Standards · Lithium on boats

ABYC E-13 explained for boat owners

Updated 2026-10-11WakeTender engineering

ABYC E-13 is the American Boat and Yacht Council's standard for lithium-ion batteries on boats. It applies to installed systems over 500 Wh, which includes any lithium start battery over about 40 Ah, and it requires a battery management system, a disconnect, labelling and manufacturer installation instructions. It does not require the battery to protect the charging source, and its recommendation that the battery warn the operator before disconnecting is a non-binding "should" that most drop-in batteries do not meet.

What E-13 is, and who it applies to

ABYC standards are voluntary industry standards that boat builders, surveyors and insurers in the United States treat as the baseline for a sound installation. E-13 was first ratified in July 2022, took effect for systems installed after 31 July 2023, and was revised in 2025. It covers lithium-ion battery systems with a capacity above 500 Wh. A 12 V, 40 Ah battery is 512 Wh, so effectively every lithium start or house battery on a wake boat falls inside the standard once it is installed.

What it requires

A battery management system that monitors cell voltage and temperature and can disconnect the battery to protect it.
A means of disconnect that the operator can use, and, since the 2025 revision, a remote disconnect may serve as the battery switch.
Manufacturer installation instructions that the installer follows, including charging requirements.
Labelling that identifies the system as lithium-ion and states its ratings.
Since 2025, mixed chemistries on one boat are permitted, with the systems kept separate as the manufacturers require.

What it only recommends

Clause 13.7.4 covers what happens when the BMS disconnects. A note to that clause says the system should provide an alarm to the operator before the battery disconnects. In ABYC language "should" is a recommendation, not a requirement, and because it sits in a note, it is the weakest kind of recommendation the standard contains. In practice almost no drop-in lithium battery on the market provides a pre-disconnect alarm. The battery simply opens.

That is the single most consequential gap in the standard for an inboard start battery, because the disconnect is the event that produces an alternator load dump. See load dump explained.

What it does not cover

E-13 does not require the battery to protect the alternator or any other charging source. It never has. It is written to protect the battery and the people around it, and it assumes the installer will follow the battery manufacturer's charging instructions. So a battery can be fully E-13 compliant and still be unsafe at the start position of an inboard engine, because the standard does not ask the question.

How to read "ABYC compliant" on a battery

Claim on the box	What it usually means	What to ask
"ABYC E-13 compliant"	Has a BMS, can be disconnected, is labelled	Does it warn before it disconnects?
"Meets or exceeds ABYC"	Marketing phrasing of the same thing	What does it do to the alternator when it trips?
"Marine certified"	Not an ABYC term	Which standard, which clause, which lab?

WakeTender meets the 13.7.4 pre-disconnect recommendation with a warning over CAN and Bluetooth before any protective action, and goes beyond the standard by keeping the load path connected when the charge path closes.

Questions

Is ABYC E-13 mandatory?

ABYC standards are voluntary, but they are the reference that US boat builders, marine surveyors and insurers use, and the US Coast Guard references ABYC standards in its own guidance. A lithium installation that does not follow E-13 may have insurance and resale consequences.

Does E-13 allow a lithium start battery?

E-13 does not prohibit any battery position. It requires the installation to follow the battery manufacturer's instructions, which is where engine-manufacturer requirements and the alternator question come in.

Does E-13 require the battery to protect the alternator?

No. E-13 addresses the battery, its BMS, disconnect and labelling. Charging-source protection is left to the manufacturer's instructions and the installer.

WakeTender 120

A 12.8 V, 120 Ah lithium battery engineered to be safe at the start position of an inboard wake boat, and to scale to a 480 Ah house bank. See the specification or talk to us.