Battle of the batteries: lithium-ion or lead-acid?
Renewable technologies are advancing at lightning speed.
We can now generate our own electricity using solar panels at home and store any surplus power for later use using batteries. But with so many different technologies available, how do you know which one to choose?
The most common types of battery used in solar PV installations are lead-acid and lithium-ion and each has its own set of merits and pitfalls.
Lead-acid batteries have existed since the 1800s, meaning it is a tried-and-tested technology used by millions worldwide. As such, it is a trusted form of energy storage with little risk or unknown variables.
When sized and installed correctly, lead-acid batteries are safe and reliable with a design life of up to three years at under just 50% DOD operation. Their widespread use also means they are easy to recycle. They also do not have a cut-off point when the battery reaches a certain depth of discharge (DOD), allowing them to provide power during emergencies.
Compared to most other storage technologies, lead-acid batteries have lower upfront costs. However, this lower price point is somewhat outweighed by the cons of the lead-acid battery.
Firstly, lead-acid batteries are large and heavy. While this is not a catastrophic issue for any large-scale stationary installations, the scale and weight of lead-acid battery banks mean a substantial amount of planning needs to go into how they are stored. What’s more, these batteries require plenty of ventilation and airflow to prevent them from overheating and so that any trace gases can escape during charging.
In addition to their size and weight, lead-acid battery banks have a fixed capacity once installed, meaning extra units cannot be added to the system retrospectively.
Lead-acid batteries also need to be charged fully to prevent serious damage to the battery’s life. However, it can take up to four hours to charge a lead-acid battery fully.
Another downfall of lead-acid storage solutions is that they should not be discharged to a depth of more than 30–40% daily. If a deeper discharge occurs regularly, the battery life will be reduced significantly.
Lithium batteries rely on more modern technology than their lead-acid counterparts. Developments within lithium battery technology take place often as researchers look for ways to boost their efficiency when used in renewable energy systems.
Compared to lead-acid, lithium batteries are typically much smaller and lighter owing to their higher energy density. And despite being roughly 30% smaller, they offer a far higher DOD. Their compact size and lighter weight offer users much greater flexibility when sizing a system — particularly as you can install additional lithium batteries at a later stage.
Lithium batteries offer outstanding efficiencies of up to 98% and usable capacities of up to 100%!
These batteries can be charged in as little as an hour and are designed to be discharged up to 90% of the battery’s total capacity. Their ability to be discharged over 70% regularly means they are ideal for daily cycling applications without affecting the battery’s life. Lithium batteries only start to degrade when the DOD reaches 60%, and recent improvement in their technology enables nearly 100% DOD without extra damage to the battery.
Additionally, most lithium batteries come with a battery management system (BMS): an excellent protection feature that monitors voltages and temperature and can shut down the battery if it gets too hot.
However, it is worth noting that lithium batteries are more expensive to purchase upfront.
All the perks when you choose Pylontech
Pylontech offers a variety of high-quality lithium batteries for both residential and large-scale commercial solar storage applications.
For residential systems, we recommend the Pylontech UP5000.
The UP5000 is a mid-range 48V battery with a five-year warranty and is perfect for daily use in the home. This battery offers a 0.5C charge rate and 4,500 cycles at 95% DOD. You can also parallel up to 16 units for larger installations.
For larger systems, the Pylontech Powercube H2 is the perfect solution.
This product is the ultimate commercial storage solution, offering flexible configuration options for easier installation, maintenance and expansion. Up to 18 batteries can be configured into a single group, and you can link up to six groups in parallel. The Powercube H2 also supports over 6,000 cycles at 0.5C operation rate and 90% DOD. Additionally, these batteries come with an incredible 10-year warranty and are compatible with inverters from Solis, BME and ATESS.