12V and 24V solar panel systems are still the most commonly used, but 48V batteries are becoming prevalent. If you want to buy a 48V battery, you have to use the right solar panel sizes and voltage to get the best charging time. Three 350 watt solar panels connected in a series can charge a 48V 100ah battery in a day.
The answer depends on how much power the solar panels have, how much sunlight is available, battery capacity and how fast you want to have the battery charged. A 100ah 48V battery holds 4800 watts, so you need solar panels that can produce at least that amount. 3 x 350W solar panels can charge the battery in 5 hours.
The duration to charge a 12V battery with 300W solar panels depends on the battery capacity and the solar panel current. For instance, at 6 peak hours and 25% system losses (efficiency is 75%), a single 300W solar panel can fully charge a 12V 50Ah battery in roughly 10 hours and 40 minutes. Let’s understand it in detail,
You need around 600-900 watts of solar panels to charge most of the 24V lithium (LiFePO4) batteries from 100% depth of discharge in 6 peak sun hours with an MPPT charge controller. Full article: What Size Solar Panel To Charge 24v Battery? What Size Solar Panel To Charge 48V Battery?
You need around 350 watts of solar panels to charge a 12V 120ah lithium battery from 100% depth of discharge in 5 peak sun hours with an MPPT charge controller. Full article: Charging 120Ah Battery Guide What Size Solar Panel To Charge 100Ah Battery?
You need around 1600-2000 watts of solar panels to charge most of the 48V lithium batteries from 100% depth of discharge in 6 peak sun hours with an MPPT charge controller. What Size Solar Panel To Charge 120Ah Battery?