Nickel-Iron Battery/User Reviews

Truth About Batteries

• First-hand reviews and experience - generally overwhelmingly positive - [1]
• Maintenance - weekly topping off with distilled water, and electrolyte must be completely replaced every so often, which is laborious. [2].
• as a user of these batteries I can tell you they are NOT what we hear about day in and day out. I purchased mine from one of the best Chinese Factories (city is Mayang) . I purchased set of 20 for 400 Ah each cell for PV backup. What I learned to my surprise, they do not hold energy at their rated maximum few weeks after usage. - comment at [[3]. Note that this is expected, and the user has incorrect expectations of NiFe - they discharge 1%/day [4]
• Batteries still need to be developed, they are the holy grail to renewable energy but are being oversold? [5]
• Fast nickel iron proven in lab - [https://news.stanford.edu/news/2012/june/ultrafast-edison-battery-062612.html
• Useful review- [I'm happy enough, spent the $$$ already, and re-rejuvenated the electrolyte this last summer, still going and I never worry about sulfation destroying them in a week. But they are inefficient thirsty bastards - [6]
• "I'm currently using NiFe off-grid. Just changed over from lead-acid. Lead-acid are not actually cheaper despite what people keep saying. The capital outlay is more for equivalent *quoted* Ah. The problem with lead-acid is that you can't effectively use more than 20% of the quoted capacity. But with NiFe you can use all of it. So NiFe is 5x more useable capacity straight off. Not to mention that lead-acid plates disolve pretty damn quickly. They can be dead in 1 yr with daily cycles. I've been quoted at least 15 yrs for my NiFe by the manufacturer.
• Also, if anyone needs to reduce the voltage to their inverter by 1 or 2 volts, a method I use is to add 2 or 3 forward biased diodes between the batteries and the inverter. It's not a particularly efficient method but it works. I charge my (38) batteries at 66v from either solar or genny and 3 diodes drop the voltage to 63.75v to the inverter, since my inverter cuts off at a little over 64v." [7]
• Electrolyte replacement - ' NiFe only goes 10 years, then you have to refresh the electrolyte That cost me a couple grand for lab grade chemicals (lab grade needed if you want a long life.)' - ? [8]
• Good experience with NiFe- [9]. Video.

Conclusions

• Must top them off - more than lead acid. Auto watering solves this.
• Electrolyte must be replaced decennially - tridecennially.

Superefficient System

• See Minimum Viable Night Time Power.
• Say we have a minimum 1kW pack and go with the suggested 60% depth of discharge - then 600Whrs powers a pellet stove overnight. If all loads are run during the day with an oversized PV system - that appears to be a viable solution. Compressed air, if made more efficient with good air engines - can likely do a decent job to top off the needs in a lifetime design system. Biofuel or hydgrogen may need to be integrated here. Only a systems solution can work - there is no easy fix.