ni-cad batteries

Plus how would the normal person drain them? and then not over drain them and cause them to reverse?

Reply to
Steve Knight
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that's a myth that has been history almost as long as the cells themselves (G)most people would have no way of completely discharging the cells anyway. and overdoing it will kill the cells pretty fast.

Reply to
Steve Knight

The "memory effect" mentioned by many "experts" occurred exactly ONCE in a satellite system battery that had precisely controlled discharge and charge cycles. A simple overcharge or slightly deeper discharge removed any possibility of the "memory effect" The chemistry and construction of the cells were changed for consumer usage - memory effect is, for all practical purposes, close to impossible in these cells.

The effect of reduced NiCad capacity observed in the outside world is strictly speaking "capacity depression" and is absolutely nothing to do with partial discharge and topping up over multiple cycles. Overcharge the battery by a few % and it no longer occurs.

Reply to
No Spam Here

batteries

Perhaps this supposed confusion stems from differing interpretations of what it means to 'completely drain' a battery. Once there is a noticeable loss of speed or torque, can one not say that the battery is 'completely drained'?

Draining a NiCad BEYOND completely does irreversible damage to it for certain values of completely.

Reply to
fredfighter

I've heard that from a number of people, none of whom ever named the satellite in question. As someone who works with satellites on a daily basis I find the story improbable given the typical variations in orbital period due to the anisotropic nature of the orbital environment.

Can you provide some information that would allow a person interested in this to run the story down to its source?

Reply to
fredfighter

??? A piece of wire won't do it?

Reply to
J. Clarke

The serious radio controlled car racers used to use NiCad batteries and discharged them nearly completely after using them and before charging them the next time. A wire has too little resistance, and could discharge the cells so fast as to cause heat damage, so resistors of the right value were used. Couldn't just use one resistor across the ends of the battery (battery = several cells in series), as some cells would discharge before others, and the one(s) that discharged first could be exposed to reverse charging from the rest; a bad thing. As a result, folks made fixtures that applied the correct resistance across each cell (if there were 6 cells in the battery, it took 6 resistors), requiring connections to the junction between each pair of cells. Don't know if this would be practical for the types of batteries used in power tools. Kerry (ex RC racer)

Reply to
KERRY MONTGOMERY

Something like this:

You guys would be shocked (no pun intended) to find out just how advanced the r/c hobby is regarding batteries.

Barry

Reply to
Ba r r y

well guys I have been in the RC Racing circuit for about 6 years now and probably have somewhere in the neighborhood of 1500 in batteries and I have two chargers @ approximately 650 a piece. and when NiCD's are used they are only run once per day then discharged and put away with a resistor keeping them completely dead 0.0 volts on the other hand if we run NiMh batteries then you can run them about 3-4 times per day and you NEVER discharge them completely (this can damage NiMh and LiON Cells) always store them with about 1.0-1.1 volts/cell or about 40-50% charge. well this is what most RC racers do for optimum cell performance. hope it helps. also reviving the cells with a high voltage for a short amount of time is common practice in RC called ZAPPING and they sell devices made for this. it is a high voltage spike (12 - 90 Volts DC) which lowers in internal cell resistance and increases capacity and cell voltage. this may or may not seem relevant but we run 3.6 A/hr packs and torture these things draining them in under 5 minutes 80 amp discharge rates. and this is what keeps them going. sorry for the long post

(P.S whenever my dewalt packs start losing performance I drain the battery completely and cycle it using one of my RC chargers works great)

Reply to
tank

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