2007 Gen 2 Prius DEAD HV BATTERY

Is there a particular reason for starting another thread on this?

 

Unfortunately, this is not the case. What you have, most likely, is a bad cell in a bad module. This cell is basically a resistor now, not an open. If you ask your dealer for the freeze frame data, it will show V1-V14 and you will most likely see that V5 is more than 1.2V lower than the rest. Thus, instead of 240V you may have 238.7V, which is plenty to spin start the ICE.

The alternative, a bad sense wire and/or terminal corrosion, still means that you need to remove the battery and inspect it.

Have you tried either of the two suggestions so far? A third would be an Enginer installer, I think there is one in greater Miami.

I wish you success.

 

I noticed in your other thread that the first symptom you mentioned was "pulsating". I think that's an unusual symptom for a dying battery.

Can you tell us a bit more about how the car drives. Normally when the traction battery is dying people experience very rapid swings in the state of charge (purple blue green 8 bar display) and loss of power with lots of revving of the engine to get anywhere. Pulsating is not usually something that's mentioned.

 

I have to ask:

Mileage? Why wouldn't you get it repaired under warranty? 8yr/100k.

 

Then I would look into a replacement pack from Ebay or the place in N. Carolina that rebuilds battery packs.

Remanufactured Hybrid Vehicle Battery Packs

 

1. I suggest that you subscribe to techinfo.toyota.com so that you can access official repair manual info and the safety warnings associated with this job. If you are not careful you could kill yourself.

2. I also suggest that you invest in a quality digital multimeter so that you can accurately measure voltages.

3. You'll need to remove the traction battery from the car so that you can disassemble it. #1 will tell you how to safely do this.

4. Once you have removed the top cover of the battery, you can use the DMM to measure voltages of each of the 28 modules. You will find that one module shows lower voltage compared to the other 27. That is the one that has failed.

5. You can try to replace that module with one that you can buy off eBay but that is likely to be a short-term solution since the module that you install may not have similar capacity as the other 27.

6. Hence, the suggestion that instead you buy an entire 2G salvage battery assembly, which may cost you ~$500 plus shipping. Good luck.

 

Yes, you have a bad battery. When the battery suffers a fault, it stops all current flow back/forth to the inverter. This means that the engine is the only source of motive power, so it runs very fast in order for MG1 to supply current to MG2 in order to move the car forward, but the car is now a turtle.

Salvage is half the price of Reinvolt.

 

This may be true for Gen 1. Gen 2 modules are more robust. Since this battery already has 100,000 miles on it, it is not likely that a replacement module would have significantly less capacity. On the other hand, it is a good idea to replace modules in pairs with matched state of charge, so that the HV battery ecu is not trying to maintain balance on stronger/weaker/higher/lower modules that are in series.

 

i would go for the rebuilt battery. you got 100K out of the first one, that's not too bad.

 

How about a strategy of buying say 10 pairs, and using the pair that matches the old battery? How close in voltage would very good have to be ?

 

For the price of 10 pairs online, you can buy a whole salvage battery assembly from a junkyard.

The idea of using a matched pair depends much on getting a matched pair from the seller. Modules coming out of the same battery are the best, but modules that have comparable amp hour capacity as determined by load/discharge test also work. Best practice is to charge the replacement modules to full, then discharge in series to the approximate voltage level of the other batteries in the string. The hv battery ecu will take care of the rest.

 

Excellent! Please do follow up and post pictures!

 

Hi there, in previous thread you wrote :

It's a shame that the symptoms at 99000 were so vague otherwise you might have had reasonable grounds to insist that the issue started before 100k. Unfortunately though, to me a description like "subtle shaking" doesn't really give any indication of a battery problem, which kind of makes it looks like a separate problem. Did you notice any other symptoms during 99000 mile incident that were more indicative of a battery problem? (like the ones we discussed earlier).