Class C Motorhomes

1.  Select a battery bank:  The battery bank is the heart of the system. We recommend LifeBlue lithium batteries because of their ease of installation, high quality, and ability to expand over time. We typically recommend installing Lithium batteries in weatherized and ideally insolated compartments. This means that most step-bay are not recommended for lithium, and adjacent side bays or interior compartments are necessary. Additional battery bank options that will fit under the step include Lifeline AGM Dual 6V 220Ah batteries.

We sell LifeBlue batteries as a base kit, which includes one battery, a Victron BMV-712 battery monitor, cable, lugs, and heat shrink, plus expansion kits, which include one battery and parallel cables. For two batteries, select one base kit and one expansion kit. If you want three batteries, get one base kit and two expansion kits.

LifeBlue batteries come in three size configurations, choose what will fit best for your application.

100Ah: H 9.4″ x W 12.5″ x D 6.5″ 28lbs

200Ah: H 10.8″ x W 20″ x D 6.9″ 57lbs

300Ah: H 9.5″ x W 20.25″ x D 11″ 83lbs

If your plan is to run an air conditioner, you will get about 1 hour of runtime on a 15,000BTU A/C running at full per every 200Ah of lithium battery capacity. You will also need at least a 3000VA Inverter, an Easy Start Kit, and three LifeBlue batteries, which means relocating the battery bank to a bay or inside.

Do not let your lithium batteries get below -10° F. Lithium batteries will not charge below 32° F.

Estimated Installation Labor

200Ah LifeBlue Lithium System with BMV-712

10 hours / $1,450

2.  Alternator Charging: When upgrading to lithium batteries you will need to upgrade your battery combiner for alternator charging. Without this modification, the higher resting voltage of a lithium battery will trick the existing battery combiner relay into thinking the alternator is running and the lithium battery bank will be paralleled to the starter battery, even when the ignition is turned off. The result is lithium batteries draining into the starter battery until they crash to a dangerously low voltage or the lithium batteries’ internal BMS engages, preventing further discharge.

If you have a battery bank consisting of two LifeBlue batteries, and/or a smart alternator, you will need to use the Sterling Battery to Battery Charger. This keeps the charging current at a safe level and can be programmable for any battery chemistry. The Sterling Battery to Battery Charger can bring a battery up to 100% state of charge.

If you have a lithium battery system that can handle a charging current of 150A or more (three or more LifeBlue lithium batteries), and you do not have a smart alternator (here’s the Smart Alternator Test) you use the Victron Cyrix-Li-Ct battery combiner, variant “Lithium / 230A”. The Victron Cyrix-Li-Ct can quickly charge a lithium battery up to about 80% state of charge.

Neither device is needed if AGM batteries are used.

Estimated Installation Labor

Sterling Battery to Battery Charger
4 hours / $580

3.  Select solar charging system: Add a solar charging system that will fit on your roof.  As a rough rule of thumb, every 100W of solar will produce about 25Ah (or 300Wh) of charge per day.  If you have a solar pre-wire, check out section 3a of the Airstream page

For a complete explanation of everything you would want to know about how to design a solar charging system, check out our Solar Charger Design Guide

One of the most popular configurations for a Class C is two 200W solar panels on the 30A charge controller.

We recommend a minimum of 500W for any system with a residential refrigerator.

If you want to use a portable panel, we recommend oversizing the central charge controller so it can handle both the roof array and the portable panel.

The Victron SmartSolar MPPT charge controllers are compatible with any battery type, can work on 12V or 24V battery systems, and communicate status via Bluetooth.\

Estimated Installation Labor

2x 200W on 30A Controller
12 hours / $1,740

4.  Select an Inverter/Charger System:  The Victron Multiplus inverter/chargers combine an inverter and a charger in one unit.  They also offer PowerAssist, which means that they can combine shore power with battery power when necessary. Our kits come with everything you need to upgrade your motorhome.

For a Class C Motorhome, you will want kit variants that include the phrase “RV Upgrade Kit”.

The 3000VA inverter/charger is only slightly more expensive than the 2000VA and shaped differently. The 3000VA inverter/charger gives you the option of running an air conditioner or running multiple appliances at the same time, like a coffee pot and a microwave. Installation time is the same for both inverters.

In order to fully support the 3000VA inverter, you will need a battery bank that can handle 300A of current outflow or three LifeBlue batteries. A 3000VA will work on a smaller battery bank, but will only work like a 2000VA inverter if only two batteries are used.

If you plan on running an air conditioner, you will need the 3000VA inverter system with an Easy Start kit. If you plan on running two air conditioners, consider a 24V system with a Victron Quattro 5000.

Estimated Installation Labor

Multiplus Inverter (RV Upgrade Kit)
17 hours / $2,465

5.  DC Distribution:  This is only necessary if you are upgrading to a 24V battery bank, which would be very unusual in a Class C.

When using a 24V battery bank it is important to step down the voltage from 24V to 12V for DC loads.

Estimated Installation Labor

24V DC Distribution Kit
2 hours / $290