That means the battery is finally dead!
If it could supply enough current for cranking, then it would also have enough volts to keep the computers happy.
In 2017, my 2008 NC’s 9 year old Panasonic battery was losing capacity (ie how many seconds worth of cranking current it could store) through simple old age.
The dead give-away was that the 3.5A Smart Charger could take it from near nothing to “full” in only twenty minutes, and then it would happily start the car, just once.
I bought a Yuasa YBX5053 from MBS via ebay. The free delivery happened next day. The case sizes and fit are identical. The long guarantee is also good.
It had been on the warehouse shelf for six months and was only about half full of electrons, so I put it on the charger before installing it in the car. It took all night to soak up current before the charger was satisfied, indicating it had a LOT of available capacity, just a bit empty.
Take care not to drop the J-bolts holding the clamp! Slacken the nuts, twist the bolts free at the J ends and remove the assembly.
I also washed out the battery tray with soda-bicarb and sprayed the bolt heads with some WD40 to prevent further rot. The hole at the bottom left corner is a fresh air duct coming from behind the bumper, to cool the battery or drop out any fumes.
And here it is installed (before top cover replacement) with the captive lead for any of my Noco Smart chargers.
