Weird stuff happening? MPGs dropping? Test The Battery

Thanks Richard. This is extremely useful. Will try it later today.

I like that P111-E V/STOL in your avatar

 

I tried using the information described in this thread to test the 12V battery.
But the procedure is apparently for 2010 and below Priii and neither work in my 2011 IV.
So I'll take my friend James' advice and invest in a mult-imeter.
And check the 12V battery in my 2011 IV monthly via the jump ports in the PDU.

 

Thanks very much Richard.
Yes, my 2011 Prius IV has NAV.
Let me know if I can help in any way.
Thanks again.

 

I've been getting an intermittent red (!) triangle at start up and ended up in the this thread.
I've got an 2008 with about 95,000 miles. I've drained the battery at least 4 times by leaving the radio on, and each time easily jump started the car at the front/engine side battery.

I went thru the test procedures as outlined in the opening post and got the following data:
(car was warmed up already, not sure if I should have done it cold..)
+first test showed a voltage of 12.2 V and started to decline fairly rapidly.
+pressing power button to put a current load, showed 9.6V
+entering "ready" mode, it showed 14.0V, so that means it's charging, yes?

The first 2 items concern me and indicate my 12V battery is on the outs.
Should I have it confirmed/further tested by Toyota?
Is it a warrantied item at 95K miles?
Or just bite the bullet and get the elearnaid.com replacement?

Thanks so much for this forum, I've learned so much about my car! Knowledge is Power!

 

The 12V battery is not warrantied. You need to replace it out of pocket.

Tom

 

I replaced mine under warranty just in the nick of time. I would have gotten the aftermarket battery if it were out of my pocket; the newer ones apparently don't require modifying the car like the old ones did, but they're really pricey. Check with your dealer; Toyota might be competitive compared with $200 plus shipping, but the elearn battery looks better...

 

a somewhat related question...
what are the 2 different batteries each for?
there is one in the engine compartment, yes?
and then this 12v battery in the trunk.

when I've had a dead battery, I've jumped the "engine" battery, but reading some posts in the topic, it sounds like the 12v battery was what I drained.

trying to better understand this...

thanks!

 

The 12v powers up the electronics, the HV battery is the big one under the rear seat that does the work of starting the car and runs the electric motors. When the car runs the HV battery is charged by braking and the ICE, and the HV also charges the 12v. If the 12v dies, the Prius basically can't "boot up", and the car won't start. That's when you need to jump the 12v.

 

Does anyone know just how much current is required to boot the car? I've always suspected that you could probably get things going with a bunch of D cells in a pinch.

 

Mine was replaced under warranty.
Made me feel alot better about having the problem with < 5K miles on the car (new).
As suggested by a friend, I bought an inexpensive multi-meter at Radio Shack.
I check the replacement 12V battery once a month.
So far, so good.

 

Yes, but the question was for 95,000 miles. That's just a touch more than you had.

Tom

 

R U kidding?

 

I tested mine and at the first stage "- Press “Vehicle Signal Check” - the battery voltage is shown and should be about 12.4 to 12.8 Volts (normal for an unloaded battery)" i get 11.8, is it ok or should I replace a battery? In my country, Prius battery (hopefully Optima) costs almost 300$.

 

If you're showing 11.8 volts at the first value you can see (while still in ACC mode), your battery is either bad or low.

You could try charging it up and seeing if it holds a charge. http://www.autoshop101.com/forms/Hybrid03.pdf says you shouldn't go over 3.5 amps. I bought Amazon.com: TecMate TM-141DUAL OptiMate 4DUAL 0.8Amp Weatherproof Desulfating Charger/Maintainer: Automotive to keep my 12 volt charged up since I have a lot of pretty short drives now and the charging system in the Prius seems too slow to keep it topped up.

 

So you are saying that if it doesn't hold a charge, I should replace?

 

Yep. If it's the original 12 volt, it's toast by now.

 

What do you think would be beneficial if I change the battery? Improve millage? I can feel that I can't even lock or unlock my car from just 10 meters in distance..