By comparison, Gel-filled VRLA has a higher internal resistance, which makes it less suitable for high-rate discharging common with UPS applications. It does offer advantages in terms of a wider operating temperature range (-40°C to +55°C) and extended design life.

This guide explains the different lithium-ion battery types. LiCoO2 and lithium polymer are appropriate for consumer electronics and have safety issues. However, LiFePO4 is the safe and reliable choice for a UPS since it is a very stable chemistry.

So to begin with, a nice easy way to check the health of your battery is looking at the state of charge indicator. This provides a snapshot of your battery's current condition. Green means it is charged and healthy, clear means it needs to be recharged, and red means it needs replacement.

Dry cells require very little maintenance compared to batteries with liquid electrolyte; therefore, for UPS applications, dry cells will be more practical. UPS sometimes suggests outdoor storage of batteries. If so, then water will have a higher freezing point than gels in dry cells.