Lithium vs lead-acid for solar storage
Both chemistries are used for solar storage. The choice depends on budget, cycle requirements and how deeply you discharge the battery.
Depth of discharge
Lead-acid batteries are usually discharged to around 50% of rated capacity to protect cycle life. Lithium-ion (LFP) batteries commonly allow a higher depth of discharge, so more of the rated capacity is usable.
Cycle life
LFP batteries generally deliver more charge-discharge cycles than lead-acid batteries of the same capacity. For daily solar cycling, this is the main reason buyers move to lithium.
Upfront cost
Lead-acid batteries have a lower upfront cost per Ah. LFP batteries cost more upfront but can be cheaper per delivered cycle over their life.
Safety and certification
For any lithium battery, check the cell chemistry (LFP is widely regarded as the safer lithium chemistry), the battery management system (BMS) protections, and whether the product carries the applicable Indian or international certification. If a certification is not yet issued, the seller should state that honestly.
APEX IONX is the residential and solar lithium (LFP) line of Natraj Energy Limited; APEX, Duracharge and Nextra are the lead-acid lines.