Deep Cycle Batteries
AGM and marine deep cycle batteries built for reliable, sustained power in RVs and boats.
AGM (Absorbed Glass Mat) deep cycle batteries are the proven workhorse of RV and marine house banks. They're sealed, maintenance-free, mount in any orientation, and tolerate vibration far better than flooded lead-acid. While LiFePO4 has overtaken AGM at the high end, AGM still wins on upfront cost and remains the right choice for budget builds, weekend rigs, and applications where you need reliable power without the lithium price tag. Properly cared for, a quality AGM battery lasts 4–6 years in cyclic use.
Top 5 Compared
| Product | Rating | Price | |
|---|---|---|---|
| Interstate 12V 100Ah Pure Matrix AGM (31-AGM5) | ★★★★ ★ 4.8 | $289 | View |
| Renogy Deep Cycle AGM 12V 100Ah Battery | ★★★★ ★ 4.7 | $229 | View |
| Renogy Deep Cycle AGM 12V 200Ah Battery | ★★★★ ★ 4.7 | $469 | View |
| Interstate 12V 100Ah AGM Marine RV Dual-Purpose | ★★★★ ★ 4.6 | $249 | View |
| VMAXTANKS 125Ah AGM Deep Cycle Battery | ★★★★ ★ 4.5 | $289 | View |
All Deep Cycle Batteries
Deep Cycle Batteries Buyer's Guide
AGM vs lithium
The honest tradeoff: AGM is cheaper upfront but you only get to use about 50% of the rated capacity without damaging the battery, and it lasts 300–500 cycles vs 3,000–5,000 for LiFePO4. If you camp 10–20 nights a year, AGM is fine. If you're full-timing or boondocking heavily, lithium pays for itself.
Group sizes explained
Group 24, 27, and 31 are the most common sizes for RV and marine use. Group 24 fits tight battery boxes (typically 70–80Ah), Group 27 hits the 90–100Ah sweet spot, and Group 31 is the big one at 100–125Ah for serious house banks. Always verify the physical dimensions fit your battery compartment before ordering.
Dual-purpose vs deep cycle
Dual-purpose batteries (like the Optima BlueTop D34M) handle both engine starting and house loads, which makes sense for small boats with a single battery. Dedicated deep cycle batteries deliver more usable amp-hours but lower cranking amps, and are the right pick whenever you have a separate starting battery.