Dealership being vague about inverter problem

measure it with the car off, after it has been off a few hours.

 

When the car is in ready the car is on and should be charging, it will say READY on the dashboard.
if the engine is on or not does not matter. The inverter gets its power from the hybrid battery and D.C. D.C. Converter takes the battery 230 volts down to 14 to charge the 12 volt battery.
Make car ready what's the volts across the front jump points. Should be 14 volts give or take a .5 volt.
Just has 12 somethings wrong most likely missing the small black 12 volt sense wire that goes to the inverter via a sense circuit. Theres 2 black wires connected to the pos post on the battery a big black wire and that small black wire.

 

What is the difference between READY and "totally running"? If in fact you measured 11.9V when READY, that is evidence the DC/DC converter has failed. That may be an intermittent condition.

 

13.7 is normal when the car is in READY. Bottom line sounds like your 12 volt battery is jacked up. Replacement asap before you blow up the Inverter.

 

It sounds like something weird is going on with the inverter - like perhaps the crash on the rear has loosened a wire and now it occasionally disconnects, causing the inverter to stop intermittently. You might try purchasing a one of those voltmeters that plugs into the cigarette lighter and monitor the voltage whenever the warning light comes on.

 

Scan Gauge is very helpful. Its got a good form factor that you can monitor water temp and 12 volts and mileage while driving and it can read and clear codes including hybrid codes. Very good investment.
There's torque app for android and there's also a mini vci which is most inclusive as it has Toyota tecjhtream software but requires a laptop.

 

Be aware after 10 years on this site it seems the dealer is incapable of properly testing the Prius 12 volt battery. Countless people have gotten the ok on there 12 volt battery only to be stranded later with a dead 12. If there's even the slightest thought the 12 may be bad freakin' replace it.

 

Have you checked the calibration of the plug in volt meter against a known reliable hand held volt meter? It is possible that the plug in volt meter is reading too high by 0.6 V. in which case your low voltage would be more like 13.1 which would be marginally low, and those high readings would be about right.

The high readings means that the voltage sense is detecting a flat battery, so cranks up the voltage to charge it. 13.2-13.6 means the voltage sense is detecting a full battery so just trickle charges it.

 

Ah ok, the MDF reading is about 0.2 - 0.3 V lower than if you read directly at the battery, but matches the voltage when read at the ACC plug. I don't know why.

 

Not necessarily. You could invest in a modern 12 V battery smart charger with AGM setting (if you don't have one already) and try charging it up. You could then put it on the charger anytime the car is not going to be used for several days.

However, you may have other issues going on with the car to cause the battery to go flat.

 

^ This. Our car often sits idle for a couple of days. I'll hook up my smart charger, just leave it on. After charging session is done (say in 4~5 hours) it'll just send occasional pulses, to maintain.

 

Ever had your HV battery fan cleaned?my two cents.