36 V, 48 V, 52 V, 60 V or 72 V — how to choose, and what each one needs

Short answer: the housing does not care what voltage you run — it cares about the cell count and the size of the BMS. So the voltage does not narrow down which case you need. What it does change is how many configurations are still possible: 10S allows eight parallel counts in our range, 20S allows four, because a 72 V pack is already big before you add any parallel groups.

The five voltages side by side

“Configs” counts the parallel counts we can actually build for, at least two housings each. “Largest” is the biggest housing ceiling in that cell format.

What each voltage is for

36 V (10S) is the older standard and still common on city bikes and folders. It needs fewer series cells, so every configuration is smaller and the housings are easier to fit. If range is not the priority it is the simplest build.

48 V (13S) is what almost everything is now. Conversion kits, most new bikes, the widest choice of controllers and chargers. It is also the voltage with the most moulds aimed at it.

52 V (14S) is a 48 V system run one cell group hotter, usually to get more speed out of the same motor. It costs you one more series group, which is one more cell in every parallel branch, so the pack is roughly 8% bigger for the same capacity.

60 V (16S) is the point where the pack starts being the constraint rather than the frame. Six parallel counts are still buildable; beyond that the housing ceiling runs out.

72 V (20S) is a performance build. Twenty cells in series means even a 3P pack is 60 cells, so only four parallel counts fit at all. If you are going here, the housing choice follows the pack rather than the other way round.

Every configuration at each voltage

36 V — 10S

At 3.6 V per cell, 10 in series gives 36 V nominal and charges to 42.0 V. 8 parallel counts are buildable in our range — the largest housing takes 200 cells, which is 10S20P at the ceiling.

• 10S3P — 30 cells, 10.5 Ah on 18650
• 10S4P — 40 cells, 14.0 Ah on 18650
• 10S5P — 50 cells, 17.5 Ah on 18650
• 10S6P — 60 cells, 21.0 Ah on 18650
• 10S7P — 70 cells, 24.5 Ah on 18650
• 10S8P — 80 cells, 28.0 Ah on 18650
• 10S9P — 90 cells, 31.5 Ah on 18650
• 10S10P — 100 cells, 35.0 Ah on 18650

48 V — 13S

At 3.6 V per cell, 13 in series gives 48 V nominal and charges to 54.6 V. 8 parallel counts are buildable in our range — the largest housing takes 200 cells, which is 13S15P at the ceiling.

• 13S3P — 39 cells, 10.5 Ah on 18650
• 13S4P — 52 cells, 14.0 Ah on 18650
• 13S5P — 65 cells, 17.5 Ah on 18650
• 13S6P — 78 cells, 21.0 Ah on 18650
• 13S7P — 91 cells, 24.5 Ah on 18650
• 13S8P — 104 cells, 28.0 Ah on 18650
• 13S9P — 117 cells, 31.5 Ah on 18650
• 13S10P — 130 cells, 35.0 Ah on 18650

52 V — 14S

At 3.6 V per cell, 14 in series gives 52 V nominal and charges to 58.8 V. 7 parallel counts are buildable in our range — the largest housing takes 200 cells, which is 14S14P at the ceiling.

• 14S3P — 42 cells, 10.5 Ah on 18650
• 14S4P — 56 cells, 14.0 Ah on 18650
• 14S5P — 70 cells, 17.5 Ah on 18650
• 14S6P — 84 cells, 21.0 Ah on 18650
• 14S7P — 98 cells, 24.5 Ah on 18650
• 14S8P — 112 cells, 28.0 Ah on 18650
• 14S9P — 126 cells, 31.5 Ah on 18650

60 V — 16S

At 3.6 V per cell, 16 in series gives 60 V nominal and charges to 67.2 V. 6 parallel counts are buildable in our range — the largest housing takes 200 cells, which is 16S12P at the ceiling.

• 16S3P — 48 cells, 10.5 Ah on 18650
• 16S4P — 64 cells, 14.0 Ah on 18650
• 16S5P — 80 cells, 17.5 Ah on 18650
• 16S6P — 96 cells, 21.0 Ah on 18650
• 16S7P — 112 cells, 24.5 Ah on 18650
• 16S8P — 128 cells, 28.0 Ah on 18650

72 V — 20S

At 3.6 V per cell, 20 in series gives 72 V nominal and charges to 84.0 V. 4 parallel counts are buildable in our range — the largest housing takes 200 cells, which is 20S10P at the ceiling.

• 20S3P — 60 cells, 10.5 Ah on 18650
• 20S4P — 80 cells, 14.0 Ah on 18650
• 20S5P — 100 cells, 17.5 Ah on 18650
• 20S6P — 120 cells, 21.0 Ah on 18650

Why the BMS is the real constraint

Whatever voltage you pick, the fitting problem is the same one. A 13S BMS is longer than the 10S board these moulds were originally designed around, and a 20S board is longer again. So a pack that fits on cell count alone can still fail to close, and it fails more often the higher the voltage goes. Allow roughly six cells of room beyond the pack. There is a longer piece on this in why your 13S5P pack will not fit.

Work out your own

The pack calculator takes any series and parallel count and returns the cell count, nominal voltage, capacity and watt-hours, then lists the housings that take it. If you would rather work from the configuration itself, the configuration index has a page for every buildable combination.