DC vs AC — 12V or 230V?
When is 12V direct current enough, and when do you need an inverter for 230V alternating current?
DC is the battery's own language
The battery stores 12V (or 24/48V) direct current. Appliances built for 12V — cool boxes, LED lighting, USB chargers, water pumps — can be connected directly without conversion. That is the most efficient route, because nothing is lost in an inverter.
AC is for household appliances
Anything with an ordinary mains plug wants 230V alternating current. To run it from a battery you need an inverter. A typical pure sine wave inverter is around 85–92% efficient — so roughly 10% of the energy disappears as heat.
- Pure sine wave: required for sensitive electronics (computers, CPAP machines, some motors)
- Modified sine wave: cheaper, but can interfere with electronics and cause a hum in speakers
- Inverter-charger: combines an inverter and a shore-power charger in one unit
When do you need an inverter?
- Induction hob → yes (no 12V version exists at a sensible power level). Microwaves and kettles do exist in 12V, but the 230V versions are more common and cheaper.
- Coffee machine, hairdryer, vacuum cleaner → yes
- TV, laptop, phone charging → usually run straight off 12V via USB-PD or a 12V adapter
- Cool box → pick a 12V model, far more efficient than a 230V fridge through an inverter
Cable size matters
At low voltage the current is high for the same power — and thick cable is needed to avoid voltage drop and heat. 1000W at 12V is 83 A (which needs 25 mm² cable over one metre). The same power at 230V is 4.3 A, where 2.5 mm² is plenty.
Current (A) = power (W) / voltage (V)