NiCad Recondtioning Secret for sale: Gimmick?
I am curious if anyone knows a about these sold called rejuvinators that are sold on ebay

Claims over 90% effective.
seller is "mr._money_saver"
Repair Fix For RYOBI 9.6 12 14.4 18 Volt Tool Battery seller is "mr._money_saver"
Repair Fix For MILWAUKEE 12 14.4 18 Volt Tool Battery

Here is another seller
seller is "plansmon"

This one Promises a 100% moneyback guarantee:

EZ BATTERY FIX 4 Milwaukee 9.6 12 14.4 18 24 volt v 18v
note you can but justabout any battery name in the search strings above.

Im suprised I didnt see anything related to this at the battery university site.

Dispite the dangers has anyone tried this? has anyone already made the purchase?

Hi

I don't know about what is being offered, but I was the ceo of a company that had a patented approach to reconditioning NiCad batteries. If you want to research approaches to reconditioning NiCad batteries, pulsing has proven to recover seriously degraded batteries. The concept basically is to pulse a NiCad with a maximum load of current that drops the voltage to half its open circuit voltage. Most products available usually conduct this pulsing whilst charging the battery. If they do it whilst pulling charge or current from the battery they would be in violation of the patent.

I don't know what they're selling either, but I'd be interested.

There was a product sold called the "BatteryMinder" that would restore dead SLAs. It was a pulse charger. I'm pretty sure it didn't restore Nicads, but I could be wrong.

Hi,
I also search ebay, and then google, and by searching "nicdfix" i found the website, they have the same information. I bought the guide, and fixed 4 nicd batteries. Now they are working good.
The technique is very simple, just give the dead battery a high voltage, and it fixed in minutes.
I am not a technical person, so i dont know what is the chemistry behind it, but it saved me $$$.
Take care.

I remember a camping gear guide that had a method for a NiCd "lobotomy" that involved hooking up wires to a 12v car battery and just barely stroking the wires over the NiCd (I can't remember what polarity), and then charging as normal. Seemed risky to me, so I never did it. I switched to NiMh anyway.
-Keith

Pulsing Nicads and NiMH batteries whether in the charge or discharge mode can benefit/recondition these batteries. It is VERY impotant that one does not overheat the batteries by appying the energy to or from the battery during the pulsing. This typically means less than a couple of milliseconds depending on the internal impedance of the battery and oviously the mass of the battery. Applying high voltage can create problems with Nicad and NiMh batteries so be very careful. Swiping a 12V car battery across a 1.3V is very dangerous! Don't do it.

NiCad and NiMh batteries like to be exercised. Fully discharging and charging. Many times a rechargeable battery is only partial discharged and then left on a battery charger/conditioner maintaining a full charge condition - like many notebook computers and cell phone users do every day. Lithium batteries like to be maintained at 60% charge for maximum life resulting in improved number of charge/discharge cycles.

So what to do with NiCad and NiMh batteries.

If the batteries have developed the inability to maintain a charge, recharge with very little charge (time to recharge) then I would recommend discharging the batteries fully, and recharging fully. Doing this up to 5 times can rejuvenate the batteries. Discharging the batteries at 3C is good way of discharging. Sony has recommended this for their camera batteries about 8 years ago when they used NiCad and NiMh batteries. Most cameras now use Lithium based batteries. Aging is the biggest culprit with this chemistry. Most can loose their capacity over about 2 years. If you are not using your batteries keep them in the refriderator to minimize aging affects due to temperature. Allow them to come up to room temperature before charging. Self discharge occurs at about 2% per month.

If i remember correctly, deep discharge and recharge does doesn't actually rejuvenate the batteries, it actually damages them but the battery damage is better than the memory that developed from shallow discharges.

Nicad and Nimh batteries should not be allowed to discharge below about 0.8V per cell as damage can be done to the cell. Deep discharging for short periods of time (milliseconds) that does not produce any heat has a very desirable affect - lowering the internal impedance. Test have been conducted on a aged 6V NiCad battery packs that were reading 4.2V at ful charge with a 0.3C load!. Maximum energy transfer through pulsing allowed the output voltage to rise gradually to the full charge voltage of 6.0V at 0.3C.

Adaptive deep discharging resulting in the maximum power transfer causes the charge particle to be redistributed within the electrolyte instead of the surface area close to the electrodes allowing more charge to be accepted and results in lower internal impedance providing increase amp hours as well as peak current pull.

So bottom line - use all the capacity of your NiCads and NiMh battery packs down to the lower voltage limits. Unfortunately in ebike applications the cutoff usually are set higher than the 0.8V per cell. For example 21V for a 24V battery pack. Nickel based batteries age slowly compared to Lithium based batteries. Nickel based batteries can be reconditioned, whereas Lithium based batteries have not responded well to pulse charging for charging or discharging. One benefit of pulse charging lithium is that they are conditioned usually within one cycle versus the normal 5-10 cycles. Also pulsing can weed out bad cells early in a battery pack. Lithium based batteries respond well to sitting after a peak current pull like in camera and cell phone applications by allowing the charge to redistribute itself and lower the internal temperature. Using LiFePo4 batteries for ebike applications is good as they can be "abused" similiar to SLAs. Over charged and deep discharged. They maintain their excellent low impedance as they discharge just like other Lithium based batteries.

In time I would expect LiFePo4 batteries to be about $1 per 18650 cell with a 4500maH capacity.