As said before, the LiTime (Ampere Time) 12V 100Ah lithium battery supports a maximum charging current of 100 Amps. But, to prolong the battery lifetime, a charging current in 20-50 Amps may be used.
It is recommended to use the CCCV charging method for charging the LiFePO4 Battery pack, that is, constant current first and then constant voltage. Constant current recommended 0.3C. Constant voltage recommendation 3.65. That is, 0.3C current charging during the constant current process.
Using a 50 amp charger, a 100ah lithium battery can be completely charged from 0% to 100% in roughly 2 hours. Using a 10 amp charger, it would alternatively take a 100ah battery up to 10 hours to be fully charged.
Most often it's a 0.5C rate, meaning the number of amps is equal to half of the battery's capacity in amp hours. For example, a 50Ah LiFePO4 battery will likely have a recommended max charge rate of 25 amps. For a 200Ah LiFePO4 battery, it'll likely be 100 amps.
A 100-amp hour LiFePO4 battery can take 2 hours to charge with a 50-amp charger. Charging time may depend on the used charger for your lithium batteries. For example, a 500AH battery needs 5 hours to charge with a 100-amp charger.
Desired Charge Time (in peak sun hours): 15
Turns out, you need a 110 watt solar panel to charge a 12V 100Ah lithium (LiFePO4) battery in 15 peak sun hours with an MPPT charge controller.
That's about 4¼ days. Based on my results, a 12V 100Ah LiFePO4 battery will run a 12V RV fridge for 3-4 days.
If you do fill your battery all the way up, don't leave the device plugged in. Instead, follow the shallow discharge and recharge cycle we just mentioned. This isn't a safety issue: Lithium-ion batteries have built-in safeguards designed to stop them from exploding if they're left charging while at maximum capacity.
The Charging Algorithm
We recommend a bulk and absorption voltage of 14.4 V. A float is unnecessary, since li-ion batteries do not leak charge, but a floating voltage under 13.6 V is fine. Here are a few FAQ videos that talk about charging LiFePO4 batteries.
A common LiFePO4 battery is rated at 100 amp hours and is roughly the size of a group 31 lead acid battery. These batteries are also rated as to their maximum discharge capacity. 100 Amps max discharge is common.
Battery current is described in units of C-Rate. For example, a 100Ah battery has a “C-Rate” of 100Amps. Thus to fully recharge a 12V 100Ah battery using a 12V/10A charger will take a nominal 10 hours if the battery is fully discharged.
Depending on the battery type and capacity, a 200-watt solar panel can charge 100Ah of battery capacity every 2.5 hours. On a sunny summer day with 7.5 hours of direct sunshine, a 200-watt solar panel can charge three 100Ah batteries, two 150Ah batteries, or one 300Ah battery.
In summary. If you have a 12 volt 100ah battery and you buy a 300w solar panel, it will only take you 4 hours to fully charge it.
Conclusion. * For 12V(12.8V) LiFePO4 battery, the recommended charge voltage is 14.4V, 14.0~14.6V charger is also accepted. 24V, 36V, 48V batteries or systems are multiplied by 2,3,4 times. That is 28.8V(28.0V~29.2V), 43.2V(42.0V~43.8V), 57.6V(56.0V~58.4V).
A lithium battery does not need a float charge like lead acid. In long-term storage applications, a lithium battery should not be stored at 100% SOC, and therefore can be maintained with a full cycle (charged and discharged) once every 6 – 12 months and then storage charged to only 50% SoC.
【LiFePO4 Battery + Dedicated Charger】Litime 12V 200Ah LiFePO4 battery can be efficiently charged by 14.6V 20A LiFePO4 battery charger in around 10 hours from 0 to 100% capacity, which takes only ½ the time of the traditional battery charger.
In order to fully charge a 12V LiFePO4 battery, a charger with a voltage of 14V to 14.6V is required. Most AGM battery chargers are within that range and they would be compatible with Canbat lithium batteries. If you have a charger with a lower voltage, it may still charge the battery, but it won't charge it to 100%.
A 12v lithium LiFePO4 battery fully charged to 100% will hold voltage around 13.3-13.4v. Its lead acid equivalent will be approximately 12.6-12.7v.
Large overcharge tolerance and safer performance
Continuous charging over 4.3V would either damage the battery performance, such as cycle life, or result in fire or explosion. A LiFePO4 battery has a much wider overcharge tolerance of about 0.7V from its charging voltage plateau of 3.5V per cell.
The most common causes for premature failure of LiFePO4 cells are overcharging and over-discharging. Even a single occurrence can cause permanent damage to the cell, and such misuse voids the warranty.
No matter what charge mode the battery is in, stop charging once the cell temperature exceeds the absolute charge temperature range. No matter what charge mode the battery is in, stop charging once the cell voltage exceeds the absolute charge voltage.
It is also recommended to store LiFePO4 batteries at about a 50% state of charge (SOC) or higher. If batteries are stored for long periods of time, cycle the batteries at least once every 6 months. Do not store batteries that are discharged.
So, with this information at hand, a common 100Ah-150Ah lithium battery of this type can deliver enough energy to operate a maximum of a 1000w inverter. When calculating the amp usage of an inverter, you take the output wattage of the inverter and divide it by the battery voltage, i.e. 1000W ÷ 12V = 83.33 Amps.
To charge a 100Ah lead-acid battery, you'll need a 3-6 watt solar panel. To charge a 12V 100Ah lead-acid battery from a 50% depth of discharge using a PWM charge controller and assuming 5 peak sun hours, you would require approximately 270 watts of solar panels.