I saw MHZ is not offering any battery packs. Can anybody recommend where to buy lithium ion batteries for a powerful DIY electric surfboard ?
Hi Sammy, maybe you can advise on [email protected] (http://www.vefoil.com/). The VeFoil current drive project will need high performance batteries before it can have the best parameters in the world. But it will also matter with the shape of the impeller and nozzle.
It is necessary to use cells with small internal resistance to not heat up at high currents (i.e. for currents 20A to 30A). A good overview of battery cells 18650 and a shop suitable for purchase in the EU should be found here. They are used unprotected (protection provided by BMS) Li-ion battery cells.
Purchase caution to choose cell capacity. An increase in cell capacity by 20% means a roughly 100% increase in cell prices.
The economic is the purchase of cells with a capacity of around 2500-2600 mAh. If you do not care about money and require a longer run, you will have to pay for the cells with a capacity of around 3600 mAh.
Battery cells are connected serially-parallel using nickel sheets (nickel tapes or cut-out bonding plates can be purchased) and must not be soldered, but electrically point-welded. On ebay and aliexpress there is a wide range of BMS for different series of battery cells and different currents.
Reliable brands are Panasonic/Sanyo, LG, Samsung, Sony. Onean Carver uses Samsung INR18650-25R 2500mAh - 20A (12S-16P = 192 cells ~ 200 * €2.65 = €530 with VAT). The price of the whole battery is 4 times higher. Here is how the battery is overpriced because the manufacturer must have a much lower purchase price for battery cells.