What battery should I get to run a 12V drywasher for a full day?

Answered by RV Parts Giant · Upland, CA · October 3, 2026

Short answer: Measure the drywasher's amp draw first, multiply by the hours you run it, add any pump, then plan to use about 80 percent of the battery's rating. For a typical day of a drywasher plus a recirculating pump that lands near a 100 amp-hour LiFePO4 battery; a small machine alone can run on a 40 to 60 amp-hour pack.

The honest answer starts with a number most drywasher makers do not publish: what your machine actually draws. Keene's instructions for its 12 volt mini drywasher only say a small motorcycle battery runs it for about four hours, and suggest a deep-cycle battery for several days. That tells you it is a modest load. It does not tell you what to buy.

Get the real draw

Two ways:

A clamp meter that reads DC amps, around the positive lead, with the machine running on real material, not empty.
A SmartShunt between the battery and everything else. It shows the current live on your phone and counts the amp-hours used across a whole day at the claim, which is the number you size from.

Do the arithmetic

Amps times hours, for each machine, then add them. If you run a recirculating pump, Rule lists its 1500 GPH bilge pump at 4.8 amps at 13.6 volts, close to where a lithium battery sits. Plan on the higher figure.

Load	Amps	Hours	Amp-hours
Rule 1500 GPH pump	4.8	6	29
Drywasher (example only, measure yours)	6	6	36
Total			65

Then divide by 0.8, because Victron rates its lithium cycle life at 80 percent depth of discharge. 65 amp-hours a day wants roughly 80 amp-hours of battery, so a 100 amp-hour battery covers it with margin.

Which battery

Victron Lithium SuperPack, 60 or 100 amp-hours. Drop-in LiFePO4 with a built-in BMS that disconnects on over-discharge, overcharge and temperature. The 60 Ah supplies 30 amps continuously and weighs about 16.5 lb; the 100 Ah supplies 100 amps and weighs about 23 lb.
Victron Peak Power Pack, 20 to 40 amp-hours. Self-contained, 30 amp output and its own car or solar input. Right for a small drywasher alone or a pump alone, not both for a long day.

Before you head out

Fuse the main lead at the battery: a waterproof 50 amp manual-reset breaker doubles as an off switch, provided the cable is rated for 50 amps. Keep the battery in shade; the SuperPack will not charge above 45°C (113°F), and a closed cab in the desert passes that within an hour. Our full guide covers solar recharge, wire gauge for long runs and the heat limits.