Product Review: Relion RB100-HP LiFePO4 Marine Battery - The Fisherman

Product Review: Relion RB100-HP LiFePO4 Marine Battery

Back in our April 2023 monthly issue, we made a strong case for considering a Lithium Iron Phosphate (LiFePO4) 12-volt battery for your boating applications. For this week’s product review, we’re going to take a closer look at one of the latest of this type of lightweight, powerful (relatively) affordable power packs to hit the market, the ReLION RB100-HP Group 31 battery from Brunswick’s Navico Group, who knows a thing or two about boat electrification.

Switch Hitter

When I recently upgraded the electrical power on my 228 EdgeWater CC, I opted for a pair of ReLION RB100-series 12.8-volt lithium batteries. One of which was the legacy RB100 deep cycle, while the other was ReLION’s latest introduction, the RB100-HP. The “HP” label signifies high-performance and this newbie is different from her sibling in that it is considered a “dual purpose” battery type. Translated, it will work equally well as both a house battery for all of your vessel’s deep-cycle electrical system needs, as well as having some extra plates onboard to create additional MCA (marine cranking amps) when it’s time to start up that big V6 or V8 outboard.

Weighing in at a svelte 29.8 pounds (in comparison, my older 27-series flooded lead acid battery was over 50 pounds), the tapered frame of the ReLION RB100-HP Group 31 fits neatly into a 27-series battery tray, so making the swap was a breeze. This 100-amp hour battery is rated at 12.8-volts, so it will produce 1280 watt hours of capacity. The reasons to make the switch over to lithium from my old lead acid batteries were extremely compelling, since the RB100-HP provides significantly reduced weight; enhanced performance with a higher amp hour rating; increased cold cranking amps; a more generous reserve capacity; plus more consistent voltage across a wider depth of discharge range. The new RB100-HP features six terminals versus the two on standard batteries, offering users more flexibility when connecting electronics to the battery.


LiFePO4 batteries essentially have a flat voltage curve down to an 80% depth of discharge, offering a somewhat linear power output as the battery discharges. The power output will not suddenly drop like similar sized FLA (flooded lead-acid) batteries. Lithium batteries can cycle up to 2,500 times or more and higher rates of discharge (up to 80%) minimally affect cycle life. Lead-acid batteries typically deliver only 300 to 400 cycles, with higher levels of discharge greatly reducing cycle life. The LiFePO4 chemistry is especially tolerant from abuse and relatively safe, with a higher thermal overload safety net compared to other types of lithium batteries.

The RB100-HP battery comes equipped with a battery management system (BMS) to insure safety and reliable, long-term operation. It protects against under-voltage during discharge, over-voltage during charge or regen conditions, over-current and over-temperature during discharge, along with a short-circuit protection that protects the battery cells from damage.  In terms of longevity, the replacement warranty on a flooded lead-acid battery is typically two years, while the warranty on the RELiON RB100-HP batteries is 10 years, which is a major advantage. For more information, visit


Nominal Voltage – 12.8 V
Nominal Capacity – 100 Ah
Self-Discharge – less than 3% per month
Maximum Continuous Discharge Current – 100 amps
Maximum Peak Discharge Current – 800 amps
Lithium Marine Cranking Amps – up to 800 amps for eight seconds
Dimensions – 13 inches L x 6.8-inches W x 8.4” D
Weight – 29.8 pounds
Terminals & Type – three each positive & negative M8
Enclosure Waterproof Protection – IP67 rating
Cell Type & Chemistry – Cylindrical; 4 x 3.2 v; LiFePO4



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