Choosing a go-kart battery
6 min Updated how-to
The battery is the most expensive consumable on an electric kart and the spec most listings describe worst. Four numbers tell you what you need: chemistry, voltage, amp hours and continuous discharge rating.
Lithium vs lead acid
| Lead acid (SLA/AGM) | Lithium (LiFePO4 / Li-ion) | |
|---|---|---|
| Cost for 48V 20Ah | $180-$280 | $450-$600 |
| Weight | 55-70 lb | 18-25 lb |
| Usable capacity | ~50% of rated | 80-90% of rated |
| Cycle life | 200-300 cycles | 500-2,000 cycles |
| Voltage under load | Sags heavily | Holds steady |
| Cold weather | Poor | Reduced but manageable |
| Cost per usable cycle | Higher | Lower |
Lead acid looks cheaper and is not, once you account for two things. You only get about half the rated capacity before damaging the pack, so a “20 Ah” lead pack behaves like a 10 Ah one. And it lasts a quarter as many cycles.
The weight matters too. Swapping 60 lb of lead for 20 lb of lithium on a kart that weighs 110 lb changes how it rotates, noticeably.
Lead acid is defensible in exactly one case: a low-budget first build where the up-front number is the constraint and you accept replacing it sooner.
Reading the specs
Voltage must match your controller and motor. Not close, match.
Amp hours (Ah) is capacity, and it sets runtime. Rough guide for a 48V adult drift kart:
- 15 Ah: 30-40 minutes
- 20 Ah: 45-60 minutes
- 30 Ah: 70-90 minutes
Drifting draws more than cruising, because you are holding the motor at high torque and low rpm for most of the session. If a manufacturer quotes runtime, assume it was measured cruising and knock 25% off for drift use.
Continuous discharge (C-rating or amps) is the one people skip and it matters most. A pack rated for 40 A continuous feeding a controller that pulls 60 A will sag, run hot, and trigger its protection mid-corner. Your pack’s continuous rating must exceed your controller’s continuous draw, with headroom.
BMS is the battery management system, and its job is to prevent over-charge, over-discharge, over-current and cell imbalance. A pack without a BMS is not a bargain, it is a fire waiting for one bad cell. Confirm it has one, and that the BMS current rating also exceeds your draw.
Connectors and serviceability
Look for a standard connector, XT90 or Anderson being the common ones. A proprietary plug means you buy replacement packs from one source at their price, forever, and it is the single best predictor of whether a kart is disposable.
Ask three questions before buying any kart or pack:
- Is a replacement pack listed for sale, with a price?
- Is the connector a standard type?
- Can the pack be removed without cutting anything?
Three yeses means the kart outlives its first battery. Any no means you are buying a countdown.
Charging habits that double pack life
- Charge after every session, even short ones. Sitting at low state of charge is what kills packs.
- Store at roughly half charge, not empty and not full, if the kart will sit for more than a couple of weeks.
- Do not charge a pack that is still hot from riding. Give it thirty minutes.
- Use the supplied charger. A charger with the wrong voltage profile will either undercharge the pack forever or overcharge it once.
- Keep it above freezing. Charging lithium below 32°F plates the anode and permanently reduces capacity. If the garage is cold, bring the pack inside to charge.
More detail on degradation and when to replace is in how long a pack lasts.
A second pack beats a bigger pack
If runtime is your constraint, two 20 Ah packs beat one 40 Ah pack for most people. You get the same total riding, a two minute swap instead of a four hour wait, a spare when one fails, and lighter individual units to carry.
This only works if the pack is removable and uses a standard connector, which is the argument for checking that before purchase rather than after.
Packs, chargers and connectors are listed on battery packs and chargers, and if you are starting a build, complete drive kits come with the pack, controller and charger already matched. Voltage selection comes first, and that is covered in picking a system voltage.