sos warning on dash ? related to lead acid battery condition

[Van substitute]

Hello Everyone

I have recently been getting the SOS warning system light on the dashboard. My lead acid battery is original ( now 6 plus years old) I wondered if this might be the cause ? any views. Also as this battery does not crank the car to start are there any other indications of when this might need to be replaced before the inevitable "oh hell "day when nothing happens when you try to start up the car and you are stuck.

[Bristol_Crosstar]

You just need to check the battery voltage using a voltmeter or tester (cheap ones available on Amazon if you don't have one)

[Lord Voltermore]

You can buy voltmeters  that plug into the cigarette lighter socket  giving a constant voltage display . But they can be a bit of a worry meter.   I used one on my 2021  car before it was 3 years and even then it often read below 12v if the car had been unused for a few days   But it still  always powered up the car.

We dont seem to get as many complaints about flat 12v batteries since Honda changed battery brand to Panasonic/Yuasa in about 2023.

The battery is comparatively small. 6 years old may be pushing your luck.

[Van substitute]

Thanks Lord Voltermore . I do have a voltmeter and like you I have noticed that it often says around 12 v ( and has done for ages )which for a cranking battery would suggest its not great BUT this doesn't have that work to do so unless anyone knows the actual voltage that it won't power up the car its still a bit of guesswork.
I only linked the two issues because one day the sos warning came on. I usually do relatively short journeys however when I drove 100 plus miles in a day shortly afterwards the green light on the sos button came back on and the warnings stopped for a few days and then went back to coming on again once i drove more routinely.

[Lord Voltermore]

Even when my 2021 car was only  year or two old the voltage sometimes only read about 11.5 volts  if the car had sat unused for more than a few days. Which is below what is considered normal for a 12v lead acid battery even  in a fairly low state of charge. And borderline on possible long term damage to the battery (It raised to a healthy 14+ volts charging voltage when the car was powered up.)

 I probably should have got the battery replaced under warranty, but never bothered    Perhaps I was too confident that my small 12v powerbank jump starter pack would get me out of trouble if necessary.  The car never failed to power up and it never got any worse. 

I never noticed any problem with the e-call sos system when the voltage was below 12v, but maybe the call system is the first to fail if voltage drops too low.   (Sorry,until now I thought you meant the battery warning indicator light had come on)

I'd be inclined to get the 12v battery condition checked by a battery specialist. They check more than just voltage. 

Check out this previous post on 12v battery problems , which includes some suggestions of cheaper options than from a Honda dealership

https://clubjazz.org/forum/index.php?topic=18298.75