Is it ok to use a 8V 650mA AC adapter for a cordless phone when the original adapter is supposed to be 9V 500m

Question

it appears to be working/charging when i plug it in

Answer 1

Yes, I believe this will be OK

Answer 2

The internal power regulation circuitry of the phone is usually designed to work with a range of voltages.  If the 8 volts is insufficient, it will simply not work.  Over voltage is usually more harmful as it can cause the componentry to fail.

Answer 3

Yes. It will work perfectly with a little effect on charging. Most cordless phone circuits only need 3Vdc except for the charging circuit. Charging time may be just a little longer.

Answer 4

If the polarity is the same, the Ma is what the phone draws from the power supply. It may take longer to charge.