Deep-Cycle Batteries

The deep-cycle battery is usually the most expensive consumable in any off-grid or mobile power system, and it's the component most often killed early by decisions made on the day it was bought. This pillar is the guide we wish every customer had read before their first battery purchase: what the chemistries actually are, what depth of discharge and C-ratings are, how to size a bank for a house or a campervan, and the safety and placement rules, including where AS/NZS 3001.2:2022 restricts lithium in habitable spaces.

A word on where we stand, because battery marketing in New Zealand is loud. Lithium is a genuinely excellent chemistry, lighter and denser than lead and far more tolerant of deep cycling, and we supply lithium chargers and DC-DC units with a lithium setting for those who run it. But our own battery range is predominantly AGM and lead-carbon, because for most NZ off-grid and RV jobs a well sized lead-carbon bank is the sweet spot on price and durability: lithium is dearer up front, it won't charge below freezing without heating or management, and it needs a BMS and a charge profile and voltages matched to it. And for applications that get only occasional use, AGM is the most economic choice. Where a shed, bach or boat isn't weight critical, lead-carbon usually wins on total cost. The right chemistry falls out of the application, which is what the guides below are for.

Each guide below takes one of those and goes into it properly. If you'd rather start from the hardware, browse the deep-cycle battery range, or send us a list of what you run and we'll size the bank with you.