expensive Batteries Hide Cheap Tricks
The trend of locked-down electronics and software is increasingly common across industries, contributing to a cycle of consumerism. While major players like automotive manufacturers and tech companies are well-known for this practice, some lesser-known companies are also adopting similar strategies. Recent analysis of Milwaukee M18 batteries suggests a potential cost-cutting measure impacting long-term performance.
as demonstrated in a video by Tool Scientist, Milwaukee battery packs may not actively balance the individual cells within the pack. Battery balancing is a crucial process that ensures all cells reach the same state of charge, maximizing battery life and capacity. While the battery management system (BMS) microcontroller is connected to each cell, data suggests this connection is used for status reporting rather than active balancing.
[Tool Scientist] rigorously tested this hypothesis. They intentionally introduced an imbalance into a battery pack and monitored the system thru several methods: observing i2c dialogue, measuring voltage drop across a resistor expected to activate during balancing, leaving the battery on a charger for 21 days, and conducting numerous charge and discharge cycles. Despite these efforts,the initial imbalance persisted,leading to the conclusion that Milwaukee batteries do not appear to implement cell balancing.
It’s possible Milwaukee resolute the cost of implementing balancing outweighed the benefits for the majority of users. The video was published nearly a year ago, suggesting potential improvements may have been made as then. However, given the increasing prevalence of revenue models focused on recurring purchases, a more critical viewpoint suggests this design choice could encourage users to replace batteries more frequently.This aligns with Milwaukee’s existing practices, such as making user repairs tough, as noted in a recent Hackaday article (https://hackaday.com/2023/09/15/reverse-engineering-the-milwaukee-m18-redlink-protocol/). The situation echoes similar concerns raised regarding the nissan Leaf’s lack of active thermal management in its battery systems (https://hackaday.com/2020/09/16/improving-more-leaf-design-flaws/).
This research was brought to light by tipster [Polykit].
