Battery pack planner
Plan a custom battery pack with live cell lookup, pack sizing, runtime estimates, and BMS recommendations.
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Search by manufacturer or part number to prefill the core voltage and capacity fields. If your exact cell is missing, enter the datasheet numbers manually and continue with the planner.
This list is by no means exhaustive. If you have cells you'd like added, or find missing data for cells we do have, please email us or fill out a contact form. Cell database made possible and initially compiled by Wolf @ the SLS.com forums.
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These values drive everything downstream. Pull them from the datasheet or your own tested cells. The C-rate will be used down below at pack level calculations, so make sure you fill this section out.
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Set the series and parallel counts, then confirm voltage, capacity, and current before moving on. You can learn more about wiring batteries in series & parallel configurations in the context of a battery pack by visiting these posts.
If this is your first time planning out a battery pack, check out our guide on how to build an 18650 battery pack.
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Estimate runtime at a fixed load to get a rough sanity check before you build anything. For now this calculates battery life at a fixed load amount. For example, if you plan on running something that consumes 1000 W and your battery pack is 1 kWh you can now estimate the life of the battery at a given load in watts.
39.2 V – 58.8 V
Pack can deliver 6.0 A but load demands 25.5 A.
~36 min at 1000 W draw.
Target a 14S 30A BMS for this pack.
No matching BMS products found for this configuration.
Search "14S 30A BMS" on AliExpress →Not sure what to put here?
Based on your current planner inputs, this recommends a BMS and shows matching products you can buy. Keep in mind that you'll also need to add a BMS to your pack, so that will add to the overall cost and weight. Check out this post about choosing a BMS for your lithium ion battery pack.
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This estimates only cell weight and cell cost. BMS, structure, nickel, wire, and enclosure still add overhead. Keep in mind that you'll also need to add a BMS to your pack, so that will add to the overall cost and weight.
How to Use Our Battery Pack Calculator and Planner
Getting the most from this planner is straightforward. Start by selecting your cell from the database or entering specs manually — the fields auto-populate from our cell data. Understanding capacity (Ah or Wh) is key to interpreting the results correctly.
Choose the appropriate cells for your application before committing to a pack design. High-drain builds like e-bikes need cells with a high C-rate, while energy storage applications can prioritize capacity over discharge rate.
The pack configuration section lets you set how many cells in series and parallel. Series cells add voltage; parallel cells add capacity. Use the quick presets as a starting point if you're not sure.
Runtime is estimated at a fixed load — real-world performance varies based on temperature, cell age, and discharge curve. Use it as a rough sanity check, not a guarantee.
The BMS section pulls live product data from AliExpress matched to your exact series count and current requirements. Always size your BMS to handle the maximum current your pack can deliver under load, not just the average draw.