Urgent battery advice please

[Noddydog]

Went to start my mk2 2013 1.2 TSI Elegance this morning and the battery is completely dead. I haven’t used it in 2 days, but during that time I’ve had a trailer attached via a tow bar that was professionally fitted 2-3 months ago. This is the first time I’ve left anything attached to the towbar (electrically) overnight. So my suspicions are it’s the towbar wiring that has drained the battery. But that’s something I’ll have to deal with in due course. My immediate problem is I need to jumpstart the car and be somewhere. We’ve only owned the Fabia for a few months, so not had to do any jumpstarting on it before.

 

On examining the battery I noticed this box (see photo) on the top of the battery containing five cables that attach to the positive terminal. What is this box of wires and does it have any impact on jumpstarting the car? The last thing I want to do is fry something expensive on the car’s electrics by jumpstarting in the normal manner with this box attached to the battery.

 

Hopefully someone can provide a quick answer since I’m supposed to be somewhere this morning and obviously need to start the car ASAP.

 

On that note I do have a fully charged leisure battery sitting in the shed. Can anyone advise whether I can use this to jumpstart the Skoda? It’s quite an expensive leisure battery, so I don’t want to damage that either. If I can’t, I’ll need to get a friend to come over so I can use their car. But that obviously takes extra time to arrange.

 

Thanks.

[Breezy_Pete]

Those are fuses. Ignore and attach jump lead to battery positive post/clamp behind them all.

If the leisure battery has a largish capacity I can't see it being damaged.

 

Let us know how you get on, please.

[Noddydog]

Ok, tried using the leisure battery, but the engine wouldn’t turn over. Instead the car alarm started going off constantly (pausing for only a few seconds, before starting again). I took one battery terminal off….it still kept going. Took the other one off, and it kept going. Reconnected both terminals and on the next cycle of the alarm it stopped.

 

Might need to get a friend to come over to jumpstart.

Edited 12 May, 2022 by Noddydog

[Murdockman]

As with most jump leads this day and age they are flimsy so i have found it's best to hold the clamps on the car battery with your hands/gloves before trying to start the car up, neg clamp should have been clamped to the engine somewhere to get the best earth, with the alarm you need to keep pressing the off button with the doner battery conected before trying to restart you might be better gettinf a mate to run his car to charge up your battery a bit first BUT DO NOT TRY TO START YOUR CAR WITH YOUR MATES CAR RUNNING YOU WILL DESTROY HIS ALTERNATOR FOR HIM, so many people do this and wonder why the alternator fails a few weeks later on thier car easy maths alternator output around 100 amps starter amps when cranking around 300-400 amps it cannot cope with this

[sepulchrave]

A leisure battery is useless, as you've found out it has no cold cranking capacity whatsoever.

It is perfectly safe to jump start a car from another vehicle with the engine running, I've been doing it for forty years and never had a problem, in fact it's better if you connect them up and use your mates alternator to boost charge your battery for a good few minutes before actually trying to start it.

[Ootohere]

Beware for the car / vehicle jump starting others.

 

Many of us have been jump starting cars from other with the donor car engine running.

 

Now there are modern cars that crap themselves. 

Warning lights appear, fault codes are logged and if lucky after the car has been switched off and restarted warning lights ans messages might go out and your power steering is OK. 

 

PS

The Mk2 Fabia alarm has it's own battery/ power source so can sound when the main battery is disconected. 

[Noddydog]

Thanks folks. A friend came over in his Landy and we jumpstarted from that…..with his engine running. 
 

So right now the Fabia is starting from cold, but who knows what tomorrow morning will bring.

 

This morning before the Landy jumpstart my battery was offering 6v. After the jumpstart and a 20 min drive it was up to 13v when first parked up. 30 mins later it was down to 12.5v…and I didn’t have time to check it after that.

 

So, a couple more questions: 1) Can I charge the battery on the Fabia tonight with terminals still connected? 2) We have my wife’s MX5 on the drive tomorrow and, if needed, I could jumpstart from that. But her car is worth a fair bit more than mine. So I’d like to avoid any chance of frying the electrics on hers.

 

Obviously I have to get to the bottom of the battery drain, which is most likely the trailer/towbar electrics. But first I need to get through an office move that requires the car and trailer between tomorrow and Monday. Once that’s over I can start chasing the towbar fitter, but it may not turn out to be that.

Edited 12 May, 2022 by Noddydog

[Breezy_Pete]

18 minutes ago, Noddydog said:

1) Can I charge the battery on the Fabia tonight with terminals still connected?

Yes.

2) is up to you and your wife.

 

[J.R.]

6 hours ago, Murdockman said:

BUT DO NOT TRY TO START YOUR CAR WITH YOUR MATES CAR RUNNING YOU WILL DESTROY HIS ALTERNATOR FOR HIM, so many people do this and wonder why the alternator fails a few weeks later on thier car easy maths alternator output around 100 amps starter amps when cranking around 300-400 amps it cannot cope with this

Complete and utter BS.

[petrolcan]

10 hours ago, Pete_Ex-Wino said:

Yes.

2) is up to you and your wife.

 

Both of them? You're funny

[petrolcan]

12 hours ago, Murdockman said:

BUT DO NOT TRY TO START YOUR CAR WITH YOUR MATES CAR RUNNING YOU WILL DESTROY HIS ALTERNATOR FOR HIM

Oh! I've not managed to destroy several cars doing exactly that.

[mrgf]

Heard people say this-never (ever) seen it happen. You pays your money, you takes your chance!

[sepulchrave]

2 hours ago, mrgf said:

Heard people say this-never (ever) seen it happen. You pays your money, you takes your chance!

 

It's utter nonsense caused by failing to understand how electricity actually works, armchair idiocy creating an urban myth.