There are many regions in this word still lacks of electricity. While we don’t have insufficient on grid electrics, most of the house owner will select a solar energy system for the residential. A solar energy system is normally included PV panels, invertor, meters and also battery storage system. The battery storage system is obviously so important for on grid /off grid residential energy system. What is the voltage should we use? and how many powers we use set up for our house? Many people are getting confused from internet information. Here let’s make it easy understanding and make a best comigration for our personal residential battery storage system.
Select the right voltage
As we all know, in the market, there are many different voltages for solar battery storage systems. especially for home. But generally, we can find out it to low voltage and high voltage battery storage. Here we can list the most popular and its unique parts.
1.12v battery storage system
12v is most common voltage seeing from our Daly life. 12 volts is also a start voltage for home storage batteries. This will include 12v lead acid batteries and 12.8v lifepo4 batteries. 12v battery can easy to find in the market. the price is also very low compared with other voltage. As this voltage is very low, it will be the best choice for small power systems. For example, it can power your lighting system. Fan, TV. Our suggestion is not over 2000W. In this way, keep the battery discharge current as much lower as possible. People will say, what if I want a 5000W consumption for my house? Well, you should consider to use a higher than 12 v voltage system.
2. 48-volt battery system
As we all know. watt=Voltage*current. So, if the watt becomes higher. the voltage is not changing, then the current will be higher as well. Higher current will require much bigger wire for connections and if the wire not big enough, it will generate heat. This will waste a lot energy each day during we use the battery system. at the same time, it increases the risk of fire. It is easy to resolve this problem by increase the system voltage. and 48v or 51.2v are the best solution for residential small solar systems.
Basic calculation for example:
A. if we have a total 5000Watt applications (TV, fan, water heater, air-conditions). When we power on all of them. If we use a 12v system. 5000/12 volt=416.6A. This is absolutely too high as you can see.
B. While if we use a 48v system: 5000W/48 volt=104A. And this a very normal current. a small cable will handle this current.
Of cause, above information is based on off grid solar battery energy storage system. When people set up an on-grid system will be different. Because the battery system will have a limit on discharge power. If the power is exceeded, the on-grid power will mix up and support as well. And we don’t need worry about that. The hybrid invertor will manage all of them automatically.
Most popular energy storage
There are some major brands like Tesla Powerwall, LG and others. A majority style we can have two type.
1. Ground mounted battery system
A ground mounted battery system is normally formed by different battery modular. Like 2.5kwh a module or 5kwh a modular. There are many different styles, basically we have 19-inch battery rack system. 2.5U, 3U, 3.5U and 4U. Some you may find 5U batteries. These batteries modular will built in a BMS. and all of them connected in parallel to increase the system energy or capacity.
2. Wall mounted system
Many years ago, people select 12v lead acid batteries. As time goes by, lithium-ion batteries are developed. and there is a chemical name Lithium iron phosphate battery. The rated nominal voltage is 12.8 volt. This kind of batteries is under bulk production for EV industry from China manufactures. And thanks to that. Solar energy storage systems user is benefit from this now. Because of the widely application and bulk production. The price for lithium iron phosphate batteries is much more affordable. Some supplier offers 12.8v LiFePo4 batteries at equal cost with lead acid or AGM one.
5kwh or 10Kwh
People sometimes get confused, how much power do I need exactly. 5kwh is enough? Or I should buy 10kwh battery storage? Well, this will always be related to type of solar energy storage system you install.
On grid or off grid
As we know, off grid system will require discharge power from storage battery packs only. The discharge capability will be limited. If your total load is 8000W. obviously 5kwh battery is not enough.
While we use on grid system. The battery system could supply 5000W power, while on grid electricity will support 3000w. In this way. The system is works properly even it is 5000wh storage.
Load of applications
We always suggest use the battery in a healthy way, it will maximum the battery storage system\s service life. 0.5C is the best discharge rate. Of cause if you use it as 0.3C or 0.2C, it will extend the cycle life obviously.
The first thing we need considered is make sure the battery system can power on all of your applications. Then calculate your daily consume power. And the capacity of the battery should possibly cover a 24 hours discharge.
Generally, based on our actual life. 5 kWh battery system is suitable for small family like 1-2 person. While you have 3-5 person at home, you need to consider use a larger system like 10 kWh or 15 kWh or even higher.
Select the invertor
Invertor is important part in a solar residential battery power system. Besides the batteries. I think invertor is the most important part. It manage the battery system, grid AC power, meters, Solar PV Array. From some point of view. A invertor is the master for the system.
Consider high quality brand Invertors
Make sure your lithium-ion battery storage system is compatible with your invertor. There are many suppliers from China nowadays provide different type residential battery system. Especially for small 5kwh or 10kwh type wall-mount and rack mount system. A majority of them is not support the communication function, or even they provide communication port, but not able to correctly communicate with your invertor. So, before you make purchase, check out this with supplier in China. Provide the brand name, model No. what type of the communication port and protocols. In this way, it avoids the misunderstanding and waste your purchase investment. Normally there are RS232, RS485 or CAN2.0 available.
Coremax Residential Battery storage system Supported Invertor List:
SMA Sunny Boy，
NO.97 MaoyuanIndistry zone, ChuangPingDongguang city Guangdong Province China.
Coremax Technology company limited