Much appreciated, knew I can count on sound advice from S Keith.
Thank you

 

When I did mine I did the following to avoid having to rotate the whole assembly:

Place 2 sturdy chairs side by side about 3-4 feet apart. Then put two or three 2-by-4s across the chairs, wide enough apart to support the center part of the modules between the screws that are underneath the case, while still allowing access to the screws.
Place the battery case on the 2-by-4s, leaving the area where the screws are between the two chairs.
Now disassemble the case and remove the top cover. Then remove all the module screws from underneath.
There will be two screws holding the whole clamped 40 module assembly to the outer metal case. remove these two screws and then lift out the whole clamped pack and stand it on end as S Keith mentioned.

There will be foam tape across all the old modules. You can use a blade to cut it between the modules. Put new foam tape of similar size and foam thickness on the new stack of modules in same location as the old modules. This will help make sure the fan airflow goes through the modules and not through the sides on top.

 

Excellent advice. Makes perfect sense. Thank you Jaime, much appreciated.

 

Since the foam has been mentioned, I would like to prepare with new foam for directing the air flow after I install the new modules. What kind of foam is it ? Something I can get at a hardware store or have to order it ?
One side adhesive probably ? White, grey, closed cell, how thick ? How wide ?

Also, to clarify, when you both say, "stand it on end"...after removing it from the pack...stand it as in vertical with the with the width (face) of the bottom module as the base like a 3 ft tall tower and take it apart ? Just want to understand the methodology... it is not done horizontally on a table then....?

Thanks again.

 

Was hoping you'd chime in Jamie...

1/4 x 1/4" open cell foam weather stripping is typical. I've also used neoprene.


The clamped modules are captured at one end by flanges on the rods. You want to stand the pack on that end (3 feet tall). Remove the end plate at the top and remove/replace all 40 modules.

 

Got it Gents. Thank you.

 

One more thing I remembered:
Not sure how prone this is to occurring, but I read somewhere that you need to stop the whole stack from twisting when tightening the end bolts.

After stacking up the new modules and putting the top end plate, tighten the bolts snug by hand to hold it together. Then rotate it and place the module stack on a flat surface (as it would be in the battery case). Verify all the modules are aligned evenly and then torque the outer clamp bolts to the full torque spec (28 ft-lbs) in increments in an X pattern.

 

I don't really concern myself with it. The clamping force provides very little torsional resistance. I use an impact driver to tighten the bolts while it's standing vertically then lay it flat and tweak the corners if needed. The longer packs are actually easier. Any unevenness will be flattened out once the pack is installed and you've driven a mile. A twisted pack won't readily accept the bus bars, so if you can get the bus bars on relatively easily, you know the pack isn't twisted too much.

Just make sure the modules are properly nested to each other at their nub/dimple/shoulder features.

Also, people can do some really dumb things when they ship loose modules... Inspect every one of them for damage to the mating features between modules. if they get jacked up, the pack won't go together correctly at that location, and it can throw other stuff off.

 

Hello all,

Update on my installation.
Replaced all 40 modules with 2019 manufactured modules, all 40 of them this past Sunday. Your help with instructions was very valuable. Appreciate it.
Took 4 hrs, cleaned everything very well and reassembled. Went without a hitch.
Runs like a new truck. Huge improvement over the old battery condition. I am driving it more every day to give it a workout. No more DIC warnings, codes etc.
Still can't get to 30 mph on battery alone but got to 25...before it was 10-15 tops...These big trucks need a lot of juice..

Temps dropped quite a lot here- 19 F this morning - hope it warms up a bit so I can repeat the load test and see how it compares.
Until then, many thanks for all of the advice received.

Last question - for a new GM Hybrid coming off the line back in '12 and '13....What was the SoC that an owner would expect to see driving around town with a brand new GM battery and charging normally with engine assist and regen ?
I see 64-68 % now with the new modules - last 2 days of driving around town.
Should it get to 80-90% or that never happens even when new ?
Thanks

Marius

 

Glad to hear it. I don't know the specific range of the GM Hybrid, but higher isn't necessarily better. If the SoC is too high, two things happen: 1) the battery SoC may be too high to capture the kinetic energy safely thus causing loss of efficiency, and 2) even if there's sufficient battery capacity, high charge rates at higher SoC is stressful to the chemistry AND less efficient.

The Prius targets a 57-60% SoC. if you see it approaching the "limits" of 80 or 40 under normal conditions (not counting A/C use), it's a sign of capacity loss.

In short - the less your SoC changes, the better.