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BrianG · 03.05.2008, 09:11 PM

The zapping method you speak of is something that has been done to NiCds in the past, but never heard of it being done to NiMH. Back in high school, I built a little 555 timer oscillator device that did just that; charged a cap and then dumped it across the cell. The supply voltage had to be about 50% higher than the cell voltage for it to work. Using a cap limits the amount of time that high current pulse lasts. This was actually called cell "renewal" and was used to bring some life back to a NiCd - a cheap way to extend its life a little.

However, with NiMh, the term zapping usually refers to conditioning a brand new cell to supply a high voltage under load. AFAIK, it's just charging at 1.5-2C and discharging at about 10C a few times.

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BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	03.05.2008, 09:11 PM The zapping method you speak of is something that has been done to NiCds in the past, but never heard of it being done to NiMH. Back in high school, I built a little 555 timer oscillator device that did just that; charged a cap and then dumped it across the cell. The supply voltage had to be about 50% higher than the cell voltage for it to work. Using a cap limits the amount of time that high current pulse lasts. This was actually called cell "renewal" and was used to bring some life back to a NiCd - a cheap way to extend its life a little. However, with NiMh, the term zapping usually refers to conditioning a brand new cell to supply a high voltage under load. AFAIK, it's just charging at 1.5-2C and discharging at about 10C a few times.