UPDATE- SELECT FOURSTROKES- Specific Spec Lithiums ACCEPTABLE!

[EuropeanAM]

UPDATE: 12/23/2022

As of 12/23/2022, Mercury has issued Service Bulletin 2022-19 and Racing Bulletin 2022-21 stating that the listed engines will be permitted to use a Lithium Iron Phosphate Battery that is designed for engine cranking, as long as it meets the listed specifications:

-2.1L 75-115hp Fourstroke, ProXS and SeaPro Models
-3.0L 150hp Fourstroke, ProXS and SeaPro
-4.6L V8 and 3.4L V6 175-300hp Fourstroke, ProXS, SeaPro and Verado Models
-2.6L L6 200-400 Pro and Verado Models
-7.6L V12 500-600hp SeaPro and Verado Models.
-ALL MERCURY RACING OUTBOARD ENGINE MODELS (Current Production)
-NO other engines approved at this time.

Minimum Specs Required:

-Chemistry/Format: Lithium IRON Phosphate designed for MARINE CRANKING USE.
-Minimum Cranking Amps: 800A for 8 second minimum @ 20 Degrees F
-Peak Charge Acceptance: 165A at 20-130 degrees F for one minute
-Max Charge Alternator Size: 150A at 20-130 degrees F
-Max Charge Voltage/Alternator Output: 14.8V
-Reserve Capacity (RC25 @ 80F): 135 Minutes
-Ingress Protection (IP rating): IP67 or greater.

Cautions that use at temperatures below 32F may require additional equipment such as a battery heater.

Bulletin also lists a Relion Battery that has been evaluated and meets the above requirements: RB100-HP.

https://relionbattery.com/products/lithium/rb100-hp

Due to the high number of posts lately that ask "is it ok, why can't I, but so-and-so does it, Mercury must be ok with it because, etc. etc.", I'm going to set this post as a "top of the Forum" sticky for the next few months (and it will remain in the FAQ Section indefinitely).

Mercury Service Bulletin 2021-06 specifically states that Lithium Ion Batteries are not to be used with any Mercury Outboard, or Mercruiser Sterndrive engines.

Mercury Service Bulletin 2021-06R1 states that Mercury has not certified any Lithium Ion Batteries for use with their engines (though some Boat manufacturers have tested them with their boats). Bulletin recommends following the installation instructions and manual, and states that any damage caused by using Lithium batteries will not be covered.

150 Fourstroke Note: 150hp (3L) Fourstroke Models do not necessarily REQUIRE an AGM type battery at this time. 150 Verado Models DO require an AGM, however.

The below excerpts are taken DIRECTLY from the Installation Instructions, Part# 8M0156797 (latest publication as of the date of this post, and the guide to proper installation and rigging of the engine):

BATTERY REQUIREMENTS:

The following specifications are regarding marine battery systems and their connectivity to outboard propulsion systems. Adherence to the following requirements is mandatory for all engine installations. Failure to follow the requirements may result in loss of warranty coverage for electrical components and systems.

CLEAN POWER CONNECTIONS:

Mercury clean power harnessing must be connected directly to the positive and negative posts of the corresponding propulsion engine's cranking battery. IMPORTANT: Any deviations from the clean power connection requirement must be approved by Mercury Marine.

There is then detail on Battery cables, cable connections, requirement of a Battery Switch for batteries that exceed 800 cca (virtually all of these engines will in a fishing application): We strongly recommend 975+ CCA AGM batteries.

ENGINE BATTERY SPECIFICATIONS:

IMPORTANT: This engine requires a 12‑volt absorbed glass mat (AGM) marine starting battery that meets the minimum ratings.

Do not use flooded (wet cell), gel cell type lead acid batteries or lithium ion batteries for starting marine engines. Each engine must be equipped with its own starting battery...

It then goes on to again restate the "Required 12‑Volt Absorbed Glass Mat (AGM) Battery Ratings" and provides two different MINIMUM battery capacity types (SAE with RC25 combined rating, and an EN (Internationally used) CCA Rating.

We recommend using the (EN) CCA Rating, which is a minimum of 975 CCA.

There is nothing ambiguous here... at least 3 times it clearly states that an AGM battery is required, and SPECIFICALLY instructs "Do not use.... lithium ion batteries".

Hopefully this will help to clear this up for those who seem confused on the topic.