V50 New battery yesterday. Flat today.

[rowdy]

Look at the last posts in my recent thread titled ‘battery keeps draining’

Flat fuse 80amp in fuse box in engine bay.
There are two 80a fuses, it is the one on the right

[HenriZ]

Thanks for your answer.. so my theories are wrong. Fact still remains something is drawing 2.5A in my car, and it has a dead start/stop battery.

Can the two be related in any way? Where could this draw come from otherwise?

[HenriZ]

Originally Posted by rowdy

Look at the last posts in my recent thread titled ‘battery keeps draining’

Flat fuse 80amp in fuse box in engine bay.
There are two 80a fuses, it is the one on the right

Ok, thanks for your reply! I'll check the mentioned fuses!

[HenriZ]

Originally Posted by rowdy

Look at the last posts in my recent thread titled ‘battery keeps draining’

Flat fuse 80amp in fuse box in engine bay.
There are two 80a fuses, it is the one on the right

I pulled this fuse, and the 2.5A draw was gone. The fuse checks out ok. Reinstalled the fuse, and the 2.A draw did not return.

Strange. I guess I'll have to wait what happens now.

Those fuses by the way, what a horrible design. Screwd in in such a way you can almost not get it out without tweezers.

[rowdy]

It’s a fuse for an electric booster heater for the cabin apparently.

Does your car have a sunroof by any chance?

[HenriZ]

Originally Posted by rowdy

It’s a fuse for an electric booster heater for the cabin apparently.

As I understood it, it's for an electric preheat function my car does not have.

Does your car have a sunroof by any chance?

Nope.

The battery was dead again today, so it's not fixed yet. When charged the battery gives 12.6v, when the engine is running 14.8 volt, which makes me believe the alternator is ok?

[rowdy]

You have replaced the fuse for a new one?
Just remove the fuse completely and then see if it’s still draining the battery. Chances are a fault with the electric booster heater itself that is causing the issue
(It’s a heater to boost the cabin heater, your car probably does have it.)

[HenriZ]

Originally Posted by rowdy

You have replaced the fuse for a new one?
Just remove the fuse completely and then see if it’s still draining the battery. Chances are a fault with the electric booster heater itself that is causing the issue
(It’s a heater to boost the cabin heater, your car probably does have it.)

The fuse doesn't need replacing, it works just fine.

I haven't had time to work on it but my next step would be to pullf uses and see exactly WHAT is drawing the current.

According to the print on the inside of the fuse box cover, the mentioned fuse is for a 'preheater', an option one could get on these cars. That you could let the car preheat on electric power without starting the engine. Mine does not have that option.

[Thassos]

Hi HenriZ,

One possibility (if you cant find the current being drawn through the plug in fuses in the fusebox or similar is the alternator, seems to be a more common fault on the (ford) derived engines, some diodes can fail and pass a current back through the alternator and starter wiring which can discharge the battery pretty quickly, this may not be your problem but if the alternator is hot when engine is stopped it may be a clue on what is happening, you might also be able to measure a volt drop across the big fuse thats inline with the + red battery lead, using millivolts on a dvm try different loads like headlamp or heated r window to see the effect & Millivolt drop which will give an idea of difference in current, without needing to put a dvm in series..

[ele288]

Originally Posted by HenriZ

The fuse doesn't need replacing, it works just fine.

I haven't had time to work on it but my next step would be to pullf uses and see exactly WHAT is drawing the current.

According to the print on the inside of the fuse box cover, the mentioned fuse is for a 'preheater', an option one could get on these cars. That you could let the car preheat on electric power without starting the engine. Mine does not have that option.

You are confusing electric heater which was an option as well as fuel heater was. This is electric heater support as used in Ford focus even Ford part nr is stamped on it. In colder climates it was a standard with diesel engine as it takes long to get warm air in to the cabin. They do fail and are draining battery, replacing fuse won't do anything, just replace the heater or remove the fuse to fix the issue.