Won’t start, even after a jump.

When the battery is connected and ready for the jump start, you can test the connections by turning on your radio/headlights/etc to see if you actually have a good connections. If the headlights are strong and radio functions work, you should be able to jump start the car.

 

AND....it is possible that your battery is SO dead that it is sapping the energy from the jump source and the voltage is still too low to start.
That is more likely if your jump source is something small.......versus a full sized real battery.

Often there is no good substitute for a multi-meter.
The little red ones from Harbor Freight are just a few cents under $7 now.

 

What difficulties finding a ground?

Hope you are using the front jump point. If battery was killed by leaving a light on it’s done replace it.

And then cross your fingers it starts because

A: We see so many people on this site blow there cars up jump starting them.
Many from reverse polarity jumping because there jumping it directly to the battery in the trunk the other I suspect the battery is so perfectly 0 volt dead it presents a dead short to the charging battery and pulls Meg’s current
I suspect that huge inrush of current from donor car damages the cars 12 volt buss and blows fuses.
Donor car should never have there engine running.

I would never ever jump start a Prius.

 

Welcome to PriusChat!!

How many hours per week are you currently driving?

Most likely your battery still has a full warranty, measure the voltage at the jump points under the hood if possible, or take it back for testing.

Bit of a haul, but maybe @PriusCamper (or another prius friend) could drive up there and sort the issue out.

 

Yes lights but we are seeing so many dead battery's now because of Covid nobody's driving like they used too.

It will kill the 12 volt battery and more importantly to your wallet $$$ the hybrid battery.

I would imagine in a 2004 the Hybrid battery has already been replaced?

Have to drive the car daily at least for 20 mins to keep both charged.

 

Yet another tidbit of BAD advice, Ed.

With a new 12 V battery, an hour once a week should be plenty.

And if you get a smart battery tender, it doesn't "need" to be driven more than once every 3 months or so.
That is assuming that the hybrid battery is healthy. IT doesn't suffer much if any ill affect from just sitting.

 

"Drive around some" after a jump was my dad's advice to me, accurate for the cars my dad knew. They usually had 60 or 90 amp alternators that would be happy to dump that much into the drained battery, so that it could be reasonably recharged after "driving around some." The disadvantage was that the battery would get damaged more by the 90 amp recharge slamming into it than it had been by the deep discharge.

In contrast, I haven't seen the Gen 2 Prius charging system go much above 7 amps even into a deeply drained battery, and after peaking there it will soon end up below 5. The good news is that's a lot less hard on the battery, so it's more likely to survive a few such incidents. But it definitely isn't going to bring a 45 amp-hour battery anywhere near full charge after 40 minutes of driving around. If you do the math (and remember you need to put about 150% of capacity back in), you end up at around 15 hours of driving around.

In a Prius you don't really have to be "driving around", as it will charge the 12 volt at the same rate whatever you're doing, so long as the READY light is on*. If you have a safe place you can park and ignore the car in READY for 15 hours, that's fine. But a drained battery being still drained after a mere 40 minutes is to be expected.

*I've seen some reports that with Gen 4 that's no longer entirely true. Those may actually charge faster when you're not driving around.