Looking for information on Edison Ed-240 Nicad batteries

Hi Mark,

Mark Cunningham wrote:

Manufacturers recommend changing out the electrolyte periodically to remove K2CO3 accumulation.  ChangHong says every 7 years or 15%.

But if you replace  a portion of the electrolyte annually you will keep that percentage down to manageable levels and avoid the costs, both in chems and labor/hassle, of a total electrolyte swap out.

That means you keep keep less KOH/LiOH on hand,  you have less electrolyte to dispose of, refreshing your electrolyte has just become like a normal watering maintenance event.

Interesting! Another good way to think about it.

Mark Cunningham wrote:


One advantage of Nickel cells is that there is no equivalent of sulfation.    I feel for the L.A. folks, having been one.  It's not really a big problem to under or over charge.  Within reason.

Yeah, so true. Makes them very well suited for solar.

I do like to use the charge controller.
We'll see how it works out. But I can understand what you mean.

Concept:
The program will quit charging (go to float) when both voltage (High enough) and current (Low enough) are met.
If any of these two conditions are not met it will continue charging.

But indeed for the batteries it does not matter

You mentioned it in your document, there are some hostile users that seems to recommend lead-acid over NiFe or NiCd.
I do not understand either. May-be Lithium, for mobile applications. (still don't like the fact that you cannot repair any degradation).
But disliking NiFe/NiCd AND at the same time recommending LA is beyond me

Mark Cunningham wrote:

Making / storing D.W. is a practice I strongly recommend .... one bottle of pond water mis - marketed as distilled water from WallyWorld can ruin your day.  Especially if your running a L.A. bank.  

Overcharging counteracts the phase change in the nickel plate that most folks think of as cell memory.
Here is a good paper on Nickel cell memory

Thanks! Good paper!
The phase change chapter starts at "Capacity Fading"
But the other parts are interesting as well for the closed systems.

Hi,
The Home Power articles are definitive.
I have #50 Edison 240AH in five 12v strings.  Used telephone company. 25 years with me now. Solar charged.
Unfortunately one cell was lost to an errant hunters bullet  So now I have 9 cells out of the pack.
My thought is to parallel some smaller pocket plate Nifes I have up to 240 or 320Ah and use that as a replacement cell in the big string but I don't know how it would affect the others or if the replacement might pop!  I welcome suggestions and will update my trial.
A new cell is $550 yikes!
Jim

James Marquardt wrote: My thought is to parallel some smaller pocket plate Nifes I have up to 240 or 320Ah and use that as a replacement cell in the big string but I don't know how it would affect the others or if the replacement might pop!

I did that for a year or so on one of my serial strings.  It worked okay ...... but .....

If the composite cell you build is larger in capacity that the other cells in that string it will under charge ..... Not a very big deal in the Ni world .... but it does have an effect.

The lower capacity cells in that same string will attempt to over charge.  Once again not a big deal ... but you will hydrolyze more DW.

Last but not least, just because all of the parallel cells in the composite "Franken batt" are connected .....  does not mean that current is flowing through them.

It is very possible, likely even, that 3 ED-80's in parallel to emulate an ED-240 .... will have a current flow that excludes, or is diminished, in one or more of the cells in that parallel grouping.

The result being that over all capacity of the serial string would be diminished to the capacity of the actively charging cells in the composite battery.  

In example .... if the majority of the current is flowing through two of the above 3 cell composite .... then the effective capacity of the entire string is now 160ah.

At least that is what my experience and measurements have been.

So ... do it as a stop gap .... while you are scrounging hard for a suitable replacement cell.


Hope this helps