Lifeline Batteries.

Lifeline Batteries: AGM Power for Marine, RV, and Off-Grid

Lifeline batteries are sealed, absorbed glass mat (AGM) lead-acid batteries built for deep-cycle service. They handle vibration well, recharge quickly, and require no watering—ideal for boat house banks, RV house systems, and solar backup where reliability matters.

When to Choose Lifeline AGM

• Choose Lifeline AGM if: You want simple integration with standard alternators and chargers, dependable cold-weather behavior, minimal maintenance, and broad service familiarity.
• Consider lithium (LFP) instead if: Weight and space are critical, you need frequent deep discharges beyond 50–60% DoD, or you want faster full recharges and higher usable capacity per pound. Ensure your charging system is LFP-ready.

AGM Basics

AGM uses a fiberglass mat to hold the electrolyte against lead plates. This design is spill-proof, resists vibration, and allows higher charge acceptance than flooded batteries. Unlike flooded batteries, AGMs don’t require watering and can be mounted in various orientations.

How to Size and Select a Model

1. Estimate daily use: Add up all loads (amp-hours per day). Target routine depth of discharge (DoD) around 50% for longevity.
2. Pick capacity: Required nameplate Ah ≈ daily Ah ÷ 0.5 (for ~50% DoD).
3. Confirm fit: Check your compartment for Group size, cable clearance, and secure mounting options.
4. Separate roles: Use starting batteries for engines and deep-cycle for house loads.

Typical Case Sizes (Approximate)

Note: Exact ratings vary by model—always verify dimensions and specs in the product data sheet.

Installation Essentials

• Secure mounting: Use proper trays and hold-downs. Batteries are heavy and must not move under shock loads.
• Correct cabling: Size cables to keep voltage drop under 3% for critical circuits. Keep parallel leads equal length.
• Protect circuits: Install main fuses within 7 inches of the positive terminal (or as close as practical). Use appropriately rated breakers/fuses on branch circuits.
• Balanced connections: For parallel banks, take loads/charging from opposite ends to promote even current sharing.
• Ventilation: AGMs emit minimal gas in normal use, but provide airflow and avoid sealed compartments.

Charging and Care

Use a three-stage charger (bulk, absorption, float) set to AGM profiles. Temperature compensation improves accuracy across seasons. Reaching full charge regularly is key to prevent sulfation.

Typical Charging Setpoints (12 V System)

• Absorption (bulk/absorb voltage): ~14.3–14.7 V at 77°F (25°C)
• Float: ~13.2–13.5 V at 77°F (25°C)
• Charge rate: Many systems use 0.2C–0.4C (20–40% of Ah capacity). Ensure voltage limits and temperature are controlled. Always confirm the exact model’s recommendations.

Generator and Alternator Tips

• Use a charger with sufficient output and adjustable absorption time to shorten generator run time.
• Pair high-output alternators with smart external regulators to avoid under-charging and overheating while maximizing acceptance.
• Enable temperature sensing on chargers/regulators whenever available.

Runtime Planner Example

Bank: two Group 31 AGMs, 105 Ah each = 210 Ah at 12 V. Plan for ~50% usable = ~105 Ah ≈ 1.26 kWh.

• 12 V fridge ~70 W average at 50% duty: ~0.84 kWh/day
• LED lights 10 W for 5 h: 0.05 kWh/day
• Water pump 60 W for 12 min/day: 0.012 kWh/day

Total ~0.90 kWh/day leaves ~0.36 kWh (margin for electronics, losses, colder days). Recharge with solar/alternator to avoid deep cycling.

Maintenance Best Practices

• Charge fully and often: Avoid chronic partial state of charge.
• Limit deep discharges: Design for ~50% routine DoD; occasional deeper draws are okay but shorten life if frequent.
• Keep connections clean: Torque to spec, protect against corrosion, and inspect regularly.
• Storage: Store fully charged; float maintain or top up monthly depending on self-discharge and controller behavior.

Pros and Cons

• Pros: Rugged and vibration-resistant, maintenance-free, easy to integrate with existing gear, predictable cold-weather performance.
• Cons: Heavier than lithium, lower usable capacity for the same nameplate Ah (plan around ~50% DoD), slower to reach 100% than LFP when charging from limited sources.

Troubleshooting

• Short runtime after “full” charge: Verify absorption voltage/time; perform a controlled capacity test.
• Uneven parallel strings: Check balanced wiring and equal cable lengths; confirm connections are tight.
• Frequent low-voltage alarms: Increase capacity, add solar/charging, or raise inverter low-voltage cutout to protect the bank.
• Slow charging: Increase charger output or improve alternator regulation; check wire size and voltage drop.

FAQ

Do Lifeline AGM batteries need watering?

No. They are sealed, valve-regulated AGM batteries and do not require watering.

Can I mount them on their sides?

Yes. The immobilized electrolyte allows flexible orientation. Secure the battery and protect terminals from short circuits.

Should I equalize AGM batteries?

Do not perform traditional flooded-battery equalization. Follow the manufacturer’s specific conditioning procedure (if recommended) for AGM.

Can I mix new and old batteries in a bank?

Avoid mixing ages or capacities. Replace batteries in a bank as a matched set for best performance.

How should I store them off-season?

Store fully charged. Maintain a float charge or top up monthly; keep in a cool, dry place.

Recycling and End-of-Life

AGM batteries are recyclable. Return spent batteries to a dealer or municipal program for proper lead reclamation; many vendors provide a core return credit.

Always confirm voltage setpoints, charge rates, and dimension/weight with the data sheet for your exact Lifeline model.