Jump start issues

Are you thinking the jump start, and/or the subsequent driving recharged the battery? It doesn’t work like that. You’ve either got a battery that’s developed a defect, or there was some discharge event recently.

Steps:

1. Have it tested with electronic load tester, see where it’s at. Automotive retailers that sell batteries will usually do for free, or dealerships for a fee. You can DIY with something like Clore Solar BA9.

2. If still viable, charge it with a smart charger (3.5 amp max rating is indicated in 2’nd gen owners manual If I recall correctly). This will likely take at least 6 hours, or up to 12 if it’s really low.

 

Measure the voltage at the jump points under the hood.

If the battery is only a year old, then it should have a warranty left on it. Might be time to swap it for another at the place of purchase.

How many hours per week do you drive?

 

The battery is about 45 amp-hours, I believe.

At 3.5 amp charge rate, even theoretical 100% charging efficiency would still be thirteen hours to replace the full charge. In real life, it's not uncommon need to put in nearly half again as much as the nominal charge to really fully charge the thing. So yeah, it takes a loooong time.

 

And if there is a substantial key off draw, then the charger has overcome that as well. So it could take even lo-o-o-onger.

Posted via the PriusChat mobile app.

 

If it is an abnormal key-off draw from some electrical problem, that could be noticeable. The ordinary key-off draw I believe to be somewhere in low tens of milliamps, which compared to a 3.5 A charge current would have a low single-digit percent effect on the charge leeeeeength.

 

Yes.... A smart charger that goes up to 8 amps made my life way easier with 12v charging hassles... LIke many I started with a cheap trickle charger, which takes an eternity if you have a drained 12v.

 

That’s very low usage, not strange at all to have battery die. There’s a low but constant background demand on the battery.

Our usage is similar and I have a smart charger pretty much constantly hooked up.

 

That amount of usage may not be able maintain a decent 12v charge, try turning off the SKS function and see if that helps some.

 

The second post in this thread might offer some clarity : What exactly is SKS? | PriusChat

 

How cold? I’d say continue, but someone with more brain cells may differ...

 

Does the FOB lock/unlock the doors when you press the buttons?

Before turning the SKS off, test the physical key (contained inside the FOB) and make sure it locks/unlocks the drivers door.

The automatic charger should go into 'standby' mode when fully charged.

 

When was the button battery inside the FOB last replaced?

22F and snow flurries in Fremont, CA ?