Lithium vs. Lead-Acid Batteries: Which Are Best For Solar?
Lithium Batteries vs. Lead Acid Batteries
Lithium Batteries in Kenya
Over recent years, lithium-ion batteries have rapidly grown in popularity and overtaken lead-acid batteries as the preferred option for home solar storage systems in Kenya and around the world. As the cost of lithium batteries decreases, they are also becoming a universally affordable option for people and one of the best power solutions!
In a nutshell, lead-acid batteries cost less up front, but they have a shorter lifespan and require regular maintenance to keep them running properly. Lithium batteries are much more costly up front, but they are maintenance-free and have a longer lifespan to match their higher price tag. Below we offer a more detailed side-by-side comparison of both options.
What are Lithium Batteries?
Lithium solar batteries are simply lithium batteries used in a solar power system. More specifically, most lithium solar batteries are deep-cycle lithium iron phosphate (LiFePO4) batteries, similar to the traditional lead-acid deep-cycle starting batteries found in cars.
LiFePO4 batteries use lithium salts to produce an incredibly efficient and long-lasting battery. Because these batteries are deep-cycle batteries, they are great for solar applications which experience irregular charging and discharging.
Below: 5kVa Power Backup System with 4.95kWh lithium battery, installed by PowerPoint Systems to power a server in Daadab. Lithium batteries come with 10 years warranty and have a lifespan of 15+ years!
Benefits of Lithium Batteries
1. Lifespan beyond 5000 cycles (equals to 10 - 15 years):
When you discharge a battery (use it to power your appliances), then charge it back up with your panels, that is referred to as one charge cycle. We measure the lifespan of batteries not in terms of years, but rather how many cycles they can handle before they expire.
Many see the price tag of lithium batteries and immediately walk away. However, one of the most important aspects to consider is how long they last. Normal lead-acid batteries can last anywhere from 200 to 900 charging cycles under ideal conditions with proper maintenance. This ends up being around 5 years at most with daily solar charging.
On the other hand, lithium batteries are known for lasting 5000+ charge cycles, translating to 10+ years of use. They come with a high investment but will last you years longer. Not needing to replace lithium batteries as often makes them one of the most cost-effective options for a solar power system battery bank.
2. Depth of Discharge
Discharge depth refers to how much overall energy capacity is used before recharging the battery. For example, if you use a quarter of your battery’s energy capacity, the depth of discharge would be 25%.
Batteries don’t discharge fully when you use them. Instead, they have a recommended depth of discharge: how much can be used before they should be refilled.
Lead-acid batteries should only be run to 50% depth of discharge. Beyond that point, you risk negatively affecting their lifespan.
In contrast, lithium batteries can handle deep discharges of 80% or more. Meaning that they feature a higher usable capacity.
Lithium batteries are more efficient. This means that more of the solar power you harvest is stored and used.
For example, lead acid batteries are only 80-85% efficient depending on the model and condition. That means if you have 1,000 watts of solar coming into the batteries, there are only 800-850 watts available after the charging and discharging process. The rest of the energy is lost in chemical reactions within the battery.
Lithium batteries are more than 95% efficient. In the same example, you’d have over 950 watts of power available.
Higher efficiency means your batteries charge faster. Depending on the configuration of your system, it could also mean you buying fewer solar panels, less battery capacity and a smaller power backup inverter.
4. Faster Charging Rate
With higher efficiency also comes a faster rate of charge for lithium batteries. They can handle a higher amperage from the charger, which means they can be refilled much faster than lead-acid.
Lead-acid batteries are limited in how much charge current they can handle, mainly because they will overheat if you charge them too quickly. In addition, the charge rate gets significantly slower as you approach full capacity. in some cases more than 2x as long as a Lithium alternative
5. Energy Density
The energy density of lithium batteries is much higher than lead-acid, meaning that they fit more storage capacity into less space.
As you can see in the picture above, it takes one lithium battery to power a 5kW system, but you’d need 8 lead-acid batteries to do the same job. When you take the size of the entire battery bank into account, lithium weighs less than half as much.
This is a real benefit especially if you don't have much space to work with. Lithium batteries can even be mounted on a wall as seen in the picture below.
Are Lithium Batteries the Best for Solar Power Systems?
Yes, lithium solar batteries outperform all other batteries when it comes to storing energy for a solar system. They’re more efficient, charge faster, require no maintenance, and last longer.
The efficiency comes from the very low internal resistance that allows the batteries to charge with minimal loss. This also means that they can discharge with minimal loss, so the energy in equals the energy out. When charging less efficient batteries, any loss is lost solar energy you cannot recover.
When you factor in these benefits, lithium solar batteries are a more cost-effective option than other battery types in the long run, despite their premium price tag.
Get A Free Quote.
PowerPoint Systems designs and installs lithium battery solar systems for institutions all over East Africa. Please fill out the form below to request a site survey/ a quote or to request for more information on Lithium Batteries. We will get back to you within 1 business day.
Solar System Installation at Nanyuki composed of 12kW Hybrid Inverter, 3 modules of 4.9kWh Lithium Ion Batteries powered by 3.6kW of Solar PV.
Why choose PowerPoint Systems?
At PowerPoint, we guide you through the entire process, providing transparent and honest advice about what you need and how to go about it. We will design a high quality solution that is built around your specific energy needs and our own highly qualified technicians will install it, protecting your home/business at every stage.
We strive to have a long-term relationship with our clients by offering the best after-sales services. We offer you a complete Annual Maintenance contract to look after your solar system (this is free of charge for one year after installation) and includes a 24 hour centralized online monitoring system and 24/7 customer care. We offer guaranteed warranties of up to 25 years!
We pride ourselves in having over 20 years of experience in the industry, over 10,000 systems installed and a team of highly qualified and dedicated engineers, technicians and electricians. You can trust that you are in good hands.
Above all, we know that good customer service builds a loyal customer. This is why we always prioritize our customer experience. We always strive to exceed your expectations with our products and services.
Talk to our Team
Our friendly, knowledgeable team are here to answer all your questions on lithium batteries.