MK3.5 TDCi S/S Battery plus Heater probs.

[J0hn]

Wednesday night I plugged in a 12v tyre inflator and blew up my tyres. 
Thursday morning car wouldn't start. Used jump leads from partners car to start.
Drove away and realised heater wasn't working. Nightmare 44 miles journey to work at 6am in -5 temperatures, 
had to keep wiping windows, ice forming inside, luckily had some deicer and a wipe. Thought I'd blown a fuse when jumping.
Found out that no one fuse controls Climate Control / Heater/ Heated screen unit, there's a few individual fuses. 

I'm thinking I probably need a new battery and this may have something to do with the heater problem, 
either way I want a new battery on before I start checking a load of fuses. 

So, could anyone tell me type of battery needed, approx cost and do I have to reset anything after fitting? 

If Heater then still doesn't work, can anyone advise what to check? There seems to be fuses under bonnet, in passenger footwell and in boot. 
I think it's unlikely one fuse would stop the whole unit from working, and unlikely to blow 4 or 5 fuses. 
It's the dual zone Climate Control with controls for front and rear heater screens, blower and temperature. Just no lights on, no power (even when driving and battery was presumably in a decent state). . 
 

[YOG]

Stop/Start?

Did it start for you to get home?

Original battery?

[J0hn]

Yes, It's Stop/start. 
It started at work after 8 hrs in the works car park, and got me home.
I used partners car Friday and Saturday so mine sat til today when I tried it and it wouldn't start. 
Jump started it and took it for a ten mile run. Started again two hours later. 

Just ordered a new battery. It's on it's original, so 5.5 years old, no harm in changing it, looks dodgy anyway. 

[YOG]

 I would have ordered a new one as well.

I would also invest in a decent battery to keep it charged, if you're not running it regularly. Car batteries don't like having low charge levels.

What battery did you order?

[J0hn]

I would have chosen a better one but urgency was a factor.

It should do.

Car is used a lot, 44 miles to work on fast A roads, often more on way home as I make a detour to see elderly mother. 

It doesn't usually have a chance to drain battery. 

[J0hn]

Saw a video showing checks on heater fuses. He checked two red 10 amp fuses, so I checked all red fuses under bonnet and in boot (where there's just one there).

Still of the opinion that one blown fuse would put the whole unit out if action. 

[J0hn]

Well, an interesting day. 

Wouldn't start, as expected. Jumped using proper jump starter I have borrowed, drove around the block and put the car on the drive. Disconnected the battery then went to unpack new battery. 
There is a diagnostic mode which told me yesterday that the voltage was 8.8v. My Voltmeter has seen better days, so I thought I'd see the cars take on battery voltage after a blast around the block. So I connected (old) battery up, and went into the diagnostics. 10v. Then I looked at the heater/ climate control unit (don't know what else to call it). 
Pushed the button and it came on! Oh joy. It seems disconnecting the battery for 5 minutes resets something, and I'd been wasting my time checking fuses. 
Over the moon.

Fitted lovely new battery (Pain in the butt but not that hard once you realise the end of the battery compartment moves down enough to give access). 

Drove to the Post Office, drove to a local garage to book MOT, drove home, moved car later to give partner the drive. All fine, everything working. 
Looking forward to the drive to work at 6am.

Only other thing of note: Shocked to see rust under the bonnet, and water in the battery compartment. 

[YOG]

[Freeze]

Does your Focus need charge adaptation for the new battery, so it won't cook it now?

[J0hn]

Now that is a good question. Do I need to reset anything, battery monitoring system maybe? 

The voltage looked a little high whilst driving. .I don't know what it's meant to be.

I just know everything is working fine. 

[J0hn]

I've reset the BMS. 

Hit Rear Fog Light Switch five times and Hazzards three times. battery light flashed to confirm.