More Nickel Iron battery questions.

Saggys

Will be upping battery voltage this spring from 12 volt to 48 volt. Was going to go to 24 volt 250 amp hour Beutilityfree NiFe battery bank but came across a 24 volt 200 amp hour Iron Edison battery bank, both used but operational and holding a good charge voltage. Both of these battery bank jars are the same physical size, same amount of electrolyte according to the Changhong spec sheet. The only difference I can find is the 250 amp hour jar is slightly heavier. The question I have is how to series these up? I am thinking alternate them 200, 250, 200 etc.
and the bank will be held at 200 amp hour rating due to the higher internal resistance of the 200 amp hour jar. Or would it be better to go 20 in a row of 200 amp hour and 20 in a row of 250 amp hour? Or groups of 10? Or maybe it does not matter, I know it is advised to use all the same amp hour rating in a series string but I think I am going to try this anyway. I will keep my 24 volt inverter if it does not work out.

Photowhit

Why keep your inverter? Doubt it will handle the wide voltage range required.


Posted this photo of the lie at Iron Edison about efficiency. Their charging range and nominal volt would indicate a max 72% efficency.

So a 20 cell bank would charge at 33.3volts out of range for most inverters. So adjustable will work, but many will shut down, If you are still planning on using the PC250 charge controller, I think it's out of range too.

I wouldn't mix to different age and capacity batteries in a bank, but please post your findings.

Saggys

I am pretty sure my Trace PS 2524 is good to 33 volts, for sure 32 volts. The PC250 is good for 110 volts input. I will use a Blue Sky 6024H if I remain at 24 volt. Going to 48 volt will be a new inverter and charge controller, this point undecided. 
Any way, back to original question,  would it matter how the series string is wired with mismatched amp hour batteries? I don't think it is going to be that big of a deal. 

Saggys

I have the SWRC for the PS 2524 so it is adjustable. 

Saggys

I would like to follow up on this post:

It has been 1.5 years plus of the mismatched battery bank, 20 - 5 year old 200 amp hour Iron Edison NIFE batteries in series with 18 - 12 year old 250 amp hour Beutiltyfree NIFE batteries (both on original electrolyte) and the results have been positive. The string has settled into a fairly consistent charge and discharge voltage with differences in the .05 voltage range.

The string is getting charged at a modest 1.54 volts per cell and has modest water consumption. (top off about 3x per year) 

I am now using a 3500 watt AIO inverter, but it has some limitations like low absorbtion voltage for this battery chemistry, the need for an inverter style generator on A/C input and high idle current, but has been a surprisingly good for the cheap price.

The thing I like best about this battery chemistry is not having to worry about state of charge and their simplicity.

I know in this day and age Lithium chemistry is the way to go, but I am going to use what I have for now,

KenMorgan

how easy it is to find iron edison batteries these days?  I was looking a few years back due to their simplicity and lack of toxic chemicals.  I have the "real estate" to put down a good sized bank for my off grid use but skipped them as i could not find any vendors that i felt were serious (at that time).  currently using liFePo4 which works well but what happens in 10 or 20 when I need to recycle the damn things?

Saggys

Iron Edison has closed the doors. I think the only distributor in the USA is Qualmega. Hopefully by the end of life of your Lithium batteries there will be suitable recyclers.