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The cabin lights dim at night, and the battery that ran the fridge all summer will not hold a charge. How long does lead acid battery last is the question every cabin, RV and boat owner asks when a battery fades, and the answer sits in the type of battery, how deep it runs down, and how it is charged and stored. The listings below give the amp-hours and the warranties to compare, and the steps below show the habits that stretch a battery and the ones that shorten it.
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The quick answer
It depends on the type and the habits. A flooded battery needs its water checked and a full charge after each use, and a sealed AGM battery needs the same full charge without the water checks. Deep discharges shorten the life of any lead acid battery, and a battery left flat or left in the cold fades faster than a battery kept charged. The listings below state warranties of 12 months to 2 years, which is the maker’s warranty, not the life of the battery. Read the amp-hours and the warranty on the label, and keep the battery charged.
Step 1: Know which type you have
Lead acid batteries come as flooded or sealed. A flooded battery has caps you open to check the water, and the Trojan T-125, T-105, US Battery US1800XC2, Crown CR-GC150 and Crown CR-235 listings all state flooded lead acid. A sealed battery keeps the acid inside an absorbent glass mat, and the Mighty Max ML35-12 and PowerStar listings state sealed lead acid with AGM technology. Sealed batteries need no water checks, and the Mighty Max listing states it can mount in any position. Flooded batteries need the water kept up and the caps kept clean. Know which type you have before you charge it, because the charger setting follows the type. See the flooded vs AGM battery charger guide before you pick a charger.
Step 2: How long does lead acid battery last
No listing states a life in years, so the figures to compare are the amp-hours and the warranty. The table below lists what each listing states.
| Battery | Volts | Amp-hours | Type | Warranty |
|---|---|---|---|---|
| Mighty Max ML35-12 | 12 | 35 | Sealed | 1 Year |
| PowerStar AGM1245 | 12 | 45 | Sealed | 2 Year |
| Trojan T-125 | 6 | 240 | Flooded | 18 Months |
| Trojan T-105 | 6 | 225 | Flooded | 18 Months |
| US Battery US1800XC2 | 6 | 208 | Flooded | 12 Month |
| Crown CR-GC150 | 12 | 150 | Flooded | 12 Month |
| Crown CR-235 | 6 | 235 | Flooded | 12 Month |
Amp-hours state how much charge the battery holds, and volts state the system it fits: a 6 volt battery suits a golf cart bank, and a 12 volt battery suits an RV or cabin. The US Battery US1800XC2 lists 208Ah at the 20-HR rate and 157Ah at the 5-HR rate, so the amp-hours depend on the rate the listing states. The warranty states how long the maker covers the battery, and the longest warranty in the table is the 2 Year term on the PowerStar. A warranty is not a life span: a battery can outlast its warranty when it is charged and stored well, and it can fade inside the warranty when it is left flat.
Step 3: Charge it back after each use
A lead acid battery lasts longest when it goes back to full charge after each use. Deep discharges shorten the life, so charge the battery before it runs flat, and use a charger that matches the battery type. The Mighty Max listing states a high discharge rate and deep discharge recover, and the PowerStar listing states deep cycle performance for cyclic and standby use, but neither one states a cycle count, so no number of cycles is given here. Keep the charger on until the battery is full, and check the manual for the charge setting that fits a flooded or a sealed battery.
Step 4: Store it charged and check it
Store the battery charged, and check it through the months it sits idle. A battery left flat fades faster than a battery kept charged, so top it up before storage and check it again while it waits. Keep it cool and dry, and keep the terminals clean. The Trojan listings state the batteries suit RVs, homes, cabins and renewable energy systems, so the same battery may sit in a cabin through the off season. Check the water on a flooded battery before storage, and charge a sealed battery the same way. See the lead acid battery maintenance guide for the charging and care steps.
Ways to make the battery last longer
- Charge it back: bring the battery to full charge after each use, and do not leave it flat.
- Keep the water up: check the water on a flooded battery, and keep the caps clean.
- Keep it cool: heat fades a battery faster, so store it in a cool spot out of the sun.
- Size it right: a battery that runs flat every day fades faster than one with room to spare, so match the amp-hours to the loads.
FAQ: power away from the grid
How long does a lead acid battery last in an RV?
It depends on the type and the habits. A flooded battery that is charged after each use and kept watered lasts longer than one left flat, and a sealed AGM battery lasts longer when it is kept charged the same way. No listing states a life in years.
Does a bigger amp-hour figure mean a longer life?
No. Amp-hours state how much charge the battery holds, not how long it lasts. The Trojan T-125 lists 240Ah and the Mighty Max ML35-12 lists 35Ah, and both need a full charge after each use to last.
What shortens the life of a lead acid battery?
Deep discharges, long spells left flat, and heat. Charge the battery back after each use, keep a flooded battery watered, and store it charged in a cool spot.
Is a sealed battery better than a flooded battery?
A sealed battery needs no water checks, and the Mighty Max and PowerStar listings state sealed lead acid with AGM technology. A flooded battery needs water checks, and the Trojan, US Battery and Crown listings state flooded lead acid. Pick the type that fits your habits.
Related solar guides
See the lead acid battery maintenance, the flooded vs AGM battery charger and the LiFePO4 vs lead acid battery for camper guides, and the batteries and charging category.
