12V 135AH Dual Purpose Starting Battery w/ BT (12135-DP)

(43 Reviews)
$949.00

Free shipping

Applications For This Battery

A POWERFUL ALL-PURPOSE BATTERY THAT’S PERFECT FOR STARTING ENGINES AND DEEP CYCLE USE IN RVS, BOATS, GOLF CARTS, AND TINY HOMES.

The Ultimate Battery in Energy Density and Versatility.

The 135AH Dual Purpose battery has 1500CCA + 135Ahrs of Deep Cycle Storage, Built in low-temp charging protection. A Dual Purpose package ready to power you passions! Bluetooth lets you monitor everything at you fingertips.

Millertech Dual Purpose meets and exceeds any charging or cranking requirements actually needed to work with the Mercury 4 stroke up to 250hp. We have many customers using them to start their motors since 2016 with no issues.

Items you may need with this battery:

Download ManualDownload Sports Series WarrantyApple StoreGoogle Playstore

Share

Capacity
135AH
Voltage
12.8V
Weight
33 lbs
Size
13” x 6.75” x 9”
Warranty
10 years

BMS: Yes
Chemistry: LFP
Efficiency: 98%
Memory: None
Max Charge/Voltage: 14.6V
Cut-off Voltage: 33V
Max Charge/Discharge Current: 1035
Operating Temp: -4°F – 140°F
Low Temp Charging Protection: Yes
Group Size: 31
Cell Type: Prismatic

Bluetooth: Yes

Dual Purpose Batteries LiFeP04 are quickly becoming a popular item that many enthusiasts demand. Our team of Engineers and Technicians are a very aggressive group and were not willing to take a backseat on this trend. This battery has enough cranking amps to start even the largest engines in the industry, plus they have enough reserve capacity to power multiple power hungry graphs for 8 plus hours. These Dual Purpose models will change the way anglers think about there power needs forever.

(KEY FEATURES)

10 year Industry Leading Warranty

BCI Group Size 31

Bluetooth activated to connect directly to our MillerTech App. The MillerTech App gives you in depth, real-time data, taking the guessing game completely away. Power with Confidence!

Custom moulded, heavy duty, reclosable battery case. This means if you ever have an issue with your battery no matter is it in year 5 or year 15 we will always have easy access to repair any defective parts. This custom case also has convenient hold down strap grooves moulded into the side corners helping to keep your straps seated securely in place.

Large heavy duty battery terminals ensuring there is no heat build up when your application demands maximum power!

The Sport Series Marine batteries are all sealed with a thick rubber gasket along the lid connection point. This means they are Marine approved IP65 rated. A completely sealed battery case will cause condensation, so we build them with a marine grade Stainless Steel breather vent. Our vent sits on the top of the case unlike some others where the vent sits down inside catching rain and dirt.

A 10 year warranty is not a commitment we take lightly. We believe a warranty is only as good as the company and the people standing behind it. We do realize there is a certain uncertainty about how a company will handle a warranty claim if the need should ever arise. With MillerTech our hope is that the customer will have no doubt in his mind about how we will approach warranty claims. Our company is built on a Golden rule priniciple that we have inherited from many generations of Anabaptist forefathers. We pledge to always put the customer and his needs first.

 

THE MILLERTECH® SPORT SERIES LITHIUM BATTERY
10 YEAR GUARANTEED WARRANTY IS SIMPLE!

TERMS:

From the date of your battery purchase through year number 10 of ownership, your battery is covered. If it stops working during this time, we will repair or replace it with a battery of equal or greater value for FREE!

SHIPPING:

We cover all shipping costs associated with shuttling your battery back and forth for repair or replacement. It is our warranty; it is our cost; not yours.

EXCLUSIONS:

There are NONE! You trusted Millertech®, and if it’s within the warranty period your Millertech® battery is completely covered for everything!

PROOF OF PURCHASE:

You don’t need one. If it’s Millertech®, it’s covered!

FOR WARRANTY SERVICE CALL: 855-MAX-LITH
EMAIL:  warranty@millertechenergy.com

Customer Reviews

Michael
Rating: 5/5
Great cranking multi-purpose deep cycle battery
I am amazed at the technology that's in this battery I fished all day today for the first time after installing the $135 amp hour cranking battery with my two lowrance HDs 12 live screens on all day when I got home and check the health of the battery it was at 99%
Wed Dec 17 2025 19:58:17 GMT+0000 (Coordinated Universal Time)
Eric Mullen
Rating: 5/5
Solid Battery
Runs entire boat including a 10 , 12 , 16 graph plus FFS unit with turret. Also running Power Brakes , 2 oxygenators and air pump for livewell. Have never got under 90% even during tournaments. This is the only 12V battery you need for the boat combined with a 36V 60ah Millertech on the trolling motor. Will last all day long and then some. Best quality and the best customer service in the business!
Tue Oct 14 2025 01:48:34 GMT+0000 (Coordinated Universal Time)
Chris Eads
Rating: 5/5
Awesome battery
Easy install, fast charging, maintains consistent power. Love the power distribution blocks as well.
Mon Oct 13 2025 01:55:33 GMT+0000 (Coordinated Universal Time)
James Bozin
Rating: 4/5
Good for electronics
I was having issues with the AGM because of the voltage. This one kept voltage rock steady all day. I'd prefer some sort of post of stud arrangement. The bolt they sent were too short. I had to purchase for ARP SS studs and washer up.
Fri Oct 03 2025 13:10:08 GMT+0000 (Coordinated Universal Time)
TJ Riley
Rating: 5/5
Awesome!
Justin Lucas turned me onto these batteries and man am I glad! They are awesome! I will definitely be recommending these to all my friends!
Fri Oct 03 2025 01:56:25 GMT+0000 (Coordinated Universal Time)
Casey Geiger
Rating: 5/5
Amazing customer service
Want to thank Millertech for not only helping me configure my power setup but explaining exactly what I needed vs trying to sell me extra equipment. Hands down one of the best experiences.
Fri Aug 29 2025 20:47:09 GMT+0000 (Coordinated Universal Time)
Rolf Deis Jr
Rating: 5/5
12v 135amp Dual Purpose Battery
Not much to say other then it was shipped quickly and had great support from the folks at Miller Tech. Got the battery in and tested starting the motor a bnch of times and really n9ot much impact on the meter. I can see it is way better than my last AGM battery. No worries about getting stranded with this battery. Not to mention its about 50lbs lighter than my old blue top. Top notch!
Tue Jul 22 2025 00:00:00 GMT+0000 (Coordinated Universal Time)
Blake Bailey - NO-LIMIT OUTDOORS
Rating: 5/5
Best batteries on the market
Running 3 graphs and live scope. Battery set up is two 12V 135ah in parallel I crank and run everything off of those. My trolling motor setup is 2 36V 50ah. I can comfortably without a shadow of a doubt fish two long days without a charge.
Thu Jul 10 2025 14:46:09 GMT+0000 (Coordinated Universal Time)
Danny Hamm
Rating: 5/5
Top of the line Lithium battery. Great power and dependability.
Wed Jul 09 2025 23:35:59 GMT+0000 (Coordinated Universal Time)
david bear
Rating: 5/5
I am super happy with MillerTech batteries. It’s a big relief to be out on the water without any worries of my batteries running down
Mon Jul 07 2025 19:01:04 GMT+0000 (Coordinated Universal Time)

What the pros are saying about Millertech batteries