12V 40Ah Lithium Starter Battery


Availability: 565 in stock

Warranty: 5 Years

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Comes with an outstanding 5-year warranty
  • Dependable cranking battery for both center console and offshore boats
  • For engines 250hp to 450hp (but can be used for smaller engines as well)
  • 1,400 cranking amps
  • 70% lighter than lead acid batteries & more compact
  • Has 2-4x the service life of lead acid batteries (3000-5000 cycles)
  • Always know the status of your battery with Bluetooth technology
  • Equipped with an Advanced Battery Management System (BMS) with power terminal cut-off & recovery
  • Cell balancing & low voltage/over voltage protection
  • Short-circuit protection
  • Plug & play ready – easy drop in replacement
  • Weighs just 14.6 lbs
  • Energy efficient w/ 99% Depth Of Discharge (DOD)
  • Features a special emergency start function, with 25% of the battery reserved for emergency purposes
  • Comes with 5 year limited warranty


Availability: 565 in stock

Warranty: 5 Years

Product Description

12V 40Ah Lithium Battery: Your Reliable Lithium Cranking Battery

rsz boat engines

The 12V 40Ah is one of the most powerful lithium cranking batteries on the market, capable of taking on some of the bigger boats. Engines up to 450hp are no sweat. It’s solid, safe, and simple to monitor your battery via Bluetooth.

But surely there’s a “catch,” right? No battery could be this good. There must be some downside, like bulky sizing or back-breaking weight. Not the case with this battery. Forget finding a catch – this is the catch.

Only the Best Battery for Your Boat: 12V 40Ah Lithium Battery Uses

Your cranking battery is what brings your boat to life. Without a battery, it’s just a dust-collecting dock decoration.

But not just any battery will do. You need one that won’t weigh down your boat, that doesn’t require maintenance, and that effortlessly fires up your engine. Good news: you’ve found it.

For offshore and center console boats, our 12V 40Ah battery is the ideal starting battery. Like all of our marine batteries, it charges five times faster than lead acid, and maintains that charge for much longer than other battery types.

Bigger Isn’t Always Better: Battery Features

Think a hefty battery equals a better battery? Think again. Weighing in at just 14.6 lbs, this lithium cranking battery is remarkably lightweight for the amount of power it delivers.

That’s incredible, especially when you consider the fact that lead acid 12V 40Ah batteries weigh at least double. Switching to lithium is an easy way to cut down on weight (which saves money in gas!) and minimize the amount of space you’re using in your center console boat. Not to mention it saves your back from lugging around a 26-pound traditional lead acid battery.

But back-saving isn’t the only super power of this power pusher. Our lithium cranking battery also cranks out anxiety-busting safety features such as:

  • An integrated microprocessor-controlled battery management system (BMS).
  • Microprocessor monitors main operating parameters while safely charging and discharging (voltage, currents, internal temperatures, etc.)
  • Smart capabilities prevent overcharging, or charging when temperatures are too low. This helps prevent damage to your battery.
  • Bluetooth function: connect your battery to your smartphone wirelessly and view data like battery status and charge left.
  • Emergency start mechanism (see details below)

State-of-the-Art Safety: Emergency Start Feature

Ever been stranded at sea with a cranking battery that won’t start? Here’s to hoping you never experience such bad luck. Actually, you don’t have to leave it to luck. With a smart lithium cranking battery, you can make sure that your engine starts every time.

The unique emergency start function saves 25% of the battery reserve for emergency start purposes. To start your engine up in an emergency, just reactivate the battery with the Ionic App on your phone or a long press of the battery’s emergency start button.

12V 40Ah Lithium Battery: How Does it Compare to Other Battery Types?

When you invest in a new battery, you want one that lasts. Not one that has to be replaced just a few years later. All those replacements add up, even if they aren’t costly up front. You’ll end up spending more money in the long run.

Maybe it’s time to choose quality over “cheap”. Our 12V 40Ah lithium battery is built to outlast the competition but comes at a competitive price. With a cycle life of 3,000 to 5,000 cycles, it’ll last roughly 10 years depending upon usage. Think about it – that could mean 10 whole years without having to replace your battery.

But that’s not the only reason why our 12V 40Ah lithium cranking battery comes out on top. Other battery types just can’t provide the same amount of efficiency. For example, lithium batteries have a 99% usable capacity. You can spend all day out on the water and not even come close to draining your battery. How much usable capacity does lead acid offer? A measly 50-60%.

Our Lithium Batteries Vs. Other Brands

How does our 12V 40Ah lithium battery (and our other lithium batteries) compare to other lithium brands? Like the winner in an Olympic race. All those runners race well, but only one wins. We offer a winning combination of top cell quality, performance, and longevity. Here’s what sets us apart:

  • High-Performing Cells: Although cheaper cells do exist, we’ve chosen to use only top quality cells in our products. Sure, cheap cells can save a buck. But as the saying goes, “you get what you pay for”.
  • Smart Batteries. We’ve outfitted our batteries with smart Bluetooth technology. Never worry about your battery status again! You can access important data in a flash via your smartphone.
  • Certified and Trustworthy: Our 40Ah cells pass the following certifications: UL1642, IEC62619, UN38.3.
  • Quality You Can Trust: Our factory meets the industry standard and holds the ISO Certification (ISO9000/14001/ OHASA18001). We produce, test, and pack our batteries in our own facilities, guaranteeing quality every step of the way.
  • Extensive Testing: We ensure our batteries deliver great performance in a variety of conditions.
  • Exceptional Service: When you contact LithiumHub, you’ll speak to a real person, right here in the USA. Our lithium battery experts can answer your questions and help you choose the right battery for your application.

Have further questions about our 12V 40Ah lithium battery battery? We’re here to help!

Model IC-12V40-S9
Voltage 12V
Capacity 40Ah, 512Wh
Chemistry LiFePo4
Weight 14.6lbs (6.6kg)
Dimensions 9″ (L) x 6.8″ (W) x 7.4″ (H)
Life Cycles 3,000 @ 80% DOD
BMS Yes (Internal)
Max Charge Voltage 14.6±0.1V
Discharge Cut-Off Voltage ~8.0V
Max Charge Current 100A
Max Discharge Current 150A
Peak Current (3S) 1000A (3S)
Operating Temperature -20~60℃
BCI Group Size 25
Terminal 3/8-16 NMC

Please read our frequently asked questions page for answers commons questions regarding lithium ion batteries.

Ionic Starter Bluetooth App Manual

12V 40Ah Lithium Starter Battery Spec Sheet

Starter Battery Manual

Customer Reviews

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Customer Reviews
5.0 Based on 5 Reviews
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Filter Reviews:
Fua C.
I recommend this product

Great battery

Easy to setup and delivers enough juice to crank the motor each time.

Anthony B.
I recommend this product

Not happy so far

Less 3 hours of fishing, electronics, & air raider, My red ionic starter battery with 1400 cranking amps, & an emergency start button, went completely dead, & stranded on water. Sending it back to ionic to see what happened. Not happy

Hunter B.
I recommend this product

Ionic 40ah Starter Battery

Extremely impressed with this battery, compact and powerful. Unfortunately fell for the marketing scam of a competitor (DL+ and the 135ah) and had nothing but issues out of that company/battery. Gave Lithium Hub a call to ask a few questions and was able to connect to a person immediately, then placed an order the same day. Customer service has been exceptional with Lithium Hub and the battery with built in Bluetooth has been an awesome feature. Extremely strong battery that starts my built Gator Tail Outboard while running over 50 amps of lights on a duck boat without even a flicker of the lights. Not to mention only 12.7lbs (weight shown on the battery itself). Truly a great product and company.

karl K.
I recommend this product

Excellent Option

Replaced a 100 pound batter with this 14 pound starter battery for my Yamaha 175 VMAX SHO. Fires right up and charges easily off the alternator in the outboard. So saved 85 pounds of weight and runs like a champ. Definitely recommended!!

Greg H.
I recommend this product

Cranking battery.

Just installed battery preparing for soft water fishing. Installation was simple, battery was extremely light compared to previous battery. Looking forward to using it soon. Needed software for monitoring battery was not found in Google Apps Play Store.

12V 40Ah Lithium Starter Battery 5.00 stars 5 reviews.

experience the most powerful lithium starting batteries on the market

red iconic

5 year

Buy with confidence with our competitive no-nonsense 5 year warranty.

grade a
cells only

Ionic uses the best cells so your battery lasts longer and performs better.


Monitor your charge at any time from our user-friendly Ionic mobile app.

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get the battery of tomorrow, today


50 percent lighter


zero maintenance


2x the power


5x faster charging

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