Driving with a failed inverter coolant pump?

Making something like that go from hot to cold quickly could cause another issue.

 

There's a substantial air gap between the aluminum cover and the internal parts of the inverter so no damage can be caused by having a bag of ice on top... It's just one extra minor step you can take to slow down how fast it takes to heat up and throw a warning light. Not using the AC or heated and driving slowly are others steps you can take...

 

Question: does the prius die when its 12V battery gets too low?

I have heard rumors that when the inverter coolant pump goes out it can blow the AM2 fuse which stops a running car in its tracks, not sure if that's related...

OK I see some people saying that a "very dead" 12V battery can make your car die while driving it:

Scary hmm...See also P0A93 - Inverter Water Pump Failure | PriusChat

The inverter coolant apparently also cools the transaxle...though haven't heard of any giving out because of it.

I have heard of people who can only drive for 1 hr then the car grinds to a halt: EMERGENCY? inverter coolant pump failure (P0A93) | PriusChat

possibly when the 12V battery is exhausted?

I personally drove for like 1 hr at 60mph on the freeway (no fans blowing, no lights turned on, little use of brakes, might have saved some 12V battery juice) and it actually made it fine without the engine going into limp mode (ICE only I assume)...I also went slow up hills which may have prevented the transmission from revving...also my battery might have been extra strong...I was able to use it around town (7 miles each way) with no problems , even the warning lights went off, though the circulation pump wasn't working. FWIW...maybe could stop and restart engine (with or without letting it cool down?) and it would try to use the inverter again and recharge the 12V...?

 

By too low you mean discharged to a useless level, like 10V? Probably not. I believe "hobbit" tested this by detaching the 12V from a running car, and it kept on running. I cannot confirm this now because (extra spaces inserted so that it won't show the current page title)

https: / /techno-fandom.org/~hobbit/cars/prius-12V/

and all the rest of his site just has a political statement regarding the 2024 US election. Trying the Wayback Machine with that URL. Nope, it isn't answering now, apparently hackers took it down a couple of days ago.

Not saying a bad 12V cannot bring the car down, of course. If somehow it shorted from the positive post to the negative pretty sure that would bring the car down promptly.

Of course if the 12V is dead and the car is not running there will be no way to start it.

 

this happened to me and yes a 12v is needed. When I bought my 2007 Prius it has a dead 12v battery (totally discharged) To make it start/run I connected my Harbor Freight jump starter and drive it around. I forgot that the jump starter has an automatic shut off and car just died in the middle of the street (luckily I was in a stop waiting to make a right turn in the intersection) I have to scramble pull the rear seats down (can't open the trunk) and turn on the jump starter again.

 

"Needed" may be mostly a matter of the HV ECU's reaction to the battery voltage sense line being open.

I have definitely started and run my gen 1 with the 12-volt battery disconnected, and no complaints. Gen 1 had the skinny voltage sense wire run back to the battery post the same way gen 2 does, but if that line was left hanging, the DC/DC converter just put out a reasonable default voltage and the car was happy.

I've also started and run my gen 3 with the 12-volt battery disconnected, and no complaints. Gen 3 no longer has the voltage sense line all the way back to the battery; it's just a short one that terminates in the front fusebox. So disconnecting the battery doesn't leave it hanging, and the car is happy.

The gen 2 situation may be different. It has the skinny sense wire back to the battery just like gen 1, but I think the gen 2 ECU programming is less tolerant if that isn't connected, and sets a trouble code and becomes unhappy.

 

Wonder if the prius operates differently with no battery than with a weak one. Maybe that's what's happening here?

In this particular case (with the failed invert coolant pump) the DC/DC converter is turned off (along with the inverter) so the 12V just gets weaker and weaker. Until it behaves kinda like having a bad 12V battery?

I've also heard the power brakes go out with weak 12V power. Weird. Warning lights, P0A93, no AC, cruise, brakes not working correctly.. | PriusChat

 

With the battery out of the circuit, of course nothing but the DC/DC converter is powering the 12-volt system, so if that turns off, the car will go immediately dark.

 

Wait, you were able to start those cars with no 12V battery? I had heard that the battery could be removed after the car was running, but I don't see where the 12V for the ECU, and the start button itself, would come from with no battery attached. The inverter isn't running before the car starts. On a gen 2 (maybe the others too) there is that box of capacitors in the back, perhaps if that was fully charged it would have just enough juice to make the transition to READY?

 

The then is implied as in, "I have definitely started and [then] run my gen 1 with the 12-volt battery disconnected, and no complaints."

 

Right, there was always a source of 12 volts at the time I started the car.

There were a couple different use cases:

• Somebody else has a very dead battery, and wants a jump start from me. I start my car, then disconnect my battery, and jump their car (from my battery posts, not from my jump point). That way, I am not exposing my DC/DC converter to the possible large current of jumping their car. When done, I just reconnect my battery. If the attempt to start their car drained my battery, I'm not worried about starting my car, 'cause it's already started.
• I have a very dead battery, and want to jump from a small jump pack. The jump pack is small enough that my very dead battery could consume all its charge before I can even start the car. So I disconnect the battery first. The 12 volts to start the car comes, of course, from the jump pack. Then, with the car READY, I can unhook the jump pack and reconnect the battery, which then gets charged by the DC/DC converter,

In both those cases, I should add, I'd disconnect the battery by unplugging the cable connection (at the battery post in gen 1/2, at the front fusebox in gen 3), not by removing any battery clamps. Certainly not the positive one. Letting that be loose and maybe bang on grounded metal while READY would not be good.