2007 Prius: no power at all (2 month new 12 v battery)

i would try to jump start. if it starts, you can leave it in ready for 8 hours to charge up the 12 volt, or drive around for a few hours.
even then, it may be irreversibly damaged. it should be under warranty.

if it doesn't start, you're going to have to get a volt meter to find out if it is the 12v or something else.

check the battery connections, and negative to ground.

 

Use a voltmeter to see what voltage the battery is at. If low, them jump start it. Or buy a 12v charger to charge it back up.

 

You can access the jump points under the hood to measure voltage.

Or access the battery after opening the hatch by crawling into the back area and accessible the hidden manual switch.

 

Pick up a trickle charger and trickle charge it for a few days, even if someone jump starts it, the system never really tops off the 12v battery, it needs monthly top off's, the age indicates a new traction battery in your future, get a toyota new factory installed sucker.

 

I just had the dead car problem on a 2004 Prius. After changing the inverter cooling pump, I started the car and the check engine light was still on so I decided to disconnect the ground wire from the 12v battery to reset the fault. Upon reconnecting the negative battery cable, the car was completely dead. No lights, no response to the key fob. After disconnecting and reconnecting the negative cable on the battery a few times with mixed success, I discovered that the positive battery cable was loose on the battery post. So, if the car is totally dead, check tightness of both battery cables,, not just the negative. I believe that every time I opened or closed a door, or the hatch, the movement could make or break the connection of the loose cable. I'm not impressed with the positive battery connection design. The battery post should be larger, or the clamp on it should be smaller to tightened better.

 

What was the issue? I have the same problem! No power at all! Could it be a loose connection? I hope so! Battery is still at 12V I check with a multimeter but zero power at all! Help please!

 

And the connector ports do have power also have 12V power meaning that the power is indeed going through the connectors. Works perfectly when jumpstarted only. And once I push the off button, it goes completely dead no light or sounds at all!

 

I have a different voltage at the rear battery (12V) and at the front terminal is 1.7V when the car is off

 

Simple to measure the battery. Just measure the front jump point to ground.
Does not matter what the battery itself measures in the trunk it only matters what is getting to the front fuse box via the jump bolt in the front fuse box. The jump bolt is bolting down the main power cable from the battery.

I go for years not looking at the battery in the trunk. Everything I need is on that jump bolt. That’s where I do routine battery charges.

 

1.7 volts is stone dead. If you have 12 volts in the rear at the battery
And no volts at the front that means the 100 amp fuse that’s in the black plastic assy boltedto the positive jump point on top of the battery.
That sometimes blows if you reverse polarity jumped it which happens a lot if your jumping the battery in the trunk.
And sometimes ifthat fuse is blown the inverter gets damaged too.

Whatever happens never jump start a g2 Prius. We have seen so many of them damaged by that. Big $$$$$$$.

 

I bought used and in a rough condition. Not sure if the previous owner did. But 100% I did not reverse polarity while jumpstarting this car. I check all the connections going to the two connectors (that attach to the black plastic assembly on top of the battery) and there are 12V at the connections. So they are good. Connectors and cables look good too. But yeah that’s so weird! I just drove 40 miles no issues whatsoever. When I jumpstart it. I hear clicking multiple times and then boom turns on! Sounds like a relay clicking but I don’t know what relay does that? Could it be the fusible link? I inspected both and look perfectly fine. Or may be the front one is damaged. I am not sure how to check that one but the rear one is definitely intact and working. The weird thing is that once. I mean ONCE, I moved around the positive connection and the car turned on. And as soon I turned it off it went dead again. I didn’t move anything. I was just removing the red cover on the positive terminal. But it never worked again. It only happened once, it tightened the connections and clean the contacts and there are 12V going through so it has good connections. I am
Not sure what wrong, any leads from this information? Please

 

Ok you have bad connections on that battery. Take the positive post assy off and using sandpaper sand the patina off the positive post. Do the same to the negative post. Remove the bolt that holds the negative cable to the back body wall. Sand down the area where the negative cable meets the body. Apply grease to that area and bolt the negative cable back on. Apply grease to the battery posts and bolt them back on.

After bolting it back up measure the battery voltage at the front jump point. Measure with the car off. Write that down. Then with the car off turn on the headlights turn on the high beams and let the headlights run for exactly 5 mins. Then with car still off shut the headlights off and wait one minute and ,then measure the front jump point.

Whats the dc measure then? I bet less than 11 volts.

Btw the relay clicking is the main power relay inside the hybrid battery box that connects the battery to the car.