Edison ED-240 flooded NiCd cells.

[plataoplomo]

Hi All,

I may have an opportunity to get a fairly large set of Edison ED-240 NiCd flooded cells.

Anyone here have experience with this cell, or older flooded NiCd cells in general?

My proposed bank would be 40 cells in series for my 48vdc system.

My charging system is 24 X 175w panels in two arrays of 12 each. Each array is serviced by an Outback FM60 charge controller. These two arrays are paralleled onto the battery bank. This is backed up by a 48v grid connected golf cart charger for cloudy days.

Your thoughts please?

Thank you

[Sunking]

You have a few challenges ahead of you, and likely result will be a BUST. Those are some very old batteries, but I knew I had some some info on Edison NiCD batteries given too me by a vendor called SAFT.SAFT bought out the Edison NiCd line back in the 70's. So that means you have 40+ years old batteries .

The first thing I am looking at in the specs is going to be trouble for you. The maximum allowable charge current for the ED 240 is 45 amps. Assuming you use a MPPT controller means 2200 watts is the maximum panel wattage you can run on them. You have 4200 watts.

[plataoplomo]

The maximum allowable charge current for the ED 240 is 45 amps.

Thank you.

The price is right on these batteries.

My source tells me these are being pulled from rail installs. Being replaced with sealed LA.

Running two strings in parallel minimizes the charging current problem, but opens up the un-equal charging problem.

Is that info you have from Saft in a transmittable format? Care to share?

Thank you

[Sunking]

Running two strings in parallel minimizes the charging current problem

No it does not. If you use all 24 panels is 4200 watts. If you use 2 60 amp MPPT controllers you mention is 4200 watts / 48 volts = 87.5 amps. That is twice the maximum allowable current.

[inetdog]

No it does not. If you use all 24 panels is 4200 watts. If you use 2 60 amp MPPT controllers you mention is 4200 watts / 48 volts = 87.5 amps. That is twice the maximum allowable current.

I think he is referring to running two strings of the Edison cells in parallel, which would give him the ability to use up to 90 Amps of charge current IF he gets an equal division between the battery strings.

[Sunking]

I think he is referring to running two strings of the Edison cells in parallel, which would give him the ability to use up to 90 Amps of charge current IF he gets an equal division between the battery strings.

That is not how I am reading it.

My charging system is 24 X 175w panels in two arrays of 12 each. Each array is serviced by an Outback FM60 charge controller. These two arrays are paralleled onto the battery bank.

[plataoplomo]

That is not how I am reading it.

I am saying that,

IF I parallel two strings of ED-240 batteries I roughly split my charging current between the battery bank serial legs.

BUT, charging parallel legs in a battery bank creates the problem of unequal charging within the bank parallel legs.

I've read that flooded NiCd batteries are more tolerant of this than lead acid batteries.

Does anybody have any documentation or real life experience with flooded NiCd cells?

If you do can you please share your knowledge with the forum?

Thank you

[Sunking]

I am saying that,

IF I parallel two strings of ED-240 batteries I roughly split my charging current between the battery bank serial legs.

No you do not. If it is a common battery bank as you describe being served by two solar arrays, the current adds. No question about it.

I've read that flooded NiCd batteries are more tolerant of this than lead acid batteries.

Does anybody have any documentation or real life experience with flooded NiCd cells?[/QUOTE]

I have experience with Flooded NiCD some of the newer models made by SAFT and Allcad can take as high as a 1C charging rate vs C/8 for flooded lead acid. Example if the battery is rated for 240 AH can be charged at 240 amps. You have a very old design and the maximum charge rate is C/5. Look it up yourself on page 5 of 19.

[plataoplomo]

I have experience with Flooded NiCD some of the newer models made by SAFT and Allcad can take as high as a 1C charging rate vs C/8 for flooded lead acid. Example if the battery is rated for 240 AH can be charged at 240 amps. You have a very old design and the maximum charge rate is C/5. Look it up yourself on page 5 of 19.

Thank you very much for the documentation. Let me study it a bit.

Now I am confused. Please humor me.


parallel.jpg

If I apply a sum of 90 charging amps to the positive and negative terminals of a battery bank consisting of two battery cells in parallel to each other, the entire charging current will travel through just one of the parallel legs?

Say leg #1 as depicted in my crude drawing? Leg #2 will not feel ANY charging current?

I would think that the amount of current flow through the respective legs, (#1 or #2), would be a function of the sum total of impedance of each leg.


I am incorrect in this?

[plataoplomo]

page 5 of 19.

Interesting read. Thank you. So far I have just quickly scanned through it. It will get a full read later today.

One thing I would like to read is the "signal supervisors" instruction manual referenced on pages I-167 and I-168.

Is it possible to "de-activate" these cells? If so how would you do it?

Drain the electrolyte prior to storage or shipping? If so how would you do it?

Then re-activate them later without damaging the cell?

[Sunking]

Now I am confused. Please humor me.

I will do my best. Going back to your OP you stated:

My proposed bank would be 40 cells in series for my 48vdc system.

That works because it takes 40 NiCd cells to make a 48 volt battery because each cell is rated at 1.2 volts. 40 x 1.2 = 48 volts everyday in school. Your drawing shows parallel connected batteries which is not possible based on the info you have provided of 40 cells.

To determine the charge current from a solar cell using a MPPT charger is Amps = Panel Wattage / Battery voltage. You have a total of panel wattage of 4200 watts operating into 48 volt battery. 4200 watts / 48 volts = 87.5 amps. Does not matter if you use two charge controllers with two solar panel arrrays supplying a common battery as the current will add from both system. So in array # 1 you have 2100 watts / 48 volts = 43.75 amps, and duplicated in array # 2 with 43.75 amps. 43.75 + 43.75 = 87.5 amps.

Understand now?

[plataoplomo]

Understand now?

I do. Thank you.

You seem to be confused by a detail that was addressed in post #3 of this thread. Please re-read the thread.

In post #2 you pointed out a design flaw. In post #3 I worked around it. I've moved forward. Please follow.

I wish this thread to be a "lets pool our knowledge on flooded NiCd cells" topic.

Not a "lets split hairs on the supporting information" topic.

In an attempt to get back on to vector .....

Does anybody have any documentation or real life experience with flooded NiCd cells?

If you do can you please share your knowledge with the forum?

One thing I would like to read is the "signal supervisors" instruction manual referenced on pages I-167 and I-168.

Is it possible to "de-activate" these cells? If so how would you do it?

Drain the electrolyte prior to storage or shipping? If so how would you do it?

Then re-activate them later without damaging the cell?

Thank you for your time.

[Sunking]

You seem to be confused by a detail that was addressed in post #3 of this thread. Please re-read the thread.

In post #2 you pointed out a design flaw. In post #3 I worked around it. I've moved forward. Please follow.

I am following along.

• So are you now saying you will have 80 cells total for 2 parallel 48 volt battery strings?
• Or are you making 2-24 volt parallel strings with 40 cells?.

If you intend on 24 volts does not get around the problem , and creates another problem for you. At 24 volts panel system #1 is 2100 watts / 24 volts = 87.5 amps. System #2 is duplicated with another 87. 5 amps and when combined is 175 amps. That current splits again at the batteries so that each 24 volt battery string is 87.5 amps. Right back where you started. If also gives you a huge problem with your two 60 amp controllers. 87.5 amps is greater than 60 amps that your controllers are rated for. .

If you are using 80 cells to make 2 48 volt battery strings will work.

[plataoplomo]

using 80 cells to make 2 48 volt battery strings will work.

I am asking .......

Is it possible to "de-activate" these cells? If so how would you do it?

Drain the electrolyte prior to storage or shipping? If so how would you do it?

Then re-activate them later without damaging the cell?

[Mike90250]

we are reading your questions, and they have been answered acording to each persons ability.

I am running NiFe cells, which are somewhat like nicad.

Any batteries in parallel will experience some inequality of load splitting between banks. clever and careful wiring layout, and cable crimps can reduce this, but the effect will still happen.

the battery manuals will explain best what you are asking. My NiFe cells came tested, and drained (just a couple tablespoons of fluid in them) and I'm sure the nicad can be treated the same for several months at a time. Longer, and I'm out of the area that I can make educated guesses at.
Mike