Battery flat(?)

[Fighter1]

So; 2 weeks ago I had a new clutch kit and dual mass flywheel installed.
Past week or so, my battery keeps being flat (not sure it's related tbh)
A friend told me to do a longer drive, so I had it jump started and Drove for 40miles, got back 8pm. At 5.30am battery was fully out of power again.
There is no lights on that indicates any faults. I'm thinking that battery is gone. Please help

 

[SJM683]

Honestly, for the price of a battery just throw one in and see. The average car battery lasts 2 years only at it’s optimum.

 

[[email protected]]

does your battery symbol display on your cluster with ign on (if it doesnt you lost connection,or light globe is dead, globe is earth connection in circuite gets disconnected when alternator starts charging, globe should then go off, if it doesnt its not charging. If this is ok,look up on you tube how to test for battery drain(parasitic)

 

[Old.Tony]

^ Good idea. Here's what I'd do (it's really easy). You only need a multimeter that can read voltage. Even a ciggy lighter one will work a treat.

1) Test the battery voltage before jump start. If the voltage is below 10V the battery is stuffed, you will need to replace it. However, continue with testing ...

2) Jump-start the engine and remove the jumper connections. Check the battery voltage while the engine is idling, it should be considerably over 13V (in fact it should be somewhere between 14.1 and 14.7V). If you are seeing the voltage falling back to below 12V (or less!) then the alternator is not working. Do NOT replace the battery without doing this test, if the alternator is not charging you'll just destroy a new battery!