The battery of a Golf 4 1.9 TDI, of colleague of mine, discharged after being not started for 3-4 weeks.

I would like to help her starting it, by giving her current from my Karoq 2.0 TDI, but I'm not sure if the two cars are compatible for this operation and if I wouldn't cause any damages to them, so I would appreciate if you would tell your opinion on that.

 

I read in the manual that:

- "The rated voltage of the two batteries must be 12V. The capacity (Ah) of the current-giving battery must not be significantly less than the capacity of thedischarged battery in your vehicle."

 ==> my battery I think that it has a bigger capacity, so it should be fine.

 

- " The jump-start cables must be attached in the following sequence:

   • Attach clamp 1 to the positive terminal of the discharged battery.

   • Attach clamp 2 to the positive terminal of the current-giving battery.

   • Attach clamp 3 to the negative terminal of the current-giving battery.

   • For vehicles  with  the START-STOP  system, secure the clamp 4 to the ground point of the engine A» Fig. 317. 

   • For vehicles  without  the START-STOP system, secure the clamp 4 to a solid metal part that is firmly attached to the engine block or secure to the engine block directly."

==> how to attach clamps 1, 2 and 3 is clear, but what about clamp 4? My car has start stop, her not. Should I attach it to her engine block/to a solid metal part that is firmly attached to the engine block?

 

- "A discharged vehicle battery may already freeze at temperatures just be-low 0 °C. If the battery is frozen, do not carry out a jump start with the battery of another vehicle – risk of explosion!"

==> outside are below 0°C. Should I unplug her battery and keep it at the room temperature to warm it up before?

 

- "Never jump-start vehicle batteries with an acid level that is too low – risk of explosion and caustic burns!"

==> How can I check that on her battery?

 

Thanks!

Edited 14 January, 20197 yr by Gabi4

If it was me I'd remove the battery, take it inside to raise the temperature and then charge it. Chances are that it's a sealed battery and the level will be fine.

 

If you have any doubts at all take it to a specialist.

First, I tried to take her battery out from the car and then to charge it with a dedicated tool, in house, but I couldn't unscriew its holder in order to release it, so, after I was already freezed, I decided to start it with my battery. And it worked. No explosion and no damage noticed to the cars. 

The only issue that I had was that I couldn't find a good point on her motor block to connect the "-", as the manual was saying, so I connected it directly to the "-" of her battery, as the manual was saying to not do it. But I did that other times, without problems, so maybe someone could explain what could happen.

Then I drove her car more than one hour and a half. I hope that the battery charged enough in order to start, tomorrow morning.