low battery al the time, won't charge

Hi Isabel,

1/ First thing to try is a different known good charger and cable, in case they are the cause.

2/ 2nd, try a different battery, as it may be defective and unable to hold a charge. If the battery is swollen, it is a sure sign that it is defective BUT it may be defective without being swollen.

3/ 3rd, charging port / very common:

3-A/ The charging port could be dirty/corroded: power off, remove the battery, clean the charging port where you plug the charging cable using a sift brush and 90%+ isopropyl alcohol. Any change?

3-B/ If none of the above solved it so far, the charging port could be damaged or have broken pins: while charging the phone, wiggle (very gently) the charging cable inside the charging port. Does the charging stop/resume in certain positions? If yes, you have broken pins and your charging port needs re-soldering or replacing. It is better to take it to a specialized technician in this case, as this repair requires specialized skills and soldering tools.

4/ Finally, the phone's charging circuit on the board could be damaged for a number of reasons, such as a defect in manufacturing, drop, liquid spill, or using a cheap charger. To fix this you also need the assistance of a specialized repair tech.

Let us know what comes out of the above and good luck.