Best Type of Battery For Solar Storage

Best Type of Battery For Solar Storage
Best Type of Battery For Solar Storage

Interest in electricity storage is increasing quickly. It’s not all about living off the grid anymore. Storage helps resolve variability problems with renewables. Adding batteries into a grid-connected residential solar project also allows the array to keep supplying power to critical loads once the grid is down, instead of having to disconnect and extend from generating electricity. Storage can also help commercial consumers reduce peak demand charges, substantially reducing their energy bills. The need for storage grows as countries pass self-consumption legislation.

Batteries in solar programs have to meet the requirements of unstable grid energy, heavy cycling (charging and discharging) and irregular complete recharging. There is a variety of battery types fitted for all these unique requirements. Factors for selecting a battery include cost, cycle life and installation and maintenance.

As a few best practices when selecting batteries for a solar setup.


Solar battery technologies

Lead acid

Lead acid
Lead acid

Deep-cycle, lead-acid batteries are utilized in renewable energy and reliably used in off-grid applications globally for decades.

Price: Average deep-cycle, lead-acid batteries cost significantly less compared to lithium.

Many AGM batteries available in the market are mainly built for dual-purpose or standby programs like emergency backup, but not profound cycling. However, new deep-cycle AGM layouts have improved performance and total energy output making them a fantastic choice for renewable energy programs at a lower price point than capsules.

In actuality, VRLA batteries with added nanocarbon are more immune to sulfation, which may lead batteries to expire over time. The carbon melts sulfation and allows the battery to charge cycle and faster more than conventional lead acid. This makes it a good choice for applications where the battery is at a partial state of control, such as energy arbitrage or off-grid.

Replacement/maintenance: Many factors such as initial design and ongoing maintenance affect battery life so that it’s hard to put a timeframe on when the batteries will require replacement. Flooded lead-acid batteries must be refilled regularly because the electrolyte that completely submerges the battery discs evaporates during charging. The battery enclosure requires ventilation to keep hydrogen gas from accumulating to harmful levels.

AGM and gel technologies, however, are recombinant, meaning they logically convert hydrogen and oxygen to water and do not require maintenance. Because there’s no free acid inside these batteries, they may be installed in almost any position besides upside down. Since solar applications may be in hard-to-reach or remote places, the capability to set up the batteries and let them operate over long periods without maintenance is an advantage.

Disposal: Proper disposal of lead-acid batteries is vital since they’re toxic. Thankfully, the automotive industry coordinated to recycle lead early on. Sometimes, the electrolyte is cleaned, reprocessed and sold as battery-grade electrolyte. In other instances, the sulfate material is removed since ammonium sulfate and used in fertilizers. The separators are frequently employed as a fuel source for the recycling procedure. Old batteries may be returned to the battery retailer, automotive service station, a battery maker or other approved collection facilities for recycling.




As per a U.S. Solar Energy Monitor Report, lithium batteries would be the most common storage technologies, regardless of application. There are 3 different types: components such as in tablets and smartphones, cylindrical such as in power tools, and prismatic (that come in various shapes) for example as in electronic vehicles. Prismatic types frequently have corrugated sides, which create air gaps between adjoining cells and will aid in heating. The prismatic may have applications in solar energy storage, especially lithium ion phosphate (LFP) batteries.

Cost: Deutsche Bank analysts estimated Lithium-ion batteries at roughly $500/kWh in the end of 2014, but one manufacturer said it is closer to $750 to $950/kWh. Overall, they are more expensive than lead acid batteries. Part of the cost comes from having a battery control system to monitor both the voltage and temperature of each cell to prevent excessive charging and charging. A BMS is not critical for other technologies like lead acid because the inverter or charger control can take care of the battery charging regime. But some producers notice that, if sized correctly, lithium-ion cells can reduce the expense of peripheral devices like charge controllers, offsetting its high original price and decreasing cost-of-ownership.

Deliver more cycles within their lifetime than lead-acid. This makes them a good option for applications when batteries are cycled to supply ancillary services to the grid such as energy smoothing or frequency and voltage support. The most significant benefit lithium-ion provides for solar is its high charge and release efficiencies, which assist harvest more energy. Lithium-ion batteries also lose less power when idle, which is useful in solar installations in which electricity is only used occasionally.

Replacement/maintenance: Lithium-ion batteries May be lighter and more self contained than lead-acid batteries, therefore can be much easier to install and replace. They can be wall-mounted and located indoors or outside. They are solid, and thus don’t require refills or maintenance.

Disposal: Lithium-ion batteries can use organic or inorganic cells. Organic-based batteries are free of any toxins. Inorganic-based cells are much harder to dispose of. Inorganic Lithium-ion is toxic so it must be disposed of properly. Manufacturers Encourage recycling, but there’s often a price. Spent lithium-ion cells have little business value. Lithium-ion manufacturing entails lengthy preparation and purification of the raw material. In recycling, the alloy must go through a Similar procedure again, so it is often cheaper to mine virgin substance than.


Flow batteries

Flow batteries
Flow batteries

Redox flow batteries are emerging as another storage option. Lux Research reports that falling costs will cause a 360-MWh market in 2020, worth $190 million. Even the vanadium redox flow battery (VRFB) is the most mature technology in this area.

Cost: VRFB developers state that sourcing vanadium VRFB developers are developing methods to boost power density, and this will further drive down prices. Integrated power electronics manage the charging and discharging procedures, providing a very low cost-of-ownership. But the sophistication of stream battery chemistry often requires ancillary equipment such as pumps, sensors, control components and secondary containment vessels. This infrastructure takes up considerable installation space. However, one producer has eased the sophistication of ancillary equipment by adding all necessary components inside the container itself thereby offering a complete built-in solution.

The vanadium electrolyte doesn’t degrade over time; therefore they could last much longer than other technology. With other technologies, including more batteries is the only way to boost hours of storage. A benefit of VRFB structure is that it is possible to increase battery size simply by adding more electrolytes.

Cycling: VRFB programmers say the technology has No cycling limitations, and batteries may be charged and discharged entirely without impact on their lifespan.

Disposal: The recycled vanadium in flow Batteries is not poisonous and can be reused repeatedly for other functions, such as in making steel. Flow batteries feature an aqueous-based electrolyte that can’t Get hot or catch fire and thus are intrinsically safe.


Nickel cadmium 

Nickel cadmium 
Nickel cadmium

Nickel cadmium or NiCd batteries have been around since the early 1900s. Even though they may not have the energy density (the power) of other technologies, they provide long life and reliability without complicated management systems.

Price: Nickel cadmium is relatively cheap Compared with other technology.

Vented to permit gases to dissipate, they traditionally require some watering, but new layouts enable the gases to recombine to form water which makes the battery almost maintenance free. This, along with the capability to withstand extreme temperatures, makes these batteries ideal for off-grid programs in harsh environments. They have been utilized for storage in megawatt-sized jobs. .With a high cycle life, some companies guarantee a service life of around 20 years.

Disposal: Cadmium is a hazardous material. In Fact Europe restricts the applications NiCd batteries may be utilised in. Toxic Materials have to be removed before the battery is disposed of. NiCd batteries can be recycled, nevertheless. The cadmium could be extracted and reused in new batteries. The nickel could be retrieved and used to make stainless steel.


Choosing the right battery

Use a sizing calculator

Battery sizing is essential but often overlooked by users and installers. Batteries in PV systems are routinely undersized because of cost or since the system loads have been underestimated. It’s important that you know the customer’s power needs and correctly plan. Several internet calculators offered by battery producers and other software simplifies discovering battery capacity for load demands.


Consider cost of ownership

There are lots of factors that should be taken into account when determining the total cost of ownership within the life span of the battery.

  • Price: A battery with a low cost is always attractive, but if low price comes at the expense of quality and battery life, the need for frequent battery replacements can boost the cost on time. That is why it’s important to think about issues other than price when making the decision.
  • Ability: Battery ability is essential because it is a measure of the total amount of energy stored in the batterylife.
  • Voltage: The battery bank voltage has to be considered to ensure it matches the system requirements. The battery bank voltage is often dependent on the inverter specifications if installing a DC-to-AC system or by the voltage of the loads in a DC system.
  • Cycle Life: The most crucial factor is cycle life, which provides the amount of discharge/charge cycles that the battery can provide before capacity drops to a predetermined percentage of rated capacity. Batteries from various manufacturers might have the same capacity and energy material and be similar in weight. However design, materials, process and quality affect how long the battery will cycle.


Battery ratings

The nameplate rating on a battery will be the fully developed capability; therefore it may be misleading to check a battery immediately after it’s purchased because it may take around 100+ cycles for it to achieve its entire capacity. Beware of batteries that promise full capability at the time of purchase or those that reach full capacity after just a few cycles. Batteries with a 100+ cycle warm-up will always outlast those touting a high initial capacity.