Charging amps depend on the battery size and battery type. Most ATVs use sealed lead acid batteries, such as AGM or gel. Some high-performance ATVs may use lithium-ion batteries. SLA batteries usually have a charge rate of 10% of their amp-hour capacity. You can charge at higher amps - you just need to shorten the charge time. For example, a battery with a 10 amp-hour capacity would charge at 1 amp with a 12-hour charge time, or at 2 amps with a 6-hour charge time.
As a general rule of thumb:
- Lead acid: SLA, AGM, gel batteries - Use 10% Amp/hr (ex: 20 A/hr battery would use a 2 Amp charger).
- Lithium batteries - Use 35% Amp/hr (ex: 10 A/hr battery would use a 3.5 Amp charger)
