identification request - old crated NCads

[audion_1908]

I would think the new electrolyte will eat the contaminants like the organic stuff that could cause problems, so you would wash out the nife cells refill with new electrolyte KOH only, charge and leave a week or more for the contaminants to get eaten then wash out with pure water and refill with new electrolyte.

I dont know if this is what you did, but I would like to know how it went.

[tandrews]

Sorry I cannot pass on my experience with this yet as my project remains focused on solar thermal due to the season.
I have several reasons for this:
1) I need heat more then power at present
2) I am still searching for an effective battery post tool that will pull 30 years of stubborn connector off some of my cells
3) I have no facility to safely do the caustic drain, rinse and refill (until spring)
4) I'm more then a little apprehensive about tackling the task...

My reading has told me that messing with bases is more of a risk than acids, since bases use the body's moisture to further react, while acid reactions are slowed by protein chains.
Not to scare anyone off, but I'm treating this like it's a bomb when the time comes to do it.

You may be right about the refill with KOH and allowing it to work - this is after all effectively drain cleaner we're working with and bug guts are easier to rinse when they're liquid.
While I'm open to an alternative method to clean the cells (alcohol rinse, distilled water with agitation), I won't know what sort of contaminants I'm dealing with until the cells have their butts in the air and I risk losing my fingerprints. This is why I'm keen to hear about your glass cells as the vent hole in a steel case doesn't offer much in the way of what's in there and how it reacts to new electrolyte or for that matter, how it changes on a slow charge. While KOH is the cheaper of the source materials for new electrolyte, I don't know that the risks inherent in changing it twice is worth the extra effort.

Some newly found reading on rejuvenation of nife's:

http://www.navitron.org.uk/forum/index.php/topic,2810.0.html

Suggesting slow charge to renew them.

I would like to understand *why* these cycles are important as they are always suggested to improve function. Few suggest why they need to be cycled, just that they do.

[audion_1908]

"2) I am still searching for an effective battery post tool that will pull 30 years of stubborn connector off some of my cells,"

I would spray some WD40 on the battery posts and let it sit for a long time, I would then tap lighty on every side every few days with a very small hammer, but make sure the hamming does not try to twist the post as it could dammage the cell.

you could also try heating the post with a hair dryer? to expaned the outer steel ring

what about refilling with the nife cells caustic soda / Sodium hydroxide as its very cheap to get read of contaminants

and why I would charge the cells is to mix up the electrolyte and to splater it across the top inside of the nife cell to get at any contaminants up there.

maby the nife cells are cycled to get all the oil off the plares and to the top of the cell where it sould be

my nife cell are only small ones

[audion_1908]

http://www.fieldlines.com/board/index.php?topic=136234.0;wap2

copyed
"I remember maintainance was simple you filled them initialy with a caustic soda, sodium hydroxide or potasium hydroxide (both worked), then checked the level occasionaly. Does anyone know where you can get these batteries now and at what cost, at one time the surplus market was awash with ex military ones."

[audion_1908]

diy nife cell 1ah

http://www.youtube.com/watch?v=K84PywMwjZg&feature=related

http://noonco.com/edison/improvements.htm

[tandrews]

I've tried several solvents, several post pullers and heat as well.
As you said, I'm banging up against the edge of destroying the post/through cell mount point by the level of effort required.
Gotcha is they are oddly shaped copper connectors with a tapered fit, so conventional post pullers do not get sufficient purchase on the rounded cast edges, and when they do they are nearly stripped by the effort applied.

A small brazing tip should focus expansion where needed when the time comes, just not time yet.
Thanks for the suggestions nevertheless.

NaOH rinse may be a cheaper method, I don't know as I've not costed a supply. KOH flake is pretty cheap @ 90%.
It does not remove the risks of playing with caustics twice though, or the extra effort of disposal.
I think a single distilled rinse will be it unless contaminants deem otherwise when the time comes.

I've speculated about reason for cycling as well, guessing though doesn't make it so.
I'd still like some reasoning for it, or even some data on performance before and after.
Since NiFe's have such a low charge/discharge curve, perhaps it's related to the time required to actually get a full charge, plate deposit removal due to gassing, or, more likely, time for the LiOH to absorb the carbonates in solution out of the box?
All speculation at this point.

[audion_1908]

wd40 is a penetrating oil in a spray can sold in the UK, and I would not expect solvents to help.
and you could be right about the LiOH absorbing the carbonates on the first charges, I can't find any supplyers of lithium hydroxide in the UK!
I think if there is still contaminants in some of the cells it could unbalence the chain of nife cells a hydometer will probly help find the worce cells

[audion_1908]

I have has a close look at your nife cell pics and a tool called a pulley puller would be what you are after

http://www.google.com/search?q=pulley%20puller&biw=1024&bih=579&sei=nSw3T8-dIsiW8gPIq-HOAg&tbm=isch

[audion_1908]

gear puller, pulley remover, ect

[tandrews]

Again, thanks for the suggestions, I have considered them myself.
WD40 is available here as well, and not as effective as some of the penetrating oils I've tried.
Simply not a concern until project phase becomes priority but thanks for the legwork.

The previous pictures are not the connectors that are difficult.
Here a snap of the copper on copper vintage stubborn fellas...


All in good time.

[audion_1908]

what mite work insted of rinseing the cells with KOH maby just fill the nife cells up with distilled water and let the old electrolyte will eat the contaminants for a few months?
then rinse with distilled water and refill with KOH and use.

[audion_1908]

book with nife 1930 cells

I have an old book with some nife cells that look like you ones, I will scan it in some time if you want

[tandrews]

I will never refuse knowledge.
Please share with the class