This is going to be "Epoch"! A Capt. Jan unOfficial unReview

iMacattack · June 8, 2025, 8:37pm

UPDATED with a YouTube Video Review below.

“If we knew what we were doing, it would not be called research, would it?”
- Albert Einstein

With those immortal words many months ago I set about researching lithium battery options. The pages of Microskiff are littered with my questions, findings and general musings on the topic. In these pages I’ve shared my findings including an incomplete list of OTS (off the shelf) battery suppliers I could find, warnings from outboard manufactures regarding incompatibilities and warning on limiting how much power you send to your trolling motor.

I watched countless YouTube video reviews, teardown and interviews.

In the end, motivated by Black Friday sales I finally (with my loving wife’s approval ) bit the bullet and purchased a lithium battery solution from Epoch Batteries.

Why Epoch?
There were a couple things that swayed my decision. Most notably is Epoch’s IP67 dust and waterproof rating. In a marine application my opinion is this is a must especially for a lithium battery especially one that has an onboard BMS. (battery management system)

Build quality of the Epoch battery (Epoch Batteries is a division of RoyPow energy. Eve, one of the largest manufacturers of LiFePO4 cells, owns RoyPow) is top notch. The cell construction, packaging and weather seals differentiate it from other batteries. Check out this YouTube review by Lithium Solar.

Or read this review by Panbo Marine Technology Hub.

panbo.com

Epoch Batteries, elegant drop-in LiFePO4

Epoch Batteries’ 100-amp-hour, 12-volt drop in reviewed. Learn about the design, construction, and performance of this LiFePO4 battery

panbo.com

Purchase and Shipping
Ordering the battery and Epoch branded charger was simple and straight forward and three days later I had everything in hand.

Specifications
BATTERY CONFIGURATION
Cell Configuration: 8S
Chemistry: LiFePO4

CURRENT
Ah Capacity: 50Ah
Max Continuous Discharge Amps: 100A
Max Charge Current Amps: 150A (10 Seconds)
Max Discharge Peak Current Amps: 150A (30 Seconds)
Series | Parallel: Max (2) in Series | Max (4) in Parallel

Weight: 34 (LBS)
Dimensions: 10.2 x 10.6 x 13.2 (inches)

CHARGER

Voltage: 24V
Amperage: 15A
Input Voltage: 120V
Easy to use: Ready to charge right out of the box.
Plugs into standard 120V A/C outlets.
Ring terminals connector for output.
Lightweight aluminum alloy.
Doubles as a heatsink.
Up to 95% charging efficiency.
Overtemperature protection: Working Temperature -40℃ to 60℃.
Ambient temperature protection.
Reverse polarity protection.
Overcharge protection.
Output overvoltage protection.
Output overcurrent protection.
Output short circuit protection
IP67 Rated
Ingress Protection: IP67 Dustproof & Waterproof!
Shock-resistant design for storage and operation (Can be used in mobile operations such as RVs, marine applications, etc.)

IMPORTANT FIRST CHARGE NOTES
After excitingly connecting the battery to perform my first charge I learned from another Epoch battery user to NOT connect the Bluetooth Epoch App to the battery until AFTER the first full charge. Seams there is a limited risk the BMS and App will not show the correct SOC (state of charge). The resolution is simple if, like me, you happen to connect the battery BMS Bluetooth App during this period, delete the app from your phone and restart your phone. Luckily I did not encounter this issue but I followed the previous steps just incase.

What are you replacing?
In my case I replaced two Odyssey M31 (group 31) batteries and Marinco 10amp 5|5 charger. The batteries are located along with the house battery under the rear seat in a battery storage compartment.

Slope Rectangle Parallel Font Auto part

These two batteries are connected in series providing 24 Volts @ 100aH of power. "But Capt, you cut your power potential in half by buying a 24 Volt 50aH lithium battery, you’re an idiot!" Well, yes I do stupid tricks but in this case there is a logical reason. I have NEVER gone through a full discharge of my previous AGM battery. After discussing 100aH vs. 50aH battery uses with several other Epoch users the general feedback is yes 100aH gives a lot of reserve power but those with 50aH who use their trolling motors all day have plenty of power in reserve. The differentiator will be the number of recharge cycles these batteries may see. This will be something I’ll report on in the coming months and years of use.

iMacattack · June 8, 2025, 8:38pm

Install
Prepping the replacement. (click on the thumbnails for full size pictures)

Two Odyssey Group 31 batteries and charger.

Out with the old!

In with the new

Battery compartment cover in place.

Couple notes on the install. I’m not an electrical wiring wizard. There are folks who can take wiring a boat to an art form. I characterize my wiring abilities as acceptable, safe and functional.

Also specifically regarding the charger. The initial charge (battery shipped at 8% SOC) took 3 hours to get to 100% SOC. I wanted to see how hot the charger would get. I’ve had luke warm coffee that was hotter than the charger body got. This in larger part I feel is due to
the built in fan and cooling fins. If you notice I removed the handle (T20 Torx bit) but left the black cover. The fan draws in cooling air from the center and pushes hot air out the sides. It’s critical in my opinion that the black cover remains in place to ensure proper cooling for the charger.

The Epoch battery also comes with a SOC dash mounted indicator. What would have been nice is if they supplied a cutting template. Since they didn’t I had to break out my grandfathers Mitutoyo calipers, rezero the dial indicator then make a bunch of measurements. Finally fire up Adobe Illustrator and make my own cutting template.

The SOC dash mounted indicator is a nice addition. While there is an app that gives the user a ton of battery charge data it’s nice that I don’t have to open the app all the time just to get a general SOC. The indicator is broken-down into 10 LED bars. Each bar represents about 10% battery state. At a quick glance I can see how much charge is left on the battery. I decided that the dash to the left of my Suzuki gauge was the best location.

Another thing that I wished they would provide with the SOC indicator would be a thing gasket. Unfortunately they don’t, so I put a very fine bead of silicone under the SOC indicator before final assembly.

Below is the template I created for the SOC dash mount indicator. USE IT AT YOUR OWN PERIL. [image]

iMacattack · June 8, 2025, 8:38pm

With a 106 pound difference between two group 31 AGM Odyssey batteries at 70 pounds each or 140 pounds combined, versus one Epoch 24 Volt 50aH lithium battery at 34lbs the skiff MUST draw less water… right? It does right Capt?

Lets find out.

Never one to forgo an opportunity for a a beauty picture of my 1998 Egret 197 Carbon | Kevlar, I dropped her in at my local boat ramp and proceeded to do highly scientific testing.

Testing
I started with by ensuring the skiff was fully loaded like a day fishing. Full fuel tank (44 gallons of REC90 @ 6 lbs a gallon or 240 pounds of fuel) My tackle, rods, even put several drinks in the cooler. I wanted real world data not fake data to impress someone on the internet. In the end fully loaded the Egret draws a touch more than 11.5" at rest. This measurement is without the two AGM batteries or my fat azz onboard.

I then added the Epoch battery.

Technically it’s “sub” 12" but only by a hair.

Finally I swapped out the Epoch and added the two AGM.

Just over 12".

I marked each observation and pulled the boat out of the water for a final inspection.

There you go, All that effort and expense I gained (or lost) less than an inch. There are many factors on how this same test would impact other skiffs. It would be ill-considered to attempt a linear estimation of this test on other skiff brands. Factors such as hull shape, displacement, heck the 167 Egret carries more fuel than just about every other skiff of similar size a 2X factor in many cases will change the results.

Am I disappointed? No. I didn’t expect a massive different but thought it may have been more. One thing I can say is based on my seat dyno the skiff “feels” like it hops up on plane a bit quicker. I don’t see any WOT differences but time to plane measurements indicate a little less than 1 second quicker plane. Worth it? If the only reason to swap from AGM to lithium is to float shallower then this result would be disappointing.

The next tests will be using the battery for its intent. All day use of the trolling motor. I’ll report back my general findings and thought in the coming week and months.

iMacattack · June 8, 2025, 8:39pm

Trip #1

Took the battery out for a spin today. Local bass fishing. I have a Minn Kota Riptide Ulterra 80lb self-deploying trolling motor with I-pilot.

Few observations. I’m running about .5 to 1 lower speed setting. The speed controller goes from 0-10 on the I-pilot. Typically I fish between 2.5-3 and today I was working 2-2.5. I think the biggest difference is an observation many others here have made which is, since the power output of lithium is very linear… till it isn’t… the end of the day you are using similar power settings as the beginning. In this chart form Battery Finds you can see that even with a very low SOC of 20% you may still get about 25 volts. The warning from Minn Kota regarding not pushing past 8.5 on the speed control makes sense since the voltage output is higher.

I also did a bit of power running, speed setting 5-7 (2-3mph) for long distances. Ended up on the trolling motor for a solid 4 hours and only used about 33% capacity. The Epoch app showed 67% SOC left at the end of today.

Very satisfied! The SOC Dash indicator was very handy I didn’t need to pull up the app to see the condition of the batteries. I was a bit concerned about how bright it would be in the early am darkness but I have to say is was not disruptive to my low light vision. If it would have been annoying I could always power to battery off, but I didn’t find it necessary to do so.

Power Button
Additional observation regarding the power button on the battery. Highlighted below. This button turns on/off the battery which is a bit strange in initial concept. Traditionally a batteries posts are always “live”. Not in the case with Epoch. When the battery is powered up (on state) the posts are live. When powered down (off state) the posts only show about 1V current vs 27V when the battery is on. Where things get a bit “wonky” if the Epoch app is running on your phone but you power down the battery, the data will stop being displayed in the app, as would be expected, however the battery starts to do a single beep every few seconds and the power light will flash. It’s an audible warning that a Bluetooth device is connected to the battery. This can be a bit confusing if you don’t associate the Bluetooth app connectivity as the source for why the battery starts to beep after being powered down.

Documentation
This IMHO is the area I have the biggest critique. Documentation provided is barely passable. Yes there is a “owners manual” but aside from giving specifications of the battery there are little no to useful operational instructions. The note in my previous post not to connect the app during the initial charge was a learned issue that had I not been on the Epoch DIY Facebook group I never would have know. This issue with the battery signaling an audible notification due to a Bluetooth app being connected but the battery is powered down is also not in the manual. I do hope they up their game for future customers.