Gen II Prius Individual Battery Module Replacement

back at the battery rebuild
I have started cleaning the bus bars.
overnight soak in vinegar, wash with water in the morning, then light wipe with emery cloth

 

going to try a load test of the pack using my 2 replaced cells.
going to hook up an amp meter and then a few switches and then switch in different loads and see how the battery modules respond.
75 watt lights and baseboard heaters.
each baseboard has an 80 ohm resistance( probably pull 3 amps if my calculations are right).
will first discharge all modules to 6 volts one at a time.
Then connect them in series and charge the whole pack.
Then do a load test on the whole pack.

 

8 more modules to discharge to 6 volts.
Since I had purchased a spare hybrid battery, I have extra parts.
I decided to build a battery monitor for watching each bank while I charge and load test, before deciding to put the pack back in the car.
each meter draws about 18 mA across the block of 2 modules.
I will monitor at the same points that the prius does, so I hope to see any issues before I put it in the car.

 

finally discharged all modules to 6 volts individually with hobbie charger.
connected my home made bank monitor and connected my home made battery charger.
I will charge at .25 of an amp and see how well it top balances.

 

I'm surprised Toyota didn't use plated bus bars. Even the cheap Chinese electrical terminals have some kind of plating on them.

I noticed that the Dorman rebuilt batteries all have plated bus bars.

Good luck with your project

 

I think the corrosion inside the prius is excessive too.
I have disassembled 2005 Ford escape hybrid packs and they have no corrosion on them(well 2 anyways, maybe I was lucky).
I would think the vent tubes should take the vapours away when charging.
Maybe ford cells have a better recombining system for low overcharge.
But we have to work with what we have. I will be happy if the cleaned bus bars last another 12 years

 

I see what you mean. How many have you done?

I had my first Prius 10 years and never had a problem with the HV battery or I am the kind of person that would have jumped in there too.
It doesn't always work out for the best or save money, but I always learn something new and as a die hard DIY I am way ahead of the game.

 

This is my first Prius. I purchased it because it also has a plugin option on it.
We have 2 ford escape hybrids in the family, so I like hybrids.
I have never had to work on the Fords. But I did buy a couple of packs to work on a battery bank for an electric boat, and to have an understanding of the technology.

 

The Gen 2 only had some aftermarket plugin kits and the manufacturers are long gone. You may find some additional plugin advice in this forum.

Prius PHEV Plug-In Modifications | PriusChat

 

Thanks for the info.
One step at a time, I have disabled the plugin box, with help from the forums.
I want to make sure I have the stock parts working right before I try the extra's.

 

Since that forum is pretty well hidden I though I should mention it.

 

top balanced all banks to 17.0 to 17.2 volts
left cells rest for about 8 hrs - all modules from 16.4 to 16.1
ran a 9 amp load for 5 minutes - all modules from 15.5 to 15.1



currently running a .5 amp load to check capacity

 

after 8 hrs discharge .5amp load , banks 1 to 14
15.3 | 14.5 | 14.7 |14.6 | 14.8 | 14.4 | 14.0 | 14.7 |14.6 | 14.7 | 14.7 | 14.6 | 14.7 | 14.8
stopped there as large difference from bank 1 to 7 15.3 to 14.0
I read somewhere should not exceed 1.2 highest to lowest.
I have used a auto taillight to drop bank 1 to 14.5.
I am going to top balance again and try another load test.
I hope bank 7 will charge a bit more this time too

 

I hope I am ready to put the battery back in the car
I charged the pack to between 17.3 and 16.9 on all modules(forgot to take picture though)
17.3 was bank #1(left side)
let the pack rest for about 5 hours
then placed a 6 amp load on the pack.
after 10 minutes
15.5 | 15.2 | 15.3 | 15.1 | 15.3 | 15.1 | 15.2 | 15.2 | 15.2 | 15.3 | 15.2 | 15.2 | 15.2 | 15.3
after 15 minutes
15.4 | 15.0 | 15.0 | 14.9 | 15.0 | 14.9 | 15.0 | 14.9 | 14.9 | 15.0 | 15.0 | 14.9 | 15.0 | 15.1
resting for 10 minutes after tests
15.9 | 15.6 | 15.4 | 15.3 | 15.4 | 15.3 | 15.4 | 15.3 | 15.3 | 15.4 | 15.4 | 15.3 | 15.3 | 15.5

I have only replaced the 2 modules that made up bank 2.
It looks to me that bank 1 may be stronger then the other banks.
Would it look to be too strong, or should I be ok to put the battery back in the car?

Thanks for any opinions.

 

Plan on regularly rebalancing this pack.
That will help mask the I'm balances.
You may need to replace more modules as you go long. Time will tell.
Would be helpful if you had a way to monitor the pack while driving. That will give you a visual idea how quickly you pack begins to get out of whack again. Will also keep you from having to guess about battery health.

 

I have torque pro on my cell phone and an elm327 adaptor. I have setup a screen with the 14 banks voltages, Hi and lowest bank voltage, 3 temp sensors, current reading, fan speed and state of charge. I hope it updates these reading while I am driving. Before I removed the battery I was able to watch the battery voltages in my driveway, I didn't try while driving, because the car wasn't really roadworthy the way it was(bad cells, limp mode). I hope to get the battery back in the car and start driving it this week. I hope the pack stays within spec. I guess if the 2 first banks are too strong, I would need to use a 4 of my weaker cells I have left. I hope I don't have to do that.

 

Hi fellows,
It took me forever to finish this fully loaded thread, a lot of information from some highly DIYs professionals along with some business professionals guys.

a 106 pages thread is too much time consuming to finish, contains some unnecessary argument, fights and merchandise advertising but though I learnt a lot of procedures, tips, what is working what is not, also how to prevent a fail and thrilling success stories, all these remarks I have copied and planning to make a summary and publish it in a new thread so it well be easy for beginners like me to start with their projects (I hope).

Thanks to all

 

Update after putting the battery in the car.
I have used torque pro to watch the module voltages.
I have used the battery drain and fill process in reverse with the brake on.
battery drain at about 3 amp and charge at about 21amps.
my modules started within .5 to .6 of a volt from each other(max and min cells).
I have done this in the driveway for about a week, once a day or so.
Today everything seems to be within .3 of a volt.
I hope to transfer my insurance over to the prius now and do some road testing/driving to and from work
here is a screen shot from my phone with torque pro, I setup the screen to show all battery modues and a few other things.

 

Homemade! I like your setup. Any links on how you built it? Could you help with them?

 

Is there anyway to discharge the pack in series before doing the charge cycle DIY vs buying a grid charger? I built a insight grid charger in the past, is it the same idea? I'm ordered a bunch of AC6's to do my cycles with the battery out since im in no real rush to fix the car, and trying to figure out the cheapest most economical way to do this. I got plenty of wire, terminals, etc. I noticed that there is no guides out there to DIY a grid charger specifically for the prius as of yet.. just ones for the honda insight, any reasons why?