Battery Run Down Reset

[mikemartin123]

Does anyone know how to reset the battery run down protection circuit on a 2007 Corolla (Australia)? A few weeks ago I returned from being away after a few months. The car had no electrical power at all. I connected a battery charger for a few seconds and noted that there was almost no amps draw to charge the battery and so disconnected the charger. That action alone had reset the circuit and everything returned immediately to normal and car started with no problems and no boost. (I only had to reset the sound system theft protection). As this run down protection is designed to do this (protect the battery from actually going flat by isolating the load circuits) is there a way to actually reset this without having to connect a charger or a set of booster cables to another car?

[invader]

Battery Run-Down Protection helps prevent battery drain if accessory lamps are left on or something is left plugged into the accessory power outlet or cigarette lighter. If accessory lamps such as the vanity mirror, cargo, reading, console, or glove box are left on, they automatically time-out after about 20 minutes. There's nothing to reset.

Your sound system theft protection drains battery a bit faster over time. Warm ambient temperatures also accelerate battery discharge... Check your battery posts and connectors to make sure they're clean and tight.

[mikemartin123]

Thanks for the reply. The car actually ended up sitting for 16 weeks due to last minute change of plans while travelling. On return the car had zero electrical power. The battery had been load tested prior to being away and was good. All posts and connections are very clean and tight. With zero power in the car, the battery voltage still read very close to 12v. even when trying to apply any normal loads. i.e. even though the battery read 12v, not even a very dim interior light or dash light glowed. As soon as battery charger was connected all power returned to car. Charger was on only a few seconds and then disconnected. Everything was back to normal. It appeared that as the normal parasitic power users started to slowly drain the battery, and were all cut off to protect the battery and was then 'reset' by bumping battery power back to a good strong 12+ volts. It acted as though there was a protection system that kicked in, and I was wondering if this is the case, and if so, is an easy way to 'reset' this without needing to have a charger, or a boost at hand? After momentarily connecting the charger, the car started without assistance and no additional battery recharge was required than after a normal start. After a few minutes running to recharge, a load test finds the battery still normal. It just seemed odd to me that it would act like this, if there was no protection that had kicked in. Any further thoughts?

[invader]

The original Delphi batteries aren't stellar. It may have suffered and sulphated to some extent from long term natural discharge and reduced specific gravity (phosporus in water bonding to lead plates) which is accelerated in warm conditions, as well as from sitting still (heavier acid seperates from rising water corroding upper portion of plates), and current draw... Switching your headlights on then off before attempting to start engine after a long standstill can help jolt the battery to life... Idealy, you want to have your battery disconnected and charged up slowly (and shaken) once every month, or hook up a battery tender to maintain it and extend its lifespan by keeping it fully charged to ~12.6 V (fully discharged: ~11.8 V).