Battery Recharge Life

Toothbrush uses the "small-discharge-no-fail" technology, assisted by the "single-cell-no-unbalance" technology. S.M.

Just about every battery you see in any consumer device these days will be Li Ion. Li Ion batteries lose their charge when the contacts erode, so the simpler the cell design the more robust the battery will be.

Also, you're leaving your cordless toothbrush plugged in all the time, so you wouldn't even know if the battery did erode. As long as the battery life is longer than five minutes you're fine. The battery can deteriorate a LOT before the life will drop under five minutes.

If you really want to learn about batteries, then have fun...

http://batteryuniversity.com/

I don't have battery powered tools, so can't speak to that. In a camera and a radio scanner I have had poor luck with rechargeable AA batteries, but good luck with lithium batteries.

In an emergency like fire,life saving,travelling etc cordless equipment including lights is worth millions of dollars

An electric toothbrush is a low-powered device, which will last at least a week on a new battery. If it is a 4yo 'sealed' unit, it will likely have Ni-Cad battery. These are prone to a memory effect which causes the time useful power is available to decrease over the life of the cell. Ni-Cad cells reduce voltage gradually as energy is used.

NiMh hold more power to begin with, and the memory effect is much less. They hold voltage well until nearly empty, then it drops off quickly. The tools you use them in are higher powered, and will drain them quickly. To prolong life, recharge fully as soon as the power begins to drop off.

Li-Ion are what is used in laptop batteries. These are better for low to mid-range power applications and last longest if they are run to empty once in a while.

I think it was on the pages of CR4 that I learnt that the memory effect is actually not as bad as many (including myself for a long time!) people think.

Basically mainly satellites used to get problems as the charge and discharge cycles were always exactly at the same time and same drain etc...

Most people damage NICADS with over charging and therefore overheating, some can be at least partially recovered with a quality charger that "reforms" properly as well as "not" over charging........

For full infos go here:-

http://en.wikipedia.org/wiki/Memory_effect

There you will find this paragraph, it tells the true reason for memory effect far better than I can:-

True memory effect

Specifically, the term 'memory' came from an aerospace nickel-cadmium application^{[citation needed]} in which the cells were repeatedly discharged to 25% of available capacity (plus or minus 1%) by exacting computer control, then recharged to 100% capacity without overcharge. This long-term, repetitive cycle regime, with no provision for overcharge, resulted in a loss of capacity beyond the 25% discharge point. Hence the birth of a "memory" phenomenon, whereby nickel-cadmium batteries purportedly lose capacity if repeatedly discharged to a specific level of capacity. True memory cannot exist if any one of the following conditions holds:

• Batteries achieve full overcharge.
• Discharge is not exactly the same each cycle, within plus or minus 3%
• Discharge is to less than 1.0 volt per cell.^[2]

True memory effect is specific to sintered-plate nickel-cadmium cells, and is exceedingly difficult to reproduce, especially in lower ampere-hour cells. In one particular test program-especially designed to induce memory-no effect was found after more than 700 precisely-controlled charge/discharge cycles. In the program, spirally-wound one-ampere-hour cells were used. In a follow-up program, 20-ampere-hour aerospace-type cells were used on a similar test regime. Memory effects showed up after a few hundred cycles.

Many thanks to the now unknown CR4 member that squared me off.......

I left my battery toothbrush in the charger without using for a few months and now it runs about 15 seconds.

Did your teeth fall out?

Marketing technology.

Because the motor in the tooth brush is so small. They can place a battery in it that will usually seem to preform longer. With out making it so cumbersome to use.

If the power tools had comparable battery. Motor current draw to battery output. Then the weight would be an issue.