related to battery voltage. You will need to obtain an external relay with a 12V DC coil (<0.7A current draw) to connect to the remote start circuit of whatever generator you buy. The GENERATOR menu (ADV/FX/PG2/GEN) has setpoints for time delay for generator warm up, the allowable AC voltage range before connecting to the generator, etc.

I'm getting all this info from my GVFX manual but I believe it applies to your VFX as well. - Mike
Mike Curran
OutBack Guru
 
Posts: 248
Joined: Sat Aug 28, 2004 6:28 pm
Location: Chagrin Falls, Ohio
My RE system: Outback: 8 (2x4) Evergreen 180's into one MX60, 6 (2×3) ALEO S79-300's into one FM80, 2 grid-tied GVFX3524's classic stacked for 120/240VAC, 12 Surrette/Rolls 2V x 1766Ah, Hub10.3, Mate3, FNDC, RTS, OpticsRE. Tigo Energy ES maximizers on each PV module.

Westinghouse Solar: 30 (2x15) 235W panels with Enphase M215 microinverters. 6,450 nameplate watts AC, grid-tied.

Re: Off-Grid system advice

Postby blackswan555 on Tue Sep 12, 2017 9:00 pm

Any suggestions on best practices to do this aside from monthly equalizing and fluid topping?
Get yourself two good hydrometers (you will break one) and read your SGs, What are they ?
But reading between the lines you have just been EQing by "pressing the button" ? EQ is not a timed operation, it can take many hours, You need to be reading SG as you go along and wait for it to stop rising,
We are interested in getting a propane generator to auto start when the batteries are discharged to a certain point.
Does anyone have suggestions or recommendations on doing this properly and/or specific generators that will work well for our configuration?

You will need "two wire start" as long as it has that the rest is up to you,
Also, does the mx 60 have an auto start setting that could kick on the generator?

not sure, never looked to be honest, Use the FX

A question, Do you know what settings have been changed from default and to what on both MX & FX ?

Tim
My comments are based on my experience and research, They are not endorsed or checked by Outback.I am an independent British electrician living in Spain, So please take this into account when reading /acting on my post`s.
blackswan555
OutBack Emperor
 
Posts: 2465
Joined: Sat Aug 30, 2008 5:50 am
Location: Ibiza Spain,
My RE system: Other peoples, VFX "E" versions, FLA`s, Generators.

Re: Off-Grid system advice

Postby JRHill on Wed Sep 13, 2017 10:13 am

Andy, to chime in with Mike and Tim, one of the most covered topics is battery charging and SGs. I'm the first one to say how much I hate taking SGs but until you get a handle on this mandatory maintenance task, you're just guessing. In most cases the guessing is on the UNDER CHARGING side which is expensive. Distilled water is cheap.

Best,
Jim
User avatar
JRHill
OutBack Guru
 
Posts: 269
Joined: Thu Feb 17, 2011 12:12 pm
Location: South central WA
My RE system: -House: FM 80, VFX 3648, FlexnetDC, FlexWare xformer, Mate 3 / Hub, WattPlot/, 2925w SunTech 195, Trojan L16RE-B Batteries. Backup 1: Champion 75531i 3100, backup 2: 11kw Miller Bobcat;
-Well: Grundfos 11-SQF-2 pump, controller & AC switch (CU200, IO101), Morningstar 15a/48vdc Controller, 780w SunTech 195, Trojan golf cart batteries.
-All running since July '11 with no critical problems.

Re: Off-Grid system advice

Postby andyporter on Wed Sep 13, 2017 7:05 pm

Wow! Jim, Tim, & Mike,Thank you all for your input and advice. I bought my system used from someone I trust so I didn't change any of their settings. I realize that I need to take a more active role in battery maintenance or I will significantly shorten the life of my batteries. I will get SG's and temps for each cell during equalization and record the results. My current settings are:

Absorb setpoint: 57.6 vdc
Charger Limit: 10 aac
Absorb Time Limit: 2 hours
Float setpoint: 53.6 vdc
Float time: 1 hour
Refloat setpoint: 50 vdc
Equalize setpoint: 61.6
Equalize time: 2 hours

Does anyone have experience using a generator to equalize batteries? If so, are there any special instructions or components that I should know about? A few hours of clear, full sun is hard to come by when I'm not working.

Thanks again for your help.
andyporter
Junior Member
 
Posts: 2
Joined: Tue Sep 12, 2017 4:05 pm
Location: www.envinity.com
My RE system: Outback VFX 3648 Inverter
Outback MX 60 charge controller
Outback Mate
(16) 4000 series Rolls Surrette S-530 6V battery bank (48V)
(12) Amerisolar 250W modules.

Re: Off-Grid system advice

Postby cabin50 on Wed Sep 13, 2017 7:43 pm

Ist time on here.
So where am I wrong. I have 9 255 w, 24 v solar panels. I will put them in series going 500 ft down hill to a charge controller. It will come down at around 377 v dc controller then
goes down to 24 v I'll be using Using no 6 wire stranded. I have a magnum RD series inverter Rd 3924. This is rough but close. There will be 3 disconnects before getting to the power house. I'm crossing one road, 1 creek. I would like some info back.
cabin50
Junior Member
 
Posts: 4
Joined: Wed Sep 13, 2017 7:06 pm
My RE system: flexmax 60
Magum rd3924
255w panel (9)
24 volt system 4 12 volt deep cycle

Re: Off-Grid system advice

Postby petertearai on Wed Sep 13, 2017 9:03 pm

hi cabin 50 . the fm 60 and 80 both have a maximum voltage of 150 . there are some cc with higher input voltages . The fm80 realy will smoke if you put over 145 volts
2220 pv. fm80. 4times rolls 450 ah 24 volts. victron battery monitor. outback fxr 2000 watt inverter
petertearai
OutBack Guru
 
Posts: 310
Joined: Fri Aug 06, 2010 4:35 pm
Location: NewZealand North Island
My RE system: 2220 watt pv, fm80, outback fxr 2000 watt inverter. Rolls s600 times 4 24 volt system victron battery moniter. optics RE

Re: Off-Grid system advice

Postby blackswan555 on Wed Sep 13, 2017 10:07 pm

Presuming these are inverter set points below, Your absorb voltage and time are too low, 58.8v & 4 hours would be a better starting place ( to be checked and adjusted when you have some SG info) & you do not use float for gen/inverter charging, Waste of fuel, set time to "0"
Absorb setpoint: 57.6 vdc
Charger Limit: 10 aac
Absorb Time Limit: 2 hours
Float setpoint: 53.6 vdc
Float time: 1 hour
Refloat setpoint: 50 vdc
Equalize setpoint: 61.6
Equalize time: 2 hours

What are the MX settings ?
Do you have battery temp sensor on all charge sources ?

Gen EQ, You will have a problem ( it will take a very long time) with only one FX as it will only give you around 40 ish Amps, (Your batteries are around 800ah total ? Recommended charge current is 5 to 20%, 10% is a "happy place" so 80amps ) Where in the world are you ? what is weather like at mo ?
A better strategy may be to up the MXs charge voltage "high" for now and watch SGs, If they are rising, all good, wait untill the are "better" then do EQ, If not look at doing a parallel gen and solar run "all day",

Tim
My comments are based on my experience and research, They are not endorsed or checked by Outback.I am an independent British electrician living in Spain, So please take this into account when reading /acting on my post`s.
blackswan555
OutBack Emperor
 
Posts: 2465
Joined: Sat Aug 30, 2008 5:50 am
Location: Ibiza Spain,
My RE system: Other peoples, VFX "E" versions, FLA`s, Generators.

Re: Off-Grid system advice

Postby cabin50 on Thu Sep 14, 2017 6:39 am

cabin 50 here. I am getting a new controller to match my system . It is about 1400 $$. I am trying to mount the panels this fall but weather may stop me. I am trying to also add a small hydro system. My solar time. I only have about 45 minutes of solar time per day for 70 days during Nov., Dec., Jan. I have good water then but in the summer from July - Oct I have very little water. So a duel system will work out the best. Just a headache. I may add more solar panels in 2 years but in a different place. I am in a steep sided canyon in Idaho.
cabin50
Junior Member
 
Posts: 4
Joined: Wed Sep 13, 2017 7:06 pm
My RE system: flexmax 60
Magum rd3924
255w panel (9)
24 volt system 4 12 volt deep cycle

Re: Off-Grid system advice

Postby JRHill on Thu Sep 14, 2017 8:17 am

Andy, this is one of my favorite threads for charging practices. Even if you don't have L-16 batteries the theory still applies but certain values are different for your system: viewtopic.php?f=17&t=3123&hilit=L16

It won't be long and I'll be switching over to the winter profile on the Mate3 but during the summer these are my set points, as an example. Please note I came up with these settings after checking EQs ON A DAILY BASIS and then kept changing the programming until my batteries were full or mostly. You can't get your system tuned by taking SGs only at equalization. In fact, you need only EQ when the SGs vary too much between cells. If your batteries are healthy and get a full charge on a regular basis you'll find there is minimal variation between cells so no need to EQ unless there are some uncooperative cells that are brought up with the EQ.
:
Absorb 59.5, 5 hrs
Float 56.5
Rebulk 55
EQ 63.2, 2 hrs; EQ is turned off
Charger control on the FNDC set to off

Come winter when I have to charge via generator, this all changes. It just isn't reasonable to run the genset for the full absorb more than once or twice a week. Even at that, last year I went to an inverter genset to get the most from my fuel $. The generator paid for itself in one winter. I occasionally do SGs in the winter on the days when I have the longer absorb run but it is rare that they get all the way to full 'cause I've lost ground and one day doesn't fix it. But I'm a heck of a lot better off than I was using default values all year and continuously under charging the batteries. Then come spring and longer days, I go back to the summer profile and start taking SGs again as the batteries are another year older and things change.

Seems everyone has their own techniques and pain point in funding their battery replacement budget.

Hope the above helps,
Jim
User avatar
JRHill
OutBack Guru
 
Posts: 269
Joined: Thu Feb 17, 2011 12:12 pm
Location: South central WA
My RE system: -House: FM 80, VFX 3648, FlexnetDC, FlexWare xformer, Mate 3 / Hub, WattPlot/, 2925w SunTech 195, Trojan L16RE-B Batteries. Backup 1: Champion 75531i 3100, backup 2: 11kw Miller Bobcat;
-Well: Grundfos 11-SQF-2 pump, controller & AC switch (CU200, IO101), Morningstar 15a/48vdc Controller, 780w SunTech 195, Trojan golf cart batteries.
-All running since July '11 with no critical problems.

Re: Off-Grid system advice

Postby cabin50 on Thu Sep 14, 2017 1:26 pm

cabin 50 back;
I have located a Schnieder Electric controller xw-mppt=80-600vdc and separate controller unit xw+scp unit that goes with it and which should handle everything I can produce. I would be able to add 3 more panels to but it would be barely within its max limits. Just a little to close. I like some cushion for the ghost gremlins that seem to hide here and there.
I read some of the other suggestions for other things and I have thought about putting just the AC voltage down the mountain but if there were any problems you couldn't get up the mountainside in the winter. There are no trails and even in the summer it is hard to get up to the panels. Winter time there is around 2 ft of snow. The nearest grid power is about $375,000.00 from me. My small creek is 25 ft in front of my house runs year long but not enough water in the summer for hydro. I heat and cook with wood.
cabin50
Junior Member
 
Posts: 4
Joined: Wed Sep 13, 2017 7:06 pm
My RE system: flexmax 60
Magum rd3924
255w panel (9)
24 volt system 4 12 volt deep cycle


Return to OutBack

Who is online

Users browsing this forum: No registered users and 3 guests