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.

No. It has DC barrel plug output for cameras and USB-A and USB-C ports through the hub. It’s built for USB gear and 12V-style camera power, not for household plug-in appliances. For bigger off-grid power, call our Support Team about Millertech’s larger batteries and inverters.

Both the Max 4.0 and the Max 8.0 have a built-in battery usage meter.

An adjustable mounting strap comes in the box, and the battery has a removable mounting plate. For bigger trees or posts, add the 48" Nylon Strap (Item #1124).

Plug in the battery charger that comes in the box. Need a second charger for the cabin or the truck? The 12.6V 3A AC Charger (Item #1123) and the 12.6V 2A AC Charger (Item #Z3085) are sold separately.

We’ll provide a prepaid UPS shipping label for your return. Simply box up the battery, attach the label, and drop it off at a UPS location.

To winterize:
• Charge the battery fully.
• Disconnect every load and cable.
• Store it with nothing attached.
LiFePO4 loses only about 1–3% of its charge per month, so it holds charge well over the off-season. Millertech’s “How to Winterize Your Boat’s Millertech Batteries” video walks through it.
How to Winterize Your Boat's MillerTech Batteries

• Charge the battery fully.
• Disconnect every load and cable, or leave a solar panel connected with the controller on a lithium setting (see "Can I Leave My Solar Connected While My RV Is in Storage?").
• Store it with nothing else attached.

LiFePO4 loses only about 1% to 3% of its charge per month, so it holds its charge well through the off-season. Millertech's winterizing video walks through it.

To wake up a lithium battery in protection mode, use a lithium charger, which is specifically designed to bring the battery out of low voltage protection/sleep mode. If the lithium charger doesn’t work, you can try “jumping” the battery by connecting it to a dedicated jump pack or another battery. Using equipment designed for lithium batteries is the most effective and recommended way to reactivate a battery in protection mode.

The simplest way is one 36V battery, which needs no series wiring. If you’re wiring three 12V batteries in series, Millertech allows up to four in a string. Watch the “Series & Parallel Battery Connections 101” video. Torque terminals to 10 ft-lb.
Series & Parallel Battery Connections 101

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.

From empty to full with the included 2A charger, the Max 8.0 takes about 14 hours and the Max 4.0 takes about seven hours.