Wiring two 12v batteries in series?

[dilligaf76]

To save the radio code can you temporarily wire up another 12v battery to the radio and then disconnect the main 12v battery?

[No ideas for a name]

dilligaf76 said:

To save the radio code can you temporarily wire up another 12v battery to the radio and then disconnect the main 12v battery?

Parallel.

It is only like jump starting, so yes. Currents might flow between though depending on states of charge.

[Scrump]

That is not connecting them in series, wiring them in series would create double the voltage output.
What you are suggesting is wiring in parallel and is okay.

If this is related to your previous welding question then how are going to apply power to the radio and not the rest of the car’s electronics? If a battery is supplying power to the cars circuits then anything powered by those circuits is vulnerable to damage from welding.

[Dogwatch]

I have seen videos where a PP9 has been used to maintain car electronics while the battery is being changed. Not used one myself but probably just sufficient voltage.

[E-bmw]

A PP3 will do it if you can get directly onto the wiring.

[dilligaf76]

Scrump said:

That is not connecting them in series, wiring them in series would create double the voltage output.
What you are suggesting is wiring in parallel and is okay.

If this is related to your previous welding question then how are going to apply power to the radio and not the rest of the car’s electronics? If a battery is supplying power to the cars circuits then anything powered by those circuits is vulnerable to damage from welding.

I thought if I wire into the positive and earth wires going to the radio and add another 12v battery, then I can disconnect the main battery so power will still be going only to the radio right?

[Scrump]

dilligaf76 said:

I thought if I wire into the positive and earth wires going to the radio and add another 12v battery, then I can disconnect the main battery so power will still be going only to the radio right?

Not if you leave the wires from the radio also connected to the car, the electricity will power the radio but will also flow down the wires to the rest of the car.
You would need to physically disconnect the radio power wires from the rest of the car. Thinking about it you could do this by removing the radio fuse.
Not sure how easy it would actually be connect a second battery to the radio wires before disconnecting the main battery. How are you intending to connect this second battery to the radio power feed?

[Dave.]

Probably not ideal but I've left a ctek connected while changing a battery before.

[E-bmw]

Can you not just read the manual/ring the dealer to see if it even needs a code, most cars haven't for many years now, as many are sized/shaped specifically to only fit one car.

[MB140]

Dave. said:

Probably not ideal but I've left a ctek connected while changing a battery before.

Not sure how the ctek would take to you wielding to the car whilst connected. (Assuming your using an arc wielding.

[dilligaf76]

Scrump said:

Not if you leave the wires from the radio also connected to the car, the electricity will power the radio but will also flow down the wires to the rest of the car.
You would need to physically disconnect the radio power wires from the rest of the car. Thinking about it you could do this by removing the radio fuse.
Not sure how easy it would actually be connect a second battery to the radio wires before disconnecting the main battery. How are you intending to connect this second battery to the radio power feed?

What I think I’ll do is run an earth and positive into the radio wires and connect them up to another battery, then cut the positive wire behind the positive wire I’ve just soldered into and the radio will still be getting power from the second battery, then run two more wires off the positive wire I’ve just cut with a male and female connector on the ends but not join them just yet until I’ve disconnected the main battery and finished the welding.

Then when I’m done I can connect the positive male and female connector together, connect the main battery up again and then remove the second battery. I know that I’ll probably be doing more welding later on but then next time it should be much easier with the pre installed wire setup.

Sounds a lot of hassle to go to but it’s a sure way of keeping power to the radio whilst the main battery is disconnected and in theory I should never need to worry about a poxy radio code again and save me having to take the glove box out and other bits and pieces just to get the radio out next time.

It should look like the crappy sketch I've done...

Edited by dilligaf76 on Thursday 25th January 16:17

Edited by dilligaf76 on Thursday 25th January 18:31

[dilligaf76]

MB140 said:

Not sure how the ctek would take to you wielding to the car whilst connected. (Assuming your using an arc wielding.

I’ll be mig welding…

[dilligaf76]

E-bmw said:

Can you not just read the manual/ring the dealer to see if it even needs a code, most cars haven't for many years now, as many are sized/shaped specifically to only fit one car.

You’re right I could but that’s too easy lol

[cuprabob]

dilligaf76 said:

E-bmw said:

Can you not just read the manual/ring the dealer to see if it even needs a code, most cars haven't for many years now, as many are sized/shaped specifically to only fit one car.

You’re right I could but that’s too easy lol

Also some cars, like my VW, only require a code if the radio fitted is not the one it left the factory with. As E-bmw says check before you try and solve a problem that may not exist.

Edited by cuprabob on Thursday 25th January 16:24

[dilligaf76]

cuprabob said:

Also some cars, like my VW, only require a code if the radio fitted is not the one it left the factory with. As E-bmw says check before you try and solve a problem that may not exist.

Edited by cuprabob on Thursday 25th January 16:24

Okay, thanks for the info and good to point that out...

[Dave.]

dilligaf76 said:

MB140 said:

Not sure how the ctek would take to you wielding to the car whilst connected. (Assuming your using an arc wielding.

I’ll be mig welding…

Didn’t realise you were welding, or wielding…. So not, don’t do the ctek thing.

[dilligaf76]

Dave. said:

Didn’t realise you were welding, or wielding…. So not, don’t do the ctek thing.

Ah yes, best not thank you buddy...

[Scrump]

dilligaf76 said:

What I think I’ll do is run an earth and positive into the radio wires and connect them up to another battery, then cut the positive wire behind the positive wire I’ve just soldered into and the radio will still be getting power from the second battery, then run two more wires off the positive wire I’ve just cut with a male and female connector on the ends but not join them just yet until I’ve disconnected the main battery and finished the welding.

Then when I’m done I can connect the positive male and female connector together, connect the main battery up again and then remove the second battery. I know that I’ll probably be doing more welding later on but then next time it should be much easier with the pre installed wire setup.

Sounds a lot of hassle to go to but it’s a sure way of keeping power to the radio whilst the main battery is disconnected and in theory I should never need to worry about a poxy radio code again and save me having to take the glove box out and other bits and pieces just to get the radio out next time.

It should look like the crappy sketch I've done...

Edited by dilligaf76 on Thursday 25th January 16:17

Edited by dilligaf76 on Thursday 25th January 18:31

Fair bit of hassle but that should work.

[dilligaf76]

I know keeps me busy and on me toes though lol, thanks buddy…

[TwinKam]

You're so over-complicating things... just buy yourself an anti-zap device, use it on any car, no need to disconect the battery then, and you have it for jump starting too, no brainer.
Both the welders we know and I myself use them and none of us have ever had a problem.