NiFe battery with Outback system

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NiFe battery with Outback system

Postby pjrpd on Wed Aug 30, 2017 7:48 pm

My Nickel Iron batteries on a vanilla Outback System.
I am publishing this because I have had difficulty finding and understanding useful reliable information on the net about how to program my Outback system to suite my off-grid setup. I started off a complete novice, and still am. Suggestion are welcome. I hope this helps some other users.

Why NiFe.
I chose the batteries first. When setting up my off grid system, I was looking for something with proven robustness able to tolerate a fairly hostile environment. My house is off grid. We come and go often for long periods of time. It can get hot – into the 40 Deg C’s with high humidity, cyclones, and go down to just above zero in winter at night.
The NiFe/Outback system replaced flooded lead acid batteries running an old square wave inverter that came with the house. Cheap lead acid batteries were “cheap” to replace but they lasted a bit under 3 years. There are better, my neighbours storage FLA's are dying at 14 years of age.
Chinese Nife’s fit the bill. Old technology, lasting up to 100 years. Chinese manufacturers have been making the Nifes for 50 years plus and some of the original Chinese batteries are still in use in the USA. My supplier told me of a set of batteries that died after 20 years because the plastic cases had been installed in the open. There are multiple manufacturers and several Australian importers. Generic NiFe’s are used by the Chinese military, railways and industry. They can be over charged, under charged, run dry then restored and topped up. They do not get thermal runaway according to the manufacturers. They do not burn. If the battery management system fails and I am a month away – the batteries should be fine. The components – nickel, iron, and potassium hydroxide electrolyte are all recyclable. If one cell fails, I can simply take it out of series and run the system as normal until a replacement is received. I do not have to replace the entire bank. And there are multiple manufacturers manufacturing to one standard.
The disadvantage was they are big. I chose 1000 Ahr units, and it takes ten in series to make 12 volts. They will need the electrolyte changed at some stage (no sign yet) and they are 70 kg each. Nife batteries are expensive, but if they last as long as advertised, I will be passing them on to my children in 40 years. I bought one set of batteries while working to last my retirement.
The biggest problem I’ve had is that despite first being put in mass production over 100 years ago, there is a large amount of misinformation about them on the WWW. A lot of contradictory information is published by people who have never owned them. My settings are consistent with Edison's published work.

The system
I chose Outback for the battery management system as they can be programmed to suite Nife batteries. It is advertised as being suitable for the local hostile environment. I like the support system and the OpticsRE cloud management. In addition, I have treated the system like a Lego set, adding bits when I was ready, spreading out the cost. There is a FM80 charger and a VFX3024E Inverter. Over time I have added a Hub4, a Mate3, replaced the Mate3 with an AXS_Port, a 4G wireless data connection to Optics RE and finally an FNDC. The Mate3 was bought to allow me to program the Inverter. It has never been able to reliably sustain a connection to Optics RE. I suspect it’s not compatible with my local teleco. The ASX_Port connection to Optics RE is stable. Outback are looking into my Mate3 problem.
I recommend anyone with NiFe batteries get an FNDC to monitor loads and state of charge. I have found just using voltage to estimate SOC confusing in view of the required charging settings due to the internal resistance of the batteries. Within two days of putting in the FNDC, a whole range of system behavior suddenly became clear. I had considered putting in more solar panels, but the FNDC is telling me that I would be wasting my time on my current behavior. I wish I had got it earlier.
I live on the Tropic of Capricorn on an island on the Australian coast. I built a tin garden shed 3 meters x 1.5 meters and have the batteries on racks. There is a tiny 0.85 x 0.85 meter shed for the Outback electronics. The first 1000 amphours of batteries went in in January 2014 with a second 1000 amphours going in at the end of 2016. The system is nominally 2000 amphours at 24 volts. The battery energy storage does improve when used, and the harder the batteries are pushed, the more energy they store. When the second bank of batteries went in, they worked a lot harder than the first bank until they were broken in. That settled after 6 months. They banks have now balanced. Very different to lead acid. Ideally one day I would like to move to a 48V system, but this will mean a new inverter, and it’s a bit beyond my budget at the moment. Being NiFe batteries, having two strings of 24 volt batteries should not hurt them.
My batteries do not contain Lithium. I checked the performance research, and took my supplier’s advice. Edison’s recipe for alkaline battery electrolyte includes 20 gms Lithium per cell. I may need to replace the electrolyte from time to time. I am medically trained and the Lithium scares me. Lithium powder in the required quantity is nasty stuff for humans and is environmentally toxic. I will only lose a small percentage of battery capacity as a result, not enough to worry about.
The system is powered by 9 x 200 W solar panels, nominally 120V, most days about 105 V x 40 Amps for about 6 hours in winter.
There is a 12 volt LED lighting system in the house as backup through a Victron 24 to 12V transformer. Should the batteries discharge below 19V. The DC water pump runs directly off the batteries.
I have a 165 Farad Ultracapacitor that I bought cheap second hand as an experiment. There are research papers that they improve the efficiency of the power supply from the battery, an issue with the NiFe's internal resistance. To be honest, I am not noticing much difference. Research indicates also are supposed to extend the life of both NiFe and FLA batteries, enough of a reason to keep it connected.

Settings
Here is where I ran into problems with being a newbie and listening to conflicting advice. The alkaline battery chemistry of the NiFe system gives a different set of charging characteristics to most batteries. Some points.
- There is a high internal resistance to both charging and discharge. This varies with the amount of use the batteries get and temperature. The voltage sags significantly with a high load, such as an electric kettle and the big microwave. It comes back quickly. On charge, a high voltage maybe required.
- Specific Gravity cannot be used to determine an absolute state of charge. I recently installed an FNDC to calculate the SOC based on current in and current out. This has made a big difference in my understanding of the system.
- If the voltage is set too high, the batteries start making lot of hydrogen. If the batteries are “boiling” due to hydrolysis, your system is wasting power generating hydrogen. Drop the charge and float voltages a small fraction. Some people state that Nife batteries need to be charged hard. Tried this last summer. I used 60 litres of distilled water in six weeks! There was little to no significant difference in battery storage capacity – the extra charge electricity went into making lots and lots of hydrogen. Whatever – do not try and charge hard. Too much out-gassing or water consumption indicates the voltage is too high. There is plenty of information on how thirsty the batteries are. This depends on the user. My Australian battery supplier has been running off his batteries (in a cold climate) for 7 years, and never needed to top them up. I have adopted his charge profile. On his settings, I have stopped needing to top up the electrolyte.
- Potassium Hydroxide in the electrolyte will react with CO2 in the air. This results in carbonate precipitates. Eventually the electrolyte will need to be washed out and replaced. This is, from my reading, needed about every 10 years. I understand that I can extend this by making sure the free hydroxide levels are kept at normal levels.
- Quotes for the Efficiency Factor of NiFe vary from 65% to 80% with most people estimating around 75%. This depends on power draw. With my house empty and the big refrigerator left running, I have calculated an EF of 90%. At high current draw the EF drops dramatically. I have followed general recommendations and am using the lower EF 75%.
- Self discharge is quoted as a problem at 1% per day, however my batteries are doing much better than that. It seems to be a little higher than new lead acid batteries. I have a modern lightweight LiFePO4 battery in the camper, its’ self discharge is the about the same rate as the Nife batteries. As the NiFe and LiFePO4 batteries are always connected to the battery management systems and solar panels, this low rate of self discharge is not an issue.
- The batteries are just different enough to require care and attention in the selection of a battery management system. There are a couple, including the Outback system. Some others require a major work around.

Settings
From the various available manuals; Nominal battery cell voltage is 1.2 volts, using 20 batteries in a string = 24 volts. From the manuals, charge 1.7V x20 = 34 volts for up to three hours. Float 1.4V x20 = 28 V. Fully charged batteries sit at 26 volts under load. I use the following settings, with little loss in storage. My settings are a little more conservative to reduce electrolysis and improve life.

• FM80 settings
Absorb Voltage 30 volts. This is adequate for my current energy consumption. Can be increased to the recommended 34 Volts. (1.7 Volts each cell x 20 cells)
Absorb time 2 hours. This can be pushed to 3 hours, but there has been very little increase in power stored from a 1 hour Absorb.
Absorb End amps 0 Volts
Rebulk voltage 26.8 volts. May be a little high, but with a float of 28V it has only kicked in once or twice.
Current Limit ADC 80 amps. Default.
Equalisation. I have left this at default. Not needed yet.
This gives me a full charge of 26 volts.

• AXS_Port settings (same as Mate 3).
AGS disabled. Grid disabled (completely offgrid).

• Inverter
AC Input Voltage limited to 6 amps from 240 V charger so the little 2000 kVa generator is not overwhelmed. I use this sometimes to run power tools in the shed.
Battery protection cut-out is 19 Volts, the lowest allowed limit on the VFX3024E with a cut in of 22V. The 12 volt house draw will run it lower, but once the first string of 24V was conditioned over a few months (It can be done faster, but water consumption is very high) the voltage has never sunk below 23.8V on high loads with lots of visitors.

• FNDC
This is new. Initial results suggest it is going to be very helpful. It tells me that I am running between 100% to 97% SOC.
Shunts A = Other DC, B= Inverter, C = Charger.
C20 for Nife @ 20 hrs is about 2200 Amphrs. This is based on a paper from Scandia labs.
Return amps 2% of amphr = 40 amps
End of Charge voltage = 30V
Battery Charge Factor 75%. I may have to lift this to avoid over charging as the batteries seem to do better than this. However, the FNDC seems to be protecting the system.
Charge parameters Met = 1 min.

Comments,
Working out available battery energy ( = (26V-19V)x2000Amphr) = 14 kWhr of usable energy, the solar panels are probably a little small and I could do with more. However, at current usage of 4 to 5 kWhr a day, I need not worry. We have enough power for several days of storms.
Would I recommend this setup? Sure. Like most people who own NiFe's :grin: , I think they are great. Make sure you get a good suitable BMS like the Outback system. If we ever move, I am tempted to take the batteries and entire Outback BMS with me. (I will of course have to replace it with some cheap system). I have lots of energy storage, reliable, low maintenance and long life if you look after them. If a cell fails, it’s easily replaced without replacing the entire battery bank. The batteries are environmentally friendly. The batteries should out last me, saving me a lot of money in the long term despite the high upfront costs.
pjrpd
Member
 
Posts: 8
Joined: Sat Apr 08, 2017 5:20 am
Location: Gladstone, Queensland, Australia
My RE system: Remote off grid location monitored with OpticsRE. AXS_Port, inverter VFX3024E, charger Flexmax 80, Batteries 24 volt, 2000 amphr nickle iron batteries. 1800 watt solar panels. AXS_Port talks to wireless repeater over 30m ethernet cable.

Re: NiFe battery with Outback system

Postby hendrik krijt on Thu Aug 31, 2017 6:20 am

Hi pjrpd!

Thanks for your comprehensive write-up, I like your reasoning and your logic. I hope it will be some time before I need new storage, but would like to know more about where these NiFe cells are available, who makes them, to see if they are available in South Africa! Also to familiarize myself with their facts!

As a young lad I found some discarded NiFe cells and had years of fun cutting my teeth on electricity with them, charging, putting them to work (play!), recharging, and generally having a ball with them. ( playing with an old FLA lasted only 3 months! :lol: )

If you would not like to post that on this site, please private message me?

Lots of South African Southern Sunshine to you all!
Hendrik Krijt
hendrik krijt
Member
 
Posts: 20
Joined: Sat Dec 31, 2016 6:33 am
Location: South Africa, KZN province
My RE system: pv=4.9Kw, 2xflexmax 80, 2x 24v-240v 50Hz outback inverters, fla's 12x Willard rt25 tubular 2v cells. rsa, kzn prov. (may change to aquion batteries)

Re: NiFe battery with Outback system

Postby Mike Curran on Thu Aug 31, 2017 9:17 am

Thanks for the post, pjrpd. I'm also interested in others' experience with FLA battery alternatives. My next (also first) battery changeout will likely be my last so hearing how these work with OB equipment is very helpful to deciding what to get next, if not FLA. Thanks again.
Mike Curran
OutBack Guru
 
Posts: 331
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: NiFe battery with Outback system

Postby Saggy on Thu Aug 31, 2017 7:06 pm

You have put them on my radar! Thanks for the write up.
Saggy
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Posts: 8
Joined: Wed Aug 09, 2017 1:01 pm

Re: NiFe battery with Outback system

Postby pjrpd on Thu Aug 31, 2017 7:49 pm

Reply to hendrik krijt. I used an Australian importer for my batteries. I went back (twice) because of good service and support.
here http://www.ironcorebatteries.com.au/
I have looked at the online documentation from Changhong Batteries, Iron Edison (USA) and other sites.
Ironcore buys generic Chinese NiFe batteries. There are multiple manufacturers in China. He will consolidate a set of orders, and import direct from the manufacturer. He looks at quality control. There is a wait, they are manufactured on order and then need to come by sea. If the Chinese Government has put in a big order, sometimes there is a delay. Two of my shipments went via him, and then were freighted up to me. The last shipment came direct to me from China with Ironcore dealing with Customs and the freight agencies.
Otherwise look at Alibaba.com

Good luck.
pjrpd
Member
 
Posts: 8
Joined: Sat Apr 08, 2017 5:20 am
Location: Gladstone, Queensland, Australia
My RE system: Remote off grid location monitored with OpticsRE. AXS_Port, inverter VFX3024E, charger Flexmax 80, Batteries 24 volt, 2000 amphr nickle iron batteries. 1800 watt solar panels. AXS_Port talks to wireless repeater over 30m ethernet cable.

Re: NiFe battery with Outback system

Postby blackswan555 on Thu Aug 31, 2017 11:04 pm

Thanks for the comprehensive write up !, New one on me :grin:

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: 2516
Joined: Sat Aug 30, 2008 5:50 am
Location: Ibiza Spain,
My RE system: Other peoples, VFX "E" versions, FLA`s, Generators.

Re: NiFe battery with Outback system

Postby Boonys on Sun Nov 05, 2017 12:06 pm

Nice batteries, but spending $12,000 for 500AH in a 48V system is out of the question.

I could be worth while....if I weren't already 62. Haha
Boonys
Junior Member
 
Posts: 4
Joined: Thu Nov 02, 2017 2:28 pm
My RE system: 2)FM80s-1)FM60, 2)3648 Inverters.....

Re: NiFe battery with Outback system

Postby Mike Curran on Tue Nov 07, 2017 9:55 am

Fyi, SimpliPhi (different chemistry, I know)sent me links to their guidelines for setting up OB equipment with their batteries. Attached below:


Mike Curran
OutBack Guru
 
Posts: 331
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.


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