Disconnecting Car Battery - Modern Cars

[dishman]

I have a car battery that is OK, but could do with a reconditioning charge, the pulse rectifier type.

However from what I can see, it is probably best to disconnect it from the car to do this, as part of the pulsing includes hitting it with voltages over 16v (or something along those lines). All I know is, it is advised to have the battery disconnected for this particular charging.

But, I am more nervous about messing with the electrics of a modern car than anything mechanical. Are there any major downsides in a modern car from having the battery disconnected for a long period?

I have looked into various memory saving options or ways to keep some kind of voltage powering the car.

1) There is the power via the 12v socket. (only seems to be viable if permanently live)
2) Power via obd.
3) Power via connecting a small pack of batteries (9v or 12v?) to the leads before disconnecting the main battery.

But all the videos about doing this are based in the US. Which makes me suspicious.

I've also seen videos that advise against trying to keep the car powered via the above methods while the battery is disconnected.

So, any thoughts about the best way to go about this?

It does not help that this car's engine bay is packed like a sardine tin and I need a degree in engineering to even access the battery.

 

[robinbanks]

If you connected another battery in parallel, clamps onto the wires so the terminal nuts are still accessible you would be able to remove one terminal from the low battery while keeping the car powered, and charge the low battery.

I recommend to remove the negative terminal if you can, as accidentally bridging from negative to an exposed bit of car bodywork using a hand held metal spanner doesn't have the same consequences as doing the same mistake with the positive terminal

 

[dishman]

What is the general view of just disconnecting the battery for an extended period? Could it actually cause a headache?

 

[Mottie]

However from what I can see, it is probably best to disconnect it from the car to do this, as part of the pulsing includes hitting it with voltages over 16v (or something along those lines). All I know is, it is advised to have the battery disconnected for this particular charging.

I can't see that you'd need the battery disconnected if you dont have anything switched on.

What is the general view of just disconnecting the battery for an extended period? Could it actually cause a headache?

I can’t see any problems there either. Most radios are coded to the ECU so no problem there. You may have to reset the clock and electric windows.

What car is it?

 

[dishman]

I can't see that you'd need the battery disconnected if you dont have anything switched on.


I can’t see any problems there either. Most radios are coded to the ECU so no problem there. You may have to reset the clock and electric windows.

What car is it?

C4 Grand Picasso/Spacetourer 2018

The only reason I was concerned it needed disconnecting was a video on youtube that analysed the pulse repair mode of a charger similar to mine. He mentions briefly about the voltage being as high as 16v on pulse repair, which he says "is probably not good for car electronics even though there are probably protections on the car side" (or something along those lines)....I'll have a watch through for it again

This is the excerpt from the manual regarding the pulse repair mode.