How Long Do RV Batteries Last? Years, Cycles and Runtime
A flooded RV battery lasts 3-5 years, AGM 4-7, LiFePO4 8-15. On one charge a 100Ah bank runs a furnace, 12V fridge and CPAP about 9 hours.
An RV battery lasts 3 to 5 years as flooded lead-acid, 4 to 7 years as AGM, and 8 to 15 years as LiFePO4. On one charge, a 100 Ah battery runs a furnace, a 12 V fridge and a CPAP for about 9 hours in lead-acid form and about 18 hours in lithium, because lead gives you half its rated amp hours and lithium gives you nearly all of them.
RV battery and power consumption calculator: how many amp-hours your day costs
Tick the appliances you actually run, correct any wattage you can read off an appliance label, and set the hours each one runs rather than the hours you are awake. The amp hour calculator turns that list into amp-hours per day and hours of runtime. The defaults describe a shoulder-season day off hookups for two people: LED lights, the water pump, a furnace cycling three hours, a roof fan, a 12 V compressor fridge, phone charging, the detectors that never switch off, and a laptop through the inverter. That comes to 119 Ah a day, which a 200 Ah lithium bank carries for about 36 hours.
RV power consumption calculator
Add up what your rig draws in a day, then see how many hours your battery bank covers it and how much a charger has to put back.
The arithmetic is watts times hours for watt-hours, watt-hours divided by the inverter efficiency for anything on 120 V, then watt-hours divided by bank voltage for amp-hours. Usable capacity is 90 percent of rated for LiFePO4 and 50 percent for AGM and flooded lead-acid, the depth-of-discharge limits published by Battle Born and Trojan respectively. Recharge is amp-hours used times a charge factor of 1.02 for lithium and 1.15 for lead-acid, because a lead battery only accepts about 87 percent of what you push into it.
There is no Peukert exponent here on purpose: it needs a battery-specific constant most owners cannot find, and it changes the answer by a few percent for the loads in this list. Instead a flat derate stands in for the same effect, applied to lead-acid only and only when a single load pulls more than 20 A from the bank, which is roughly a C/5 rate on a 100 Ah battery. Lithium holds its rated capacity at those currents and gets no penalty.
What the model leaves out: temperature (a lead-acid battery gives about 20 percent less at 32 °F), age (a four-year-old bank is not delivering its label), the DC-DC converter loss on a 24 V system feeding 12 V lights, and any charging that happens during the day. Treat the result as a planning figure and confirm it with a shunt-based monitor that counts amp-hours in and out.
Switch the chemistry pill from LiFePO4 to AGM and touch nothing else. The same 200 Ah bank drops to 100 usable amp-hours and runs out before the day ends. That one click is the battery bank arithmetic most owners get wrong: rated capacity is a label, usable capacity is what you actually get to spend. The second lever is the inverter. Every 120 V row is divided by the efficiency box, so a 1,000 W microwave pulls 98 amps from a 12 V bank while it runs, and six minutes with a hair dryer costs more than the ceiling lights burn all evening.
Write down two of the outputs. The first is amp-hours per day, because that is what a solar array or a generator has to replace, and the recharge tile already adds the charge factor a lead bank wastes as heat. The second is the state of charge bar: if one day drops it below the floor marked for your chemistry, the bank is undersized for the way you camp, whatever its rating says.
How long do RV batteries last in years, by chemistry?
Chemistry sets the ceiling and your habits decide where you land under it. The figures below are what RV owners actually get, not laboratory cycle counts: a battery bank that lives in a Phoenix storage lot and gets flattened every weekend dies at the low end, and one that sits on a maintainer between trips and never drops below 12.4 V reaches the high end.
| Chemistry | Cycles at 50% depth of discharge | Real RV lifespan | Usable Ah from a 100 Ah battery | Self-discharge per month |
|---|---|---|---|---|
| Flooded lead-acid (FLA) | 300–500 | 3–5 years | 50 Ah | 5–15% |
| AGM | 400–700 | 4–7 years | 50 Ah, 80 Ah occasionally | 1–3% |
| Gel | 500–800 | 4–6 years | 50 Ah | 1–3% |
| Two 6 V golf-cart batteries in series | 800–1,200 | 5–8 years | 105–115 Ah from a 210–230 Ah pair | 5–15% |
| LiFePO4 | 3,000–5,000 (rated at 80–100% DoD) | 8–15 years | 90–100 Ah | 1–3% |
Trojan publishes roughly 1,200 cycles at 50 percent depth of discharge for the T-105 6-volt battery and about 750 at 80 percent, which is why a pair of golf-cart batteries outlives the group 24 that came with the trailer. Battle Born rates its LiFePO4 drop-ins at 3,000 to 5,000 cycles at full depth. Cycle away 60 percent of a 100 Ah lithium battery every night of a two-week trip and you have used 14 of at least 3,000.
Lithium also carries a calendar limit that cycles do not describe. A LiFePO4 cell loses capacity slowly whether you use it or not, so 10 to 15 years is the practical end even for a battery that stays in a weekend trailer. The trade is that the lithium battery is still delivering 80 percent of its rated capacity in year 8, while a flooded battery is delivering 60 percent of its by year 4.
How long does an RV battery last on one charge?
Divide usable amp hours by the amps your loads draw. A 100 Ah lead-acid battery holds 50 usable amp hours before it drops under 12.2 V and starts damaging itself; a 100 Ah LiFePO4 gives 90 to 100 before the BMS cuts out. Here is what that buys, one load at a time.
| Load | 12 V draw | Hours on a 100 Ah lead-acid (50 Ah usable) | Hours on a 100 Ah LiFePO4 (95 Ah usable) |
|---|---|---|---|
| Furnace blower running flat out | 8 A | 6 | 12 |
| Furnace at 30 °F, cycling 20 min per hour | 2.7 Ah/hour | 18 | 35 |
| 12 V compressor fridge, 10 cu ft, 40% duty | 2.0 Ah/hour | 25 | 47 |
| Absorption fridge on propane (control board only) | 0.4 A | 125 | 235 |
| Four LED ceiling lights | 1.2 A | 41 | 79 |
| CPAP, no humidifier, on 12 V | 3.5 A | 14 | 27 |
| CPAP with heated hose and humidifier | 6.5 A | 7.7 | 14.5 |
| Roof vent fan on medium | 2.5 A | 20 | 38 |
| Water pump while running | 5 A | 10 | 19 |
| Propane and CO detectors, stereo memory, antenna booster | 0.7 A | 71 | 135 |
Nobody runs one load at a time. Stack a real 30 °F night from 10 pm to 7 am: furnace 24 Ah, 12 V fridge 18 Ah, CPAP without humidifier 28 Ah, parasitic detectors 6 Ah, half an hour of lights 0.6 Ah. That is 77 Ah in nine hours. The 100 Ah AGM has 50 usable, so it hits 50 percent around 4 am and the furnace blower starts stuttering. The 100 Ah lithium finishes the night with about 18 Ah in hand. Repeat that night for years and the cycle ratings widen the gap again, 500 to 1,000 cycles for AGM against 3,000 to 5,000 for LiFePO4, which is the arithmetic behind LiFePO4 against AGM over five years.
How do you calculate runtime for your own rig?
Three lines of arithmetic. First, convert every appliance to 12 V amps: watts divided by 12.6 for anything wired to the DC panel, and watts divided by 12.6 then divided by 0.85 for anything running through an inverter, since inverters give back 85 to 90 percent of what they take. Second, multiply each by the hours it actually runs, not the hours you are in the RV; a furnace at 30 °F runs about a third of each hour and a 12 V fridge compressor about 40 percent. Third, divide usable amp hours by the total.
A 700 W microwave is the clearest example of why the inverter changes the answer. 700 W divided by 12.6 V divided by 0.85 is 65 A from the battery, so ten minutes of reheating costs about 11 Ah, a fifth of everything a 100 Ah AGM will legally give you. Two coffee cycles and a phone charge and the night has not started yet.
Sizing a bank for several days off hookups is a bigger calculation with solar input and recharge rates in it, and that belongs on the RV battery for boondocking page rather than here. For a single night, the table above plus your own hours is enough. If your usable amp hours land under your daily total, the honest options are a bigger bank, charging the batteries mid-trip from a generator or solar, or dropping the load that costs the most, which is nearly always the 12 V fridge or the CPAP humidifier.
What actually shortens RV battery life?
Five things kill RV batteries years early, and four of them are lead-acid problems that lithium simply does not have.
- Deep discharge. Take a flooded battery to 80 percent discharged instead of 50 and its cycle count drops from roughly 500 to roughly 200. Take it to 100 percent a few times and the plates shed active material that never comes back. This is the single biggest difference between a battery that lasts 5 years and one that lasts 18 months.
- Sulfation from sitting part-charged. Lead sulfate forms every time the battery discharges, and it dissolves back into the electrolyte only when the battery is recharged promptly. Leave a battery below 12.4 V for a few weeks and those crystals harden into an insulating layer on the plates. A battery stored at 50 percent over a winter can lose a third of its capacity permanently before spring.
- Heat. Battery life roughly halves for every 15 °F of average temperature above 77 °F. A bank in an uninsulated compartment on the sunny side of a rig in Arizona runs 100 to 110 °F for months, which turns a 5-year AGM into a 2 to 3-year AGM. Heat also drives water loss in flooded cells.
- Chronic undercharging. A cheap single-stage converter holds 13.5 V and never reaches the 14.4 to 14.8 V absorption stage a lead battery needs to finish. Weekend after weekend the battery comes back to 90 percent instead of 100, and the missing 10 percent sulfates. Under 13.0 V at the posts on shore power is a different fault, a converter that has actually quit rather than one with the wrong profile.
- Dry cells and loose hold-downs. Plates exposed to air in a flooded battery are ruined in one charge cycle. Check the water every 1 to 2 months in summer and top with distilled water only, to about a quarter inch above the plates. A battery bouncing loose in its tray sheds plate material through vibration.
What are the signs an RV battery is dying?
The first sign is almost always runtime, not voltage: the bank that used to hold overnight now dies by 2 am, and it charges back to “full” in an hour because there is very little left to fill. Watch for these together, not one at a time.
- Resting voltage sits at 12.4 V or lower four hours after the charger comes off.
- The furnace blower slows or the lights dim visibly when the water pump kicks in.
- A flooded battery that needed distilled water twice a season now needs it monthly, which means it is being cooked.
- The case sides bulge, or the top is warm to the touch after charging.
- A rotten-egg smell near the battery compartment, which is hydrogen sulfide from an overcharged or shorted cell. Ventilate and stop charging.
- On a hydrometer, one cell reads more than 0.050 specific gravity below the others, which is a dead cell and is not fixable.
- Terminals grow white or blue corrosion again within weeks of being cleaned.
- On lithium, the BMS shuts off far earlier than it used to, or an app-monitored battery reports capacity under 80 percent of rated.
How do you test an RV battery with a multimeter?
Set a multimeter to DC volts on the 20 V range, disconnect shore power and the solar controller, turn the battery disconnect off, and wait. Lead-acid needs 4 to 12 hours to settle before the reading means anything; a battery read five minutes after charging shows a surface charge of 13 V and tells you nothing. Then touch red to positive, black to negative, and compare.
| State of charge | Flooded lead-acid | AGM | LiFePO4 (12 V) |
|---|---|---|---|
| 100% | 12.7–12.8 V | 12.8–12.9 V | 13.3–13.4 V |
| 75% | 12.5 V | 12.6 V | 13.2 V |
| 50% | 12.2 V | 12.3 V | 13.1 V |
| 25% | 12.0 V | 12.0 V | 12.9 V |
| Empty | 11.8 V or below | 11.8 V or below | 12.0 V, then BMS cutoff |
Two cautions. Voltage tells you state of charge, not capacity: a worn-out battery with 20 Ah left in it still reads 12.7 V when it is full of those 20 Ah. To find capacity, run a timed capacity test against a known load, or watch the voltage while the furnace runs; a healthy battery holds above 12.0 V under a 10 A load, and a failing one sags to 11.5 V within a minute. And the LiFePO4 column is nearly useless in practice, because the curve is flat from 90 percent down to 20 percent. Lithium owners need a shunt-based monitor such as a Victron SmartShunt, which counts amp hours in and out for about $90 to $150.
Do you need a battery if your RV is plugged in?
Yes, in almost every rig. The converter makes 12 V for the lights, the fridge control board and the slide motors, but it is a current-limited supply, not a buffer. Pull the battery out and a slide or leveling-jack motor that surges to 60 or 80 amps will trip or damage a 45 A converter, and some fridge and furnace boards fault on the ripple that a converter produces with no battery smoothing it. On a towable, the breakaway switch is required to have a charged battery behind it, since its whole job is to apply the trailer brakes when the trailer leaves the hitch.
The battery is also what keeps the propane detector, the fridge and the CO alarm alive through a campground power cut. What you can do is turn the disconnect off, or pull the battery entirely, while the rig sits in storage on shore power for months. That is a different question from running without one. The difference between the two boxes doing this work is covered on the RV inverter vs converter page.
Do RV outlets work on battery?
No, not on their own. The 120 V outlets in an RV are fed from the shore cord or the generator through the breaker panel, so with the rig unplugged they are dead even with a fully charged battery. What the battery runs is the 12 V side: ceiling lights, roof fans, the water pump, the furnace blower and igniter, the fridge control board, the propane and CO detectors, USB ports and the slide and jack motors.
To get 120 V from the battery you need an inverter between the two systems. Many newer rigs ship with a 1,000 to 2,000 W inverter wired to two or three outlets, often labelled with a different color faceplate, and the rest stay dead off shore power. Adding one is a normal upgrade, but the arithmetic above applies: everything you plug into that outlet costs about 1 amp of battery for every 10 watts it uses.
What storage routine gets you to year seven?
Store lead-acid full and lithium half full, and disconnect either one. Those two sentences are most of the difference between a battery that dies in its third spring and one still working in its seventh.
For flooded and AGM: charge to 100 percent, top the cells with distilled water first if flooded, clean and grease the terminals, then turn the battery disconnect off or lift the negative cable. Parasitic draws of 0.5 to 1 A add up to 12 to 24 Ah a day and flatten an unattended bank in a fortnight. Check voltage every 4 to 6 weeks and recharge whenever it reads below 12.4 V, or leave a 1 to 2 A maintainer or a small solar panel on it. If the rig winters somewhere below freezing, a full battery is safe outside; a half-empty one is not.
For LiFePO4: charge or discharge to roughly 50 percent, disconnect the battery or pull the main fuse, and leave it off any charger. Lithium sitting at 100 percent for six months ages faster than lithium sitting at 50 percent, and it must not be charged in an unheated yard below 32 °F. Check it every three months. If you are replacing a bank rather than storing one, the lithium RV battery picks compare cases, BMS ratings and cold-weather versions, and the rest of the power and electrical guides cover what has to change in the charging side when you switch chemistry.
Frequently asked questions
How accurate is the RV power consumption calculator?
It is as accurate as your hours. The wattages are typical for RV appliances and the conversions are exact, so the error comes from guessing that a furnace runs two hours when it runs five. Owners who compare it against a shunt-based monitor for a week usually land within 10 percent, and the gap closes once the furnace and fridge hours are measured rather than estimated.
Does the RV battery calculator include inverter losses and charging losses?
Yes, both. Anything on the 120 V list is divided by the inverter efficiency you set, which defaults to 85 percent, so a 100 W laptop costs the battery 118 W. The recharge figure adds a charge factor on top: 1.15 for AGM and flooded lead-acid, which accept only about 87 percent of what a charger pushes in, and 1.02 for LiFePO4. Temperature and battery age are not modelled.
How many years do RV batteries last?
Flooded lead-acid deep-cycle batteries last 3 to 5 years in RV use, AGM 4 to 7, gel 4 to 6, a pair of 6-volt golf-cart batteries 5 to 8, and LiFePO4 8 to 15. Depth of discharge and storage temperature move any of those by years in either direction.
How long do RV house batteries last on one charge?
A single 100 Ah lead-acid house battery covers about 9 hours of a mild night with a furnace, a 12 V fridge and modest lights, and less than that if a CPAP or an inverter is in the mix. The same 100 Ah in LiFePO4 covers roughly twice as long, because you can use 95 amp hours instead of 50.
Is it bad to leave an RV plugged in all the time?
It is fine with a three-stage or lithium-profile converter that drops to a float around 13.2 to 13.6 V. It is hard on flooded batteries with an older single-stage converter that holds 13.8 V or higher for months, because it boils the electrolyte away. Check water monthly if the rig lives plugged in.
Why did my new RV battery die in a year?
Almost always one of three things: it was taken below 50 percent repeatedly, it sat all winter at partial charge and sulfated, or a parasitic draw of about 1 A flattened it in storage with the disconnect left on. A twelve-month failure is rarely a defect in the battery.
Can you recover a sulfated RV battery?
Sometimes, and only partly. A desulfating charger or an equalization charge at 15.5 V for 2 to 4 hours on a flooded battery can dissolve soft sulfation and return some capacity. Hardened crystals after months at low charge are permanent, and equalization must never be used on AGM, gel or lithium.
How long will an RV battery last with just the fridge running?
An absorption fridge burning propane draws only its 0.4 A control board, so a 100 Ah lead-acid battery carries it about 5 days if nothing else is on. A 12 V compressor fridge pulls 2 Ah per hour averaged over the day, which empties the same battery's 50 usable amp hours in about a day.
Does a bigger battery bank last longer in years?
Yes, for lead-acid. Two 100 Ah batteries covering a 40 Ah night are each cycled to 80 percent state of charge instead of one being cycled to 60, and shallower cycles mean more of them. Doubling a lead bank often more than doubles its service life.
RV owner since childhood trips in a Class C. Mr RV Expert is where I write down what actually works after fixing, replacing and testing the gear myself.
About Mr RV Expert →Keep reading in Power & Electrical
30 Amp vs 50 Amp RV Service: Volts, Watts and Adapters
A 30 amp RV plug is one 120V leg, 3,600 watts. A 50 amp plug is two 120V legs, 12,000 watts. Adapters change the plug shape, never the power.
Best 6 Volt RV Batteries: GC2 Pairs, AGM and Flooded
Two 6-volt GC2 batteries in series give 12V at 225Ah, about 112 usable amp hours, on plates no 12V pair matches. AGM and flooded picks plus wiring.
Best Generator for a 30 Amp RV: Why 3,600 Watts Is the Cap
A 30 amp cord carries 3,600 watts maximum, so a 3,600 to 4,800 peak inverter with a TT-30R outlet is right. Picks by AC size, noise and fuel.
Best Generator for a 50 Amp RV: Size, Outlet and Two-AC Picks
A 50 amp RV needs 6,500 to 8,000 running watts, not 12,000. Picks with a 120/240V 14-50R outlet that will start two air conditioners.