Just fitted a new Yuasa Battery, when I connected up the negative lead it flashed, there were no keys in the ignition and in theory nothing switched on, what is still live in those circumstances?

Completely normal, don't worry. Just a load of capacitors in the power supply circuits of all manner of electronic modules charging themselves up.

 

A lot of control units have permanent live connections, and are 'woken from sleep' as necessary, by digital comms.

So they are effectively always powered in a very low power state as long as there is 12V from the battery. Once that goes, the capacitors completely discharge, and take a surge of current to 'refill' when power is restored.

 

 

Its unnerving though for someone whose reflexes have been honed on older vehicles, the initial spark is so intense indicating a high current like a failed alternator diode, were that to be the case then the vehicle wiring would start smoking in moments before hopefully a fusible link let go, so my reaction every time is to whip the terminal off again immediately, as it is I keep my hand on it and the main loom feed cable to fell any heat generated.

Thanks JR and Wino, I was brought up on the old style electrics, that puts my mind at rest.

Apologies for hijacking this thread. I have a 63 reg Roomster with a 7 speed DSG gearbox.  It has stood idle since 6th March as we have been on lockdown due to health problems.  I am concerned that the battery will run flat.  Can I charge it leaving it connected in the car, or should it be disconnected to charge?  I don't want to fry anything!

 

Col

4 hours ago, Camyarm said:

Apologies for hijacking this thread. I have a 63 reg Roomster with a 7 speed DSG gearbox.  It has stood idle since 6th March as we have been on lockdown due to health problems.  I am concerned that the battery will run flat.  Can I charge it leaving it connected in the car, or should it be disconnected to charge?  I don't want to fry anything!

 

Col

I have just charged my battery using a AA trickle charger I got off Amazon for £26. I have a DSG Karoq and put one clip on the + and the other on the bulkhead negative connector not the battery terminal! but I have stop/start. The battery was in place on the car and all was well.

Amazon delivered much faster than the 30th of April quoted !! 

Edited 1 April, 20206 yr by Gomezz
spelling

11 minutes ago, Gomezz said:

I have just charged my battery using a AA trickle charger I got off Amazon for £26. I have a DSG Karoq and put one clip on the + and the other on the bulkhead negative connector not the battery terminal! but I have stop/start. The battery was in place on the car and all was well.

Amazon delivered much faster than the 30th of April quoted !! 

Thanks mate - I will do the same with my trickle charger, also sourced from Amazon!

 

Col

Have a similiar problem on our roomster, battery would be nearly 8 years old now

 

Bought a CTEK automatic charger.  

Amazon delivery is now estimated as a month, but I found a company SmarterChargers.co.uk and they delivered next day (for extra delivery fee) and even with fast delivery add on, was cheaper than Amazon

 

At the current time, many stockists have quite a wait time, as many cars not doing very much, so was impressed at getting next day

 

One other thing, switched both interior lights to off, rather than on door mode to minimise drain down

 

 

 

14 minutes ago, SurreyJohn said:

Have a similiar problem on our roomster, battery would be nearly 8 years old now

 

Bought a CTEK automatic charger.  

Amazon delivery is now estimated as a month, but I found a company SmarterChargers.co.uk and they delivered next day (for extra delivery fee) and even with fast delivery add on, was cheaper than Amazon

 

At the current time, many stockists have quite a wait time, as many cars not doing very much, so was impressed at getting next day

 

One other thing, switched both interior lights to off, rather than on door mode to minimise drain down

 

 

 

Thanks - mine is now on trickle charge.  I bought the charger just after Christmas so no wait.  Since, because of our poor health, I expect it to be unused until September earliest, the car is on axle stands to take the weight off the tyres.

 

Col

Because of lack of use at the moment, I bought a Solar Charger off ebay, plugs in to the cigar lighter, seems to work Ok, I start the car every week and it turns over very quickly, so it is keeping the battery topped up.