Possible modification to HV battery

Every pack is different... Some packs are stronger, some are weaker... The goal is to make sure all the modules perform equally. When doing reconditioning of individual modules my current rig can monitor the voltages of up to 5 modules as they discharge for 1/2 hour to 45 minutes. That's the most ideal time to find a module that drops off a cliff and has sudden voltage drop, possibly failing cell.

Though there's also many instances when batteries in need of reconditioning will lose lots of voltage quickly and then plateau in voltage while all the other modules eventually drain down to lower voltages than that one, which makes a suspect bad module turn into a pack's strongest module. Once reconditioning is done however, if that voltage drop is not due to a failing cell, the modules discharge at a much more steady pace that's equivalent to each other, which is the goal of rebuilding a healthy pack.

 

The ones on the ends, module #1 and #28 typically have slightly more... NiMH batteries do most of their self-discharging in the first 24 hours after a full charge, but sometimes depending on my workflow, I'll pull and add those self-discharge numbers days or even months afterwards.

One pack of Honda modules I worked on I got those numbers after more than 5 months / 4000 hours... That same pack when I first got it had sat in a garage for 5 years and voltages in those modules were down in the under 3v range and I took a very gentle path of light charge and discharge to revive them back to what some rebuilders have told me are some of the best numbers they've seen on a pack with that kind of history.

 

The ones on the ends, module #1 and #28 typically have slightly more... NiMH batteries do most of their self-discharging in the first 24 hours after a full charge, but sometimes depending on my workflow, I'll pull and add those self-discharge numbers days or even months afterwards. One pack of Honda modules I worked on I got those numbers after more than 5 months / 4000 hours... That same pack when I first got it had sat in a garage for 5 years and voltages in those modules were down in the under 3v range and I took a very gentle path of light charge and discharge to revive them back to what some rebuilders have told me are some of the best numbers they've seen on a pack with that kind of history.

 

Yes, you understand the concept... Rapid self-discharge, or more rapid than other modules, is one of a dozen different way to find a bad module before your dash lights find it.