2006 Battery Drain

<div class='quotetop'>QUOTE(jmccord @ May 6 2006, 01:40 AM) [snapback]250670[/snapback]</div>

1. Others have reported that the ICE does cycle on and off in these situations. Since the computer is supposed to keep the batteries between certain percentages (being 0 bars and full bars), perhaps it is also smart enough to see that the car isn't going anywhere and there is little chance of suddenly needing a little extra juice from the batteries, so it's "safe" to drain them a little closer to the preset "bottom line".

2. The auto location is available in Canada, but not the US. instead, all we get is the auto-off feature when we turn the car off and leave.

3. it shouldn't be too harmful, as this isn't below the preset minimum level for the SOC.

4. yes, running any electronic accessory long enough while in park will drain the batteries down. but like mentioned above, the ICE will kick in before you fall below the preset level.

5. The accessories run on the 12V system (aka the 12V battery). however, there is a converter between the high voltage system and the 12V system that steps down the voltage so the 12V system can recharge (rather than having to include more hardware under the trunk, this can be done using a *relatively* simple circuit system). so if you drain the 12V battery, it recharges from the high voltage batteries.

 

Just a few more comments:

1. The ICE will cycle on if the SOC becomes too low. In my 2004 it comes on at two bars, but possibly the new software lets it get down to one bar. Keep in mind that when the battery gauge shows empty, the SOC is actually 40%. The only way to adversely discharge the HV battery is to continue driving (or leave the car in park with the system on) when you run out of gas.

3. It's not at all harmful. Think of it being like a fuel gauge; any car will run just as well with a full tank or one that's just above empty. Because the battery guage is showing the SOC between 40 and 80% the buffer outside this range is used to protect the battery.

5. If the car is left in the ready mode, you only have to worry about running out of gas. When the car is turned off, the HV batteries are isolated from the rest of the car by a relay. This includes the circuit that recharges the 12V battery. If you leave something on or plugged in (if you've modified one of the accessory outlets), then the 12V battery can be discharged. However, this battery is only needed to start up the computers and close the relay to the HV battery.

I rarely use the park button and instead just power off before leaving the car. I do use the park button if I am parked, but want to hear the rest of something on the radio, or need to look for something and want to keep the A/C running.

 

<div class='quotetop'>QUOTE(jmccord @ May 6 2006, 10:21 AM) [snapback]250715[/snapback]</div>

That would be nice, but there has to be power from the 12V battery for the relay to close. However, there are terminals in the main fusebox under the hood just in case the 12V battery is depleted.

 

<div class='quotetop'>QUOTE(eagle33199 @ May 5 2006, 11:08 PM) [snapback]250678[/snapback]</div>

There has been discussion of if you used the Prius at a drive-in that uses FM for audio, would the radio last for a whole evening even with the MFD turned off. The consensus was that it should last, but some have left in in "Ready" just to make sure.

 

I wonder if that Prius owner didn't have SKS. I got out of the car intending to walk away and left it in READY only *once*... and I immediately corrected the mistake because the car let me know:

My 2005 will complain quite insistantly if I try to leave without first turning her off. Car in READY, open door, exit, close door -- beeps at least 3 times. Try to lock the car via the SKS button on the door handle -- beeps the long "um, you forgot something, idiot" beep.

The worst thing I've ever managed to do for an extended period of time is leave the car OFF but unlocked by forgetting to press the lock button on the oustide. That's when I'm glad I had the security system automatically arm after 30 seconds... my doors are still stupidly unlocked, but at least Yeesha will complain if someone starts poking around.

 

<div class='quotetop'>QUOTE(jmccord @ May 6 2006, 07:21 AM) [snapback]250715[/snapback]</div>

That would be lovely, and quite possible - just not included on the car. There's no reason why the Aux battery couldn't conveniently be "jumped" by the traction pack via a button on the dash. I've had one EV that had this feature, and it was a life-saver. Crazy to need a jump when you have gobs of energy in the traction pack that you can't get toQ

 

If he was originally in ready mode driving and simply put it in park and forgot to hit the power button, he should still be in "ready mode". While in this mode the 12V battery is tied to the highvoltage.... meaning that even though the accessories are running off the 12V, they will be reimbursed by the high voltage NiMh batteries ... the confusing part is that the 12V battery only gets low once the highvoltage are drained since the inverter is engaged and continually keeps the 12V charged until drained at which time the ICE kicks on to charge back the high voltage NiMH batteries.
In this "ready Mode" state you only danger is if you run out of gas.... A nice mode to be in for camping to keep the car warm while you lay the seats down and sleep!

The other mode which is pure accessory mode "not Ready mode" you are merely running off the 12V battery.
This battery is small and in a non ready mode will not be tied to the inverter to the high voltage batteries nor will the ICE kick on to help in any way as you are only in accessory mode.

Its my understanding that this is a dangerous mode to be in for too long.... as if you drain the 12V far enough, the computer may not even boot up when you try to restart.
A simple jump would alleviate the issue if this ever happens. I like to carry a portable 12V battery you can pick up at many stores for 50 bucks that has an air pump and light combined.
A nice insurance plan for careless mistakes.

I don't care for the idea of having someone try to jump my car, nor do I like being dependent upon that.

If I'm wrong, I'm sure I will be corrected... but unless I'm wrong the mode he was in sounded like "ready Mode".

It does drain down quite a bit and when the ICE kicks on, it doesn't take the battery "high voltage NiMH" back up that far either. Nevertheless all was well and he only ended up with a hit in Mpg for that gas tank!

5) Do the accessories drain the hybrid battery pack, and not the 12v battery? If so, wouldn't the 12v battery remain charged, and is this all that is needed to start the car?

This story would seem to support the idea of powering off the car without first pressing Park. By just using the Power button, there is less chance of accidently leaving the car "running".

Forgive me if this is answered elsewhere. These forums are getting huge, and my search didn't turn up the answers I was looking for.
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1. Everything but the drive system runs off of the 12V battery.
2. As long as the car is in READY, the HV battery will keep the 12V battery charged.
3. The engine will only start to charge the HV battery when in READY.
4. The HV battery is *required* to start the engine.

A bit about #4...
The Prius has a very small 12V battery; it's not designed to start an engine. In fact, you don't even have a 12V starter under the hood. The smaller motor/generator is the *only* thing that can start the engine, and the MG requires power from the HV battery.

This is why you have to get a "jump" if the 12V dies. The 12V runs the computer that turns on the HV battery that can then start the engine. It's also why it's very important to never let the HV battery go completely dead (repeated attempts to start w/ no gas is one way). If the HV battery doesn't have the juice to start the engine, it doesn't matter how charged your 12V is.

 

<div class='quotetop'>QUOTE(wrprice @ May 9 2006, 09:52 PM) [snapback]252618[/snapback]</div>

That sounds right.... the HV battery turns the engine over.. but without the 12V to energize the computer, you never get to access the highvoltage battery.
Its all about the computer first, then second the HV battery to turn the ICE over.

If you ever completely kill the HV battery... good luck!