Rechargable batteries

[Taf]

Our DECT phone system is getting a bit old, but still works perfectly. But our daughter decided to buy a new one, BT7660.

I decided to read the instructions, and was puzzled to see this on one of the first pages:

"To keep the batteries in the best condition, leave the handset off the base for a few hours at a time.

Running the batteries right down at least once a week will help them last as long as possible."

Don't charge constantly like the one we already have (no battery changes in about 8 years)?

And running the batteries until flat before an 8-hour recharge, with the system down until at least some charge is in the batteries? And how would we manage to totally flatten the battery packs (2 x AAA)?

Has battery tech (NiMH) gone backwards?

[Mr K]

Originally Posted by Taf

Our DECT phone system is getting a bit old, but still works perfectly. But our daughter decided to buy a new one, BT7660.

I decided to read the instructions, and was puzzled to see this on one of the first pages:

"To keep the batteries in the best condition, leave the handset off the base for a few hours at a time.

Running the batteries right down at least once a week will help them last as long as possible."

Don't charge constantly like the one we already have (no battery changes in about 8 years)?

And running the batteries until flat before an 8-hour recharge, with the system down until at least some charge is in the batteries? And how would we manage to totally flatten the battery packs (2 x AAA)?

Has battery tech (NiMH) gone backwards?

Think thats the same for most rechargeable batteries. e.g. Laptops you're not advised to keep them plugged in all time and let the battery run down occasionally.

[Jaymoss]

I thought only old Nicads suffered the memory effect

[thenry]

My OnePlus 9 Pro advises to charge to 80%, it has its own cut off and it also has night charge which lowers the charging rate so it doesn't over charge, sit on 100%. I of course have decided against the recommendations.

I had a home BT cordless phone. The batteries were cheap China clone quality, a nightmare.

Originally Posted by Jaymoss

I thought only old Nicads suffered the memory effect

That is correct, however, other types have other issues which can seem similar.

In fact, it appears that fully [deep] discharging rechargables can actually be bad for them.

Ref: https://en.wikipedia.org/wiki/Memory_effect