Electrical issue ,probably alternator knackered but firstly check the earth and live plug that goes to it and wiggle wires check theres nothing loose
otherwise get a reconditioned alternator save a few quid, sod to get to fit as in very tight to fit but can be done with someone who kinda knows a bit about cars. Or take to garage sorry wrong side of £100+
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cars.