Car battery temporarily died on the motorway. Restarted after a while. Next action?

molerat

IanMSpencer wrote: »

Regardless. OP identified that they had good reason to believe they had flattened the battery and after letting it recharge for 20 minutes it drove normally.

Based on that I would not be inclined to assume any other fault than low voltage inducing faults in electronics.

If faults re-emerge, given this incident, I would first get the battery checked, free, rather than assume there is a gearbox fault.

Put another way, if you know you have a flat battery, why would you not fix it before trying to diagnose more expensive faults? If the battery has flattened it might hint that the battery is also in poor condition.

Kokolot wrote: »

So what happened was I was driving as normal, and then during a traffic jam I breaked as usual, but then when I hit the accelerator to move ahead again it wouldn't go forward.

The engine was revving but no forward motion.

A dodgy battery is not going to cause that.

IamNotAllowedToUseMyName

molerat wrote: »

A dodgy battery is not going to cause that.

I'm being simple here. What made it fail and what made it clear?

All I am saying is that I would not dismiss voltage issues causing problems with car systems. If you are saying a 2008 Nissan has no electric component to the gearbox then fine, but if it has, then how it behaves with out of spec power supply is anyone's guess - either due to self-check failsafe or glitch due to insufficient voltage.

Old car, lights left on, gearbox glitched, now working ok, what is the most obvious cause here?

(I am not saying it isn't the gearbox, just that in winter, poor battery, stop start traffic, it is something to eliminate first).

Put it this way, I wouldn't be rushing down to the garage based on one incident.

oldagetraveller

https://www.toyotaownersclub.com/forums/topic/181823-car-battery-died-on-the-road-after-a-while-it-restarted-what-to-do-next/

How strange, someone has a similar problem with their 2008 Toyota Auris with a Multimode transmission (MMT).:shocked:

Herzlos

IanMSpencer wrote: »

I'm being simple here. What made it fail and what made it clear?

All I am saying is that I would not dismiss voltage issues causing problems with car systems.

If the engine was running, electrical power would be coming from the alternator. It can't have anything to do with the battery, unless the alternator has also had it. If it came back a while later it could somehow be overheating or some worn connections. Going by the original thread, it worked after turning the engine off and on, so could have been almost anything electrical.

By all means test and replace the battery, but I'd also get the gearbox looked at first.

The_Biff

I had a Toyota Yaris (very reliable). One day I did an emergecy stop and the car stalled. Eventually started, but apparently the Stop & Go batteries give very little warning that they are on the way out. A week later it died completely. Battery was finished.

unholyangel

IanMSpencer wrote: »

Regardless. OP identified that they had good reason to believe they had flattened the battery and after letting it recharge for 20 minutes it drove normally.

I'm not a mechanic or auto electrician so maybe i'm barking up the wrong tree but from everything I do know, a battery can't recharge when the car is turned off. The alternator recharges your battery, but only while you are driving - from what i recall its driven by a belt from the engine so idling won't recharge it as quickly as motorway driving. Ergo if the engine is off, its not turning at all so isn't generating any electricity in order to recharge the battery.

IamNotAllowedToUseMyName

unholyangel wrote: »

I'm not a mechanic or auto electrician so maybe i'm barking up the wrong tree but from everything I do know, a battery can't recharge when the car is turned off. The alternator recharges your battery, but only while you are driving - from what i recall its driven by a belt from the engine so idling won't recharge it as quickly as motorway driving. Ergo if the engine is off, its not turning at all so isn't generating any electricity in order to recharge the battery.

I assumed the OP meant sitting at the side of the road, running the engine.

arcon5

unholyangel wrote: »

I'm not a mechanic or auto electrician so maybe i'm barking up the wrong tree but from everything I do know, a battery can't recharge when the car is turned off. The alternator recharges your battery, but only while you are driving - from what i recall its driven by a belt from the engine so idling won't recharge it as quickly as motorway driving. Ergo if the engine is off, its not turning at all so isn't generating any electricity in order to recharge the battery.

That's pretty much how they work. They have voltage regulators though which ensure voltage output at lower and higher revs isn't at all that different.

unholyangel

IanMSpencer wrote: »

I assumed the OP meant sitting at the side of the road, running the engine.

Ah okay that explains it perhaps. OP said the car stalled, that they shut the car down completely (except headlights) and that they restarted the car so I had assumed the engine would be off from when it stalled to when it was restarted.

arcon5 wrote: »

That's pretty much how they work. They have voltage regulators though which ensure voltage output at lower and higher revs isn't at all that different.

Thanks, good to know i'm not completely clueless about cars