Lithium Boat Battery Upgrade: Charge Your Trolling Motor While You Run
Lithium Boat Battery Upgrade: Charge Your Trolling Motor While You Run
What if your trolling motor batteries charged themselves every time you ran down the lake?
That’s the setup one customer drove home with. He stopped in at our shop with his boat and everything he needed. He just wanted a lithium boat battery upgrade: lead-acid out, MillerTech lithium in. Here’s what we did and why it works so well.
Five Lead-Acid Batteries Out, Four Lithium Batteries In
We pulled five Interstate lead-acid batteries out of his boat and replaced them with four MillerTech Sport Series lithium batteries and one smart charger:
- Two 12V 135Ah Sport Series Dual Purpose batteries to crank the outboard. Each one delivers 1,500 cold cranking amps (CCA) in a Group 31 case and weighs 33 lb.
- Two 36V 60Ah Sport Series trolling motor batteries to run the trolling motor. One of these does the job of three Group 27 lead-acid batteries.
- One Dark Speed “On The Run” 12V/36V charger to keep both banks charged, at the dock and on the water.
Fewer batteries means fewer connections to wire and fewer things to check.
How the Dark Speed Charger Keeps Everything Full
The Dark Speed is a dual-bank charger, so one charger handles both his 12V cranking batteries and his 36V trolling motor batteries.
At home: plug it into a regular outlet and it charges both banks at the same time.
On the water: this is where it gets good.
- While the outboard runs, its alternator charges the 12V cranking batteries first.
- Once those are full, the Dark Speed sends the extra power to the 36V trolling motor batteries.
- You keep fishing on batteries that were topping off during every run across the lake.
His outboard has a big 80A alternator, so it fills the cranking batteries fast and has plenty left over for the trolling motor. “With this setup, there’s a good chance he might never have to plug these batteries into an AC outlet,” our tech said.
No daily shore power, no generator, and no cutting your day short because the trolling motor is running low.
Why Switch From Lead-Acid to Lithium
- It lasts years longer. MillerTech lithium iron phosphate (LiFePO4) batteries are rated for more than 3,000 cycles and about 10 years. Lead-acid typically gets 150 to 300 cycles and lasts one to two years.
- You get the power you paid for. Lithium delivers 99% of its rated capacity. Lead-acid gives you 50% to 60%.
- No maintenance. No watering and no acid.
- You can see what’s left. Every Sport Series battery has Bluetooth, so the MillerTech app shows capacity, voltage, and temperature on your phone. With your permission, our team can also log in through the app and help fix a problem remotely.
- It’s backed for 10 years. Sport Series batteries carry a 10-year warranty. If one fails, we repair or replace it and pay shipping both ways. The warranty even transfers if you sell the boat.
- Cold-weather option. Fish late in the season? The 12V 135Ah and 36V 60Ah both come in heated models that can charge below freezing.
Ready to Upgrade Your Boat
Stop in at the shop and we’ll swap your batteries for you. Or order online at millertechenergy.com and we’ll ship them to you. Most orders arrive in two to three days.
Not sure which batteries or charger fit your boat? Call 855-MAX-LITH (855-629-5484) and a real person who knows the products will help you build your setup. You can also email [email protected].
How Point5Garage Powers a 52-Foot Houseboat Off-Grid
How Point5Garage Powers a 52-Foot Houseboat Off-Grid
The Point5Garage crew took on a trip most people would never try: more than 1,000 miles of river, from Cincinnati, Ohio, to Mobile, Alabama, completely off-grid. They made the run on a 52-foot custom-built articulating pontoon barge, with Pops, a 77-year-old Amish man, along for the ride. They named the boat Pop’s 77.
Everything on board runs on battery power: the refrigerator, lights, trolling motor, navigation equipment, and even the desktop computer used to edit the trip videos. After plenty of research, they figured they’d need about 1,000Ah to keep it all running.
A Battery That’s Never Let Him Down
Point5Garage already knew MillerTech before this trip. A MillerTech battery has powered his e-bike for years. “I’ve had other types of batteries, and I have faults. I have issues,” he says. “MillerTech batteries, I’ve never had an issue.”
So he reached out to Roman on our team and shared the plan. MillerTech stepped up to partner on the trip. “He didn’t just try to sell me something off the shelf,” he says. “He listened, and he heard what we need.”
We make batteries in many voltages, but so much of the gear on the barge was already built for 12V that a 12V system made the most sense.
The Battery Bank: 1,120Ah of 12V Lithium
The whole barge runs on two 12V 560Ah Sport Series batteries, for 1,120Ah of lithium iron phosphate (LiFePO4) power. “Just looking at them, you can see that they’re built different,” he says.
Each battery delivers:
- 200A continuous charge and discharge (400A across the bank)
- 500A peak discharge for five seconds
- Built-in Bluetooth and the Millertech app
- A built-in heater for charging in cold weather
- A 10-year Sport Series warranty
Two 40A MillerTech lithium chargers keep the bank topped off. We make bigger chargers, but 40A was the right match for the generator on board.
The Math: Lithium vs. Lead-Acid
Each battery weighs 126 lb, so the full bank comes in at 252 lb. Point5Garage ran the numbers on doing the same job with lead-acid. You can only use about half of a lead-acid battery’s rated capacity, so he’d have needed more than 2,200Ah of it.
| MillerTech Lithium | Lead-Acid (Point5Garage’s Estimate) | |
|---|---|---|
| Batteries | Two 12V 560Ah | About 23 Group 31 marine batteries |
| Rated capacity | 1,120Ah | More than 2,200Ah |
| Weight | 252 lb | Almost 1,600 lb |
“It just would not have been possible to put that onto the barge,” he says. The only other choice was running a generator 24 hours a day.
Every Battery, Right on His Phone
With the MillerTech app, he can check each battery’s state of charge anytime. He can also see its history, including charge cycles, overheating, and over- or under-current events.
The barge also has Starlink. If anything goes wrong, our Support Team can connect to the batteries remotely, with his permission, to diagnose and fix problems. “The customer service that stands behind these is phenomenal,” he says.
Peace of Mind for 1,000 Miles
For Point5Garage, this setup is about more than comfort. “Having dependable power isn’t just about creature comforts,” he says. “It’s about safety, and it’s about peace of mind.”
Before they set off, he was 100% confident the electrical system wouldn’t be a problem anywhere between Ohio and Mobile. About 26 days and more than 1,100 miles later, they tied up at Dog River in Mobile.
The two MillerTech batteries ran the barge the whole way. “Everything that took electricity on that boat was powered by those two batteries,” he says in the final video. Two solar panels and a solar charge controller kept the bank charged, so they didn’t have to run a generator 24 hours a day.
There’s a lot more to this story. Point5Garage shares the whole journey on YouTube, from the shop to life on the river. Subscribe to the Point5Garage YouTube channel and follow along.
Power for Your Off-Grid Setup
Whether you’re powering an off-grid cabin, a camper, a boat, or an RV, we have a battery for it, in voltages from 12V to 48V. Every Sport Series battery is designed and serviced in Ohio and backed by a 10-year warranty, with shipping paid both ways.
Not sure what your setup needs? Call 855-MAX-LITH (855-629-5484), email [email protected], or visit millertechenergy.com.
MillerTech Powers Media Day at The Champions | 2026
Why We’re Powering Media Day at The Champions: “Before Anyone Makes a
Cast”
Media Day is the one day of a tournament nobody makes a cast. It’s the anglers, the cameras and the stories behind the field.
That’s the day we picked. Media Day at The Champions is Powered by MillerTech. It’s the first time the top pros from the Bassmaster Elite Series and the Major League Fishing Bass Pro Tour share the same water, and before anyone launches, they’ll sit down with the media.
Fifteen of them run our batteries.
Watch the laser lay down the logo in the video above. It’s a small way to say thanks to the anglers and the event team, and a keepsake from a historic first year.
That group includes Jacob Wheeler, Dustin Connell and Brent Chapman. Connell is a three-time REDCREST champion who carries a third 36-volt on a quick connect because he’s lived the alternative. That’s the standard of angler in this field.
“The best anglers in the world will be in one room before anyone makes a cast,” said Lester Miller, founder and owner of MillerTech. “A lot of them already count on our batteries to get through a tournament day. Powering Media Day was an easy decision.”
Our batteries do their work where nobody’s filming: the first crank at takeoff, the trolling motor at 2 p.m. after three hours in the wind. What people see is the angler, and Media Day is where the angler talks. For a lot of this field, it’s the most money they’ve ever fished for. We’d rather put our name on that moment than on a logo in the corner of a leaderboard.
Media representatives leave with a limited-edition MillerTech 3LED Rechargeable Flashlight engraved with The Champions WBE logo. It runs on a high-capacity MillerTech lithium-ion battery, puts out 1,500 lumens on high, runs up to 150 hours on its lowest setting and has a built-in fuel gauge.
Every MillerTech battery carries a 10-year warranty, because power should be the one part of the rig an angler doesn’t think about.
Our in-house team is on site all week with daily features on every MillerTech angler in the field, plus a nightly “MillerTech Hard Chargers” ranking of our top three bags.
Media Day is the one day nobody makes a cast. Starting Thursday, they all do, and 15 of them will have MillerTech in their rigging compartment.
Mark Zona on MillerTech’s Service and 10-Year Warranty
Mark Zona wants what every angler wants: to be on the water every day he can. On the road or fishing local, his boat and electronics run from daylight to dark, and that takes power he doesn’t have to think about.“I’m a nutbag about the batteries that are in my boat,” Mark says. “I’m very specific about how I need things rigged, just to make sure I don’t have to worry.”
In the video below, Mark, a member of the MillerTech pro team, shares three things he’s learned about MillerTech, not just as batteries but as a company.
1. A Real Person Answers in Seconds
If you have a problem with your battery, in any way, shape, or form, you won’t be stuck pressing buttons through an automated menu. “There is nothing that makes me more insane than that,” Mark says. “You are going to talk to a human being within 10 seconds.”When you call MillerTech, a real person picks up. Our support team is based in Ohio, knows the batteries inside and out, and gives you practical answers on the spot.
2. A 10-Year Warranty That Stays With the Battery
Every Sport Series battery comes with a 10-year warranty. “A 10-year warranty is unbelievable,” Mark says.What he likes most is that it goes with the battery, not just the first buyer. “If I run my batteries for five years and then I sell my boat, whoever gets it, they have another five years,” he explains.If a Sport Series battery fails, we’ll repair it or replace it with one of equal or greater value, free. We pay shipping both ways, too. It’s our warranty, so it’s our cost, not yours.
3. Daylight-to-Dark Power You Don’t Have to Worry About
For Mark, this one matters most. “It is the best battery that I have ever used in my boat,” he says. “Daylight to dark power, right? That’s what we all want when we go out on the water.”The last thing you want, whether you’re on vacation or at a tournament, is to sit in your hotel room wondering if your batteries will hold up tomorrow. As Mark puts it: “You don’t need to worry if MillerTechs are in your boat.”
Power, Backed by People
A battery is only as good as the company behind it. With MillerTech, you get Sport Series batteries designed and serviced in Ohio, a 10-year warranty with shipping paid both ways, and a real person on the phone when you need one.
Got a question about your boat’s setup? Call 855-MAX-LITH (855-629-5484), email: [email protected], or visit millertechenergy.com.
Joey Antonelli Pulls Three Batteries for One MillerTech Before Opening Day of Red Snapper
Joey Antonelli made the biggest upgrade yet to his 26-foot Yellowfin Hybrid the day before opening day of East Coast recreational red snapper season. He had owned the boat for about six months. Three 12-volt batteries had been running his trolling motor the whole time, and they had to go.
In their place is a single 36-volt, 105 amp hour MillerTech lithium, plus a MillerTech lithium charger and the rugged battery tray to hold it all down.
Joey isn’t fishing a quiet cove. He’s working offshore structure out of Jupiter, and a lot of his day is spent sitting on a spot with the trolling motor fighting current.
“Sometimes we’re literally anchoring in the Gulf Stream with incredible currents for hours and hours and hours, and the smaller batteries just aren’t cutting it,” according to Antonelli. “So that 105 amp is going to give me the power I need to run all day, or two trips or three trips, and just be confident that I have the power to do what I want to do.”
That’s the job. Hold the boat in the Stream long enough to put a bait in front of the fish you came for, and do it again tomorrow without wondering what’s left in the tank.
Wondering is the other thing he got rid of. The MillerTech connects to his phone over Bluetooth, so battery life is a glance at the app instead of a guess. With the old lead-acid bank, guessing was all he had.
Then there’s room. A center console doesn’t give you much of it, and Joey’s had been swallowed by batteries and a charger.
“Here’s a look inside my center console. This was all batteries,” he said. “Every single bit of this was batteries and charger. So I’m going to be able to free up a lot of space in here.”
One battery takes up a fraction of the footprint three did. The tray lets him mount it solid wherever it fits best, and the space that used to belong to the power system is back in his hands for storage.
He expected the install to take up a good chunk of the video. It didn’t.
“I thought I was going to have more to show you for the install, but it was just so simple,” Antonelli said. “The wires were already there for the trolling motor. So all we had to do was mount the charger, mount the battery tray, strap it in, and connect four wires. It was literally that simple.”
Four wires. That’s the whole conversion.
After some time in the app that afternoon, Joey pointed out the part of owning a MillerTech that doesn’t show up until you need it. Every battery carries a 10-year warranty, and if something ever goes sideways, our support team can access the battery remotely, troubleshoot it, and tell the owner exactly what needs to happen. Nobody has to haul a battery anywhere to find out what’s wrong.
The next morning was the real test. Joey ran offshore with Captain Matt from Jupiter Fishing Academy into 3 to 4 foot seas at seven seconds. Red snapper season had already been canceled once, and with only two fish allowed per angler, the day was about quality, not quantity.
Matt put the first one in the boat, a red Joey figured at around 15 pounds. Joey had to work for his. He had one slurp the bait right off the bottom and another pull the hook on the way up before a solid snapper finally made it to the net. Then a flatline bait got crushed late in the day and stripped about 100 yards before the fight went to the bottom, where things down there were looking for a meal of their own.
“I am freaking pumped. Red snapper season 2026,” he said. “It got cancelled once, but we got out before they canceled this one.”
Not once did the trolling motor come up after they left the dock. That’s how it should be. The battery is supposed to be the one thing on the boat you don’t have to think about while you’re holding a spot in the Stream with a limit on the line.
Watch Joey’s full install and opening-day snapper trip on his YouTube channel
Jacob Wheeler and MillerTech: Power He Can Count On
Tournament bass fishing comes down to small margins. One fish, one cast, one good decision can be the difference between a trophy and a long drive home. Jacob Wheeler has spent his career winning those small margins, and for years he’s trusted MillerTech batteries to keep his boat powered while he does it.
Who Is Jacob Wheeler
Wheeler won the 2012 Forrest Wood Cup at 21. Since then he’s done just about everything there is to do in the sport: a Bassmaster Elite Series win, 12 Bass Pro Tour wins, and four Angler of the Year titles (2021, 2022, 2024, and 2025).
This April, he added the one title that had slipped away from him for years. Wheeler won REDCREST 2026 on Table Rock Lake with 21 bass for 51 pounds, 11 ounces, and took home $300,000. It was emotional. He dedicated the win to his late father, who had asked him to win one for him.
“It means the world. It really does,” Wheeler said after the final weigh-in.
With that trophy, he joined MillerTech teammate Kevin VanDam as the only anglers ever to win multiple tour championships and four or more Angler of the Year titles.
Years on MillerTech Power
Wheeler’s history with MillerTech goes back well before REDCREST. When he won Bass Pro Tour Stage 4 and $100,000 in May 2023, he’d already been running MillerTech batteries for four years. He’s been part of the MillerTech pro team ever since.
That trust comes from real days on the water. Before he won on Dale Hollow Lake in April 2024 (his eighth Major League Fishing win at the time), a breaker failed overnight and his batteries didn’t charge. Most anglers would be in trouble. Wheeler had a plan.
“MillerTech batteries, I’ve been running them all year. I run three 36V MillerTechs, so I had a backup … plugged that in and I was good to go.” — Jacob Wheeler
Another time, on Lake Erie, Wheeler ran out of gas far from the ramp. His MillerTech batteries had enough left to get him back on the trolling motor, and he made it in as the last boat of the day.
“I Need to Rely on Power”
When Wheeler rigged his new boat for the 2026 season, he posted a video walking through it. He skipped past the electronics and tackle to show what he called “one of the most important pieces in my boat”: his batteries. His caption put it simply:
“When it comes to the new rig for the 2026 season I need to rely on power, which is why I only run MillerTech batteries.” — Jacob Wheeler, Jan. 9, 2026
That season, he went on to win REDCREST.
What He Runs: 36V Trolling Motor Power
In that video, Wheeler walks through his setup. A few years ago he was running two 36V lithium batteries, but fishing as much as he does, he wanted a backup. Now he runs three MillerTech 36V 60Ah Sport Series batteries (#3660-BT) on a quick-disconnect system.
“Now I run three 36-volt, 60-amp-hour MillerTech batteries. … I can quick disconnect two of them that are running parallel and connect it to a backup 36-volt system.” — Jacob Wheeler
Two batteries run his trolling motor in parallel, and the third stays ready as a backup. On the road, that backup has bailed him out more than once. It’s the same backup that saved his morning at Dale Hollow.
“When you’re out there on the road … you’re in an Airbnb a lot of times … storm comes through, you always have backup power. If I went hard on my batteries the day before, now I’m still good to go with that backup 36, and it has saved me a lot of times.” — Jacob Wheeler
The 36V 60Ah Sport Series battery he runs weighs 41.23 lb and replaces three Group 27 lead-acid batteries, cutting more than half the weight. It fits a Group 31 tray. Lithium iron phosphate (LiFePO4) holds a steady voltage as it drains, so your trolling motor pulls as hard in the afternoon as it did at sunrise.
Bluetooth is built in, so you can check every battery on the MillerTech app, up to six at once. It also comes heated (#3660-BTH) if you charge in cold weather, and like every Sport Series battery, it carries our 10-year warranty with shipping paid both ways. We also make 36V batteries in 50Ah and 105Ah.
Team MillerTech on the Water
Wheeler doesn’t just run MillerTech. He fishes for us.
- 2025 Patriot Cup: Wheeler and MillerTech pro Dustin Connell won the Major League Fishing (MLF) Team Series Patriot Cup as Team MillerTech.
- 2025 Black Bass World Championship: Wheeler fished for Team USA in South Africa, and Team USA won team gold.
- 2026 Heritage Cup: On Tims Ford Lake this October, Wheeler and MillerTech pro Adrian Avena won Elimination Match 3 with 40 pounds, 9 ounces of scorable bass and moved on to the Knockout Round.
Power Your Boat Like Wheeler
You don’t need a REDCREST trophy to need batteries you can count on. Whether you run a 24V or 36V trolling motor, we’ll help you match the right MillerTech batteries to your boat.
Call 855-MAX-LITH (855-629-5484) and a real person on our Support Team will pick up in about 10 seconds. You can also email [email protected] or visit millertechenergy.com.
Dustin Connell's MillerTech Lithium Battery Setup | 2026
Dustin Connell’s MillerTech Lithium Battery Setup: “That Is a Bulletproof Setup”
Dustin Connell learned to fish Lake Mitchell, a stretch of the Coosa River outside Clanton, Alabama, from a 14-foot boat with a little 25-horse Mercury on the back. No graphs worth mentioning. No lithium. Nobody was checking battery voltage from the kitchen table.
He’s a three-time REDCREST champion now. When he filmed his 2026 boat walkthrough on the bank of that same lake, the first compartment he opened after the outboard and jack plate was the one holding his MillerTech lithium batteries.
He’ll admit it’s not his natural state.
“I really enjoy opening this compartment,” Connell said. “I’m not really an organized guy. I don’t really keep my stuff organized, but this is organized. This don’t even look like me, does it?”
The tackle box two compartments up proved his point. The battery box is the one place on the boat he doesn’t leave to chance, and his career explains why.
From a 14-Footer to Three REDCREST Titles
Connell won Elite Series Rookie of the Year in 2017, then moved to Major League Fishing and became the first angler to win REDCREST twice: Lake Eufaula in 2021, then Lay Lake in 2024, just up the Coosa from where he filmed this. He made it three in 2025 on Guntersville. Add five Bass Pro Tour wins, three of them in 2022 alone, including Stage Seven on Mille Lacs, and a 2024 season opener on Toledo Bend. That’s nine MLF wins, 35 top 10s, more than $2.29 million in MLF earnings, and a fourth-place ranking on the 2026 Bass Pro Tour.
At that level a dead trolling motor isn’t an inconvenience. It’s the tournament. Connell has been there.
“I remember a day probably on this lake,” he said. “I’ve had it happen on EVERY lake. I had it happen on Lake Dardanelle. We’ve all had it happen. You run your batteries down. You’re done. Your day is over with, bud. It happened here to me several times.”
Three 36V Lithium Trolling Motor Batteries
His answer starts with three MillerTech 36-volt 60Ah Sport Series batteries on the trolling motor side of his Ranger 520R. Each one packs 2,304 watt-hours into a Group 31 case. Two would get the job done. The third is there because he’s lived the alternative.
“I got the 36-volt 60 amp. I have three of them,” Connell said. “I love the lithiums. They have complete power all day long. I am running three. Three is not a must. I never run these two down. But I have a third connected right back there. I have enough room in this 20-footer to have a third. It has a quick connect right here. So, if I had an issue where these two run completely dead or they didn’t charge, something happened … boom. I got a whole other 36-volt. That is a bulletproof setup right there.”
Charging on the Run With Dark Speed
Keeping that bank full is the MillerTech Dark Speed On The Run charger. It pulls from the outboard’s alternator, takes care of the starting side first, then sends the extra to the 36-volt trolling bank while the boat is on plane. Every run between spots puts power back.
“We’re running the Dark Speed Marine charger from MillerTech. I love that charger,” Connell said. “It actually charges while you’re on the run. I’ve just ran that this year and I’m very happy with it. Keeps these batteries fully charged all the time. No battery issues.”
12V Lithium for Cranking and Electronics
The 12-volt side gets the same over-built treatment. Connell runs two MillerTech 12V 135Ah batteries for cranking and electronics, and his electronics list is long. There’s a Lowrance HDS Pro 16 and a 12 at the console, another 16 and 12 on the bow, two ActiveTarget 2 units, NEMA-linked deck lighting and a stereo. He runs it all through a Sea Clear Power harness wired straight to the breaker so the graphs see
full voltage all day.
“I run two. I don’t honestly think I need two, but I have two just in case, because we’re running two 16s, we have two 12s,” he said. “If I am fishing five-fish limit tournaments, I would want to have two as well just for the fact that I’m running live wells. When you’re running live wells, four graphs, whatever you got, you got everything powered up. Let’s say you’re fishing at night, you got lights on. Just have you one more in there just in case.”
Then he made the case for the 135 in plainer terms.
“I’ve got a pontoon. I’ve literally set out on a sandbar drinking sweet tea, listening to music,” Connell said. “You can listen to music for five hours out there.”
Checking Batteries From the House With the MillerTech App
Halfway through the shoot, his buddy Josh idled up in the Ranger 521R Connell ran last season. Connell opened the MillerTech app to show the batteries, and his phone grabbed Josh’s bank before his own. Both boats were reporting in from the bank of Lake Mitchell. That’s the feature he uses most, and he uses it from the house.
“You can be sitting in your house and check them out,” he said. “If you’re getting ready to go fishing and let’s say your batteries were ran low, I need to know if they’re charging for sure, because you never know, a breaker may trip. I do not want to wake up with batteries that are dead.”
He’s had the other version. At one event, his crew plugged a row of boats in for the night, and somebody walked down later to find the power cables pulled completely off.
“Who wants to walk around their garage or outside in their underwear checking their batteries?” Connell said.
We hear some version of that from a lot of the anglers who run our batteries. They don’t want to think about power. They want to fish the grass point, run 20 miles to the next one and know the trolling motor will be there when the boat comes off plane. Connell is a three-time REDCREST champion, and he still spends part of his boat walkthrough on what happens if two batteries fail at once. That’s the
standard we build to.
He gave the full 2026 rig a 10 out of 10. It’s a long way from that 14-footer on Lake Mitchell, and that boat never had a spare 36-volt battery on a quick connect.
Follow Dustin’s season on his Major League Fishing angler page.
How to Winterize Your MillerTech Lithium Batteries
Boats are going into storage, and our phones and inboxes fill up with the same question every fall: how do I store my MillerTech batteries for the winter? The answer is simpler than most people expect. Charge them full, disconnect everything, and put the boat away.
In the video below, Lester Miller, Founder of MillerTech, walks through the questions we hear most this time of year. Here’s what he covers.
The Short Version
- Charge the battery to 100%.
- Disconnect the charger and every load: trolling motor, graphs, all of it.
- Store the boat. Heated or cold, it doesn’t matter.
- Charge the battery to full again in the spring, or at six months, whichever comes first.
Do I Need to Take My Batteries Out of the Boat?No. Storing batteries at room temperature is nice, but it isn’t a must. Most boats have a lot of wires running to the batteries, and there’s no reason to spend an hour pulling them out. If your boat is under a cover or in an unheated building, your batteries can stay right where they are.
Should I Store My Battery Fully Charged?Yes. Charge the battery to 100%, then disconnect the charger. A lithium battery loses only a little charge each month, so you can go six months without recharging.If you want to get technical, 50% is the ideal storage charge. But we’ve done a lot of testing, and the extra battery life you’d gain over one winter isn’t worth the hassle of running it down to 50%. As Lester puts it: “Fully charge it, pull the charger off, and you’re going to be perfectly fine.” Your Sport Series battery is covered by a 10-year warranty either way.
What If I’m Storing It Longer Than One Winter?For long-term storage, say a few years, 50% is worth the effort. Discharge the battery to 50%. When it drifts down to 30%, recharge it back to 50%. That’s the sweet spot for a battery that’s sitting for the long haul.
Should I Disconnect My Charger?Absolutely. Even when it isn’t plugged into the wall, a charger still draws a little power from the battery. Every MillerTech charger has a quick disconnect, so just pull it apart and you’re done.While you’re at it, unhook the trolling motor and remove every other wire connected to the battery. Nothing should be drawing on it over the winter.
How Cold Is Too Cold to Charge?Your battery can sit in the cold all winter. It just won’t take a charge when the temperature drops to 28°F. That’s by design, to protect the cells. Once the battery warms to 32°F, whether the weather turns or you bring it inside, it starts charging again.That’s why the simple routine works: charge it full in the fall, and charge it again when it’s warm enough in the spring. If you need to charge on the boat in freezing weather, ask us about our heated Sport Series models. A built-in heater warms the cells so they can take a charge in the cold.We know cold-weather charging matters to a lot of anglers in northern states, and we’re always testing new battery technology. We’ll share updates as we have them.
Keep It SimpleWinterizing a MillerTech battery comes down to a few steps. Charge it full, take off every wire, and put the boat away, cold or heated. At six months or when spring comes, charge it full again and you’re ready to fish.
Got a question about your setup? Call 855-MAX-LITH (855-629-5484) and a real person will pick up. You can also email [email protected] or visit millertechenergy.com/.
MillerTech Anglers Bring Home Two World Championships
It’s been a big season on the water for Team MillerTech.
Gold for Team USA
MillerTech-sponsored anglers Kevin VanDam and Dustin Connell brought home gold for Team USA at the 2026 Black Bass World Championship!
Held October 1–3 on Lake Hamilton in Hot Springs, Arkansas, the championship brought together top anglers from 22 nations for three days of intense international competition.
VanDam and Connell delivered an outstanding performance, finishing among the top four pairs each day and securing the World Champion title in the pairs division. Their impressive final-day catch of 16.71 pounds helped seal the victory.
Team USA also captured the overall team gold medal, finishing ahead of South Africa and France and claiming its second consecutive world championship.
Congratulations to Kevin, Dustin, and all of Team USA! MillerTech is proud to sponsor these talented anglers and celebrate their incredible achievement on the world stage.
A $500,000 win for Nick LeBrun
Nick LeBrun claimed an incredible victory at the 2026 Ultimate Angler World Championship, taking home the $500,000 first-place prize!
Held October 1–3 on Lake Guntersville in Scottsboro, Alabama, the championship brought together 200 anglers competing for one of the biggest payouts in professional bass fishing.
LeBrun entered the final day in 10th place but delivered a remarkable comeback, weighing in an impressive 28 lb. 2 oz. five-fish limit. His outstanding performance brought his three-day total to 69 lb. 2 oz., securing the World Champion title by 1 lb. 10 oz.
Despite mechanical difficulties earlier in the competition, LeBrun demonstrated determination, adaptability, and exceptional fishing skills to rise to the top of the leaderboard.
Congratulations to Nick LeBrun on this incredible achievement! MillerTech celebrates his well-earned victory and an unforgettable moment in competitive bass fishing.
Congratulations to all three
We’re proud to power anglers who compete at the highest level. Congratulations to Kevin, Dustin, and Nick on an incredible showing.
The same lithium power our pros trust on the water is available for your boat.
Golf Cart Upgrade: Lead-Acid to MillerTech Lithium
These are the projects we love doing. A customer brought his golf cart to us. It was running on lead-acid batteries, and he wanted an upgrade.
We pulled the lead-acid batteries and put in two of our 48V 50Ah Sport Series lithium batteries, installed everything for him, and took the cart out for a test drive. Watch how it went.
Why Switch From Lead-Acid?
- It lasts years longer. MillerTech lithium iron phosphate (LiFePO4) batteries are rated for more than 3,000 cycles and a calendar life of about 10 years. Lead-acid typically gets 150 to 300 cycles and lasts one to two years.
- You get the power you paid for. Lithium delivers 99% of its rated capacity. Lead-acid gives you 50% to 60%.
- No maintenance. No watering and no acid.
- You can see what’s left. Every Sport Series battery has Bluetooth, so the MillerTech app shows remaining capacity, voltage, and temperature on your phone. One app tracks up to six batteries.
- It’s backed for 10 years. Sport Series batteries carry a 10-year warranty. If one fails, we repair or replace it free and pay shipping both ways. The warranty even transfers if you sell the cart.
The Battery We Used:
48V 50Ah Sport Series (Item #4850-BT)Capacity: 50AhVoltage: 51.2VWeight : 48 lbSize: 11.02 × 7.07 × 10.91 inGroup size: GC2Max continuous charge and discharge: 50APeak discharge: 150A for five secondsOperating temperature: -4°F to 140°FBluetooth: YesWarranty: 10 years
Need more range? The 48V 105Ah Sport Series (Item #48105-BT) comes with a power switch and meter you can install right in your dash.
Can Your Golf Cart Do Burnouts?
We bet it can’t. Maybe it’s time for MillerTech batteries.Thinking about upgrading your own cart? Call 855-MAX-LITH (855-629-5484) and a real person will help you pick the right battery. You can also email [email protected] or visit millertechenergy.com.