Common Ground MarineCommon Ground Marine

    Battery Systems

    Complete house and start banks — lithium or AGM — plus the distribution and charging hardware around them.

    Spec a battery bankShop batteries

    Choose your path

    House and start battery banks in LiFePO4 and AGM, plus the supporting cast: ACR / VSR isolators, Lynx distribution, busbars, BMV-712 / SmartShunt monitors, and DC-DC chargers. We size the bank to the daily amp-hour budget and the charge sources to refill it in the time you have.

    Lithium vs. AGM — when each makes sense

    Lithium gives you 2–3× usable capacity for the same footprint and cycles 5–10× longer, but the charge sources have to play nice. AGM is still the right answer when budget or alternator-only charging dominates the decision.

    Read the lithium upgrade guide

    Chemistries compared

    ChemistryUsable %Cycle lifeBest for
    LiFePO4~95%3,000–5,000House bank, frequent use
    AGM~50%400–700Like-for-like swap
    Flooded~50%300–500Budget builds only

    Banks that match your boat's charge math

    We size the bank to your daily amp-hour use and then check that your alternator, charger, and solar can refill it in the hours you have at the dock or under way.

    • Daily amp-hour budget worksheet
    • Charge-source compatibility check (lithium)
    • Bus and cable sizing per ABYC E-11

    Technical support

    Not sure which one fits your build?

    Our marine electrical team can compare options against your boat, helm layout, and circuit list — so you order the right part the first time.

    Get product help

    Frequently asked questions

    Can I drop lithium into my existing AGM bank's spot?

    Usually yes for the bank itself, but you'll need to confirm the alternator regulator and charger profiles are lithium-safe before you flip the switch.

    Do I need a battery monitor?

    On lithium, yes — voltage alone doesn't tell you state of charge. A BMV-712 or SmartShunt is the standard answer.

    Shipping & returns

    • Stocked items typically ship the next business day from our US warehouse.
    • 30-day returns on unused stocked items. Exclusions apply. See policy
    • Custom and quoted items are non-returnable once production begins.

    Certifications & training

    • ABYC-aware build practices
    • OEM-grade marine wire & terminals

    Additional capabilities are based on hands-on experience building marine wiring systems rather than third-party certification.

    Brands we carry

    Why work with our team

    Marine electrical experience behind every part we ship.

    • Picked for marine use

      We carry parts that hold up in salt, vibration, and heat — and we'll tell you when a cheaper option will give you trouble.

    • Real engineering review

      Send your circuit list or layout and our team will sanity-check wire sizes, breakers, and connectors before you order.

    • Direct support

      Talk to the team that builds custom harnesses and helm panels for boat builders, dealers, and refit yards.

    Ask about your project