12 v battery and listening to the radio

Be in Ready, in Park. That way the HV battery is charging the 12v battery constantly, and the ICE can step in to recharge the HV battery.

 

Or ... dump your stocker auxilary batter for the similarly sized yellow top optima. Then you'll have a battery designed with real live cranking amps ... and doing a simple task like running the radio won't kill it, if you listen too long. It's all a mater of preference. If one preferes to not want to waste a charg/discharg cycle on the traction pack (plus the gas to do it) then the optima is another alternative.

 

Park and in READY is a better way than spending unnecessary money for a new battery that is not needed now. When the original battery needs replacement, that would be the time for replacement with the Optima.

 

I believe that my experience with the Gen II is transferrable to the
Gen III.

Without additional gauging, the safest way to listen to the radio while
the car is at rest is to put the car in Ready, as noted by JimboPalmer.

In lieu of purchasing a better battery as suggested by hill, you
might consider getting a ScanGauge.

With the SG, you can monitor the status of the 12V battery, even when
the car is Off. (By far, the least battery drain is when the car is On
(one press of the Power button without depressing the brake pedal) By
setting the standard VLT gauge on the SG you can ocasionaly check
the 12V battery with the car sitting and the radio on.

When the voltage drops to a preselected value, say 12.3V, either shut
the car off or go to Ready to recharge the 12V battery from the HV
battery, or with the ICE running if the SOC gets below 3 bars. In my
Gen II in the On condition, voltage drops ~0.1V every 20 min. (Note:
in the On condition nothing else electrical is energized, even the many
ECUs, etc. that are powered up in the Accessory mode.)

Purchase of a ScanGauge for this purpose alone would not be justified.
However, it has many other uses as well as given in many threads
that can be found using the search function.

IMHO, all in all, a SG is the best first "mod." :rockon:

Hope this helps.

 

Do note that if the lights were on and you turn them off but don't get out of the drivers side of the car they may not actually turn off. To be certain they are off open and close the drivers side door. Several people posting on this forum have drained the 12V battery because of the headlamps not turning off.

The Optima battery conversion is at: 12 Volt (12v) Toyota Prius Auxilary Battery for 2004, 2005, 2006, 2007, 2008, 2009 and 2010 with installation kit. Note that there are two types, one for the G1, and one for the GII (which I understand is also applicable to the GIII). If you want to get it you will also need the post adapters, also sold by the same people.

 

Thanks db for posting the link. One tends to forget it's not common knowledge after posting & re-posting the info for a half decade now (not that I mind in the least)


.

 

There is a timer or low battery shut off when you have the car in auxiliary power mode.
When I was de-tarring my paint I had the radio on and it automatically shut itself off after a period time. It would not turn back on unless I put the car in READY mode. So there must be a safety interlock to prevent the owner from killing the battery by draining the 12V in accessory mode.

I don't recommend doing this to find out.

 

Outside of getting a larger capacity 12V battery, might I suggest switching to a lighter load (passenger seat). Both will help your situation - the other option is a nice sports bar that I am sure is within walking distance...