How much is enough?

Discussions on John Welsford Small Craft Designs FB page re battery life and power needs of handheld VHF radios opened the door to what I’ll call “Supplemental Power Supplies.” Small, particularly open, boats do not often, usually, have a ship’s power system - primarily because such small craft do not carry much in the way of electronics. (Yes, I know I am painting with a large brush and that last statement is a sweeping generality. And, yes, given what I am contemplating for Gardens may mean I should consider some elaborate ship’s power…)

What came up in the discussion were portable car jump start batteries. Twelve or fourteen years ago I used one of these to power a GPS, fish finder, and VHF radio on my 24’ Columbia Challenger sailboat in the California Delta. That device was about the size of a shoe box and would provide power for a long weekend of long days on the water. How I managed to forget about that device is a mystery to me…

A comment in the FB discussion stated that jump starters come as small as a couple decks of cards and provide enough power to charge handheld radios, smartphones, cameras and other small electronics. Obviously, the technology has evolved over the last 14 years or so.

Research, beginning with “car jump starters,” has taken me down a rabbit hole - there are so many such devices (car jump starters, booster batteries, battery packs, power banks, and more) ranging in size from toaster-sized jump starters with air compressors to cigarette lighter-size (think Zippo lighters) external batteries for cell phones and other small electronics. Of course, the capacity of these devices covers a wide range as well - as do the prices.

Another complication came about with responses to the question, “How to figure out how much battery capacity is needed?” Do a power budget - listing all the planned electronics and how much current they draw, was one approach. Find the largest battery you’re willing to haul in and out of the boat and plan your electronics around that, was another. A third was, Duration. How long you need power will color all other decision re electronics. So, more than one way to skin a cat…

In short, I am overwhelmed with the choices… On top of which, I don’t know much about electricity, 12V or otherwise. So, back to studying the basics… Maybe then I'll be able to answer, "How much is enough?"