Question 1

Why does my car battery keep going flat overnight?

Accepted Answer

A battery that dies overnight is almost always caused by a parasitic drain — something in the car is staying live when it should switch off. Common culprits include an ECU or comfort module not entering sleep mode, an aftermarket alarm or stereo wired incorrectly, a faulty relay holding a circuit open, or a failing alternator diode feeding current backwards. A proper amp-clamp fuse-pull test identifies exactly which circuit is responsible.

Question 2

How much does parasitic drain diagnosis cost in Hornsey?

Accepted Answer

At MnF Motors, electrical fault diagnosis starts from around £65–£95 depending on vehicle complexity. Because we use a systematic amp-clamp fuse-pull method, we find the fault in one visit rather than guessing — which keeps your total cost down. Call 020 8803 1231 for a firm quote for your vehicle.

Question 3

How long does it take to find a parasitic battery drain?

Accepted Answer

Most parasitic drain diagnoses take between 1 and 3 hours. Some vehicles with complex CAN-bus sleep cycles require the car to sit and settle before the measurement is taken, so we sometimes need the vehicle for a full day. We'll give you an honest time estimate when you book.

Question 4

Will a new battery fix a car that keeps going flat overnight?

Accepted Answer

No — if you have a parasitic drain, fitting a new battery will not solve it. The new battery will go flat just as quickly. You need to find and fix the source of the drain first. Fitting a battery without diagnosing the root cause is a false economy.

Question 5

Can MnF Motors help if my car is still under warranty and going flat overnight?

Accepted Answer

Yes. MnF Motors handles warranty claims work for vehicles up to 100 miles away. We can document the fault properly with scan data and test results so your warranty claim is supported by real evidence. Visit our warranty claims page or call 020 8803 1231 to discuss your situation.