Rod, What are your Recommended Drop-In Batteries for Marine Use?
Disclaimer: I still type with one finger as my left arm is still 100% paralyzed. Typo’s happen and I try to edit them when I see them or readers point them out. The Million dollar Question:
“Rod, What are your recommended drop-in LiFeP04 batteries?” is a question we get asked at least twice a week. Over the years our recommended batteries have changed a number of times. In 2009/10 it was to DIY, Then Genasun came along with amazing batteries, then Mastervolt and then Lithionics. Genasun is no longer making LFP batteries, Mastervolt has priced their batts to the stratosphere though they are great batteries if you want a whole Mastervolt boat. Lithionics still produces some of the absolute finest LFP batteries made but when a single G31 drop in costs upwards of $1500.00, that recommendation is really getting absurd when there are quality alternatives at less than half the Price of Lithionics. If you want Lithionics (drop-ins are not suitable for every boat) the only company to deal with is Ocean Planet Energy….
To cut through the clutter and information overload of our other articles, I decided it would be best to pick two brands, a “Premium” offering and a “budget” offering. While inflation is running rampant in most business sectors the drop-in LFP market has seen the Chinese stumbling over themselves, for the last 18 months, in a race to the lowest price. This is a huge win for the consumer and murder to American businesses eg: Lithionics, Dakota, Battleborn, Relion etc. trying to build LFP batteries in the US and sell them at margins that can support US jobs and US regulations.
Two years ago at this time a Bluetooth BMS, 1C 100Ah battery, that is self heating, (can be charged below freezing) did not even exist at sub $500.00. Today the Vatrer 100Ah is $288.00. This is a price point I never thought possible. When I first started in LFP back in 2007 a single 100Ah cell (you need four to make a 100Ah battery) cost $288.00.00 ea.. This makes LFP so much less expensive than lead acid the discussion of lead vs. LFP for house banks is officially over!
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In the premium class, the brand that smashes the competition on price and features are the Epoch Batteries. Pictured above is the 1ooAh B12100A. We also highly recommend the new 460Ah battery which can integrate with Victron. These battery hit all the marks including a removable lid, on/off switch, a very detailed BT BMS, IP67 case, CANBUS, Wired Alarm (ABYC), internal self heating, cell compression, built in mounting feet, ON/OFF switch 1.2C BMS ETC.. The 460Ah version also has a 500A EV fuse inside it with Class T mounting and an AIC of 50,000A which far exceeds ABYC!
With any LFP battery it is the build and cell quality that matter. In this regard Epoch batteries are designed in the US and manufactured by RoyPow in China.
Why is this a good thing?
1- RoyPow is a division of EVE
2- EVE is one of the largest /LFP cell manufacturers in the world. This gives Epoch direct access to premium EV grade cells!
Not content to use an off the shelf BMS from the likes of JBD, JK, Daly etc. RoyPow manufacturers their own BMS!
I have not seen any other manufacturer place a temp sensor on B+/B-. It is a very smart move and can shut down the battery in a situation where high resistance becomes an issue.
The internals are very well laid out and the BMS resides in its own metal enclosure insulated from the cells! In testing I pulled 120A for 20 minutes and the BMS temp moved 3 degrees. This is a sign of a robustly built BMS that is conservatively rated..
How does it Perform to its rating? As can be seen above the 100Ah battery delivered about 6% over the 100Ah rating at a .2C discharge. For capacity testing we use a computerized constant current discharger masde by an American company that is extremely accurate and includes dedicated volt sensing.
How well are the Epoch Cells matched?
A trick we employ here on the test bench is to capture the cell volt differential at BMS disconnect. This is a great quick test to determine how closely the cells are matched. Anything below 0.2V at 0% is considered excellent! This screen shot was snapped the split second the BMS shut off discharging. As can be seen even at BMS disconnect the cells are still only off by 0.18V! This is as good a cell match to any battery we’ve tested here, including Lithionics & Kilovault… The fault message“Cell UV Prot” just means cell under voltage protection. FWIW with just 2 cycles the BMS SoC has proven to be spot on.
Budget = Vatrer
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Vatrer has all the right features, good build quality, prismatic cells BT BMS and internal heating all at an amazing price. These batteries ship directly from the manufacturer but, they both have been quite responsive on the customer service front. Before I ever add a battery to our list I pretend to be a DIY and ask a few dumb questions via email. How the manufacturer responds and how accurately, all goes the decision to recommend a battery.
These batteries are an excellent value but they do not lack critical featuressuch as internal heating, a Bluetooth BMS and low and high temp protection that are found on the slightly more expensive Epoch & Kilovault batteries…. If your budget is tight it’s hard to beat Vatrer…. The 100Ah heated BT battery is currently sub $300.00 on Amazon.. Any Chins batteries that use pouch cells have been removed from the store. Please note we are no longer and will never again recommend any LFP battery that does not have a Bluetooth BMS so you can see what’s going on inside..
For a sub $300.00 battery it actually performs quite well! It came in at nearly 5% over rated capacity. As for the 0% test the app is not as accurate for SoC as the Epoch battery, so when it cuts off you lose the BT connection and it does not give a count down like Epoch making it tough to catch.. I am still trying to get a screen shot as close to 0% as possible. Suffice it to say it is a hell of a battery for less than $300.00! Budget batteries a moving target;
Our budget battery recommendation has changed a few times. We first started with Ampertime /Li Time but the lack of a Bluetooth BMS had me fielding too many questions about random batteries disconnecting at voltages well below 14.4V. With no way to see individual cell voltages we bought/tested some Chins batteries that had a BT BMS.Then, I discovered Chins made a move to “Pouch cells” and away from prismatic cells and never told anyone. This is what I call the old “Bait & switch”. They send Will Prowse a prismatic cell battery, which got a decent review, then ship pouch cell batteries after the review has been completed.. Pouch cells can be fine provided they are assembled correctly. On the budget end of the spectrum “correctly” is rare. Until I see pouch cells done correctly we will not be recommending any pouch cell batteries on MHT… I rest my case with the image below.. Buyer beware with Pouch cell batteries.