Yes. It is possible to charge solar batteries with electricity. However, there are certain things that you should know before you charge solar batteries with electricity. 1) You will be charging the batteries from the local grid. You are not using it to run any equipment, but powering another battery will cost you more.
Most solar chargers used for charging batteries charges at slow rate: C/10 or 0.1C. For Li-ion batteries, the safe limit is up to C/2. This means that if a battery has a capacity of 10 Amps and its charging limit is C/2, you can charge the battery at a constant current of 5 Amps.
Batteries can be charged and discharged safely within their own specified C ratings. Most solar chargers used for charging batteries charges at slow rate: C/10 or 0.1C. For Li-ion batteries, the safe limit is up to C/2.
Whether you connect a solar array or grid supply, it doesn’t matter what source you use to charge your battery. However, you have to ensure that the appropriate voltage passes through the cable to recharge the battery in safe mode. Solar batteries are known for their slower discharge rate.
In fact, any battery or cell can be charged with the right type of charger. Solar batteries are simply rechargeable cells. The only important part of finding a backup charger for your solar batteries is identifying the type of cell you’re using and choosing an appropriate charger for that particular kind.
To charge your solar battery at night, you can utilize the electrical grid. However, it’s important to consider the cost difference between grid power and solar power.