Is low power mode in iOS good for battery?

Solution 1:

Depends on what you mean by 'health.' If you mean time before you need to recharge, then yes - by reducing the background services, the battery will last longer until you need to recharge it. If you are really strapped for energy, turning on airplane mode or just shutting the phone off entirely until you absolutely need to use it.

However, if by 'health', you mean the number of charge cycles the battery will last, that should remain unaffected.

Solution 2:

Low Power Mode reduces the amount of power that your iPhone uses when the battery gets low.

When Low Power Mode is on, your iPhone will last longer before you need to charge it, but some features might take longer to update or complete.

https://support.apple.com/kb/HT205234