batteries have a memory?

[rusty JEDI]

Is this a fact or just some myth.

You should always let certain items drain right down before recharging them because the batteries have a memory (cordless phones) If when you first buy it you just use it and let it sit on the cradle all the time, when you finally want the battery to last a while it wont because its memory has taught it to not stay charged long.

If this is true, what if you just teach it the memory the first time or first few times. Will it later unlearn this if you stop?

If true is this all batteries or just some?

Thanks

rJ

[The Dude]

I'm pretty sure this is true for all types of rechargable batteries. I don't know the specific reason, but I did hear this from a source I trust on the matter. He tells me it's a good idea to let my laptop completely run out of juice somewhat regularly.

[Freakin]

[ QUOTE ]
I'm pretty sure this is true for all types of rechargable batteries. I don't know the specific reason, but I did hear this from a source I trust on the matter. He tells me it's a good idea to let my laptop completely run out of juice somewhat regularly.

[/ QUOTE ]

Not for all types. I'm fairly sure that NiMH (Nickle Metal Hydride) do not experience the "memory effect" that plagues LIon or NiCad batteries. I believe dansdata.com somewhat debunked the "memory effect" myth, but what do they know.

[AncientPC]

Ni-MH does experience memory effect as well as Ni-CD or Lithium Ion batteries (don't know about Lithium Polymer), but at a much slower rate than the latter.

Also, some chargers have a refresh option when recharging batteries that forcefully drain all juice before recharging, i.e. resetting the memory. I haven't seen this feature on any Ni-MH battery charges in Best Buy, but I bought a Sony charger from Asia that does this.