The cheapest lithium battery on Amazon is down to $150. The cheapest lead acid is also $150! The average price for BOTH on Amazon excluding sales is about $200. Very similar in pricing and lithium seems to be getting just as affordable as anything else!
This officially begs the question, which one should you pick specifically for your boat's trolling motor? I’ve used both lithium and lead acid extensively. I have pretty strong opinions for each. I personally still own both and will always keep one of each handy and charged up. Let’s dig in!
Benefits of Lead Acid Over Lithium
- You can use any lead acid charger. They’re sold at Walmart, Autozone, West Marine and most large department stores. These are simple, basic chargers that are also the most affordable. I have the Everstart Maxx from Walmart. I picked it up for $30 and it works amazing! Lithium requires a special charger. I had to find one online and they are for sure more expensive! Here’s the cheapest lithium charger I could find.
- Lead acid batteries also work with a lot more accessories including my Newport Smart Battery Box. My battery box has a “test” button so see how much battery I have left on a scale of 0-25-50-75-100%. A lot of people with small boats, like mine, run their whole boat via trolling motor and don’t have a safe space to keep their battery under the deck. If this is you, you’ll likely already have one of these battery boxes from Newport or Minn kota. Lithium batteries do not work with this “test” feature on these boxes so you have no idea how much battery life you actually have left!
- Lithium requires not only a special charger but a special battery meter specifically made for lithium if you want to know how much time you have left on the water. Now, I actually have a lithium battery that connects to your phone via bluetooth. This app shows me an incredible amount of information, including precisely my battery life remaining as well as an estimated time on the water. It’s a bit pricey, but you can pick yours up right here.
- The last benefit of lead acid is the accessibility and average pricing. If you go into a department store, usually they only keep the top, most reputable brands on the shelves. Meaning, on average, you’ll be spending a lot more in-store on lithium than lead acid. Lead acids also have way more options at the more affordable price range. You’ll need to search online to get a truly good deal for a lithium battery.
Benefits of Lithium Over Lead Acid
- Lithium has a longer life span and requires less maintenance. Although you may spend more upfront for a name brand lithium battery, you’ll likely save money over the course of 5-15 years. Lead acid batteries have an average life span of 3-6 years. Lithium batteries can last up to 15 years! That’s some serious savings if everything is properly taken care of.
- You get more of that 100ah with lithium than you would with lead acid. Much more, even though it has the same AH rating. I’ve learned this the hard way. I had to get towed back home after my lead acid died prematurely! In fact, lithium batteries can have up to 50% more usable energy than lead acid.
- You can use 100% of a lithium battery's AH rating. Lead acid, on the other hand, is only advisable to use 30%-50% of its AH rating. If you buy a 100ah lead acid, you’ll likely max out at only 55ah. What a rip off!
- On the other hand, Lithium can use 100% of its AH rating. This means a 100ah lithium will have at minimum, twice the time on the water as a lead acid! We will talk more about the difference in discharge rates here in a moment.
- Lithium batteries are actually lighter than lead acid. My 100ah lithium is lighter than my small 55ah lead acid by almost 20 pounds.
- Lithium batteries, from my understanding, are actually safer as they don’t contain battery acids and don’t emit gasses while charging.
Here’s the single reason alone why I will never run a lead acid on my trolling motor powered fishing boat that I use to travel miles and miles. RANGE. In fact, my lead acid now only acts as a backup battery for long trips and/or for another boat. Let’s take a look at this discharge rate chart to show you why lithium kicks butt in terms of time on the water and overall speed/ power given to your trolling motor over the course of its battery life.
Lead acid starts at 13 volts, giving the most power to the motor and slowly losing voltage as you run it. Meaning you’re slowly going slower and slower and slower and slower. By the time I was ready to head towards the ramp, I was already running less than 12 volts, underpowering my motor and going seriously slow.
This is scary as this has happened more times than I want to admit. Being on the ocean, the wind, tide and current can make a situation like this very dangerous, very quickly. I actually had to get towed home once because I used only 60% of my lead acid battery but was only running 1.5mph!
Lithium batteries hold their voltage until the last 5 percent, then you’ll very quickly drop in voltage. When I am fishing for 4 hours and am ready to head back to the ramp, I am going just as fast as when I first launched, holding the same voltage as 4 hours before.
This is a game changer! Being able to use 95% of my 100ah lithium battery without dropping voltage/ speed makes a massive, massive difference. Realistically, I get 3-4x the usable battery life from my 100ah lithium vs a comparable 100ah lead acid.
Lithium keeps me on the water longer, maintains full power all day, chargers quicker, lasts longer and will save me money years down the road. Personally, I am team lithium for THIS particular application. I don’t use these batteries for anything but powering my motor, cameras and fish finder.
Let me give you a quick example of why you should not throw away your lead acid batteries. You can not use lithium as your starting battery in a car or boat. You’ll still need a lead acid starting battery from my understanding. Also, lead acids make great backups, so keep them around!
Lastly, you can pick up my lithium battery with the super cool app right here. It does cost about double what the cheapest lithium battery on Amazon cost, so I don’t blame you for passing on it. In fact, I got it for free. I otherwise would have bought this exact lithium battery right here. Happy boating and tight lines!