Deep-Cycle Batteries

LiFePO4 or AGM, real amp-hours, right depth of discharge.

LiFePO4 deep-cycle battery with terminals and BMS indicator, product photography on white background

Deep-cycle batteries are rated in amp-hours but what you can actually use depends on chemistry and depth of discharge. Choosing the wrong type or undersizing means your system fails on the nights you need it most.

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Guides

Battery guides that go beyond amp-hours — chemistry comparison, usable capacity math, and wiring configurations for solar and off-grid systems.

Buying guide How to choose a deep-cycle battery: LiFePO4 vs AGM and capacity LiFePO4 vs AGM vs flooded lead-acid, usable amp-hours and depth of discharge, charge profiles, and how to wire a 12V bank. The numbers that actually determine how long your system runs.

Why this page exists

Battery capacity is consistently misunderstood because amp-hour ratings are measured at full depth of discharge — a condition that damages lead-acid chemistries and shortens their life dramatically. A 100Ah AGM battery has roughly 50Ah of usable capacity if you want it to last. A 100Ah LiFePO4 battery has 80–95Ah of usable capacity and will last 2,000–4,000 cycles to that depth vs 200–400 for AGM.

The upfront cost difference is significant. The lifetime cost picture is often the reverse. This page puts the numbers in one place so you can make an honest comparison.

Plain note about money. Links below go to eBay searches with an affiliate tag. If you buy through one, a small commission comes to this site. Your price is identical either way. The searches are ones we'd actually run — not sponsored placements.

Deep-cycle batteries worth searching on eBay

LiFePO4, AGM, and marine deep-cycle batteries for solar, RV, boat, and off-grid use. We earn a small commission on qualifying sales; your price is unchanged. Full disclosure.

🔍 Shop Deep-Cycle Batteries on eBay →
12V 100Ah LiFePO4 Lithium Battery Cycle Deep Built-in BMS for Solar RV Off-grid LiFePO4 Battery 100Ah The most popular size for van, RV, and small off-grid setups. Look for a built-in BMS (battery management system) — it's required for safe operation and should be non-negotiable. Verify the max continuous discharge current meets your inverter's needs. View on eBay → Renogy Deep Cycle AGM Battery 12 Volt 100Ah 1100A Max Discharge Current Off-Grid AGM Deep-Cycle Battery Absorbed glass mat lead-acid. Sealed, spill-proof, can be mounted in any orientation. Lower upfront cost than LiFePO4 but limit discharge to 50% for longevity. True deep-cycle AGM (not dual-purpose) has thicker plates for sustained discharge. View on eBay → 12V 100Ah LiFePO4 Lithium Battery BMS Deep Cycle For RVs Backup Power Off-grid 12V Deep-Cycle Battery Standard voltage for most van, RV, and small cabin systems. When searching, filter by amp-hour rating (50Ah, 100Ah, 200Ah) and chemistry. "Deep cycle" alone includes both AGM and flooded lead-acid — check the spec sheet to confirm which you're getting. View on eBay → 2026 Super 10000000mAh USB Portable Charger Solar Power Bank For Cell Phone Solar Battery Bank Pre-matched batteries intended for solar storage — often sold with compatible charge settings listed. Useful for finding batteries whose manufacturers publish recommended charge profiles. Mix-and-match from different sellers risks mismatched capacity and internal resistance. View on eBay → POERUNI 12V 100Ah Lithium LiFePO4 Battery 8000+ Deep Cycles For RV Solar Marine Marine Deep-Cycle Battery Marine-rated deep-cycle batteries are built for vibration resistance and often come in Group 24, 27, or 31 form factors that fit standard marine battery boxes. Dual-purpose marine batteries (start + cycle) are not ideal for solar storage — look for dedicated deep-cycle models. View on eBay →
Browse all Deep-Cycle Battery listings on eBay →

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