Yes, with a Dual Purpose battery:
• 12V 135Ah and 190Ah: 1,500 cold cranking amps (CCA), rated for Mercury four-stroke engines up to 250hp
• 12V 100Ah: 1,000 CCA
• 12V 40Ah: 600 CCA

Yes.

Yes. It’s a good fit for barns, cabins, gates and job sites with no power nearby. Many security cameras need the Security Camera Adapter USB-C 5V (Item #1118-SEC), sold separately.

Yes! Millertech offers reliable lithium batteries for boats, trolling motors, RVs, and more. Our team can help you find the right replacement, backed by our 10-year, no-questions-asked warranty.

Yes. Millertech batteries perform “extremely well in cold conditions during discharge.” Sport Series batteries are rated to run from -4°F to 140°F. The limit is charging in the cold, not fishing in it (see question 25). Greg Hackney ran his while breaking ice: “nothing but raw power, the same as if it was 90° every day.”

It’s the cleanest way to run serious electronics. Millertech’s Electronics batteries are built to give “consistently clearer images and stronger signals” on your graphs all day. They also keep electronics off your trolling motor and cranking batteries. If you’d rather run one battery, the Dual Purpose line cranks your engine and runs graphs and accessories too.

No. The heater turns on only when a charger is connected and the battery is below 32°F. It warms the cells, then charging starts.

Most RVs use the same 12V house system, so the same batteries work across them. The differences are in charging:
• Travel trailers and fifth wheels: charging from the tow vehicle is limited (see question 42).
• Motorhomes: the engine’s alternator can charge your house batteries, but only if its output tops out at 14.6V or below.
• Camper vans: space is tight, so the smaller size and lighter weight of lithium matter most.
Tell our Support Team what you drive and we’ll match a battery to it.

Rather than trade claims, compare what you can check – Millertech offers the following:
• Warranty: 10 years, shipping paid both ways, no proof of purchase needed.
• Support: a real person in Ohio answers in about 10 seconds.
• Remote help: Millertech can troubleshoot a Sport Series battery through the app.
• App: monitors up to six batteries in one place.

Roughly half or more. One 36V 60Ah Sport Series battery (3660-BT) weighs 41.23 lb and replaces three Group 27 lead-acid batteries. Millertech says that cuts more than 50% of the weight. For 12V, a Millertech 100Ah AGM weighs 70 lb, while the 12V 100Ah Dual Purpose lithium weighs 31 lb.

It’s still worth a look, but for different reasons. If you’re always plugged in, you won’t feel the extra run time much. You will notice the weight: our 12V 100Ah weighs 26.55 lb, about a third of a 100Ah AGM. You’ll also skip the water checks and corroded terminals, and you won’t be replacing batteries every few seasons. If you’re starting to think about dry camping, lithium is where it really pays off.

Yes, once you look at cost per cycle and not just the price tag. A Millertech LiFePO4 battery is rated for more than 3,000 cycles, compared with 600–800 for an AGM. It can also last up to 10 times longer than sealed lead-acid. Add the 10-year Sport Series warranty and it costs less over the life of your boat.

No. Phones and laptops use lithium-ion cells built to pack the most power into the least space. Millertech RV batteries use lithium iron phosphate (LiFePO4), which is widely recognized as one of the most stable lithium chemistries. It gives off no gas while charging, and our batteries are UL certified to UL 1973. (Myths blog; UL certified page)

1Ah equals 1,000mAh, so the Max 8.0 is a 28,000mAh battery and the Max 4.0 is a 14,000mAh battery. Watt-hours (Wh) are the fairest way to compare packs at different voltages: the Max 8.0 stores 310Wh and the Max 4.0 stores 155Wh.

The BMS is the battery’s built-in brain. It watches voltage, current and internal temperature, and it protects against:
• Overcharge and over-discharge
• Over-temperature
• Short circuit
• Reverse polarity and over-current (through a dual-blade fuse)
Millertech uses a commercial-grade BMS sized at least 20A above the battery’s rating.