Quick answer
On the route this series recommends — high desert in summer, low desert from mid-October — a full-time rig running a Summit 2 12V pencils out to an estimated ~65–155Ah a day in winter, ~85–245Ah in spring, ~170–245Ah from June through August (roughly 350–445Ah on a day that ends in a hot night), ~115–240Ah in September and ~65–215Ah in fall: arithmetic on the unit's 29A Eco and 21A Sleep draws plus the ~55–100Ah a day our watts guide budgets for everything else on the bus. On this arithmetic the 460Ah Power Hub covers that year with margin, the 230Ah covers winter, fall and early spring (through April) with a daily refill, and the 630Ah is for the full-timer who keeps hot nights on the calendar. Every figure is an estimate from stated assumptions, not a measurement; solar refill is a 600W array through the watts guide's formula on your own site's sun hours — a range extender, never a guarantee.
| Month | Where (route) | Typical day (monthly normal) | Cooling (hours × mode) | Heat | Est. unit Ah/day ‡ | Est. total Ah/day † | Solar refill, 600W (est.) | Bank |
|---|---|---|---|---|---|---|---|---|
| Jan | Low desert (Yuma / Quartzsite) | Yuma ~70/48°F | Off; fan 2 h (4.5A ≈ 9Ah) | Diesel; or, on Glacier Pro rigs, a dawn heat-pump hour (48°F is above its 36°F floor) — not both | ~9–55 | ~65–155 | ~145Ah (Yuma 3.6 h) | 230 + daily refill; 460 comfortable |
| Feb | Low desert | Between the Jan and Apr anchors | Off; fan 2 h (≈9Ah), or 1 h Eco (≈29Ah) | As Jan; dawn hour or Eco hour, not both | ~9–55 | ~65–155 | ~185Ah (Yuma 4.6 h) | 230 + daily refill |
| Mar | Low desert | Between the Jan and Apr anchors | 1–2 h Eco (≈29–58Ah) | Dawn heat-pump hour above 36°F (Glacier Pro rigs) on top of the Eco hours | ~30–115 | ~85–215 | ~240Ah (Yuma 6.0 h) | 230; 460 margin |
| Apr | Low desert | Yuma ~86/60°F | 2–4 h Eco (3 h ≈ 87Ah); night off | None | ~60–115 | ~115–215 | ~295Ah (Yuma 7.4 h) | 230; 460 margin |
| May | Low desert, moving up | Past the Apr anchor | 4 h Eco (≈116Ah) + a Turbo pull-down on the hottest days (≈29Ah) | None | ~115–145 | ~170–245 | ~325Ah (Yuma 8.2 h) | 460 |
| Jun | High desert (Flagstaff, ~7,000 ft) | See the Jul anchor | As May | None | ~115–145 | ~170–245 | ~335Ah (Flagstaff 8.4 h) | 460 |
| Jul | High desert | Flagstaff ~82/51°F | As May; night off (cool nights) | None | ~115–145 | ~170–245 | ~275Ah (Flagstaff 6.9 h) | 230 tight; 460 right |
| Aug | High desert | Flagstaff ~79/51°F (Quartzsite ~107/81°F) | As Jul; a hot night adds the Aug 27 night (roughly 150–200Ah) | None | ~115–145 (~295–345 with a hot night) | ~170–245 (~350–445) | ~255Ah (Flagstaff 6.4 h) | 460; 630 if the night is on |
| Sep | High desert | Flagstaff ~74/43°F | 2–3 h Eco (≈58–87Ah) | Dawn heat-pump hour (Glacier Pro rigs) on top; 43°F is above its 36°F floor | ~60–140 | ~115–240 | ~235Ah (Flagstaff 5.9 h) | 230; 460 margin |
| Oct | Low desert from mid-month | Quartzsite ~89/60°F | 2–4 h Eco (3 h ≈ 87Ah); night off | None | ~60–115 | ~115–215 | ~205Ah (Yuma 5.1 h; Flagstaff 4.8 h early in the month) | 230; 460 margin |
| Nov | Low desert | Between the Oct and Jan anchors | Off; fan 2 h (≈9Ah), or 1 h Eco (≈29Ah) | Dawn heat-pump hour (Glacier Pro rigs) or the Eco hour, not both; diesel when a night nears 36°F | ~9–55 | ~65–155 | ~155Ah (Yuma 3.9 h) | 230 + daily refill |
| Dec | Low desert | Near the Jan anchor | Off; fan 2 h (≈9Ah) | As Nov | ~9–55 | ~65–155 | ~130Ah (Yuma 3.3 h) | 230 + daily refill; 460 comfortable |
Solar refill = 600W × 0.8 × NASA POWER monthly peak-sun-hours ÷ 12V (40Ah per sun-hour) at Yuma for the low-desert months and Flagstaff for the high-desert months — a 25-year satellite climatology (2001–2025), not your roof, and before the cold-morning charge delay; a day on the parked-sun row of §5 explains the formula.
† Total = unit + ~55–100Ah for everything else on the bus (the watts guide's typical-build range). Refill — drive, sun or pedestal — is §5. ‡ Summit 2 12V draws; a Glacier Pro rig's dawn heat-pump hour above its 36°F floor (§1) is ceiling-case, 1 h × 55A max ≈ 55Ah. The diesel heater's electrical draw is not published and not counted.
1. Spring (March–May): the cheap season, with one cold-morning catch
Estimated ~85–245Ah a day: 1–4 hours of afternoon Eco at 29A (≈29–116Ah), a half-hour Turbo pull-down on the hottest May afternoons (≈29Ah, this ledger's assumption), a dawn heat-pump hour above 36°F on Glacier Pro rigs (≤55Ah ceiling-case, March mornings only — the range is the rows' span, not a stacked sum), nothing overnight, and ~55–100Ah for the rest of the bus. An April day at Yuma (~86/60°F): 3 h Eco × 29A ≈ 87Ah for the unit, ~140–190Ah for the bus. A Glacier Pro rig has the Glacier Pro 12V as its one rooftop unit instead of the Summit 2; its cooling draws are 62A Turbo / 30A Eco / 22A Sleep, so add roughly 1A per Eco hour to the unit column.
Once the night is cool enough that bedding does the job (the shoulder-season post's day/night profile), the unit's night shift is over — a cool night is fan-only (4.5A) or a cracked window. The BMS suspends charging below 32°F, so on a frosty March dawn the refill waits until the pack warms while discharge continues; the cold-weather battery post owns the slow morning.
An ~85–215Ah March–April day is one a 230Ah bank can get through with a same-day refill — drive, sun or pedestal (§5) — on this arithmetic; a May day (~170–245Ah) is 460Ah territory, as the table says.
2. Summer (June–September): the expensive season, and elevation is the lever
Estimated ~170–245Ah a day on the high-desert route from June through August — 4 hours of Eco (≈116Ah), a Turbo pull-down on the hottest afternoons (≈29Ah) and ~55–100Ah for the rest of the bus — easing to ~115–240Ah in September as the afternoon shortens to 2–3 hours of Eco, and ~350–445Ah on any day that ends in a hot night, because the all-night post's verified 8-hour Sleep/Eco night adds roughly 150–200Ah by itself. A July day at Flagstaff (~82/51°F): 0.5 h Turbo × 58A ≈ 29Ah, 4 h Eco × 29A ≈ 116Ah, then off once the evening is cool enough for bedding (the shoulder-season post's profile) — ~145Ah for the unit.
The lever is the desert boondocking guide's elevation rule: by NOAA 1991–2020 normals Flagstaff averages ~79/51°F in August, while Quartzsite runs ~107/81°F. A 51°F night turns the unit off; an 80°F night keeps it in Sleep (21A) and puts the whole roughly 150–200Ah night on the ledger — the day roughly doubles, which is the 460-versus-630Ah gap. The mode figures are nameplate draws, not constant draws; the variable-speed DC compressor modulates down as the cabin nears setpoint, and extreme heat can push draw above nameplate (the all-night post has the figure). Turbo is a timed pull-down mode that exits automatically by design and is never an overnight mode; this ledger assumes a half-hour of it (0.5 h × 58A ≈ 29Ah) on the hottest afternoons. Pre-cool while driving so the DC-DC charger refills the bank while the unit pulls down.
The hot-night day is where the refill decides the week: on this arithmetic a 630Ah bank carries the first hot night and still declines over a week if the refill replaces less than the day consumes. The May full-time post owns the generator-free build and the climate-routing argument this ledger prices.
3. Fall (October–November): the second cheap season
Estimated ~65–215Ah a day: 0–4 hours of Eco (≈0–116Ah), a dawn heat-pump hour above 36°F on Glacier Pro rigs (≤55Ah ceiling-case, November mornings only, in place of that day's Eco hour — the range is the rows' span), nothing overnight (1W standby is noise), and ~55–100Ah for the rest of the bus. An October day at Quartzsite (~89/60°F): 3 h Eco × 29A ≈ 87Ah, the night off, ~140–190Ah for the bus.
The move down happens mid-October because Flagstaff's October normal low is about 32°F — the air temperature at which a pack left outside overnight can reach the BMS's 32°F charge cutoff — while Quartzsite's is 60°F; the fall destinations post owns the October destinations. The watts guide's 5-peak-sun-hour refill example (600W ≈ 200Ah) is, as the heating post says, a summer number; fall sun is shorter and the refill shrinks with it.
4. Winter (December–February): the diesel season
Estimated ~65–155Ah a day: cooling off, the fan 2 hours at 4.5A (≈9Ah) to move heater air, or — on Glacier Pro rigs — one heat-pump hour (≤55Ah ceiling-case) on low-desert mornings above 36°F, and ~55–100Ah for the rest of the bus. A January day at Yuma (~70/48°F): no cooling, 2 h fan × 4.5A ≈ 9Ah, the diesel heater's fan and pump on top, ~65–110Ah for the bus.
Heat is the one line the cooling-only Summit 2 cannot carry. The Glacier Pro's reverse-cycle heat pump delivers 8,500 BTU on 12V at a variable draw of up to 55A and stops heating effectively below 36°F; a documented support case saw it throttle to roughly 20A in a protection mode below the floor, which is low draw and low heat, not efficiency. Below 36°F the 5 kW diesel heater makes heat from fuel; the battery runs only its fan and pump, a draw that is not published. The heating post owns the comparison and the per-bank arithmetic.
Solar is weakest now — the shortest days and lowest sun of the year — so the budget closes only on good-sun days; the alternator and the pedestal do the rest (§5).
5. Travel days vs. parked days
On a travel day the alternator refills the bank through a 40–60A DC-DC charger capped at the bank's charge ceiling — 50A on the 230Ah (so 40–50A there), 75A on the 460Ah and 630Ah; on a parked day the array does it through an MPPT controller; on either day the bank feeds the unit, and nothing else does.
| Day type | Refill path | Estimated refill |
|---|---|---|
| Travel (4 h driving) | Alternator → DC-DC charger → bank, 40–60A within the 50A / 75A ceilings | ≈160–240Ah of arithmetic (4 h × 40–60A; 160–200Ah on the 230Ah, where the 50A ceiling caps the charger); acceptance tapers as the bank fills |
| Parked, sun | 600W → MPPT → bank | The watts guide's formula (600W × 0.8 × peak-sun hours ÷ 12V) on NASA POWER monthly sun hours: Yuma October 5.1 h ≈ ~205Ah, December 3.3 h ≈ ~130Ah, Flagstaff July 6.9 h ≈ ~275Ah — the 5-hour example (≈200Ah) is an October-in-the-desert number, not a winter one |
Shore power, a portable generator and the chargers-feed-the-bank architecture are in the watts guide; the Summit 2's 100A-continuous BMS requirement is in the all-night post.
6. The verdict by full-timer type
Three profiles, three banks, against the daily totals above and the spec's estimated Summit 2 runtime ranges (mode and conditions unspecified).
| Full-timer type | Est. daily Ah (AC + bus) | Bank | Why |
|---|---|---|---|
| The route follower — low desert Oct–May, high desert Jun–Sep, nights mostly off | ~65–245Ah | 460Ah Power Hub (~5.8 kWh, ~8–22 h) | AC plus everything with margin every month, on this arithmetic |
| The hot-night stayer — low desert into June, Gulf Coast nights, any 80°F night | ~350–445Ah on hot-night days | 630Ah Power Hub (~7.5 kWh, ~11–30 h; "up to 30 hours in Sleep" is a conditional maximum) | Carries one hot-night day with reserve on this arithmetic; a second needs the refill to match the day, or it declines over a week |
| The mild-climate minimalist — afternoons only, cold nights off, drives or plugs in most days | ~65–215Ah (the top of that range needs its refill the same day) | 230Ah Standard Edition (~2.7 kWh, ~4–11 h) | A real day outside summer with a daily refill; tight on a hot night (the all-night post's 400Ah-usable floor), little left for the fridge |
FAQ
How big a battery bank do you need for full-time RV living with a 12V AC?
On this route, an estimated ~65–245Ah a day, which the 460Ah Power Hub (~8–22 h estimated Summit 2 runtime) covers with margin every month on the ledger's arithmetic. A 230Ah Standard Edition (~4–11 h) covers winter, fall and early spring with a daily refill but is tight from May through summer; the 630Ah Power Hub (~11–30 h) is for the full-timer whose calendar keeps hot nights, where a day can reach ~350–445Ah; whatever bank runs a Summit 2 needs a BMS rated 100A continuous — our three are rated 200A (230Ah) and 300A (460Ah/630Ah), so the requirement matters when you bring your own bank.
Can you run a 12V RV air conditioner year-round on battery?
Yes for cooling: an estimated 2–4 hours of Eco a day at 29A in spring and fall, 4 hours plus a pull-down in a high-desert summer, and nothing on cool nights, where the shoulder-season post's profile hands the shift to bedding. Heating is a different device — the Glacier Pro's heat pump above 36°F, the diesel heater below it.
How many amp-hours does an RV use per day?
Without the air conditioner, the watts guide's typical-build range is ~55–100Ah a day. With the unit, the ledger reads ~65–155Ah in winter, ~85–245Ah in spring, ~170–245Ah in a high-desert summer and ~65–215Ah in fall; a hot night alone adds roughly 150–200Ah.
Do full-time RVers need a generator?
Not on this route, where a 600W array's estimated refill (see the watts guide's formula) and a DC-DC charger (40–60A, never above the bank's 50A or 75A charge ceiling) on driving days can cover a ~65–245Ah day in most months, on this arithmetic. A portable generator or a pedestal earns its place in December and January and on hot-night weeks; either feeds the bank through an AC-DC converter (100A / 1,200W recommended).
How do full-timers heat without propane?
Above 36°F, the Glacier Pro's reverse-cycle heat pump (8,500 BTU on 12V, variable draw up to 55A) heats off the bank where it is the rooftop unit; one dawn hour is ≤55Ah ceiling-case. Below 36°F the 5 kW diesel heater takes over — fuel makes the heat; the battery runs only its fan and pump, a draw we do not publish. The heating post has the comparison.
Related reading
- Can You Run a 12V RV AC All Night on Battery? (2026)
- Can You Heat an RV Without Propane? (2026)
- Watts and Batteries to Run a 12V RV AC Off-Grid (2026)
- Desert Boondocking in 2026: The Best Regions to Camp Off-Grid
- Fall RV Travel 2026: 10 Shoulder-Season Destinations
- LiFePO4 in the Cold: The 32°F Charging Cutoff and Fall Solar Yield (2026)
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Prices as listed October 13, 2026; verify on the product pages.
