SeaWill Ni-Fe Batteries w/ double terminals

[nyyankees588]

Ok - question for everybody here - not sure if this is the correct sub-forum... I'm helping somebody setup a basic off-grid solar system. They have a bank of SeaWill brand, nickel iron batteries, that they bought from somebody used. I've done lots of lithium-based van/trailer setups, but never one with this setup.

My initial big question - is there a purpose for each battery have 2 positive and 2 negative terminals (see image in link for reference)? I am going to be connecting the batteries in a series and based on what I can visually see inside of the batteries and the little information on the alibaba page, it doesn't seem like there are two separate cells in each battery... so I plan on only using 1 negative and 1 positive terminal per battery. Does that seem right to others?

I've also found some vague outlines online for charge controller settings for Ni-Fe, but open to any input from people on here if they have experience getting the charging parameters correct. Thanks!

 

[sunshine_eggo]

Wrong place. This is for variations on Lithium.

Since Ni-Fe can handle very high currents, it's likely just an option for dual-post connections, i.e., double wires for reduced resistance.

Would assume they would supply suitable datasheets for the battery to address your concerns. If they refuse, I would not buy.

Here is what ironedison has to say:

Nickel Iron (Ni-Fe) Battery

Nickel Iron batteries are by far the most rugged and longest lasting battery option available today, and a great option for off grid solar & renewable energy applications! Nickel Iron batteries have the Lowest Total Cost of Ownership of ANY battery chemistry available today! Amortized over the...

ironedison.com

Chemical System: Nickel Iron (NiFe)
Battery Type: Rechargeable Deep Cycle, Flooded with Alkaline Electrolyte
Electrolyte Chemistry: Potassium Hydroxide (KOH) And Lithium Hydroxide (LiOH)
Electrolyte Refresh Rate: Suggested every 7-10 years to sustain maximum performance
Terminal Poles, Cell-To-Cell Busbars: Nickel-Plated Steel, Tinned Copper
Cell Container: Translucent, Corrosion-Free Polypropylene or ABS Engineering Plastic
Vents: Flame-Arresting Flip-Top Vents
Nominal Voltage: 1.2 Volts (per cell)
Charging Voltage: 1.65 Volts (per cell)
Efficiency: 80%
Cycle Life: 11,000 Cycles At 80% Depth of Discharge
Float Life / Shelf Life: 30 Years / 85 Years
Optimum Charge & Discharge Current: C/4
Minimum Charging Current: C/20
Maximum Continuous Charging Current: C/2
Maximum Pulsed Charging Current: 1C
Maximum Discharge Current: C/2
Self-Discharge Rate: 1% per day
Operating Temperature: -30⁰ C To +60⁰ C (-22⁰ F To +140⁰ F)

from me: Cell depletion is typically at 1.0V/cell.

 

[nyyankees588]

Wrong place. This is for variations on Lithium.

Since Ni-Fe can handle very high currents, it's likely just an option for dual-post connections, i.e., double wires for reduced resistance.

Would assume they would supply suitable datasheets for the battery to address your concerns. If they refuse, I would not buy.

Here is what ironedison has to say:

Nickel Iron (Ni-Fe) Battery

Nickel Iron batteries are by far the most rugged and longest lasting battery option available today, and a great option for off grid solar & renewable energy applications! Nickel Iron batteries have the Lowest Total Cost of Ownership of ANY battery chemistry available today! Amortized over the...

ironedison.com

Chemical System: Nickel Iron (NiFe)
Battery Type: Rechargeable Deep Cycle, Flooded with Alkaline Electrolyte
Electrolyte Chemistry: Potassium Hydroxide (KOH) And Lithium Hydroxide (LiOH)
Electrolyte Refresh Rate: Suggested every 7-10 years to sustain maximum performance
Terminal Poles, Cell-To-Cell Busbars: Nickel-Plated Steel, Tinned Copper
Cell Container: Translucent, Corrosion-Free Polypropylene or ABS Engineering Plastic
Vents: Flame-Arresting Flip-Top Vents
Nominal Voltage: 1.2 Volts (per cell)
Charging Voltage: 1.65 Volts (per cell)
Efficiency: 80%
Cycle Life: 11,000 Cycles At 80% Depth of Discharge
Float Life / Shelf Life: 30 Years / 85 Years
Optimum Charge & Discharge Current: C/4
Minimum Charging Current: C/20
Maximum Continuous Charging Current: C/2
Maximum Pulsed Charging Current: 1C
Maximum Discharge Current: C/2
Self-Discharge Rate: 1% per day
Operating Temperature: -30⁰ C To +60⁰ C (-22⁰ F To +140⁰ F)

from me: Cell depletion is typically at 1.0V/cell.

Ahh, sorry. Did not realize that this was for only lithium variations. Appreciate the specs. I would LOVE to have manufacturer specs, but of course these were purchased from the original purchaser who bought them on Alibaba. So sourcing spec sheets for anything related to these isn't very feasible. The second terminals for added connections make sense to me - I'll move forward based on that belief! Thanks for your input.

 

[sunshine_eggo]

I went without saying it, but I should have said it. Easy to verify my theory with a voltmeter. Like color to like color should be 0V. Unlike color to either un-like color terminal should show cell voltage.

The cells should have come with data. I would encourage the owner to pursue obtaining the data.

 

[saggys]

went without saying it, but I should have said it. Easy to verify my theory with a voltmeter. Like color to like color should be 0V. Unlike color to either un-like color terminal should show cell voltage.

That is correct, as I have 40 of these cells. The double posts are because of the higher internal resistance of the cell, double posts help keep connection resistance to a minimum,

 

[Cow Bay Bob]

Ok - question for everybody here - not sure if this is the correct sub-forum... I'm helping somebody setup a basic off-grid solar system. They have a bank of SeaWill brand, nickel iron batteries, that they bought from somebody used. I've done lots of lithium-based van/trailer setups, but never one with this setup.

My initial big question - is there a purpose for each battery have 2 positive and 2 negative terminals (see image in link for reference)? I am going to be connecting the batteries in a series and based on what I can visually see inside of the batteries and the little information on the alibaba page, it doesn't seem like there are two separate cells in each battery... so I plan on only using 1 negative and 1 positive terminal per battery. Does that seem right to others?

I've also found some vague outlines online for charge controller settings for Ni-Fe, but open to any input from people on here if they have experience getting the charging parameters correct. Thanks!

I have a 24 volt system of Nickle Iron Batteries , they came with 4 terminals an substantial stainless steel plates to join them. From looking at the pictures on your link I would hazard a quess that they came from the same factory in China, same terminals on top. Cheers Bob