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For Sale: Custom Battery Pack, 1008 Boston Electric Batteries, Charger, 28p36s. 3.7V, nominal 133V peak 151V, 19.5Kwh - $4000

1219 Views 0 Replies 1 Participant Last post by  jwolin
This is a completely custom, engineered battery pack for an electric car or another high-energy application. If someone wanted to do an electric super beetle conversion this would drop in exactly where the gas tank mounted. The unit is composed of 1008 Boston Power sonata 5300 cells (datasheet on cells can be found here: The battery pack only has 500 miles on it so most of the cells are nearly new (see below). Total capacity of pack = 19.5KwH. For reference on my VW bug I could get about 60 miles depending on conditions (I never tested it down to a critical level).

The frames for the modules were custom CNC'd and then each battery was hand-soldered to the bus bars such that there are 28 cells in parallel and 36 in series for a fully charged voltage of 151.2v. The soldering and assembly is top-notch and care was taken at every point to make a top-quality pack. Fans are mounted to the side to keep the battery cool and can be controlled from a tablet (see below)

Custom hardware was added to these BMS boards to make a BMS (battery management system) for the vehicle. Custom code (source code given upon purchase) was written to interface via Bluetooth to a tablet and custom software was written that gives real-time information on the status of the battery pack, charging details, GPS speed, and more.

A charger comes with the unit that charges the pack intelligently at either 120v or 240v (cable included) at up to 16amps (value set in tablet). The charger also acts as a DC/DC converter so when you are not plugged in and charging it converts the battery pack voltage to the required 12V (really 13.8v) for the onboard car accessories (headlights, radio, windshield wipers, etc). It's pretty trick and works really well!

The only downside to the pack is that two of the 28 battery cells have a few bad batteries in them (cell 11 and 12). This is the only regret I have in building this pack. All the cells were brand new with an exception of about 10 that were sprinkled into these two sagging cells. This only slightly affects the performance of the pack and could easily be fixed if the pack was disassembled and the cells tested and replaced. Replacement cells are reasonably priced and it would restore that 28 battery cell back to its fresh condition. The pack could run for years as is without problems.

The car was hit by an inattentive driver but fortunately, the pack was not damaged. It's waiting for a good home. I would be happy to do what I could to explain as much as possible. The ideal buyer would be someone who understands electronics (Arduino in particular) and loves to tinker. The tablet, batteries, and materials are worth far more than I'm asking, plus you get hundreds of hours of developed code and a giant jumpstart on that dream project of yours!

Green Circuit component Hardware programmer Electrical wiring Gas

Here's a link to a youtube video where I walk through how it looks right now so you can get a feel for the basic idea.
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