What every new Prius owner, including me, should know

welcome! yup. and the 12v doesn't get much charge when you're driving either. it's really designed to maintain a quality charge. you're better off with a smart charger to charge a low battery.

and if that's your original battery? caution, it may not hold a charge for very long anymore. i wonder if there is anything in the owners manual.

 

no prolemo, you can google it. all the best!

 

This is incorrect as the prius will charge the 12v battery at idle or while it's driven. What happened in your case is your battery is not holding a charge and dies. A fresh/new battery will not have a problem charging, even at idle.

 

Can always get a battery tender. I have one for those trip I take when the car just sit in the garage. Work good! Hope that help

 

sorry! didn't mean to offriend you.

 

yes it does not charge like a "regular" car, as it doesn't have an alternator. What the heck is a Prius dealer?

Believe what you want, surely you have the expertise to know better.

 

I don't recall ever attacking anyone. I was correcting what you said about the Prius and you flat out said I was wrong. You compared a Prius to a car with an alternator? Even a car with an alternator doesn't have to be driven to charge.

Just a FYI, we don't value the misinformation that TOYOTA dealers provide.

 

OK, here is a real attack. Are you off your meds today?

Look up at your post #12, that I quoted you. You said I was attacking. But I'll quote it again just in case you can't scroll up to your post #12

If you want people to go hybrid you certaintly aren't helping your cause dude by attacking people.

I am not bashing Toyota or their cars......when did I do that? What is hostile about my comment to you? I said the car charges even if not driven. WOW THAT'S HOSTILE...

 

Hi Dilante, welcome to PriusChat. It's great that you like your Prius!

With regard to the 12 volt battery charging, let's try to treat each other a bit thoughtfully here. As you yourself said to bisco, this is a forum for first time owners ... such as you! We don't want you to feel unwelcome, and we hope that what you can learn by coming to PriusChat will help you understand and appreciate your car more and more. There are a lot of people on PriusChat who have very deep technical understanding of the car and there is always something to learn from somebody. In this case, what JC91006 told you about the charging of the 12 volt battery turns out to be correct. Here's why:

Whenever your car is in the "READY" state, the power on the 12 volt circuits is coming from a unit under the hood called the DC/DC converter, which takes the high voltage of the hybrid power circuits and converts it down to near 12 volts. Now here's where things get different from an ordinary car.

A typical car will have an alternator driven by a belt off the engine. The faster the engine turns, the faster the alternator turns. Typical cars have voltage regulators that try to solve that problem by controlling the magnetic field inside the alternator so it keeps producing roughly 12 volts no matter how fast it's turning, but only roughly; the typical car might be producing nearly 15 volts driven at speed, down to under 13 volts at idle. In a lot of cars you can notice the headlight brightness changing when you race the engine. In a typical car, the battery can be recharged a lot faster when you're driving at speed, and it will charge only slowly at idle.

Here's where the Prius is different. Its DC/DC converter is a purely electronic circuit with precise voltage regulation, more like what's in a computer than what's in a car. If you stick a voltmeter on it when your car is READY, you'll see it pretty much at 13.8 or 13.9 volts no matter what you're doing: idling, city driving, highway driving, even sitting at a stop light where the engine has shut down. On a Prius, you don't see the headlights get brighter when you floor it. The converter produces a single regulated voltage all the time the car is READY.

And that means the 12 volt battery is getting charged not one bit faster or slower depending on whether you're idling, driving fast, driving slow, or shut down at a light. If you leave the car in READY and walk away, the 12 volt is getting charged just as it would be if you were in it driving down the highway.

Now it turns out 13.8 volts is just barely enough to get a decent charge on a 12 volt battery. It's not what you'd call a fast charge under any circumstances. So, while it really doesn't matter how fast or slow you drive, it does matter how long you have the car in READY. Short jaunts may never last long enough to keep the 12 volt fully charged, so there might be some situations where you'd want to use a battery charger to top it off. If you do that, be sure to use a charger whose current is less than the limit printed on top of your battery. It can't handle the larger currents from typical car battery chargers.

So, I hope that clears up some of the mystery about the battery and how it charges. There's the whole other thing about what the dealer told you and, yeah, that's a whole other thing. Reading your posting and JC91006's, it almost sounds like you think every dealer tech is always right, and JC91006 thinks every one is wrong, or even providing misinformation.

It probably depends some on where you are and what dealership you're used to. I've got a decent one here, and I can usually find a tech who knows pretty well what he's talking about, though that might not always be the first one I talk to, and sometimes you have to know the signs that the first guy is out of his depth and politely ask for somebody else. I haven't ever really thought they were trying to misinform me, but they have a lot of different Toyota car models they have to know about, some of them are new, some of them are young, and they don't have infinite time for training. Sometimes you do hear things from the dealer that just aren't quite right.

Cheers,
-Chap

 

welcome! Best to call the two batteries in the prius, either the (aux) auxiliary or 12v battery, or referring to the other/big one as the traction pack. IOW, 'regular' battery forces the readers to guess from the context - which ..... after trying to help folks - thru hundreds & hundreds of questions - never gets easier. So ... just as helpful folks can get impatient .... newbies might get impatient with some of us thick skinned crusty ol' timers

So yes - the 12v battery powers up the traction pack & all the rest of the car. But no ... a prius doesnt have to be in drive, in order to charge the car. All the 12v needs to charge, is for the prius to be 'ignition on' .... and NOT in neutral. Hope that helps!
Btw - here's my smart charger of choice;

XC100-P Xtreme Charge 12V Battery Maintenance Charger Desulfator

some may not want to recommend this oil or that charger, because others will get on and say "oh no - better check this one out" You may want to think about that as a decent reason why someone may suggest that you google the topic, so helpful folk can avoid that kind of endless debate - becoming another issue that you have to hear dozens of times, time and time again.
I hope you enjoy your ride as much we all do!
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