my acer 5315 runs fine when i put in fully charged battery but it will not charge when pluged in to power supply .laptop display says plugged in and charging but it is not charging and battery runs out
Sounds like your Power Supply is not working as it should. Source a high quality universal Power Supply for your Laptop. They are not to expensive. Make sure you get one that offers the correct voltage. Your Laptop may be an odd bod that does not fit in the range on the devoce in question.
1) Your battery (If computer works with AC adaptor, just will not charge battery)
2) The ac adaptor (if Can not power computer w/o battery installed)
3) The input pwr converter in the laptop (converts the 19 VDC to 12 VDC and other low voltages required) - least likely.
How old is the Battery?
(1) Are you able to power on the laptop with the AC power adaptor, or are you just looking at the LED indicating battery is charging. If the Power pack will allow you to power on the laptop, but is not charging the battery, then I would suspect the battery has reached the end of it's life - time for a new battery.
(2) if the laptop will NOT power on using the AC adaptor, then I would suspect the Power pac. Try powering on with and without the battery.
Most of the power packs are universal, that is the output is 19VDC @ approx 4 plus Amps. You can verify this by looking on your pwr pack. The next thing is the connector, believe most use a 5.5 mm plug, but the "Hole" can very. NOTE this is higher than your battery voltage which is prabably between 10.9 and 11.1 Volts.
In lieu of a 2nd power adaptor, you can also use the Car adaptor (if you have one). Just plug into the Cig lighter.