what to do after jumpstart

When you first get into the car, is the dome-light at normal brightness, or is it dimmer than usual?

I don't know how experienced you are re. electronics. Have you access to, and do you know how to use a digital multi-meter? If all else fails, you here is a way of checking the 12V AuxBattery which doesn't require any equipment:

DO-IT-YOURSELF TEST PROCEDURE (thanks to jdenenberg):
- Without brake pedal, press the Power button once and release to enter ACC mode
- Press and hold the MFD Info button, then turn the headlights on and off three times to enter Maintenance mode; release Info button
- Press “Menu” (on screen)
- Press “Display Check”
- Press “Vehicle Signal Check” - the battery voltage is shown and should be about 12.4 to 12.8 Volts (normal for an unloaded* battery)
- Again without brake pedal, press Power button and release to put a current load on the battery - the voltage should stay above 12.0V (if less than 12.0V the battery is not well, or there is a fault or unusual load somewhere)
- Press brake pedal and press Power button once to enter "Ready" mode - the battery is now charging at about 14V (if less than 13.6V or more than 14.4 there may be a problem with the charging circuit)
- Turn car OFF to leave Maintenance mode

* you can load the battery by turning on the headlights!

Good luck! - hope this helps - Wil

 

Hopefully the roadside person knows how to jump start the vehicle correctly (from under the hood, instructions are in the owners manual) without blowing something up. Once the vehicle is running you can drive it again. If your 12v battery is old it may not take much of a charge and might need to be replaced (autozone, pepboys, dealer, etc).

Can you safely let the vehicle charge itself in "Ready" and "P" at work for the day?

How old is your existing battery?

Now might be a good time to consider a new/used lock set for one of the doors.

 

There is a mechanical key located inside of your key fob. Do you not have that key? Was your headlight switch physicaly on?

 

If it is the original 12 V. battery I would replace it and then go from there. You need to get friendly with your owners manual and lean a few 12V skills, they will pay off in the future.

 

I would get the battery tested first, to see if it's viable. You can do a rudimentary check of voltage with a digital multimeter, that'll get you started, but a more in-depth test with an electronic load tester is better, will report voltage and test the Cold Cranking Amps, which is a good barometer of the battery's "health" You can DIY this test with something like Solar BA5, or take it round to most automotive retailers selling batteries, likely test for free. Or dealership, for maybe $50. Maybe free if you're a regular.

Next step, if it seems viable, would be to hook it up to a smart charger, 3~4 amp range. The kind that will do a full charge regimen, then taper off, trickle charge, if you want. CTEK 4.3 is an example. And see how it goes from there.

All that said, you can also just go the charger route: the charger will not commence charging if the battery is toast, so can act as an assessor as well. And it if keeps running and running, never indicating complete, you know it's time for a new battery.

And all that said, lol, if it's over 5~6 year old, it's time for a new battery in any event.

 

This is a great question. I'm having dead battery issues with my 2020 Prius Prime.
I saw the advice from Toyota to leave it in Ready mode for 8 hours to charge the battery. (They also say "or you can leave it plugged into an EV charger and it should be fine".)
I left my car plugged into an EV charger, but my car is charged in 2 hours and then the charger stops, so I suspect this is why I had enough charge to start my car and move it back in front of my house, but when I came outside today it died when I tried to start it.
I live in a city where I park on the street. How is the "leave it running for 8 hours" a viable solution? I'm assuming I can leave the headlights off which will make it less obvious that it's running.
Maybe I can lock the door with the mechanical key? But even then, this seems absurdly dangerous.

 

No, leaving the car READY but "unattended" is really not a good solution (it gets suggested because it does let the car charge the 12V and doesn't require additional tools).

If your charger functioned properly but the car still won't start, then you should have the 12V battery tested and likely replaced. You might have a poor battery connection, or possibly an electrical draw that kills the 12V when parked.

Gotta do some testing otherwise it's all guesswork.

Posted via the PriusChat mobile app.

 

This vehicle seems new enough that it could be covered under warranty, have you inquired at one of the local dealerships already?

How many hours per week are you driving your Prime?

On many generations, it is best to leave the vehicle in "ready" or "off" mode; never in accessory mode, as this will drain the 12v battery.

Try starting a dead or dying 12v battery thread, or search for a related thread in one of the "Prime" subs (below), where you might find more specific advice from other prime owners : Prime Care, Maintenance and Troubleshooting | PriusChat

This thread may offer some insight into proper 12v maintenance "tips", as it could be an owner related issue (extended traction charging, short trips, etc) : 121R oversized battery replacement for Prius Prime 140R battery | PriusChat