GPEV
A good BMS, or Battery Management System is one of the most critical components on your EV when it comes to performance and good battery life. An effective BMS can extend range up to 20% (depending on pack condition and age) and will extend the life of the average battery pack by 300%.
Our entry level BMS consists of two basic components. The first component is an electronic balancing system that actively works to keep the batteries in the pack balanced with each other at all times. If batteries are not held in balance during charging, weaker batteries are under-charged while stronger ones are destroyed by overcharging. This is a progressive and expensive problem that one-by-one kills the batteries in your pack. Electronic balancing allows the charger to accurately charge each battery, dramatically improving performance and battery life.
Unlike other systems, our balancing system is “always on,” working to balance the pack during discharge as well as charge. This allows stronger batteries to give weaker batteries some help, further extending the life of older batteries.
The second element to our BMS is the human interface. We use KJHall’s PakTrakr for this task, giving the driver detailed and very useful information about the individual batteries, the pack and the state of charge. The driver is notified of potential problems before these problems have a chance to damage the pack. The BMS’s balancing system combined with your EV’s “smart” charger will automatically correct 90% of the problems your pack may encounter, but when your intervention is needed, the PakTrakr will not only notify you, but in most cases give you exact, detailed information about the problem. You get instant diagnosis, saving dozens of hours of troubleshooting the “old way”.
Our BMS allows the users to replace failed batteries in the pack regardless of the age of the rest of the pack. Without a management system, new batteries placed inline with older batteries are quickly damaged by the charging system do the charge curve differences. Our BMS will balance the new battery with the conditioned pack and allow “hot swaps” as batteries fail; virtually eliminating the need to ever replace the pack as a whole. Now EV owners can use 100% of the life of each battery in their pack, translating into huge savings over the life of the vehicle.
The cost/return ratio of our BMS is ridiculous. Price for a basic BMS for a 72v system is $443.95. Figuring pack replacement cost at a conservative $1,500 + labor, the BMS saves the user in the area of $4,500 during the life of the first pack alone. This figure factors the average 300% lifespan the BMS affords plus the benefit of only replacing actual failing batteries once the pack does age. This does not factor in the many hours of diagnostic work the driver without a BMS will spend correcting the battery problems he will encounter during this time.
BMS Basics
As fast as EV usage is growing, there are many new drivers that are struggling with the associated learning curve and many drivers are not sure what they “need to have” as opposed to what is “nice to have.” Probably because BMS’ in the past were expensive, the systems themselves have historically been viewed as “nice to have” but not a necessity. I suggest that unless an EV driver has a burning desire to throw away $4,500.00 (or more) in the first 3 – 5 years and is not particular about how well the EV performs, this is no longer the case. Good BMS’ are so cost effective now that there is no good reason for not having at least the basic system.
A basic BMS
A basic BMS will consist of three elements.
BMS add-ons
The basic system above is the minimum recommended, but there are a number of plug-in enhancements available for the system that can improve the human interface portion of the BMS. As with most equipment, more information is better, and more instrumentation equals more information in an easier to understand format.
The Woodward Display
The stock PakTrakr Display affords the user access to a plethora of valuable information about pack condition, status and health. It is, however, small and the readings are abbreviated and somewhat cryptic. The Woodward after-market display takes the data collected by the PakTrakr system and displays it in a much larger easier to read format. It is recommended for those that want more information, faster, with less of a learning curve.
Woodward Display + Data Logger
This fantastic tool is identical to the display above, but adds a data-logging function that is captured on a standard SD card. This tool is the ultimate for anyone wishing to track battery usage data, and makes pack diagnosis virtual child’s play. In addition to it’s hard-mount use, no EV mechanic’s toolbox is complete without one of these in it.
Current Sensor
This add-on allows the PakTrakr to read, track and display current through the batteries giving you an amp meter.
ES1 and ES1R Serial Interface cable
This interface cable outputs data to any serial device such as a computer or Woodward Display. The “R” model has a memory feature for data storage.
Our goal is to make EV use as care-free and economical as possible. Our dedication to this mission has resulted in our systems being used world-wide in a huge array of EVs. Please contact us if you have any questions about our systems or how they might work in your application.
Purchasing
We work to keep all components and accessories in stock, and orders are normally shipped within one business day. Fast, online processing is available at www.shop.gpev.us
You can contact our sales staff at (541) 244-1418 or gpev@losthighway.us
Dealers / Volume Discounts
Provide your customers with the best possible EV experience. Contact our sales staff about volume discounts and purchase programs.