12v memory saver

[eybic]

We recently bought a 2006 Civic and I think the battery may not be in the best condition (halfords one with a recharge date of 2015) so I'm looking to get a replacement. A spanner in the works is that I'm not sure of the headunit code so if the battery is disconnected, I fear we may have a rigmarole getting the radio working again.

Does anyone have any recommendations for devices to save the memory of bits? I know you can get 12v socket ones but it seems they need connecting to a good battery which obviously could cause issues if we replace with a new battery as I don't have a good battery sitting around anywhere, are there any that can use (for example 8 AA batteries) a few smaller batteries to get up to 12v? It will literally just be for a few minutes whilst the battery is replaced.

Thank you

[Durzel]

Does such a thing exist? Not an electrician but I can't see how you could add something to a circuit, whether that be a battery or whatever else, without breaking the circuit to actually add it.

[norush]

I have a 57 plate Civic with the original radio and it doesn't ask for a code whenever I have disconnected the battery; hope that helps.

[Durzel]

57 plate Civic is FN2. 06 is (I think) EP3?

The radio definitely did need a code when it lost power on my 04 Civic.

[MikeyC]

norush said:

I have a 57 plate Civic with the original radio and it doesn't ask for a code whenever I have disconnected the battery; hope that helps.

Just guessing it might be a time thing, ie there's an internal battery which keeps it alive for a short period of time ?
I have no info to back this up tho' !

[eybic]

Durzel said:

57 plate Civic is FN2. 06 is (I think) EP3?

The radio definitely did need a code when it lost power on my 04 Civic.

It's an FK27 (1.8 sport), first of the FK's (2006)

[M_A_S]

You can get them to plug into the cigarette lighter socket, OBD socket etc. but I've never seen one that didn't require an external power source such as another 12V battery.

[Sheepshanks]

People on the honda Jazz site I follow say this works: https://hondaradiocodes.com/

I'm not sure if you can test it until the radio needs the code though.


I've seen the memory saver things but haven't paid them any attention. Thinking about, the standby-by power is likely to be quite high while you're messing about with the car as they often take a while to more fully shut down, so something with AA cells or whatever isn't likely to cut it.

Edited by Sheepshanks on Monday 21st October 11:35

[98elise]

Durzel said:

Does such a thing exist? Not an electrician but I can't see how you could add something to a circuit, whether that be a battery or whatever else, without breaking the circuit to actually add it.

Yes you can, simply parallel another battery. If you have a live cigarette lighter you can do it through that. I'm pretty sure I've seen it done with a 9v battery and a diode, but that was 30 years ago!

[Durzel]

Learn something new every day Thanks.

[RazerSauber]

I always wondered if you could just put on a jumper pack while you swap the battery and disconnect afterwards?

[Chiswickboy]

98elise said:

Durzel said:

Does such a thing exist? Not an electrician but I can't see how you could add something to a circuit, whether that be a battery or whatever else, without breaking the circuit to actually add it.

Yes you can, simply parallel another battery. If you have a live cigarette lighter you can do it through that. I'm pretty sure I've seen it done with a 9v battery and a diode, but that was 30 years ago!

They used to be a self-contained unit powered by a small PP9 9volt battery and plugged into the cigarette lighter socket and were sold everywhere. Just looked on the usual suspects websites but they all now appear to be, basically, an OBD II plug with a connection to another car's battery either through the cigarette lighter socket or direct via crocodile clips.

Would your local main dealer be able / willing to look up the code against VIN? This presumes that the radio is the original.

[Max5476]

I did similar with a motorbike battery, but without jump leads. I hooked up a trickle charger cable, it worked fine until the car autolocked as the door hadn't been opened, which blew the fuse in the cable.

Oops

[miniman]

Do you have a standard battery charger? If you want to borrow an Accumate you are welcome to but I’m in Wiltshire so may be a long trip.

[Sardonicus]

Had something like this for years still gets used occasionally , just use another friend or family members car to piggy back off if you dont have a spare battery and whilst you swap the battery do not allow the cars + terminal cable to ground to the chassis or you will be defeating the object and the internal fuse in the unit will blow or possibly your cigarette/cigar lighter socket fuse and you may lose your radio code

[Penelope Stopit]

Sheepshanks said:

I've seen the memory saver things but haven't paid them any attention. Thinking about, the standby-by power is likely to be quite high while you're messing about with the car as they often take a while to more fully shut down, so something with AA cells or whatever isn't likely to cut it.

Me too, the method often falls over due to numerous scenarios

Borrow a battery and jump leads from someone, this method will definitely work

[eybic]

Thanks for all the help guys, it turns out that the radio doesn't have a code anyway so I was worrying for nothing.

[Sheepshanks]

Sardonicus said:

Had something like this for years still gets used occasionally , just use another friend or family members car to piggy back off if you dont have a spare battery and whilst you swap the battery do not allow the cars + terminal cable to ground to the chassis or you will be defeating the object and the internal fuse in the unit will blow or possibly your cigarette/cigar lighter socket fuse and you may lose your radio code

In most (all?) cars you'd have to have the ignition on for the cigarette lighter to be live, and changing the battery with the ignition on feels like madness as lots of things on modern cars don't like voltage spikes.

I don't know though - maybe with 12V always connected it's OK as everything is already powered up?

[Penelope Stopit]

Sheepshanks said:

Sardonicus said:

Had something like this for years still gets used occasionally , just use another friend or family members car to piggy back off if you dont have a spare battery and whilst you swap the battery do not allow the cars + terminal cable to ground to the chassis or you will be defeating the object and the internal fuse in the unit will blow or possibly your cigarette/cigar lighter socket fuse and you may lose your radio code

In most (all?) cars you'd have to have the ignition on for the cigarette lighter to be live, and changing the battery with the ignition on feels like madness as lots of things on modern cars don't like voltage spikes.

I don't know though - maybe with 12V always connected it's OK as everything is already powered up?

Nothing wrong with linking one car to another through that unit apart from

The cable used for that units jump leads are the limiting factor

Cables look 5 perhaps 8 Amps max

Ignition on may draw more than 8 Amps

[Scrump]

Sheepshanks said:

In most (all?) cars you'd have to have the ignition on for the cigarette lighter to be live, and changing the battery with the ignition on feels like madness as lots of things on modern cars don't like voltage spikes.

I don't know though - maybe with 12V always connected it's OK as everything is already powered up?

One of my cars has a permanently live cigarette socket so definitely not all cars.