Nimh/nicd ponderings...

[bdebde]

You could always pick up a charger that is specific for nicd, with the reverse pulse option. I have a Tekin bc112c (not for sale as i use it for tool packs also) which works very well. Here is one on ebay.

[lincpimp]

Originally Posted by bdebde

You could always pick up a charger that is specific for nicd, with the reverse pulse option. I have a Tekin bc112c (not for sale as i use it for tool packs also) which works very well. Here is one on ebay.

Very interesting. No idea this existed. What exactly does the reverse pulse do? Similar to the welder method?

Not sure I completely understand why the welder method is used with both reverse and normal polarity. Semms like the reversed polarity would discharge the pack, and the pos would recharge it... Not quite understanding which way breaks up the crystals... Need someone with more knowledge of dc to explain this to me...

[bdebde]

Originally Posted by lincpimp

Very interesting. No idea this existed. What exactly does the reverse pulse do? Similar to the welder method?

Not sure I completely understand why the welder method is used with both reverse and normal polarity. Semms like the reversed polarity would discharge the pack, and the pos would recharge it... Not quite understanding which way breaks up the crystals... Need someone with more knowledge of dc to explain this to me...

From the Tekin manual

Normally a cell will noticeably begin to lose its edge and crispness to throttle
response after just a few hard runs. This is caused by a gradual buildup of impurity
nd crystal formation inside the cell, which is unavoidable. With each run the impuries
increase, resulting in increasing internal resistance, and therefore reduced voltage
nd power output. Discharging the battery fully after each run will help reduce this to
certain extent, but the only way to totally minimize this deterioration, and even actuly
reverse any previous deterioration, is to use the TEKIN Power-Flex process.
wer-Flex makes your batteries perform like no other charge process can, and
creases horsepower beyond what even a new fresh cell could deliver.
The Power-Flex circuit is a refined version of the Pro-Flex circuit introduced by
EKIN in 1989. Power-Flex works by periodically turning off the charge current, and
pplying a short-duration, high-amperage discharge pulse of negative current to the
attery. This so called “burping”of the battery acts to relieve the pressure buildup which
ccurs inside a cell during charging, and to restore its chemical balance. The net result
that the cell stays cooler during the charging process, and delivers more voltage and
apacity under a load. With the BC112, the amount of Power-Flex conditioning that
ccurs is computer controlled.There are three user-settable levels.

[lincpimp]

Originally Posted by bdebde

You could always pick up a charger that is specific for nicd, with the reverse pulse option. I have a Tekin bc112c (not for sale as i use it for tool packs also) which works very well. Here is one on ebay.

Only issue I am seeing with this charger is that it is only good for 12cells... Need something that does at least 16. I guess I could use some sort of alligator clips to "break up" the packs to less than 12 cells.

[glassdoctor]

I think you should first try a simple cycling process, before worrying about zapping, etc.

The voodoo tricks and zapping was going out of style somewhat with the later generations of nickel cells. The internal resistance and capacities were better with every new batch it seemed. I think only the on road and boat guys were still obsessed with battery voodoo.

The FLEX charging was for the nicd... IIRC it was not recommended so much for Nimh. Same with dead short storage... that was great for the old 2000 cells but nobody was still doing it with the 3700, 4200, 4600 etc.

To bring old pack back to life... best thing to do is cycle it... over and over. I recently cycled an 11 cell pack that I had not used in a couple years. It's not for an rc... it was for "overclocking" my 12v ultraviolet fluorescent cure lights (I do windshield repair... thus the "glassdoctor"). Did the same with a black and decker "wizard" 3.6v tool battery.

I used my Hyperion charger and cycled them both several times. The first cycle of the B&D battery was only like 150mah... second one was about 2x that.... and after 4-5 cycles it was putting out over 1500mah.... about 80% of a fresh pack. Not bad.

Sometimes old cells are just junk... and you won't get much out of them. And it may not matter how much they were used. I've had brand new cells that were never used.... but would barely take any charge after sitting a few years. Others were fine. Same with well used rc packs...