Custom inverter / charge controller settings for Nickel Iron batteries

Iron Bran · February 2013

I have been talking to a lot of people about setting up their charge controllers and inverters for use with Nickel Iron batteries.

Most recently, I was working on a Xantrex XW 6048 system with a 400Ah 48V Ni-Fe battery. There was one XW60 charge controller, the 6000 Watt 48Volt inverter, and a System Control Panel.

This system was previously configured to use lead acid batteries, so the charger was set to bulk up to 54 Volts. With the Nickel Iron battery, we need to charge up to a higher voltage. I took detailed notes while configuring the system to work with the new battery, and the setpoints we changed are shared below.

In general, we want each cell to charge at 1.6 Volts or higher. Ideally, we would like to get each cell up to 1.65 - 1.67 Volts per cell. Now is a good time to grab your calculator...

1.2 = nominal Voltage of a Ni-Fe cell
1.2 Volts x 40 cells in series = 48 Volt battery

1.45 = Voltage per cell when full, at rest, not charging or discharging
1.45 Volts x 40 cells = 58 Volts This is already higher than the 54V set point for the lead acid battery.

1.65 = Voltage we want to hold for full charge
1.65 V x 40 cells = 66 Volts For many inverters, this is higher than the HBCO (high battery cut out)

At this point, we change the configuration of the battery to run with 38 cells instead of 40 cells.

1.2 x 38 cells = 45.6 Volt nominal capacity. The SMA Sunny Island inverters actually default to this nominal voltage when you select Nickel-type battery in the setup menu.

1.45 x 38 cells = 55.1 Volts The normal operating range for this battery is 55.1V - 45.6 Volts. The LBCO (low battery cut out) for most inverters is down at 40 Volts, although the old trace Trace can run down to a super-low 36 Volts. At 40 Volts, with 38 cells, each cell is working at 1.05 Volts. The very low point for a Ni-Fe cell is 1.0 Volts, so we are only 5 one-hundredths of a volt away from terminal voltage.

1.65 x 38 cells = 62.7 Volts This voltage is well below the 64V HBCO (high battery cut out) for most inverters. The key here is that we can set the charge controller and inverter / charger set points a little higher and achieve a near constant current charge algorithm, no matter what kind of equipment we are using. When the charge controller or inverter has to work all day to get up to the max charge voltage, it is delivering max current in the Bulk charge cycle. We are basically telling the equipment to achieve a battery voltage that is unattainable, which keeps the chargers working at max output as they do their best to get the battery up to that level.

Some inverters like Outback allow you to set the Absorb exit amps, which means that even if the charge cycle were to go from Bulk to Absorb, the amps do not taper to 0. Rather, the Absorb exit amps setpoint allows us to deliver 80% of the charger output at the very end of the absorb cycle. When we set the Max Absorb Time to 5 hours or more, we can lengthen the time it takes to taper the current from 100% to 80%. Remember that we would likely have spent most of the day in Bulk, and only a fraction of the actual charge time in Absorb. The point here is that we can configure nearly any piece of equipment to work with a 24V or 48V Nickel Iron battery.

Please let me know if you have any questions, I am happy to help!

Attachment not found.

Attachment not found.

XW Inverter settings

LBCO 40 Volts (sadly, the new Outback Radian is limited to a relatively high 44V LBCO, but a change may be in the works)
LBCO delay 20 seconds
High batt cut out 70 Volts (this is the highest I have seen in any 48V inverter)

Battery type Custom
Capacity 400 Ah
Recharge Volts 49.5
Absorb time 300 minutes

Eq support Active
Eq Voltage 64 V
Bulk Voltage 63.4 V
Absorb 63.4
Float 55.1
Temp Comp -32

XW Charge Controller

Re-charge volts 53 volts
Capacity 400 Ah

Custom menu
EQ support 64V
Bulk 64V
Absorb 64V
Float 55.1
Temp Comp -32

SMA Inverter Setup
Attachment not found.

Attachment not found.

Cariboocoot · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

Note: if the system was set to Bulk/Absorb at 54 Volts for either FLA's or AGM's it was set wrong to begin with.

NorthGuy · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

Iron Bran wrote: »

When we set the Max Absorb Time to 5 hours or more, we can lengthen the time it takes to taper the current from 100% to 80%. Remember that we would likely have spent most of the day in Bulk, and only a fraction of the actual charge time in Absorb.

That's obviously a different approach than with Lead-Acid. So, the idea is to keep them at 100A until they reach 1.67V/cell, and then taper down to 80A in 5 hours?

Looking a the pictures, looks like the 400AH bank takes much more space than mine 673AH lead-acid. What's the size of one battery?

SCharles · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

NorthGuy wrote: »

Looking a the pictures, looks like the 400AH bank takes much more space than mine 673AH lead-acid. What's the size of one battery?

Don't know what pictures are showing the bank, I don't see them. However, I have a 700 amp hr. bank and, yes, the banks take more physical space than comparable lead acid. My 700 amp hr. bank is larger in size than the 1800 amp hr. lead acid bank it replaced. Mostly that is because the nickel iron bank requires ten cells to the lead acid's six cells. [1.2 volt cells to lead acid's 2.0 volt cells.] My cells are each about 18" tall by 7" wide. So, ten cells in a row require almost six feet of space against the wall where my lead acids only needed 4 1/2 feet. I could cut that 6' down by arranging two rows of five cells each, next to one another, but my area does not allow that [too narrow, a pantry area].

The cells are quite light in weight, about 60 lb. empty. Don't recall what they are with the electrolyte, several pounds more but still easy to maneuver around to rearrange. My old lead acid cells topped 300 lb. each. You put them in place and left them there.

NorthGuy · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

SCharles wrote: »

Don't know what pictures are showing the bank, I don't see them.

I clicked on OP's name and there was a recent post with lots of pictures:

Iron Bran wrote: »

Here are some recent project photos...

Somehow, I thought they were here. I'm sorry.

SCharles wrote: »

My 700 amp hr. bank is larger in size than the 1800 amp hr. lead acid bank it replaced.

I found their Web site. I would need a box which is twice as big as mine (673AH) to hold the same AH array of NI (700AH). And that is despite my batterieas are huge. I could easily fit 1300AH bank of L-16s in my box.

I also compared some other characteristics to the data sheet for mine batteries (IND13-6V) from Trojan's web site. Surrettes 5000 would be similar. This is all on paper, of course.

- battery life - NI: 25 years; LA: 13 years (based on the life cycle chart for my usage) - NI is two times better!
- max recommended discharge - the same at 80%
- efficiency - NI: 46/63 = 73%; LA: 48/55 = 87% - LA is way better
- maintenance: NI - looks like no maintenance is needed; LA may require long absorptions, equalizations, adding water

Overall, looks about the same. With NI you get much lower efficiency, need to use more space, but in return you get a longer maintenance-free life.

However, NI price is almost three times higher! This actually gives them 50% shorter life per dollar spent compared to LA. Of course, every situation is different, but I don't think this is a viable option for me.

SCharles · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

The cost of Ni Fe batteries is a deal killer for many, obviously. I thought about it a very long time before I decided to take the plunge. For me, passing 60 yr. old, I decided it was worth it to never again have to wrestle a ton or more of batteries in a change-out. I have done it now three times. I can do it, but it is a bear. The idea that I could get these [relatively] very light cells and [perhaps] never have to make a change again was the deal-seller. Plus, with the Fed. tax credit and the 15% off by the co. I bought them from, it brought the price down to about twice what I anticipated spending on a new forklift set. Something around twice, give or take. I ended up not calling around to find the current prices on new lead acids, so I don't know what they go for now. My last set I bought in 1991 for $2200 plus trucking. They lasted 20 yr., and if a new set lasted at least that long, I'd have been faced, possibly, with another replacement at roughly about the time I turn 80, assuming I make it that far. Who knows whether I'll be capable of wrestling 300-pd. cells around by then????

Time will tell whether the nickel irons truly are a lifetime battery bank. No way to know until they do last. Fingers crossed. Worst case scenario: I paid a lot of money and STILL had to replace the batteries. Fingers crossed again.

Anyhow, I was also fascinated with the batteries and the idea of their lighter weight and longevity, so that factored in, too, the intellectual interest. At the price for them, they are definitely not for everyone and are in no position to scare the manufacturers of other battery technologies. But I am quite pleased with mine, so far. And I am successfully using my same controllers and inverter [both Outback] so I didn't have to purchase new electronics.

NorthGuy · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

SCharles wrote: »

The cost of Ni Fe batteries is a deal killer for many, obviously. I thought about it a very long time before I decided to take the plunge. For me, passing 60 yr. old, I decided it was worth it to never again have to wrestle a ton or more of batteries in a change-out. I have done it now three times. I can do it, but it is a bear. The idea that I could get these [relatively] very light cells and [perhaps] never have to make a change again was the deal-seller. Plus, with the Fed. tax credit and the 15% off by the co. I bought them from, it brought the price down to about twice what I anticipated spending on a new forklift set. Something around twice, give or take. I ended up not calling around to find the current prices on new lead acids, so I don't know what they go for now. My last set I bought in 1991 for $2200 plus trucking. They lasted 20 yr., and if a new set lasted at least that long, I'd have been faced, possibly, with another replacement at roughly about the time I turn 80, assuming I make it that far. Who knows whether I'll be capable of wrestling 300-pd. cells around by then????

Time will tell whether the nickel irons truly are a lifetime battery bank. No way to know until they do last. Fingers crossed. Worst case scenario: I paid a lot of money and STILL had to replace the batteries. Fingers crossed again.

Anyhow, I was also fascinated with the batteries and the idea of their lighter weight and longevity, so that factored in, too, the intellectual interest. At the price for them, they are definitely not for everyone and are in no position to scare the manufacturers of other battery technologies. But I am quite pleased with mine, so far. And I am successfully using my same controllers and inverter [both Outback] so I didn't have to purchase new electronics.

When I was buying my batteries, I only looked at lead-acid ones. May that was a mistake. I bought the ones that promised the longest life on their spec sheet, even though they were the most expensive. I do have problems with mine, but hopefully it doesn't affect their life span. After we installed these batteries, which were 315 pounds each, I though that next time I'd better buy something lighter.

BB. · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

"Iron Bran" is, most likely, associated with:

http://ironedison.com/nickel-iron-ni-fe-battery

Iron Bran, what is the life of the electrolyte (1-5 years? Oxygen+carbon dioxide from air affect life?), the process for changing/refreshing electrolyte, cost and disposal of electrolyte, etc...

-Bill

mike95490 · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

For me, passing 60 yr. old, I decided it was worth it to never again have to wrestle a ton or more of batteries in a change-out.

I've got an 42 cell, 800ah bank, and the cells are about 70# empty, and closer to 90# when filled. But I've not discovered a good way to drain and refill the cells when that time comes. I'm thinking of a hoist and motor mount, to dump them out, or finding some compatible material, and drilling into the case to get a siphon tube to the base of the cell. Then sealing it up.

And to speak to maintenance

- maintenance: NI - looks like no maintenance is needed; LA may require long absorptions, equalizations, adding water

1) the lower efficiency means that a lot of water gets electrolyzed into gas. I'm adding 20 gall of distilled every couple of months. way more than I did with lead acid.

2) Electrolyte change out. I covered the heavy part above, and there is still the mixing of a new 95 gallon batch of electrolyte for change out when it gets carbonated.

So, it's a new world, and I'll see what happens

NorthGuy · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

mike95490 wrote: »

1) the lower efficiency means that a lot of water gets electrolyzed into gas. I'm adding 20 gall of distilled every couple of months. way more than I did with lead acid.

That's not bad. Looks like you can see through the walls and the difference between "MAX" and "MIN" is rather big, so you need more water, but probably do not need to change it more often than with lead acid.

mike95490 wrote: »

2) Electrolyte change out. I covered the heavy part above, and there is still the mixing of a new 95 gallon batch of electrolyte for change out when it gets carbonated.

I didn't see anything on their Web site about changing electrolyte. I probably didn't look well. That's not an easy task for 40 batteries. How often do you need to change it?

westbranch · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

Mike do you use an 'electrolyte oil' to minimize air contact like used in NiCd?

mike95490 · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

No oil used here, just the sealed caps with the rubber ball check valve.

story is, the oil, on top of the lye, eventually makes soap ! Not good, and no longer recommended (unless you like to wash a lot with lye soap).

Battery filling, it's about every 3-4 months, and that big gap between ADD and FULL, is just jug space, and holds a gallon of distilled. When was the last time you went to the grocery to buy 42 gallons of distilled ??

Electrolyte change out, when the Carbonate Test Kit says you need to, typically 4-7 years. And the KoH crystals only store well for a year. They want to suck Co2 right through everything, and there are some that think the new plastic cases are permeable to Co2.

NorthGuy · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

mike95490 wrote: »

Battery filling, it's about every 3-4 months, and that big gap between ADD and FULL, is just jug space, and holds a gallon of distilled. When was the last time you went to the grocery to buy 42 gallons of distilled ??.

You can make your own. My RO (Reverse Osmosis) system produces water with 3-5 ppm of solids. Distilled water is usually 5-10 ppm. So, my water is actually cleaner. Although the well water that is used as an input to RO is not that bad in the first place - no heavy metals etc. and only 800 ppm of solids.

mike95490 wrote: »

Electrolyte change out, when the Carbonate Test Kit says you need to, typically 4-7 years. And the KoH crystals only store well for a year. They want to suck Co2 right through everything, and there are some that think the new plastic cases are permeable to Co2.

That would mean 4-5 changes during the lifetime of batteries. Have you done a change yet?

mike95490 · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

Water plant: I use pond/rain water, and pump it uphill to storage tanks. Potable water is filtered by a slow sand filter, at 5gpH, quite slowly (it's a slow sand filter ! ) I also have .3 micron silt / clay in the water, I let a 3,000 tank sit undisturbed for a year, and it still looks like milk, I can't filter it out. That will clog a RO filter in days. Additionally, the RO filters waste a lot of potable water on the dirty side of the membrane, they all connect to the sewer line to dispose of it. And you have to replace membranes annually, at a pretty high cost.

Electrolyte: No, I've not done a change yet. haven't had time to run the test.

NorthGuy · February 2013

Re: Custom inverter / charge controller settings for Nickel Iron batteries

mike95490 wrote: »

Water plant: I use pond/rain water, and pump it uphill to storage tanks. Potable water is filtered by a slow sand filter, at 5gpH, quite slowly (it's a slow sand filter ! ) I also have .3 micron silt / clay in the water, I let a 3,000 tank sit undisturbed for a year, and it still looks like milk, I can't filter it out. That will clog a RO filter in days. Additionally, the RO filters waste a lot of potable water on the dirty side of the membrane, they all connect to the sewer line to dispose of it. And you have to replace membranes annually, at a pretty high cost.

Of course, when the water is so difficult to get you cannot waste it. You can re-use water that comes from the "dirty" side of RO. It's just a little bit dirtier than the original water, so it is quite usable. You do need more or less clean water for RO, or the membrane will die. So you would probably need to run it though pre-filters first, which would also waste a lot of water on backwashing. Probably, not a good idea overall.

I am lucky to have relatively clean and aboundant water that I can use for RO and membrane can last several years (I hope).

midijeep · April 2017

What are the setting for the SMA Sunny Island and NiFe Batteries?

I am finding that the SI recalculates SOC and in a matter of minutes as I use the power from the batteries. The SI SOC drops from 95% to 12% in a mtter of a minute. My external battery monitor (Victron) is not doing showing the drop the SI is showing. If the SI Calculates the SOC at 12% or below it shuts down to protect the NiFe batteries but the Victron readings are not even close (stays around 95%).

Any suggestions on how to keep the SI on, even though the SOC of the NiFe Batteries are well above 90% and the NiFe batteries haven't used much of the stored energy?

Dave Angelini · April 2017

I think I would figure a way to disable the SOC from the inverter. On an XW I would just change the low voltage cut-out and disable the battery monitor by unplugging it from the network. Is there a shunt? Tell us some voltages?

mike95490 · April 2017

Does the SI have a battery Type Selection ? Battery Size Selection?

midijeep · April 2017

mike95490 said:

Does the SI have a battery Type Selection ? Battery Size Selection?

The Si does have both battery type an size. I chose the NiCd type and put in my Ah of the battery bank.
I have always had trouble getting the SI to read or get to 100% SOC, where the Victron external battery monitor always did get to 100% after running loads on the battery bank. Yesterday I changed the Boost charge voltage to 1.66 and let the battery bank charge for 6 hours. The battery bank SOC did slowly increase, then at the end of the 6 hr boost charge I changed the Boost charge voltage to 1.5v Then the SOC recalculate and the SOC shot up to 100% SOC (see attached pic). All along the Victron went from 93% SOC to 100% during the initial Boost charge. It only took a few hours for the Victron to read 100% SOC.

I am not sure what to make of all this. Very annoying, especially not really knowing the true SOC (using SI readings) when running off the battery bank.

I have NiFe 200 aH battery bank. Each cell is nominal 1.2v. I had to use 38 1.2v cells instead of the 40 (to make a 48 volt bank) because the SI NiCd setting is 62,7 volts.

The problem is I think the Victron monitor is correct but the SI reads differently and is controlling the loads and charging. SMA tells me that I need to have the battery manufacturer to send them the specs, etc.... and they would look into making a setting for NiFe batteries.

Any ideas on how to get the SI to read the SOC correctly?

mike95490 · April 2017

I can't help you with SI stuff, but also consider that the NiFe battery is only about 70% efficient, so what used to take 1 day with lead acid to recharge, can take longer with NiFe, Monitor your voltage rise, and follow the battery vendors instructions to set voltages, I don't want to tell you mine, I don't want to fry your warranty.

Dave Angelini · April 2017

I am confused but probably because there is very little in your post that is useful for troubleshooting.
so,
Who sold this/installed the system? Offgrid? Where? The more time you spend the better the advice will be.
Is there solar, grid, or generator?
You are losing AC out because of the low battery cut-out correct? You need to fool the inverter until you get more support if you really believe the battery is charged. It seems correct that the inverter would shut down with your nominal 45.6V battery.

midijeep · April 2017

This is a grid tied System using a 48 volt battery backup, SMA SunnyBoy & Sunny Island, an autoformer and NiFe batteries (Using 38 --- 1.2v cells instead of 40). My single SI is capable up to 56 amps (two SI's together would be double, so on so forth). With the Autoformer the system become 240v.

The graphic above represent me manually disconnecting from the grid via main breaker out on the utility main. Also, the battery bank voltage never got below 45.6V during this period. I have checked each battery's voltage during float and charging and it corresponds to the voltage being applied by the charge controller (Sunny Island). Every time test my system by disconnecting from the grid this voltage drop occurs via SI reading but the Victron does not and there is hardly any load on the battery bank.

I have been using the following parameters in the SI:
Boost charge = 1.55
Float = 1.45
Equalization = 1.65
Full charging = 1.65

The manual that came with the NiFe batteries says to charge at 1.7v /cell but using a charging voltage of 1.66v in the SI is the upper limit (62.7v).

I thinking that maybe the battery bank is not completely charged even though the SOC may read 100% and the battery bank voltage is corresponding to charge controller read?

mike95490 · April 2017

With NiFe, you cannot use any state of charge meter, the battery voltage is way too variable.
If all you can manage is 1.66Vper cell, then, that's all you can do. My inverter (xw-6048) can only charge up to 64V, but it does not fault until 67.5V So, my solar charge controllers get the daily voltage up, and I have a couple hours of absorb on them before dropping back to float. Winter (cloudy weather) I'm much lower in the voltage curve and can only charge to 64v until the sun returns. Then the battery sucks power from the PV for hours before it gets to absorb.

midijeep · April 2017

mike95490 said:

With NiFe, you cannot use any state of charge meter, the battery voltage is way too variable.
If all you can manage is 1.66Vper cell, then, that's all you can do. My inverter (xw-6048) can only charge up to 64V, but it does not fault until 67.5V So, my solar charge controllers get the daily voltage up, and I have a couple hours of absorb on them before dropping back to float. Winter (cloudy weather) I'm much lower in the voltage curve and can only charge to 64v until the sun returns. Then the battery sucks power from the PV for hours before it gets to absorb.

Thank you Mike, much appreciated the information. The guy I bought the NiFe batteries from in Colorado is clueless and that is why I came here to see if anyone had NiFe batteries and how they handle them.

To clarify what you do, so I can understand is you set your boost and float to as high as voltage your charge controller can do? That would be 1.66v per cell for my setup. Is this correct? Or do you drop the voltage on the float charge lower? The absorption, do you use a different voltage?

mike95490 · April 2017

You stay below the fry point of any electronics (67V for my $4,000 inverter), otherwise, you aim for as much voltage as recommended to charge with.
Both my Classic and Morningstar MPPT chargers can exceed the fry point of my inverter. be careful.

Blayd · April 2017

I am seriously considering going the NiFe route. I currently use Trojan L16 RE B's for the battery bank which with the best care possible might make 4 years before they are junk.

From my research so far, the Ni-Fe are not perfect by any means. However I am leaning towards at least dabbling with a low Ah set to trial them. At three times the cost of Pb/acid, these cells need to last at least 12 years as the break even point.

I am totally off-grid, and reside full time at this residence so I dont desire to invest in a product that may fail prematurely.

Certainly this will be an expensive learning curve regardless of the outcome. The technical stuff I understand.

I would like to hear from those that have employed the Ni-Fe cells over the long haul as a final sanity check before I I place an order, hopefully factory direct.

mike95490 · April 2017

Factory direct means you deal with china for service Yucch !

NiFe means Larger PV array, to support all the electrolyte you are going to be electrolizing (gassing off) and refilling with distilled. I go through about 5 gallons every 2 weeks, and AFIK, there is not automatic watering system for them that maintains the air-tight seal to keep Co2 out of the cell. (Co2 poisoning is the cause for the replacement of electrolyte every 5-10 years)

Because of the high internal resistance, you need larger bank to handle short surge loads

Wide voltage swing between empty and full. Some gear can't handle the swing (inverter over voltage, inverter under voltage) My bank would want to charge at 68 or 70V, but my inverter will die, so there are times I'm not at full charge.

Source to purchase replacement electrolyte supplies in 7 years.

They work, I live off them, but they are different ,

Blayd · April 2017

The wide voltage swing is of concern, since I run garbage inverters. I will probably use the NiFe set for the lower draw continous duty items to avoid low voltage fault protection kicking in, with just nine jugs rather than ten which avoids over-limit, and gives me a spare jug just in case.

I have plenty of spare panel capacity at the moment, and worse case, can add more as I upgrade ancient equipment, which after installing an Outback flexmax 80 which makes the old equipment look pretty pathetic efficiency wise.

I only use heavy draw items during peak charging time at any rate. A possible curative for the voltage swing would be the lower Ah jugs, with multiple strings in parallel to smooth out draw down.

Probably the best selling point for the NiFe is handling temperature. The SoCal mountains here can go from below freezing to over 100F degrees. I have had one low end Pb/acid battery experience run-away thermal, many years back, so high heat degradation/damage is a major concern.

The factory customer service would only be for defective product. Lets see how pricing plays out. I dont feel the need to pay for a paper pusher to place a drop ship order, and I can drive to the Port of Los Angeles and back in a day for less than a tank of bunkerer oil in Queen Mary.

BB. · April 2017

I wonder if you can work with a MFG of Inverters directly (or through a distributor) to get a NiFe friendly inverter (appropriate voltage range)?

http://exeltech.com/choosing-an-inverter-manufacturer-the-benefits-of-product-customization/

Our host is a distributor for Exeltech.

https://www.solar-electric.com/contacts

-Bill (I don't work for NAWS/Solar-Electric) B.

Blayd · April 2017

For an inverter to be viable from a manufacturing standpoint, and to keep pricing in reasonable bounds, there would have to be a massive demand for a product that would have the wider range needed for NiFe. Even at that there would have to be 3 or 4 different models to cover the most common voltage ranges.

For me, the el-cheapo units off the shelf are the most cost effective given the enviorment they operate in here. Expensive units can cook just as fast as crap units given hard use, heat, dust, acts of stupidity, et el.

In a perfect world, the battery fairy and equipment fairy would get together and drop ship a trailer load of stuff in driveway. Some how they keep missing my address. I even leave the gate open.

Dave Angelini · April 2017

Custom inverter / charge controller settings for Nickel Iron batteries

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