NiFe Electrolyte Refurbishment/Replacement 8-20128 (& DIY battery inverter )

[TPA]

Ok then,

1. Did it appear that you could store the electrolyte for a number of years without ill effect
if you were able to adequately seal the boxes it comes in? I have a prepper mentality.

2. Are you still running 42 cells? I think I read somewhere that you were absorbing at 67.5V.

3. I will be using the same xw6048 inverter and was wondering if you have noticed
any kind of stress on the inverter by inputting from batteries at near max votage for extended
periods of time. (BTW my charge controller is MPPT 60-150 Xantrex/Schneider/Conext)

4. For charging, what are your bulk, absorb, and float settings? You stated elsewhere
that you changed your absorb time and noticed improvement, what did you change it to?

5. Is there ever a use for equalization i.e. is there ever a circumstance where it is helpful
for NiFe batteries?

6. Do you consider the old electrolyte harmless, or even fertilizer as some have suggested?

As I read forum post, it always leads to more questions. I hope you bear with me, you are
a wealth of info.

[Mike90250]

Ok then,

1. Did it appear that you could store the electrolyte for a number of years without ill effect
if you were able to adequately seal the boxes it comes in? I have a prepper mentality.

You need to seal it in airtight containers, that can withstand caustic potash (KoH) You need to prevent Co2 from getting to it.

2. Are you still running 42 cells? I think I read somewhere that you were absorbing at 67.5V. Yes

3. I will be using the same xw6048 inverter and was wondering if you have noticed
any kind of stress on the inverter by inputting from batteries at near max votage for extended
periods of time. (BTW my charge controller is MPPT 60-150 Xantrex/Schneider/Conext) Nothing yet, generator charging is limited to 64V

4. For charging, what are your bulk, absorb, and float settings? You stated elsewhere
that you changed your absorb time and noticed improvement, what did you change it to?
I'm at 2 hrs of Absorb. Absorb & bulk are 67.5v Float is 66V

5. Is there ever a use for equalization i.e. is there ever a circumstance where it is helpful
for NiFe batteries?
Never EQ's not needed, just add an hour to Absorb for a week if you think they are unbalanced

6. Do you consider the old electrolyte harmless, or even fertilizer as some have suggested?
Will dilute and add to irrigation water for orchard, it's not harmless, still strong KoH

As I read forum post, it always leads to more questions. I hope you bear with me, you are
a wealth of info.

replies in green

[TPA]

I was just looking through the Inverter manual, and saw that the max input voltage is 64V. Does yours say the same thing?

voltage.png

[Mike90250]

Mine gives warnings at 68V and shuts down @ 69V

[TPA]

What carbonate test kit do you have, and where would one go to buy it?

[Mike90250]

I bought the kit from the battery vendor.

[plataoplomo]

carbonate test

Here is my method. Hope this helps.

[TPA]

Thanks for that. The first page describes testing distilled water. From other readings, I have learned that water will absorb all of its carbon dioxide from the air within 2 hours of distilling and will have a pH of about 5.7 within that timeframe. If you can't use acidic distilled water, how do you prepare it for use in batteries?

[plataoplomo]

how do you prepare it for use in batteries?

Here is how I do it. Energy and labor intensive but it works very well in primitive conditions with rudimentary canning equipment.

I have added the references appendix from the manual I wrote so you can see the source information I got this method from. In the case of Low Carbon Distilled Water read "Patent 4055709 - Rejuvenation of Nickel Cadmium Battery Cells. Medford."

Most of the references are for Nickel Cadmium cells. After years of use I can find no discernible difference between the two as it relates to testing and basic chemistry.

Hope this helps.

[TPA]

Have you tried boiling store bought distilled water to see if pH is corrected?

[plataoplomo]

Have you tried boiling store bought distilled water to see if pH is corrected?

Yes it is. Why wouldn't it be?

The only problem with store bought distilled water is that some times its not distilled water. And you have no indication of when that occurs. You can buy 50 gallons of Wally World distilled water. Maybe gallon #27 is just plain pond water. Without testing each one you don't know for sure.


On the topic of routine replacement of electrolyte, I thought I might highlight something for those folks interested.

The important thing about KOH electrolyte is the K2CO3 level.

Some background reading ...... "The Effect of Carbonated electrolyte on the Performance of Sintered Plate Nickel-Cadmium Cells" P.J. Rappaport.

"www.dtic.mil/dtic/tr/fulltext/u2/614104.pdf"


Please read US Patent 4,628,011 dated Dec. 9, 1986. "Rejuvenation of Nickel Cadmium Aircraft Battery Electrolyte".

"patentimages.storage.googleapis.com/pdfs/US4628011.pdf"

Don't get hung up on the fancy apparatus. Focus on the procedures accomplished, amounts, and effects.



If you titrate your electrolyte after 7 years and find that it is below the OEM recommended K2CO3 levels, with no appreciable sediment in the bottom of the cell, then changing the electrolyte is not necessary. Or productive.

What is necessary is to keep the K2CO3 percentage below the manufacturers recommended value, (In ChangHong's case 60g K2CO3 / L), And keep the specific gravity of the electrolyte at the recommended level for your operating environment.

At maintenance time you could lower the potassium carbonate level in the cell by replacing "X" liters of electrolyte with freshly brewed electrolyte.


This facility dramatically lowers the hassle, and the cost of Nickel cell ownership.


Hope this helps.