Lead vs. lithium in off-grid
A battery, by definition, is a device that stores energy that can be converted into electrical energy. In this sense, all battery types can meet off-grid storage needs, but some are better than others at meeting today’s power demands and cycling schedules.
“Off-grid is less about batteries and more about use cases,” Norman said. “If you only do backup power, lead acid works. It’s not cycled regularly. It’s mostly just in preparation for power outages or failures. But for pay-as-you-go, It is better to use any lithium battery. “
Trojan AGM lead-acid batteries
Lead-acid batteries are great for occasional short-term backup needs. However, if someone wanted to switch power to take advantage of utility time rates or to avoid the grid for extended periods, it would require more frequent and deeper cycling than lead acid can provide.
“Lithium is changing off-grid,” Norman said. “You can still go off-grid with lead acid, but lithium is more efficient.”
It all boils down to the number of cycles the battery has and its depth of discharge – how many times the battery can be drained and how much power it can use. KiloVault also offers lead-acid and lithium-ion batteries as Jay Galasso, VP of Sales and Marketing, often explains Charging specifications for both chemical types.
“Off-grid solar systems require batteries that can be discharged and charged daily,” Galasso said. “A cycle might be to charge the battery during the day and then release the stored energy for use at night. The more the battery discharges, the more ‘Deepen’ loop. “
Lead acid batteries degrade more with each cycle. Lithium batteries are guaranteed for 10,000 cycles, and lead-acid batteries peak at 2,500 when discharged to 50%. Lithium batteries can be discharged to almost zero, or all the juice in a Lithium battery can be used in one battery. In cycling, lead-based batteries can only use half their juice before degrading faster.
Modern Off-Grid Setup Using Discover Lithium Batteries
“A lead-acid battery costs less for the same voltage and capacity but doesn’t last for multiple cycles,” Galasso said. “[Lithium-based] designs can use fewer batteries in a given application because higher charge/discharge rates result in lower initial costs.”
SimpliPhi Power was established in the early 2000s and is a lithium battery supplier. They know the value of lithium batteries in off-grid applications because its initial market is the remote power supply scenario.
“Lead-acid is a legacy product for off-grid use. This is the birthplace of the solar industry. In the early days, it was impossible to have a photovoltaic system without lead batteries,” said Sequoya Cross, Director of Global Sales and Business Development at SimpliPhi. “Why are we seeing more People extend to lithium: you can have the more usable capacity in a smaller space. You can pull them to 100% depth of discharge. “
Physical space is another reason lead-acid has fallen out of favor in grid-separated settings in today’s urban environment.
Today when someone wants to take their active home off the grid, that usually means they want the refrigerator to work at the same time as the computer, internet, TV, lights, and everything else. Just backing up an emergency load can’t be reduced any more, especially in some places. Like in California, life has to go on when the utility company shuts down the power. This requires larger battery capacity, faster-charging rates, and deeper depths of discharge – something lead acid cannot provide.
“Lead is dying off-grid. Lead acid can last longer but requires a lot of maintenance,” Norman said. “It doesn’t make sense to sell good lead when I can sell lithium for only 10% more. Lead still works in the automotive market, but on the solar and Fixed side, leads are dead. “