My new 2005 Prius hybrid battery trouble shooting

Hi Everyone. I'm new to prius. My friend got one and I loved the way they drive and the possibilities I hope of making it a plugin. So i ventured and bought a used 2005 prius with 255,000 miles on it with the triangle and exclamation point on. It drove great and was cheap enough -- $1250.00. The owner had had a refurbished pack from Falcon put in less than 2 years ago and brakes done last year and threw in the Bentley manual . So now my adventures begin.

My autel maxidas scanner read codes on the Hybrid Battery and Control modules
P3020 -- battery block 10 becomes weak.
P3000 -- Battery control system

In order to clear the codes , I had to clear the HV Battery codes first - P3020, and the triangle would go away and it would drive good. Then i could clear the Hybrid Control module codes - P3000 and the exclamation point would go away. So then the car drove great for a while. I get over 40 mpg. 43 - 46 mpg sometimes. But every few hours it would throw the code.

I would monitor the battery blocks . Block 10's voltage was always jumping around with the others either .1 V lower or higher. It was never crazy low though. There were always some lower than it. I noticed the Internal resistance of most blocks is .26 with block 10 being a little higher -- .29 , .33. One time it got to .40.

Anyway, so the car started throwing the codes more frequently -- every 10 minutes sometimes and i drive it with my scanner hooked up and just clear the codes on the fly. Also it seemed to go into limp mode sometimes with the triangle on.

Then i thought about overheating. So i removed the cover to the hybrid battery, removed cover to the fan and intake duct going to the fan and always keep the ac on and windows closed. The fan is now wide open to the cool cabin and can get all the cool air it wants . Low and behold it did not throw a code for 260 miles. Then it did when i had the ac on and windows down. The code it threw this time was "Replace hybrid battery" .

So I'm thinking if i am going to have to be replacing some modules, i might invest in a grid charger from Max volts so i can just plop in modules and stick the thing back in my car and let it charge and balance it overnight.
Thoughts on this? I'm thinking that evenutually i'll have to replace every module and have a brand new battery pack. But if i can do it one or two modules at a time, why not. I'm a mechanic and it doesn't seem hard to get at the battery pack.

Toyota wants 4K for brand new battery pack. I don't think that is too bad for 200,000 miles of service but i'd rather build my own brand new battery for 1500 or so . Does anyone know if the new battery packs for toyota are better than what was in 2005?

What are the best modules to buy for this? I'd like brand new modules . I figure if i get a brand new battery , then i can hang on to it take it with me as it is worth more than the car.

Thanks

 

Thanks Everyone. Yeah I'm pretty much coming to the conclusion that ultimately a new battery pack is the long term simple solution. But i would like to see how long i can get out of an old pack. I ordered a grid charger from Maxx Volts. I read the threads about charging and discharging the individual cells over 2 weeks time and that is just not practical for me. If this grid charger doesn't work to balance new modules , I will just get a new pack.

For the last week i have been fine keeping my scanner hooked up and just clearing the code when it throws it. It didn't throw the code at all today. I wonder how long this can last. I have at least one backup car at all times so I'm not worried if i break down yet. Until i'm ready to go on a long trip.

If it comes time that a new battery makes sense, which it looks like it does for most people and probably me
A) Can you buy all new modules and bus bars and build your own cheaper?
B) Or where can you get the best price one? My dealer in Nashville said 4000 or 3500 with a shop account.

I'd appreciate some links. And i would drive to another state to save a grand on one if someone has a source.

Thanks again.

 

TMR-JWAP -- want to sell one of those packs? How much? What do you do with them?

 

Yeah. It's only 6+ hrs from me. Not bad. I have to drive to DC in a couple months possibly. Not too far out of the way. Let me know TMR-WAP.

I got some new codes this morning. So my battery has been being confused in the morning it seems. I started it and it shows real low. Then goes to all green really fast. Today when i first took off I was adjusting the AC and it shut down , computer went crazy and threw a bunch of codes on various modules. Everything lost communication. Many faults have been triggered by the AC which is understandable as that is drawing a big surge from the battery pack. So I am hopeful that once the battery is straightened out I won't have any other computer or control module errors.

Codes i got on the HV Battery module :
P0A80 -- Replace hybrid battery pack (*normal code i get now)
U0100 -- Lost communication with ecm/pcm 'a'
U0293 -- Lost communication with hybrid vehicle control system

Hybrid control system
P3000 -- Battery control system (*Always get this when i get a battery code)
U0100 -- Lost communication with ecm/pcm 'a'
U0111 -- Lost communication with battery energy control module 'a'
U0129 -- Lost communication with brake system control module

I waited a minute, started car and drove to a safe place to park and clear the codes. Then i went on too work and drove 20 miles without incident.

Hopefully my grid charger will come soon. I'm curious to understand these symtoms.

I'm going to check the state of charge of batteries when i park at night and in the morning before i start. I think that that should tell me something.

Do the prius brains get confused and can be reset?

Or is my battery just giving it so many mixed signals all the time that it does not get along with it and wants a divorce and a new younger model ?

To me I would think the prius brain could be a little more forgiving of weak batteries given the car is driving great and getting 47 mpg on my daily mixed commute. But I am no electrical engineer.

Thanks