Thank you again! I’ll let everyone knows how it goes.

 

HNY! It’s been a long month of holidays and expenses. Finally finished up the battery swap on the Tahoe today. Noticeably better immediately. Running idle, smooth transitions and not clonking out at slow speeds. No stored codes either.

One thing I did notice while driving. On the dash menu, you can cycle through to the instant MPGs and engine mode. This used to change as you accelerate. From different MPGS and V6 to V8 engine modes depending on acceleration. However, now MPGs still go up and down but the engine mode doesn’t change from V8.

Any ideas or suggestions on this? Should I be concerned?

thanks all

 

 

V4 can not be used in all cases. It's all about POWER!


Same power from 4 as 8 uses just about as much gasoline.

 

Hello, my first post here i'm normally on priuschat. I have a customer who needs the hybrid battery replaced on their 2008 Tahoe hybrid. I've rebuilt tons of Prius packs, and this pack looks almost identical to a Gen 1 Prius. The modules look the same, there's 40 of them instead of the gen 1's 38, and since it's an '08 these are Gen 2 Prius Panasonic modules. I have 2 gen 2 packs, one of them has one bad module and the other is good, so I have 55 modules to choose from. I haven't run them on the cycle charger (GT500) I have a variable DC power supply that goes up to 600v at 1A, what i'm thinking is pick out the closest matching voltage modules, assemble the pack, trickle charge at 300v 1A watching voltage, once voltage plateaus and then begins to rise again turn off charger, hook up 2 120v space heaters and discharge down to 6.3v-6.4v per module, trickle charge back up to full watching the voltage level off, once it starts rising again cut off the charger. I could do another discharge/charge cycle but from my experience this should work fine. Anybody else rebuild one of these packs yet? I guess theres a few other threads on here I should look at. Thanks

 

The pack and battery computer are made by Panasonic EV Energy. They are the prismatic modules.


As a pack, it's unique to GM, but it's highly similar to the Lexus GS450h 40 module pack.


Count on 100% module replacement and 0% recoverability/reconditioning, i.e., you will get nothing usable out of the GM pack, so your normal "recycling" model won't work. When I consider this, and I compare it to the value I can provide, I direct all GM hybrid battery callers to purchase a new one from the dealership. Sure, I could make some money off them, but I don't feel it's ethical. Sure, I could save them nearly $2000, but I'm still ripping them off for what I'm giving them in terms of value. That's now how I do business.


I won't build a pack that I don't believe will last 3-4 years - which is about as long as you can expect a PROPERLY reconditioned pack to last.


Your "reconditioning" efforts are very amateurish for a "for-hire" option. Your initial selection criterion is nonsensical. You are neglecting all aspects of important performance parameters. In my opinion, you are offering a product only marginally better than the dopes that just measure voltage and replace the 1 or 2 low voltage modules.


I realize I am being blunt, and you may feel offended by my comments, but after testing over 3,500 individual prismatic modules along with several hundred Honda sticks with detailed data on every one of them, I can confidently say that your process is marginal at best, and it's not ethical from a business standpoint, IMHO.


It's also clear that you don't even have a minimal working knowledge of NiMH chemistry. You've just cobbled together a bunch of stuff available from the internet, tweaked it with what you have available, and made it your own.


You are not providing value for your customers. You are just providing a cheaper option.

 

To somewhat temper S Keith's bluntness, your customer would be best off buying a new one from a dealer (between $3500-$4500). Expected life expectancy is around 8 years.


A very distant second option is the one I chose - a $2345 warrantied (kinda) battery from Greenbeanbattery.com. Expected life expectancy 3-4 years.


Last choice would be trying to service the unit on a module by module basis - $300 - 400. Expected life expectancy 6 mo - 1 yr, or until the next module fails.


Yes, Mr. Keith is blunt and harsh, but he's also right. He and I spat for nearly 6 months over the what if's. I proudly defer to him for expert advise.

 

I''ll agree with much of what Mr. Keith has said, and I should make a few things clear. The modules i'm talking about using are all good and at the same voltage, just from 2 different packs. I am honest with my customers when it comes to rebuilding packs and I do think rebuilding with used modules can be a waste of time and if people want to keep the vehicle they should go with new modules. Rebuilding with new modules is what I prefer to do as cycling/balancing shouldn't be required. As for my method, its not my method, and i didn't describe it in very much detail I was just trying to give the general overview of what i'm doing. This method was explained to me by a colleague who is a very experienced EE and works with EV's regularly. Usually we just use the variable DC power supply to charge whole packs, used packs in good condition. Trickle charging at 1A or less with a NiMH pack will balance it, not as good as cycling, as long as you watch the voltage and stop charging after plateauing and then rising again. The 2 packs i'm talking about using have the same mileage and both were driven in the same region, I have data for each block from Techstream, they match very closely. There's not much more you can do besides balance them together. It would be best to do 3 charge/discharge cycles but I have to babysit them and it takes a while and in this case isn't really necessary.

 

Just quoted the original post for posterity in case you decide to revise or delete it.

Unfortunately, the additional information you have provided further confirms your lack of knowledge concerning the process. If you have been given this information by a very experienced EE who works with EV's regularly, someone is not being honest about their education or expertise, or you have misheard/misinterpreted it.

"The modules I'm talking about using are all good modules and at the same voltage." - You have not demonstrated that you can accurately identify them as "good". Voltage in no way indicates "good". The ONLY thing resting voltage can tell you is if a cell has shorted/failed or not. That's it.

So, you can confirm:
1) both cars were driven in highly similar fashions over the same terrain and the same traffic conditions?
2) both were stored in the same manner (garage vs. curb, covered parking at work vs. not, etc.)?
3) both practiced the same heat management methods (cracked windows, sun shade, use of cargo cover, etc.)?

Even with confirmation of the above, there are variations in manufacturing facilities that produce different levels of quality.

I've seen an 07 with 256K miles. It failed due to P0AA6. After reconditioning, it has one of the best packs I've ever seen. It was also a black car in Phoenix.

I've seen another 07 with 137K miles. Garage kept with covered parking at work. 10 modules had shorted cells after a 3 week sit during a vacation. One of the WORST packs I've ever seen. It was so bad, I went back to him to do a full cooling system evaluation to make sure it was working. It was.

Both were original packs as determined by VIN manufacture date and module serial numbers.

Here is a list of the 28 module voltages from a 2010 with 175K miles and a P0A80:

8.00
7.99
8.00
7.99
8.00
8.01
8.00
8.01
8.02
8.02
8.02
8.02
8.05
8.00
8.03
8.00
8.00
8.00
8.00
8.00
8.00
8.00
8.00
8.00
8.00
7.98
7.99
7.99

These are resting voltages AFTER the car sat without running in any way for 4 days. Which ones are good? Which ones are bad?

I'll give you a hint: 16 of them were BAD, and 4 more were marginal. The remaining 8 ranged from decent to very good.

Your username is pretty specific. Is this you? Jordan?

https://www.voltek.biz/take-action/

If so, you put forth a much higher image of expertise on that site than you confess to here, which really makes me question if you're actually honest with your victims... erm... customers.

I will give you one thing... you are doing more than the dopes I mentioned in my earlier post. At least you're trying to do SOMETHING. It just remains to be seen if you're charging accordingly. I'd put the value of YOUR work at about $400 including removal/"reconditioning"/build/installation. If you're charging ACTUAL material cost + tax + $400, you might just be ethical.

Otherwise, you're just exploiting the market and providing dramatically less value than full price for a new battery. I'm all for opportunity, but I won't support overcharging for **** work.

 

Yup thats me! and yes I normally charge $300 labor to do a swap for a Prius, something like this would be $400 labor with one more hour labor for rebuilding (no mark-up on materials). I think you missed the part where I explained I had data from both packs from techstream, not just voltages, but tested under load voltage and IR, then out of 55 modules I can matchup the best by IR, all I meant by voltage was that if the IR is the same then i'm gonna pick the ones with best IR and closest voltage and then balance. Both packs at 120k, one is totally good the other had one bad module, both have been charged to same level, both are 2007, I have carfax for both cars they came out of, both were in MI and OH their whole life, I know that doesn't mean their gonna be the same but it's the best starting scenario you could hope for. Are you saying that NiMH can't be trickle charged at 1A to get a pack balanced where the modules are all already at the same voltage? If that method doesn't work why has my friend been doing it since 2008 with no problems? TS provides the best data on blocks besides load testing each module individually. As for my customers, they're all happy, go ahead and ask any of them, never had any issues, **** I really need to start charging more if anything I go over the top for my customers. Actually i'm supposed to go do a diagnostic on this truck tomorrow, I haven't even seen it yet, I was just trying to have a plan if indeed the battery is bad, and like I said above, if the customer likes the car and wants to keep it, I'll highly recommend going with a new pack or rebuilding with new modules, but some people can't afford it, so that's where rebuilt with used comes in. I don't rebuild with modules that are over 120k because I think its a waste of time, ya like you said some modules at 256k might be great but i'd never take that chance. Also, of the 25+ packs i've rebuilt over the last 3 years including 3 gen 1's rebuilt with gen 2 modules, all are still driving with no problems. When I made my first post I was just trying to socialize and get a little feedback and I didn't give much detail, next time i'll come in swinging, if just to please you Mr. Keith!