Nickel Iron Battery - NREL Test Results

Don't do that and waste your money. Lithium is not ready yet. Consider a good Industrial Lead Acid Battery like Trojan IND line up or Rolls 5000 Series. They cost less than LFP and last longer.

All you got to do is look at the warrant. At best you may get 2 year warranty on LFP batteries. Trojan and you are looking at 8 years. Not even close.

Trojan (13.5 kWh) and Sonnen Lithium batteries are warranted to produce 70% at 10 years or something like 5000 cycles.... There is also no maintenance and the batteries include a 120/240 split phase inverter rated at something like 5000 or 7000 watts.
One must consider what it costs to purchase an equivalent inverter, charge controller, and battery bank and then put them all together.. With the Tesla, its all one unit.

And while I'm still getting my information straightened out, I think the Tesla battery can accept AC or DC input to charge. As for the Tesla, they are certified to work with SMA inverters, which is what I have.. but I'm still working on figuring out exactly what that means.. Does it mean they can override the anti-islanding feature like the SMA Sunny Island or the Schneider Conext units? Still working on it.

They've made some big improvements this year.... Does that information change your opinion in any way?

Nope, Tesla does not impress me one little bit.

Which part specifically? I'm totally open so please feel free to drag them through the dirt.. I have no preconceived notions one way or the other...

I realize this is an ancient thread, but it came up on a search and seemed worthy of a reply.

First off, a potential real world partial solution for the spectacular bubbling is a load dump. Wastes juice? Well yeah. But it only wastes the juice you are not "dumping" through your inverter, or on other low voltage loads. I run this arrangement in conjunction with solar on a 48v lead antimony (lead acid) battery bank and it dramatically cut down watering and bubbling woes, while allowing borderline inputs. Why would I take this approach? So that batteries can maintain an adequate charge in winter, but not boil and froth during summer. Theoretically the MPPT charge controller should keep things under control, but in reality it did not. Yes I'm a redneck, so "less than nice people" can save themselves the trouble. But it works *very* well for me. And I suspect this approach would help quite a bit with NiFe batteries as well, and for similar reasons- and most dumps are programmable.

On to NiFe: First off, most commercial products essentially capitalize on industrial waste shavings for the media. Which is fine, whatever. Once plated it's no problem. But the other way is with stacks of flat steel alternating plated. Yeah, composition is proprietary, but price nickel costs and the truth is obvious. Wanna make your own? Nickel acetate costs cure that pipe dream. Right until you realize that you can make your own with any random chunk of pure nickel, and a few jugs of vinegar.

I can already hear all the naysaying and negativity. The internet is the new road rage. But I have no intention of playing with the trolls. Oh, excuse me, experts.

But for those who are curious and might consider it: A 6 gallon bucket full of home made plates gets in the range of 100+ AH "on paper" depending on durability vs capacity. Cut sheets 7 shortways (7x48) then to 7x24. Cut in half again at a 60ish (but consistent) degree angle. Drill "ears" from angle to tie plates together with SS washers for spacers, and isolate opposing plates with KOH resistant fabric. Vertical SS straps from plate tie bolts go through slots in the lid to hook wires. Push a hot section of strap stock through a fixture to melt the pass through slots dead ended against a block of wood. Do the same for watering/vents. I am fond of using auto water valves- Get a big jug and drill a hole in the cap to match the watering tubing (can't remember what size off the top of my head) but this arrangement also eliminates the need for a more complicated vent/fill port. And makes battery watering a snap. Jug sits alongside cells, so no leaks, then raise upside down and all the cells get topped.

Having said all that, and since LFP has been mentioned: The key to long life lithium is keeping charge rate in the middle of the road so to speak. Current CC's don't do this AFAIK. Nickel hydrogen batteries last essentially forever- cycles be damned. But the things that make such exotic tech what it is, may soon be coming to more attainable NiMH cells. Lab proven, but hasn't left the lab yet. If the tech is scalable, lithium will be irrelevant. And the Japanese just discovered a rare earth ore deposit of epic scale, making "shipstone" quality NiMH tech basically limitless. Better even than a solid state lithium battery- which so far remains elusive. IE *everlasting* holy grail NiMH cells have been *built*. If they make it past the lab and into production all of this may be moot.

Welcome. I think.
For a first post, and semi-technical attempt at content, it's not very coherent, and to play further, you are going to have to step up your game. If you are going to throw big words around, at least get them in the right order. I'll ignore the latter half of your post, till I understand this first part.

First, I'm running a large NiFe bank. NiFe are notorious for gassing and electrolyzing the water, it's the nature of the chemistry. i have my controller (s) setpoints configured properly and am at the low voltage side of the limits. If I follow your suggestion and added a "load dump", all that would do is lower the charge voltage and prevent the cells from fully charging. That saves water but wastes battery capacity. I actually have "summer" and "winter" set points for my controllers, summer is a bit lower voltage, shorter absorb time, winter I jack the voltage up and longer absorb times to more fully utilize the available solar. Water is cheaper than diesel (for now).

So maybe I've misunderstood how you utilize a "load dump" and I welcome a chance to hear what you have it doing.
What do you use for a charge controller? Size of PV array? Battery bank size ? You can use the signature line to describe your system.