Would a Prolong Charger deal with this issue?...

Just finished replacing a bad module in my HV batt, and so far is working great. I've noticed the new block pair is consistently running about a half a volt lower than the others however. I tried matching them by draining the two paired modules to the others using a headlight and multimeter before re-installing.

Here are some screenshots

block voltages before repair....
this is while draining the battery



block voltages after repair.....
while draining




voltage graphs before.... Note that all blocks filled up to the same top voltages during charging, but the one separated during exertion, like climbing a hill or rolling on the electr motor only.




voltage graphs after.... Here the voltage is uniformly lower, but seems to faithfully follow those of the others under most conditions.




1) Can the car be driven and used like this? Will this eventually even out as a result of the repeated charge/discharging cycles of normal driving?

2) or, Should I try to bump up those errant voltages using my single module balance charger?

3) If I bought one of those Prolong Chargers, would that device smooth out those voltage differences for me en-mass?

Oh, and 4) Can the Prolong be used to charge a battery pack that is not installed in a car? (I have a spare in the garage)?

 

Okay, so I bought the Prolong charger and automatic discharger set, hooked it up to the car and did the complete 3 cycle routine. Took several days. Finished up with a complete recharge and balancing, and the results are.... Block 7 still won't fall in line with the other blocks.

I also had to replace a module in Block 2, which is now working fine, and all block voltages converge very nicely during idle or steady state driving, but Block 7 will now over volt when charging (breaking, etc), and then undervolt while under load.

Unlike before the repair, when the voltage dropped off sharply when they were taxed, that block will merely drift higher in voltage, and then lower in voltage during the various load phases compared to the other blocks which appear more in lock-step (within a few tenths of a volt). Block 7 routinely drifts up about 1/2 a volt, or down 1/2 a volt or so, making it alternately the highest, and then the lowest block voltage outlier.

Other than that, the car drives fine, it's just not happy because the computer eventually throws the P3017 code, and then eventually goes into limp mode.

I tested both modules in Block 7 before replacing them in the pack, and they compared to others I randomly tested elsewhere in the pack.

Any ideas on this issue? Is this something another few hits with the Prolong would deal with?....Or is there some super subtle module issue I'm missing here?

 

Found Something curious!

With that one errant block, I've been tracking the voltages, and when I measure the module voltages and compare
them to the total block voltage, I find there is a discrepency. The total block voltage does not add up to the
two individual module voltages for that one block like they do for all the other blocked pairs. Under all
circumstances (car on/car off/car on with load applied); all the module voltages are matching each other all
within 0.1V of each other, however, even though the module voltages are matching, that one block voltage can be
off from the others by as much as the error I keep finding in my block monitoring app, and can be off by as much
as more than half a volt or so. So I start checking around that block and find I'm getting a voltage difference
across the big brass strap connecting the two modules of that block (see picture).





This voltage difference goes away with the car turned off or in accessory position, but comes back when I turn it
on and put it under load, like chocking the wheels and putting it in reverse. I get anywhere from .3V to more than
half a volt in the few simple tests I've put it through. It seems the more current I put through it, the greater
that voltage drop through the strap.

Can somebody tell me what's happening and how to deal with it? ....And can that be what is setting off my computer
DTC's?

 

What is the best way to clean the bus bars? Would sand blasting do the trick?

I used a small hobbyist's wire wheel on a roto-tool on them the first time, but I don't think it did
the job. I also did the faces of the terminal nuts. The posts of the modules themselves looked
pristine so I didn't spend time on them

Currently, the bus metal is shiny and polished, but still appears dark in color on some sections.

I

 

Got the acid and soaked the bus bars. There were stubborn dark stains that would not soak off, so I got a cheap rock tumbler and tumbled them in sand and water for an hour and that finished the job.

I then soaked the terminal nuts in a separate solution of vinegar and salt as I've read and seen on numerous YouTube videos, to get rid of the heavy crystaline deposits on them. While the soak worked, instead of getting shiny silver terminal nuts out the other end, mine turned all dark. I tumbled them to no avail, so I re-tumbled them in vinegar & sand this time. That got rid of the darkness, but turned them copper colored.
Are they still fit to use with this new copper color? If so, all I need to do is re-assemble the battery.