A Toasted HV Pack?

Hi Guys,

I've got some strange readings on my main battery and I wanted to get you guys opinions.

Some history on the car. '01 Prius, 154k miles. last 65k miles put on it in Mesa AZ over the last 5 years. Driven a dozen miles daily until about 6 months ago. (It's my wife Car, and I finally got the Cylinder Head back on my '96 Corolla about 6 months ago and could drive my own car) Then, I wanted to "save the car for trips" so we drove my crappy $300 car every chance we got, but the Prius still got a weekly trip of at least a dozen miles (my wife doesn't drive much).

That brings us to about 6 weeks ago, (2 days before a 1500 mile trip). Usual codes that show there is a module with a too far out of balance SOC. I reset the computer, hope it goes away, it doesn't, shows up in the next mile. Our 5 week trip is in two days, so I park the Prius, and we put 3500 miles on the Corolla. I get home, pull the pack out, buy a "Thunder AC6" charger so I can log the capacity of the battery as it charges and dis-charges. I first check the voltage on the packs, and there isn't a single module with more then 3v in it. (5 weeks is a while to self discharge). I start putting the packs through a charge discharge cycle (1.2A charge, 1A discharge, 5mv delta v for complete charge, min voltage 6v, 5 cycles). So far, all the modules are toast (The 6th one is on it's first cycle now). The best one maintains 8v for 250 mah before it drops 1.2v (weakest cell dies).

It seems very odd to me, that the car didn't throw out a warning earlier. While the batteries are all pretty well matched for capacity (80 to 250mah, aka, dead lol...) I'm just extremely surprised that all 6 of the batteries I've tested so far are so far gone, yet the car was working so well before it threw a code. So, I'm asking to see if any of you guys have ever seen a pack with so little capacity actually work in the car like mine apparently did until 6 weeks ago... Or is it extremely unlikely that the car worked with a well balanced HV pack with 200mah capacity, and something is wrong with my testing? If anyone is interested, I have the charge / discharge data, but don't have enough posts yet to add the url's here.

My wife LOVES the car (tears have been shed), so it is going to get fixed, but at this point, I'm really leaning towards saving money for a few months, and just buying a brand new pack from Toyota so that we'll know the car is good for another 150k miles. Just looking for a sanity check from you guys and your experience. I'm shocked (and not quite sure I believe) the car worked on this toasted pack with less the .5ahr capacity for so long...

Joey

 

Thanks Bob! Yeah, I'm thinking the heat here (110+ some days, and an especially hot trip through Nevada (temperature on the road was 120+)) may have caused them to loose most of their electrolyte. I'm just finishing up the 8th module, with still no capacities greater then 250mah