{"product_id":"12v-load-energy-budget-worksheet-pdf","title":"12V Load \u0026 Energy Budget Worksheet PDF — Measured Draw, Duty by Regime \u0026 Autonomy","description":"\u003cp style=\"font-size:1.05em;line-height:1.7;\"\u003e\u003cstrong\u003eThe figure on the data plate and the figure on the shunt are not the same number — and the difference is never in your favour.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThe plate figure was measured on a new unit, at a bench voltage, in a laboratory. Yours is ten years old, at the end of a long cable run, through a connection that is not what it was. Across twenty loads that gap is the difference between a bank that lasts three days and one that lasts one.\u003c\/p\u003e\n\n\u003cp\u003eEvery load in this worksheet has a column for what the appliance claims and a column for what it actually drew. It is the single column nobody fills in, and it is why most energy budgets are optimistic fiction.\u003c\/p\u003e\n\n\u003cdiv style=\"background:#0A3F5C;border-left:4px solid #C5A059;border-radius:4px;padding:22px 24px;margin:26px 0;color:#F7F9FA;\"\u003e\n  \u003cp style=\"margin:0 0 4px;font-size:0.72em;letter-spacing:0.14em;text-transform:uppercase;color:#C5A059;font-weight:700;\"\u003eWhat you receive\u003c\/p\u003e\n  \u003cp style=\"margin:0 0 14px;font-size:1.25em;line-height:1.35;color:#FFFFFF;\"\u003eA seven-part worksheet built on measurement\u003c\/p\u003e\n  \u003cul style=\"margin:0;padding-left:18px;line-height:1.75;color:#DCE6EC;\"\u003e\n    \u003cli\u003e\n\u003cstrong style=\"color:#FFFFFF;\"\u003eA 24-line reference page\u003c\/strong\u003e for the figures you transcribe from your own cells, monitor, inverter and data plates — including usable capacity, which is not rated capacity\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong style=\"color:#FFFFFF;\"\u003e28 loads measured at the shunt\u003c\/strong\u003e, plate figure beside measured figure, with the gap computed per load\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong style=\"color:#FFFFFF;\"\u003eA 16-session measurement register\u003c\/strong\u003e recording ambient temperature and bank state, because two readings without them are not comparable\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong style=\"color:#FFFFFF;\"\u003eThe same 28 loads across four usage regimes\u003c\/strong\u003e — at sea, at anchor, in harbour, laid up — with a daily total and an autonomy figure for each\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong style=\"color:#FFFFFF;\"\u003e14 logged days\u003c\/strong\u003e comparing what actually happened against what the budget predicted\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong style=\"color:#FFFFFF;\"\u003e6 calculation models\u003c\/strong\u003e and a parasitic draw register for everything still live with the boat switched off\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\n\u003ch3 style=\"color:#0A3F5C;margin:30px 0 8px;\"\u003eFour regimes, not one average\u003c\/h3\u003e\n\u003cp\u003eA fridge at anchor in thirty degrees and the same fridge under way on a cool passage are different appliances. A single averaged consumption figure is what makes people buy the wrong bank — too small for the Mediterranean in August, too large for a boat that mostly sits on a mooring.\u003c\/p\u003e\n\u003cp\u003eThis worksheet gives you four columns and four autonomy figures. The laid-up column is the one that surprises people: three weeks on a mooring with a bilge float, an alarm and an inverter on standby will flatten a bank that seemed generous all summer. Model B6 exists for exactly that.\u003c\/p\u003e\n\n\u003cdiv style=\"background:#F7F9FA;border:1px solid #E1E8EC;border-left:4px solid #A2803C;border-radius:4px;padding:20px 22px;margin:26px 0;\"\u003e\n  \u003cp style=\"margin:0 0 6px;color:#0A3F5C;font-weight:700;\"\u003eNot one published consumption figure. Deliberately.\u003c\/p\u003e\n  \u003cp style=\"margin:0;line-height:1.7;\"\u003eA table of typical draws copied from a forum is the single commonest reason an energy budget turns out wrong. Appliances differ by make, by age, by how they are installed and by how their owner uses them. You measure yours once, at your own shunt, and every calculation afterwards rests on your own boat.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003ch3 style=\"color:#0A3F5C;margin:30px 0 8px;\"\u003eHours, not switch positions\u003c\/h3\u003e\n\u003cp\u003eThe trap in an energy budget is never the current — it is the hours. A fridge is not on for twenty-four hours; it cycles, and the honest figure is total running time over a day. A windlass draws an enormous current for ninety seconds, which looks catastrophic expressed hourly and is a rounding error expressed per anchoring. The worksheet is built around getting that column right.\u003c\/p\u003e\n\n\u003ch3 style=\"color:#0A3F5C;margin:30px 0 8px;\"\u003eFourteen days that test the arithmetic\u003c\/h3\u003e\n\u003cp\u003ePart IV logs real days against the predicted figures. A budget that survives contact with fourteen days is a budget; anything else is arithmetic. And where the two diverge, the fault is almost always in the hours rather than the current — which is worth knowing before you spend four figures on more battery.\u003c\/p\u003e\n\n\u003ch3 style=\"color:#0A3F5C;margin:30px 0 8px;\"\u003eHow it completes the Electrical \u0026amp; Power set\u003c\/h3\u003e\n\u003cp\u003eThe Lithium \u0026amp; DC System Record covers what stores the energy. The Solar \u0026amp; Hydro Yield Record covers what generates it. This one covers what spends it — and model B5 turns the whole thing into the one number that decides how you live aboard: engine hours per day.\u003c\/p\u003e\n\n\u003ch3 style=\"color:#0A3F5C;margin:30px 0 8px;\"\u003eWho it is for\u003c\/h3\u003e\n\u003cul style=\"line-height:1.75;\"\u003e\n  \u003cli\u003eOwners sizing a new bank, or being quoted for one, who want measurements rather than assumptions\u003c\/li\u003e\n  \u003cli\u003eLiveaboards and long-distance cruisers planning for passages rather than weekends\u003c\/li\u003e\n  \u003cli\u003eAnyone whose batteries are flat after a few weeks away and who does not know what did it\u003c\/li\u003e\n  \u003cli\u003eOwners adding a watermaker, a freezer or air conditioning who need the real cost first\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3 style=\"color:#0A3F5C;margin:30px 0 8px;\"\u003eTechnical specification\u003c\/h3\u003e\n\u003ctable style=\"width:100%;border-collapse:collapse;font-size:0.95em;margin:12px 0 4px;\"\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;color:#0A3F5C;font-weight:600;width:42%;\"\u003eProduct ID\u003c\/td\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;\"\u003eAML-ELEC-2026-03\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;color:#0A3F5C;font-weight:600;\"\u003eExtent\u003c\/td\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;\"\u003e23 pages · 7 parts · 6 calculation models\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;color:#0A3F5C;font-weight:600;\"\u003eRegister lines\u003c\/td\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;\"\u003e180 across reference, measurement, regimes, observation and verification\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;color:#0A3F5C;font-weight:600;\"\u003eInteractivity\u003c\/td\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;\"\u003e780 live PDF form fields — 38 tick boxes and 742 entry fields\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;color:#0A3F5C;font-weight:600;\"\u003eFormats included\u003c\/td\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;\"\u003eA4 and US Letter, both fillable and print-ready, 23 pages each\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;color:#0A3F5C;font-weight:600;\"\u003eSystems\u003c\/td\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;\"\u003e12V or 24V, any chemistry, up to 28 loads — four lines unlabelled\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;color:#0A3F5C;font-weight:600;\"\u003eRequires\u003c\/td\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;\"\u003eA battery monitor with a shunt — the measurements depend on it\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;color:#0A3F5C;font-weight:600;\"\u003eOffline\u003c\/td\u003e\n\u003ctd style=\"padding:9px 0;border-bottom:1px solid #E1E8EC;\"\u003eNo app, no account, no connection required once downloaded\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch3 style=\"color:#0A3F5C;margin:30px 0 8px;\"\u003eWhat it is not\u003c\/h3\u003e\n\u003cp\u003eThis worksheet records, structures and compares figures that you supply. It publishes no current draw, no duty cycle, no depth of discharge and no consumption figure, and it reaches no conclusion about any installation.\u003c\/p\u003e\n\u003cp\u003eSizing a battery bank, a charge source or a circuit is qualified work. An autonomy figure computed here is an estimate built on your own measurements — not an assurance that any bank will last any particular length of time at sea.\u003c\/p\u003e\n\n\u003cp style=\"margin-top:26px;\"\u003e\u003cstrong style=\"color:#0A3F5C;\"\u003eInstant download.\u003c\/strong\u003e Your links appear on screen the moment payment clears, and arrive by email within a minute. They do not expire.\u003c\/p\u003e\n\n\u003cp style=\"font-size:0.9em;color:#5C6B75;line-height:1.65;margin-top:22px;border-top:1px solid #E1E8EC;padding-top:16px;\"\u003e\u003cem\u003e2026 Captain's Edition · Revision 1.0 · AML-ELEC-2026-03. Apex Marine Labs designs the organisational process behind good seamanship. Our documents record and organise; they do not replace a certified marine survey, an installation standard, or a qualified marine electrician.\u003c\/em\u003e\u003c\/p\u003e","brand":"Apex Marine Labs","offers":[{"title":"Default Title","offer_id":56016819159208,"sku":"AML-ELEC-2026-03","price":97.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/1161\/2072\/files\/apex-12v-energy-budget-01-cover_3b6b1f1a-ea9a-46c1-86f8-30646fc3b2f5.webp?v=1789774925","url":"https:\/\/apexmarinelabs.com\/products\/12v-load-energy-budget-worksheet-pdf","provider":"Apex Marine Labs","version":"1.0","type":"link"}