Rechargeable batteries in cordless phones?

Q. Rechargeable batteries in cordless phones?
A.
1.Don't place any rechargeable batteries all time to charger for any devices like phones, cellphones, and etc.Why? Because only super complicated and expensive chargers have current cut off option to switch charging current to zero, wait some time and charge again.The best way is charge battery for your Panasonic and when finished use your phone outside of your base.Each phone has indicator, when you'll see one bar place the phone to charge.I use that technique many years. I have Panasonic 7 years with one battery so far.
2. You can buy any battery from 80% to 120% from initial value. For example you had 1000mAh, you can replace with 800mAh(less talk time)-1200mAh(more talk time and will be OK for your charger inside phone).Make sure your connector is the same and type of the battery(NM or..) is the same.