Fieldlines.com: The Otherpower discussion board

Probably the military were the main users, the things have always been incredibly expensive.

I believe there have been some sources form Russia or other eastern parts but I haven't seen a source from the west for years. Not sure what happened to Britannia Batteries interests, they were based at Redditch.

They were robust though not very efficient. They have awkward voltage characteristics to interface with lead acid controllers and inverters. Fine if you can get them at a realistic price but at their original price not so attractive unless you are young and intend to stay in the RE business for a long time.

Flux

At one point I was curious if it was possible to make NiFe batteries, but the processes  were too complex for me, and nickel is hard to get and expensive.

If you use "Google search the board" (from the menu on the top right of this page) with the phrase "nife edison battery" it will get you to a lot of previous discussion.

Chagrin,

Golf cart battery is 225 at 6v or near equal to the 122ah 12v.

Current report of golf cart battery cost is $67 (@sam's? Or Costco?

NiFe $840 / $67 = 12.5 sets of golf cart batteries.

Assuming golf cart battery last 7 years, for the same money have

Life of 12.5 *  7 = 87.5 years for the same money.

Anything past 50 years is no concern to me, don't expect to be here!

Golf cart battery life I hear is 3 to 7 and more years, depends on battery care.

Mine is 3 years old still going.

Charging efficiency for NiFe is low at 70%.

Lead acid is 91% when SOC blow 80% dropping down as SOC goes up.

Charging system must be 120% to place same charge in battery.

Solar this is very expensive, wind maybe no big deal?

Summery

NiFe is interesting, currently price and needs it's too expensive in several ways.

Have fun,

Scott.

But lead acid can not handle 100% discharge cycles.  The cost comparison gets much more reasonable when you impose a discharge floor on the lead acids.  If that floor is 80% SoC than their cost per amp-hour just quintupled.

Part of being off-grid for many people on this board is independence and self-reliance.  Lead-acid batteries are basically a consumable, so the permanence of ni-fe batteries are quite attractive and worth some premium.

I think batteries are going to get much better in the next ten years, so it might be worth burning through a set of lead-acids before a big purchase of ni-fe's.  It is a big investment.

What good are they if the inverter kicks off at 14.9V and the battery bank is 15.1V?

Can the 0% DOD voltage be included if the inverter kicks off at 10.5V?

Will DC items such as CFL, stereo, TV, LED bulb... function at below 10.5V?

To me it sounds like comparing the total WH in a giant cap to a small battery.

I only give a hoot about power available between 11.0 and 14.8V.

A 12V system with 10KW of 10V available doesn't mean anything to me.

Scott,

Gas was $1/G then?  PVs are $5/W now.

A basic marketing twist gives us <$1/W PVs!  :-)

And a 1 terrabite HDD was how much in the 70'S?  So now PVs are almost free!

I admit I didn't look at any charts.  I am stressed at the moment.

G-

No argument, the NiFe battery handles abuse Way better than Lead acid, if abusing it is an every day thing NiFe is the best choice. But just what does abusing it mean? Lets read on about golf carts.

Looking for applications abusing lead acid battery's.

Do we really need to work at the top 20% to get decent life from a battery?

Fork lift or golf carts are good examples.

Pick Golfing since often recommend golf cart batteries for RE applications.

Ask around at local golf courses with electric carts:-). Some golf courses replace the batteries every couple year. Others let them go until near dead. What I hear a set of batteries may last 3 to 8 years.

http://golfcartsalesllc.com/tech.shtml

"Batteries last from 3 to 8 years under normal circumstances". (bottom of page)

Most RE systems are designed for a number of days power.

Worst case for MI is around 11 days, to size a battery for this is way over Kill, worst case does not happen Every year! Just may seem like it.

Battery charging efficiency, to operate above 80% SOC is deliberately working at the lowest charging efficiency of the battery. Makes NiFe look good.

If a golf course can get 3 (and more) years with deep cycling their lead acid batteries, why can't RE? With better care extending it out to the 7-8 is very reasonable expectations. Mine have 3 years and still going.

I ran into a guy off grid using solar panels, he had a HUGE battery 11 days only discarged to 50%, designed for worst case. His battery was about 5 years old and not holding a charge past 5-6 days forced to run the generator. Equalizing charge was done Quarterly using a generator. Expensive battery. Solar panels were sized about 20% larger than his normal (average) loads. Realized due to the battery charging efficiency above 80%, the batteries were  fully charged only once each quarter. Batteries were sulfating due to all the time below fully charged. Considering the charger efficiency and battery charging efficiency the battery on the average was never above 80% SOC! To be honest I did not figure this out until years later. I had him deep cycle the battery which brought back some life. Told him to deep cycle the battery to 50% before each equalizing charge. I took care of a 1Mwhr battery in the Navy. We discharged the battery 25% or more before each equalizing charge. Battery was replaced every 7 years, still had most of its capacity. Very expensive battery. The battery was pampered, frequent SP readings, watered weekly, cell voltage measured every hour etc. any changes the battery was immediately gone over to see what was going on.

What are the dangers of following this advice?

Why saving 75% on the cost of a battery.

Deep cycle lead acid batteries are designed to be deep cycled. To baby them is a huge waste of money. Yes the life may be longer than the 25% sized battery, yet the life will NOT be 4x. Charging system must be much larger to keep battery nearly fully charged more frequently than once each quarter. Doing an equalizing charge more than quarterly actually abuses the battery. :-) don't you love it?

Understand industrial batteries life are around 20 years, if you get 5 or so years from your battery, by 20 years you will have spend less than an industrial battery.

In summery

I would size NiFe to handle what I needed and make the Lead acid 20% bigger to match the capacity.

Be careful of optimizing one efficiency, each system has many possible efficiency's, to over optimize on one and ignore the rest will not get the results your looking for.

Have fun,

Scott.

The off grid battery system in practice is well described by Scottsai. My system (currently lead acid golf cart batteries) does not use a charge controller. Either additional loads are added or panels subtracted to control things. The angles of the sun and hours of sunlight during the year call for some monitoring but usually it purrs along for a month at a time and I supplement electrolyte at the same time of making other changes. I'll be changing to NiFe batteries soon (see other comments by me-Shay).

Usually, operating the lead acids in the top 10-20% of charge is not possible without having 'sleepy' batteries. This is aggravated by age when individual cells differ and begin to slack off or take more of the load. I've never gotten a weeks worth of energy out of lead acids (40-220Ah golf carts) here on the homestead. Dissimilar cells can drag a system down. Equalization helps, so do it once a month if possible. In practice, the details of tending lead acid deep cycle batteries (replacement, especially) add up to using Edison/NiFe cells if you can get them for less than 7-10 times the cost of cheap golf cart deep cycle lead acids. A bad cell can be replaced. No controller needed. Complete discharge doesn't damage the battery, etc. I expect that the bank size can be reduced by half as well.

Do your homework when sizing and purchasing NiFe cells. I'm currently haggling over misrepresentation, "bait and switch type" tactics with a NiFe seller. Changshou Hongba makes good NiFe's. More to follow........  

Shay,

Nice price drop, have you sorted through your problems.

Have you gotten them to work?

Inverter issues etc?

Load testing, do the batteries deliver?

Have fun,

Scott.

Situation looks grim now....but the cell technology was proven in the old days. The answer is probably separate chargers (single cell and bank) and swapping cells in and out of the bank to meet current inverter limitations.