Megawatt RV
Plan my solar

Calculators / Battery bank

Battery bank

How much battery does my rig need?

Tick what you run, pick how many nights you want off the cord, and get a lithium bank from the same Vatrer lineup the original Megawatt calculator used.

How the math works
  • Daily use is the sum of the loads you ticked, in watt-hours (Wh) per day. These are the same load rows and numbers the old Megawatt widget used.
  • Trip use is daily use times the number of days.
  • Solar offset is solar watts × 4 sun hours × 0.75 × days. The 0.75 covers wiring, heat, and charge losses.
  • Storage you need is trip use minus solar offset. It never drops below one and a half days of use, and never below 1,280 Wh (one 12V 100Ah battery).
  • Voltage follows the peak watts of everything ticked: 12V up to 3,000 W, 24V up to 5,000 W, 48V above that.
  • The pick is the smallest Vatrer battery at that voltage that covers the storage. If none does, the biggest one is doubled up until it does.

Same formula and constants as the calculator on the previous megawattrv.com. This is a planning tool. Have a qualified electrician check anything you wire.

Try another tool

How many solar watts should go on the roof?

Daily use and sun hours in. Panel watts and pack counts out.

How long will my coffee maker run?

Any load, any battery. Hours of runtime.

What size wire should I run?

DC gauge, voltage drop, and fuse size.