Table of Contents
Batteries
You will need batteries! Batteries are governed by section 1.8 in the official rules. consult there for the most up-to-date/official determinations about technical specs.
Generally, you'll be selecting either Lead-Acid batteries or one of the assorted Lithium Chemistries.
Lead-Acid batteries are tempting because they are free on the BOM, but they are heavy and have a lower energy density. They are generally discouraged for new builds if your aim is to drive half-competitively, but they are a fine option for getting a “baby's first kart” off the ground and on four wheels.
Lithium batteries are generally higher energy density, which means a lower overall weight on your kart. since Lithium is less inherently safe than lead-acid (risk of fire) you'll have to make extra sure that you know what you're doing when you get into building your own packs, manipulating others' home-brew packs, and charging or discharging either homemade or store-bought packs.
All chemistries which cost on the BOM are calculated in the same fashion, whether it's Ni-Cd/Ni-MH (not recommended due to poor energy density) LiPo/LiIon/LiFePo4, or other technologies: $0.06/Watt-Hour as calculated by: “Battery Sticker Amp-Hours” x Nominal Cell Voltage.
For Example, a 12S3P Chevy Volt pack of Lithium batteries, which contains pouches stickered at 15AH per pouch, calculates as follows:
15AH x 3 cells in Parallel (3P) = 45 AH per cell. 12 cells in Series (12s) * 3.7v nominal voltage = 44.4v 44.4v * 45AH = 1998 Watt Hours 1998 WH * $0.06 = $119.88 total battery cost on the Bill of Materials, regardless of how much you paid for it.
This value does not degrade over time (even if you bought your batteries a decade ago and they don't hold as much energy, the BOM is still calculated off the Sticker, not a measured actual AH)
Approved Battery Technologies
- Lead-Acid
- SLA
- Gel Cell
- AGM
- Ni-Cd
- Ni-Mh
- Toyota Prius
- Ford Fusion
- LiFePO4
- A123
- Lithium-Ion (Fire extinguisher required)