Lithium or Tubular Battery for Solar: Which Should You Buy?

If your solar system uses its batteries every day, go for lithium. If the inverter only has to cover the odd power cut, a tubular battery is still the sensible, cheaper choice. It comes down to how often the battery gets discharged.

Side by side

When tubular is the right choice

• Power cuts are occasional. A battery that sits fully charged most of the week barely uses its cycle life, so paying for extra cycles gets you very little.
• Budget matters more to you than weight. Tubular is the cheaper way to buy a given amount of backup.
• Your inverter only works with lead-acid. Many home inverters are like that, and a new inverter adds to the cost of switching.
• You have floor space. A 48 V tubular bank weighs over 200 kg and needs a solid, ventilated spot.

When lithium pays for itself

• The battery is cycled every day. Hybrid and off-grid systems often discharge each evening, and at one full cycle a day, 1,500 cycles lasts about 4 years while 3,000 lasts about 8.
• Weight or space is a problem. One lithium pack weighs roughly a sixth of the tubular bank it replaces.
• Nobody is going to top up the water. Lithium needs no maintenance.

Check these before you switch

• The inverter has to support lithium. UTL sells lithium-ready versions, such as the GAMMA+ 3 kVA, 24 V.
• The voltages have to match. A 25.6 V pack goes with a 24 V system, and a 48 V or 51.2 V pack with a 48 V system.
• Keep to one chemistry per bank. Don’t mix lithium and lead-acid batteries on the same inverter.

What about SMF batteries?

Sealed maintenance-free (SMF) batteries save you the water top-ups, but they are built for shallow, occasional discharge, as in a UPS. For solar that discharges every day, pick tubular or lithium.