(46 Reviews)

12V 135Ah Dual Purpose Lithium Battery

12135-DP

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.


Customer Reviews

Danny
Rating: 5/5
This company exceeds expectations in every way!
I decided to purchase my new 12 volt lithium battery and charger from this company and was blown away by the quality of the products and the free delivery. I recently purchased another 24 volt lithium battery and charger for my trolling motor setup because of the superior product and service.
Fri May 01 2026 00:29:03 GMT+0000 (Coordinated Universal Time)
Bryan
Rating: 5/5
Customer Service review
I researched Lithium batteries for marine use and came across Millertech batteries. I ordered the dual purpose 12v battery and I was amazed at how quickly they shipped it out. I downloaded the app for bluetooth and read about their warranty and service and I have to say they have all the bases covered. I like the layout of the battery terminals and the carrying handle. I like their warranty. Thanks so much!
Fri Apr 24 2026 14:53:40 GMT+0000 (Coordinated Universal Time)
Ralph
Rating: 5/5
Unbelievable Battery
This battery ran 2 humminbird units and mega live 2 all day and I never dipped below 12.6 volts. I did run around a bit but when I got home I was sitting at 95% charged. Great unit I should have upgraded long ago. The blue tooth is very handy to keep up with what's happening.
Tue Mar 10 2026 03:20:01 GMT+0000 (Coordinated Universal Time)
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)

What the pros are saying about MillerTech batteries