Gen II Prius Individual Battery Module Replacement

x2

Anyone working on these batteries should know the FIRST step should always be to disconnect the 12V battery and to remove the orange service plug from the hybrid battery. Yes, some of the early Prius can leak and discharge to the case but that also means the car body is electrified too.....again this is why the volt meter is always your friend when working on these batteries so when in doubt always check before touching with bare skin. I also used the colors on the speaker wires to identify polarity, works great and makes sure you don't get screwed up by accident.

 

The zig zag harness is a pita, and takes time, and you must be careful. The wires are exposed at the ends and you dont want to let it short out on you. All positive terminals connected and all negatives. Dont let a neg touch a pos or vice versa, it would probably fry modules pretty quick. It takes awhile and you'll need many 12" sections of speaker wire, and strip each end. A box of ring terminals would have been nice but I just assembled the harness as I went, twisting the ends together and securing with the nuts on the terminals. Worked fine, all my mods read 7.84 across the board after a few hours wired up. After sitting overnight with the harness removed, my voltage variances were negligible, +/- .01 volt. Be very careful removing the harness as well, dont have your beer till your done haha! Oh and btw... my charger said it was capable of up to a 15 cell module I think. There was no setting to select 6 cells. Just set all your other setting and it should be fine. It'll take sometime with a single charger but I had 10 more modules than you so I got the 4 port charger.

 

I got 2 of the DC6 chargers but if it takes 1 and half days for 2 modules it is going to take awhile . Not sure if I want a Hitec 4x charger because then I will need a power source also but I might get a little impatient

 

This charger will do 4 at a time for $109.95 and free shipping.

Thunder T6 Multi-LiPo Battery Charger (4X 6-Cell) Professional Balance Charger/DisCharger w/ LCD Display

with two of theses you could balance a pack in about a week.

 

The Hitec x4 AC Plus has it's own power supply, you just plug it into the wall and start cycling.

TowerHobbies.com |Hitec X4 Plus AC/DC Charger

The zigzag harness is a big waste of wire IMHO, alot easier/simpler to just do something like this (see below).......ring/spade terminals should really be used so you get a solid connection and don't run a chance of stray wires shorting on nearby terminals. Having a good harness also helps if you need to balance multiple times (you can get a box of 50 spade terminals at Home Depot for less than $10). Also if you connect them wrong it won't damage the modules but you will see big sparks (ask me how I know).

 

That Picture of how you connect them all together is genius I would have zig zagged all over the place and used up 5 times the amount of wire . I already have some speaker wire but will buy some spade terminals thanks for the picture

 

You have a good charger, and you're doing fine. Its all a matter of situation to justify a 4 port charger. And the hitec x4 ac has its disadvantages for me, I have limited abilities with my power outlets and amperage. I could have bought the x4 ac, but would have likely woken up to a popped gfi outlet or a breaker. I knew ahead of time that I had to run a 12v setup. It worked fine, prius 12v battery was never below 70%, it was connected to an automatic charger, and I never had to worry about a popped gfi or breaker to mess up my cycles etc... I got impatient even with the x4, but couldnt justify 2 of them. I then would have needed a larger 12v battery, and the further investment should be reserved for those who are doing this more regularly... I.e. own more than one prius, have prius friends, or run a service etc..

 

Wish I would have thought of this!

 

Update. Battery is in, pulling no codes. Test driving tomorrow. Prior to this, codes showed up within 10 seconds of starting. Running without ICE, goes into gear rolls back and forth on electric and still throws no codes. True test will come once its driven at speed for awhile. Fingers crossed for tomorrow

 

Done with my first 2 modules . Number 17 near the middle of the pack didn't do so well
Discharge 1 3355 Discharge 2 4951 Discharge 3 5527
Charge 1 6693 Charge 2 7086 Charge 3 7183

Module 1
Discharge 1 4333 Discharge 2 5733 Discharge 3 6189
Charge 1 7479 Charge 2 7500 Charge 3 7500

Guess I will need to try a few more on module 17 to see if it recovers more .
The car use to be a pharmacy delivery car so I think it had a rough life and was at 160K miles .

 

Those modules don't look that bad at all. I would buy more chargers and keep cycling any modules returning less than 6000 mAh until they don't improve anymore. Then you'll need to decide what your minimum acceptable capacity will be (keeping in mind the battery is only as good as its weakest link) and then get replacement modules for any that are too low. I used 6000 mAh as my minimum but that doesn't mean that lower minimums won't work too (I would never go less than 5000 mAh under any circumstances though). Then run a load test on them all and again replace any that aren't keeping up. Then balance the pack and reinstall.

 

X2
My numbers were way lower. I would have loved to see numbers like that, and they are improving each cycle, mine were sometimes not.

 

Update: 20 miles driven so far, climbed to 40mpg avg after reset and the 20 miles. These were city miles as i didnt want to hit any highways yet just in case. No codes or warnings! Seems to be fine, ill keep driving it and hopefully nothing shows up. The pack is degraded as far as capacity but oh well.

 

As long as the modules all passed the load test and are within a reasonable amount (capacity wise) it shouldn't throw any codes but you will obviously see worse MPG than you would with a pack that had better average capacity. So if and when you get your new pack set up, you should see operation pretty much the same except a favourable improvement in fuel economy afterwards.

 

Thanks, im gonna drive it this weekend and try to stress test it and see what happens. Heading to the mountains, ill report back with avg mpg after the weekend.

 

I have a O8 Prius with 265k miles which at some point soon I think the battery will need attention. I have bought 2 battery assemblies with which I hope to learn on. I have a IMax B6 which I am confused after reading the manual. I cannot switch from man to auto. When I try charging for the longest time it would shut off at 3min 15sec regardless of the amp setting. This morning I turned the 12 volt power off and when I turned it back on it charged for 131 minutes at 1 amp to about 8.65 volts. When I tried to do the dis/chg cycle it went thru 3 cycles in just about 2/3 hours. I think the charge time was at the 3 1/2 min so the mod wasn't getting charged. What should the settings be on the charger. Amp discharge to what voltage and the amp charge? I appreciate any help I can get.
I also have an 07 Prius with 372k miles which was a taxi and Toyota replaced the battery in it at about 300k miles.

 

5AH is too high threshold. 3 year old Prius with 160K ODO can easily reach that number (see DOE tests for details, link on my page) The more capcity the better of course, but even 2.7Ah with identical discharge curves were working in NHW-11. 4.5 was working in 2009 NHW-20 model.

 

I don't use the Imax, but I know I had a bit of trouble figuring out how to set the Auto on the Thunder T6. I bet its the same.... What I did was get to the frame where you see the "MAN" indicator. Press start to allow the charge number indicator to blink continuously. Then press the two middle buttons simultaneously (inc and dec). This will change manual to auto
Hope this helps!
Jessica

 

Kiwi- I would like to check out your DOE tests link, but I am not seeing it. What page are you referring to?
Thanks,
Jessica

 

Here's the whole list of all the vehicles they tested:
Advanced Vehicle Testing Activity: Hybrid Electric Vehicle Testing Reports

Here's the 2nd gen Prius:
http://www1.eere.energy.gov/vehiclesandfuels/avta/pdfs/hev/batteryprius1052.pdf

Kiwi, I'd still stand by my statement (5000 mAh as the lower limit when doing a good rebuild) if you are looking to maximize your fuel economy and hopefully not touch it again for a long time, but of course you can run much lower average capacities. danahurling has already proved here in this thread (averaging less than 2000 mAh) it can certainly be done assuming the modules are all load tested and well matched. The way a vehicle is used and the climate the packs operate in will dictate alot of how well they will fare over time (places with cold winters tend to be the most likely to recover most of their capacity when cycled, jdenenberg showed this earlier too). A good example is my Highlander which had gone well over 220K when the pack was serviced and ALL of the modules (even the "bad" one) recovered to over 6000 mAh while the DOE test shows I should have gotten less than 4000 mAh. So indeed you need to temper your expectations depending on where you live and how the vehicle has been driven.