BatteryBlocs were born from my desire to Loop the USA on an electric bike. I needed a battery that I could service on the road. The present design is the culmination of years of failing forward. Suggestions for improvements are welcome.
BatteryBlocs are being used around the world in applications as diverse as underwater tugs, car stereo woofers, portable audio recording gear, emergency medical equipment, portable Ham Radios, electric wheelchairs, golf carts, trolling motors, power walls, and all kinds of homemade electric vehicles.
BatteryBlocs are made of 3d printed plastic. 3d printing at production speeds presently does not create smooth slick flawless parts. The parts have .6 mm printing ridges as the print head builds layers. In addition, there may be small printing artifacts and some tiny strings. Don’t expect the injection molded look. The parts are good looking in a 3d printed sort of way and durable and do the job. They are now printed from ABS plastic, the same plastic used in plastic drain pipe. BatteryBlocs can be made to accommodate almost any cylindrical cell. Contact me if you have a cell size not shown.
The neodymium magnets are fun to work with as they snap the cells in place. They are nickel plated for high conductivity and about the size of the positive terminal on an 18650 cell. They are highly magnetic and metal shavings will stick to them. Do not set a BatteryBloc in a box of metal filings! All magnets have a temperature at which they degauss- lose their magnetism. Neodymium magnets start degaussing at 80C or 176F and lose all magnetism at 310C or 510F. If your battery gets that hot, you have more serious problems!
Poor performance will occur if a magnet is missing or if two magnets are stuck together. Doing a magnet check is part of the assembly process.
The compression bolts are made of 6mm x 80mm nylon, as are the nuts and washers. 1/4″ x 3.5″ nylon bolts can be used too.
The plates the magnets stick to are called the parallel plates- as they connect cells in parallel, and the plastic pieces glued to them are called magnet retainers. The magnet retainers also serve the purpose of keeping the negative lip of the cell case from making contact with the positive parallel plate. Cell salvagers can leave the tabbing on, saving a lot of time.
Parallel plates are made of zinc plated steel for economy and corrosion resistance. People often ask why I don’t make them of copper or aluminum. The answer is cost, corrosion, and because the magnets won’t stick. Nickel plated steel or solid nickel strips are used in spot welded batteries, not copper, because you need resistance for spot welding to work. The zinc plating on the parallel plates is about 5% less conductive than nickel, plus the parallel plates are massive compared to the thin little nickel spot welding strips. And in conductors, size matters. Even the smallest 4P BatteryBloc will carry at least 50 amps of current. I have never seen an instance of cells putting out so much current that the resistance of the conductors caused the conductor to get hotter than the cells.
We start building any battery by putting a group of cells in parallel. A 10P1S battery blocs holds 10 cells in parallel to multiply amperage. The cells are then connected in series to multiply voltage. A 10P10S battery would be made of ten, 10P1S BatteryBlocs connected in series. BatteryBlocs do not work with odd numbers of cells in the parallel groups because of the 1 bolt for every 4 cells design. So, 3P, 5P, 7P batteries are out. Sorry! But 4P, 6P, 8P etc- sure.
BatteryBlocs are made to be reused. When your cells get old you replace them. Has a parallel group gone bad? Unbolt the battery and replace the cells.
BatteryBlocs have top tubes that allow 1/4 threaded steel rod or zip ties to be passed through to hold the Blocs tighter together. This is optional. You can use the same top tubes to bolt BatteryBlocs to a flat surface, like a sheet of plywood.
When you order BatteryBlocs you get the Blocs, the parallel plates with magnets and enough series connectors to connect your Blocs together to make a battery. You get two large-wire ring terminals with each battery- for the power wires. You also get small ring terminals for the balance wires. If you order a 10S battery you get 11, if you order a 4S battery you get 5, etc. Cells and balancers are not included. I do have links to those products throughout the website.
BatteryBlocs make a battery that is nice to look at. I think you will be proud of what you have built and want to show it off.