Prius Battery Died, Display is gone

You're probably correct about the forward current, but even with 10 mA, it would add up to significant battery drain, especially if the car is not being driven regularly. Given how grossly unnecessary this LED is, why have it there in the first place? It's very shortsighted engineering.

 

There is a lot of chatter about the Prius battery...just what exactly does the battery do....the engine has no starter nor alternator. So this battery in the trunk does not start the ICE....what does it do.??????

 

The Battery in the trunk allows the on board computers to keep their memory, as well as your radio presets and clock memory are also kept with the aux battery. It also powers the accessories when the prius is not in 'ready' mode.

 

I believe that your correct. Then why are people paying hundreds of $$$$ for a large CCA battery, since the 12V battery does not turn over the ICE to start it.
A toyota certified mechanic told me that when you jump start the Prius from under the hood the jump battery only closes a circuit that allows the Traction battery to turn over & start the ICE. I believe this as the contact for jumping the 12V battery is a very flimsy piece of metal, nothing designed to carry a lot of current. I would like to know what amount of power is required to close this circuit.....could it be done with a few D cell batteries ????

 

Yes, you could probably get the car into Ready mode with just a few D batteries, or almost any medium-sized 12V battery. You might want to pull the fuses for the brake booster pump first though, as that draws something like 40-50 amps briefly when you open the driver's door. One posting here speculates that it's fuses 20 and 21 in the engine compartment, but I don't see confirmation of that. (They're certainly big enough; 30A each, bigger than the other 5 fuses labeled as being part of the brake system.) All you need is enough juice to boot the computers and close a couple relays, then the HV battery will supply any needed 12V power through the DC-DC converter.

 

Thanks for the information, very useful....then why the expensive battery in the truck......I read where someone actually used a lawn tractor battery....that seems like it would be all that is really needed.