ICE Running More Frequently than Usual. Cause?

First impression would be your HV battery is losing capacity meaning that it discharges faster. That would make the ICE come on to charge it again. It would be most noticeable at long stop lights or extremely low speed stop and go traffic. The Dr Prius app combined with a bluetooth OBD2 reader could give you an estimate of HV battery life expectancy. I have linked the OBD2 reader I use below.

If you have an original 12v battery from 2012, I would shop around and replace it (assuming you are keeping the car) but don't expect that to fix it. Basically the 12v battery acts as an electronics and lights power source before you reach Ready mode but does not actually "crank" the engine. The inverter converts part of the HV 201v to handle the 12v loads and charge the 12v battery while in Ready mode. Effectively a solid state alternator with no moving parts. The 12v battery does act as a ballast for the low voltage system and could drag down the 12v battery is it was totally failed, but you would not be able to start the car in that case.

I would get the inverter recall flash update as soon as possible. The inverter can fail unexpectedly and leave you stranded. At that point a tow to a dealer is the only option to get it running again.

 

replace the 12v

 

On top of the above two messages about replacing the 12 V battery or a week HV battery.
But this would only make a difference if you’re the type of person who runs the air-conditioning all the time like myself. A few scenarios that cause your HP battery to drain more quickly and causes your ICE come on more often.
1: when the electric compressors refrigerant level gets low the AC system reacts to it sensors the inability to cool down the passenger compartment it sends a message to the compressor to increase the RPMs therefore drawing more amps of power continuously that draw down to HV battery causing the engine to come on more often. The programming for the mode of operation for the air conditioning is stupid does not know the refrigerant level is low and will forever keep increasing the RPM level of the compressor to compensate for the lack of cooling due to a low refrigerant charge.
2: if you’ve just recently been in a body shop for a front an accident and the condenser was replaced three scenarios happen A or B
A: after repair work was performed the car refrigerant level was either overcharged or under charged in both case scenario will cause the compressor to consume more amperage from the HV battery causing the ICE to come on more often. Over a long period of time cycles the HV battery shortening its life from an improperly charged air-conditioning system very few people know about this .
B: body shop or Machanic shop used one of the cheaper lower quality condenser with fewer refrigerant passage tubes and fewer cooling fins. This leads to reduced heat capacity rejection on warmer day what in turn greatly increases the high side pressure that increases the AMP draw on the HV battery. This lower the cooling capacity. The car system is looking for the temperature to be approached. If the temp is not achieved after a period of time. The computer will command the compressor to spin up in RPMs to pump more refrigerant past expansion valve to provide cooling. This interns continuously consumes more amps of power away from the HV battery at the same time making a high-pressure condition and lowering the efficiency of the refrigerant system that’s in terms send another command to the compressor to increase the RPMs even more you can see where this is going. In the end the customer complains about lower gas mileage and a lot of unnecessary diagnostics or engine trouble or electric battery problems parts get replaced customer ends up with a lot of high bills and the vehicle still has poor gas mileage due to the air conditioning system not working properly and 98% of the mechanics do not know about this problem . Who would think . this is probably not your problem but just in case, food for thought in case any of the above scenarios have recently taken place . Over the years you would not believe how many Prius is or electric cars with electric compressors in general I have seen on a regular Basis with their compressors whining their life away at 5000 to 7000 RPMs continuously nonstop trying to keep the car cool in some cases depending on the scenario it can cool the car but I have a high cost of current amp draw from the HV battery. Well the majority of customers or technicians cannot hear the pitch difference in the compressor and don’t even know what’s going on under their noses.

 

Is it safe to "refill" the freon with over the counter refrigerant that is specifically used for hybrids? Where should the needle be in the green zone? In the middle or in the higher side of the green zone?

 

Good info on the ac compressors. I knew they were variable capacity but did not think about how much hv battery capacity they use. Do you know if there are techstream data points that either report the rpms or directly measure the power consumed?

 

Yes there is you could read it right off text stream it’ll give you your amps and RPMs.

Good question.

You even have the option of commanding the RPMs yourself to your desired setpoint. I would not recommend this to somebody who is really really really not extremely familiar what’s happening to the refrigerant in the oil return if you’re going to do this for diagnosis purposes otherwise you may hear that compressor lunch while you’re doing it if you keep it there too long into pieces. I would not recommend this to somebody who is really really really not extremely familiar what’s happening to the refrigerant in the oil return if you’re going to do this for diagnosis purposes otherwise you may hear that compressor lunch while you’re doing it if you keep it there too long into pieces This is where a little information is more dangerous than no information at all .

But with those guys who believe you don’t need to drain and refill the air conditioning and it’s OK to let it go low.But with those guys who believe you don’t need to drain and refill the air conditioning and it’s OK to let it go low For those particular individuals the ones who use the bubbles in the site glass in the green zone in the little pressure gauge on the can be my guess go right ahead. But let me break out the video camera because this will be entertaining.

 

You have no idea it’s in-fathomable amount of misdiagnosis around this topic. I’m only going to mention one of many that is just related to air conditioning only. I have seen HV batteries replaced because the air conditioning charge was low. I have seen many inverters replaced because the air conditioning charge chargeI have seen many inverters replaced because the air conditioning charge was low. I seen ignition coils replaced spark plugs replaced fuel components replaced many comebacks and returns beyond any human-beans imagination. Just because the refrigerant charge with a few ounces low.Just because the refrigerant charge with a few ounces low. The air conditioning compressor and the software programming so long as it’s trying to satisfy the call for cabin temperatures that you have selected. The software in the system does not know the refrigerant charge is low that is not part of its perimeter it will just keep dumping more amperage more wattage from the HV battery into the compressor to increase the RPMs more and more forever climbing to try to satisfy the temperature that was called for in the cabin.

And if the refrigerant level is several ounces low he could never do this so it will forever hold the RPMs up at six or 7000 RPMs trying to cool off the passenger.

So far those YouTube professors and armchair engineers to give advice just let your air-conditioning go low until it needs to be fixed your HV battery suffers its life by continuously being charged and discharged your gas mileage goes down and eventually your compressor decides to become a cluster bomb and tear it self apart on the inside.

 

I wouldn't do that......probably ruin everything.....

 

The answer to that question is twofold it’s a double edge knife be careful. 1: Yes there is only one chemical with the designation letters of R134a. It’s all exactly the same no matter what brand is on the can so long as the ingredients are only that one ingredient no other chemicals no sealants no special super magic lubricants nothing else but refrigerant only then yes it can go into any automotive air conditioning bulletin designed for that specific type of refrigerant even if the bottle came from China because most of our refrigerant with the American names on it did come from China.

2: Now is it safe that depends on the Training education knowledge experience and ability to get it right when performing the procedure.

When everything is done right it always works if everything is in good condition 99.9% of the time.

when it’s not done right you might get cold out of the dash and think whoever did it did a good job but the way they did it set up to be a ticking time bomb that might cause the compressor to terret south apart six months or a year later it’s usually not instant unless they really really do it very very wrong. and that happens sometimes I’ve witnessed it it’s quite amusing.

 

Hi. My issue is a little different i think. My 2005 Prius ICE also keeps running far more than it used to previously. Its been over a year now since its been showing this behaviour. Even when Hybrid battery SOC is at 6 or 7 bars the ICE comes in for no good reason. Regardless of how long I have been driving it. It does this even with the Heater and Ac turned OFF. Tyre pressure is normal. 12v battery is also fine. Local Hybrid garage also checked it, they said the battery was charging as it should and they did not find any fault codes for the H/battery.

My driving pattern has not changed. I drive to the same locations as I did before when it would return 48-52 mpg with ease in local traffic. But for over a year now it only manages 40mpg at best in Summer temps and gets worse in winter around 30-33mpg!

Also in contrast to how it used to be over a year ago, now even the slightest tap on the throttle will make the ICE kick in again even when H/battery soc is at 6-7 bars?

Also got the Throttle body replaced but that did not make any difference at all. The Ice still keeps kicking in for no logical reason be it at the traffic lights, Cruising on the motorway, even going down hill and foot off the throttle the ICE kicks in. I just don't get it and have run out of ideas. As i said my one does this even with AC and heater turned OFF!

Any suggestions would be welcome!

Thanks

 

Just a quick sanity check. You mention your Prius is a 2005. This is the Prius V forum (first introduced in 2012), so everyone in here assumes that you have an AC system that is driven by an electric motor (like a window AC for your home). Older prius' ran with the traditional AC powered by the Internal Combustion Engine. The ICE would always come on if the AC was turned on. I don't know which system is used in a 2005 Prius, and a lot of the above discussion would be wrong for the ICE driven AC.

Any chance you meant to type 2015 for your year?

 

Electric AC compressor since 2004

 

Its a 2005 Gen 2 Prius. Sorry for posting it on this forum. Anyway I found a work around and its fixed I believe. Basically in the morning when you power on the car with the power on/off button, you need to wait for the ICE to kick in which it does within a few seconds after pressing the power button. The ICE will warm up for around 2mins and shut down. When the ICE shuts down, you need to press the power on/off button again and turn off the power, you then wait a few seconds, and press the power on/off button again and turn on the power. You can now drive the car as normal and the ICE will not kick un for no good reason like it was previously in my case. The mpg has also started improving since the ICE does not come on all the time like before. This is the only solution I have found so far that seems to fix the problem of the ICE running unnecessarily much of the time..... rjparker is right I believe Electric AC compressor was introduced since the gen 2 Prius was introduced in 2004.

 

Good info here. I might need to pay you a visit @lech auto air conditionin shop.

 

He seems to be always right!

 

Yes this is well documented as
Prius Deranged Syndrome

 

I am sure he is but it appears he hasn't addressed my ICE running all the time issue yet. My Gen 2 ICE runs too much even with the Heating and A/C turned off. So I am not sure my problem is Compressor related.