How A lot Photo voltaic Does Your RV Want?


Many fashionable RVs now function roof-mounted photo voltaic panels and the accompanying electrical programs to retailer and convert photo voltaic vitality to be used with inside lights and home equipment. However how a lot solar energy does your RV want? And can your photo voltaic system present sufficient?

The reply is a bit advanced and, as you’d think about, requires some math. However earlier than we dive into the main points, let’s discuss in regards to the important elements of an RV photo voltaic vitality system. 

How Ought to You Use Photo voltaic Vitality in an RV?

Most RVers make the most of photo voltaic panels to trickle cost their battery financial institution, to not present energy for an prolonged boondocking keep. Photo voltaic panels may also provide help to keep away from over-discharging your batteries once you aren’t related to an influence hookup. 

The facility that comes from photo voltaic vitality is in DC, which then should be inverted to AC to energy AC home equipment. 

However, realistically, photo voltaic vitality ought to be used to complement your RV’s vitality calls for, as you’ll with a moveable energy station, an onboard generator, or a transportable generator  Sure, photo voltaic can be utilized to energy a whole RV for just a few days. However the restricted roof area on most RVs makes putting in the requisite variety of panels for prolonged photo voltaic viability practically not possible. 

Usually, maximizing your RV’s photo voltaic potential is a matter of maximizing out there roof area. If you would like as a lot photo voltaic assortment potential as potential, cowl as a lot of your roof with photo voltaic panels as is secure and reasonable. 

After all, it’s essential to retain area to entry a totally walkable roof for repairs and your annual RV roof inspection. Your panels shouldn’t crowd current roof equipment like your air conditioner and roof vents.

Should you’re a full-time RVer that seeks long-term stays, you’ll have extra freedom to make use of moveable photo voltaic panels or briefly mount additional panels on the roof or the bottom round your RV. Nonetheless, the effectivity of most photo voltaic panels makes putting in sufficient – with the correct elements – cost-prohibitive as a standalone energy supply on your RV. 

Study extra about conserving and creating energy when boondocking.

RV Photo voltaic Parts

Listed here are the principle elements put in in RVs with photo voltaic functionality – often known as photo voltaic prep. These elements are crucial whatever the dimension of your photo voltaic vitality system.

Photo voltaic Panels

RV solar panels
Photograph by Tenting World

Photo voltaic panels collect vitality from the solar and ship it via electrical wiring to your system’s cost controller. Including photo voltaic panels permits you to collect extra vitality, however you might also have to improve different elements to securely switch and efficiently retailer that vitality.

There are two varieties of photo voltaic panels: monocrystalline and polycrystalline. Monocrystalline photo voltaic panels are extra frequent for RVs as a result of they supply extra effectivity for the restricted roof area you’ll have on most models.

Discover our number of moveable and mounted photo voltaic panels.

Photo voltaic Cost Controller

Close up of solar charge controller
Photograph by Tenting World

A cost controller takes the vitality that your photo voltaic panels harness and regulates it right down to a helpful voltage. The vitality coming out of your panels varies in voltage. A cost controller is crucial for changing that voltage into the 12-15 volt vary to correctly cost your battery financial institution.

The 2 foremost varieties of photo voltaic cost controllers are most energy level monitoring (MPPT) and pulse width modulation (PWM). PWM controllers use older expertise and are much less environment friendly however are extra reasonably priced. MPPT controllers value extra, however they’re rather more technologically superior and offers you extra long-term worth on your funding.

Store for photo voltaic chargers and controllers. 

Batteries

Man connecting electrical cables to RV battery
Photograph by Tenting World

Your battery financial institution supplies the space for storing for the vitality your photo voltaic panels harness. They retailer vitality till you turn on an RV equipment and demand vitality out of your batteries. 

There are three foremost varieties of RV batteries: lead acid, absorbent glass mat (AGM), and lithium. 

Lead acid batteries had been the standard normal, however AGM and lithium batteries are extra generally utilized in RVs with photo voltaic setups at present.   

Study extra in regards to the professionals and cons of the various kinds of RV batteries.

Inverter

Technician testing RV inverter
Photograph by Tenting World

An inverter takes the 12-volt vitality saved in your batteries and converts it to 120-volt vitality to serve retailers and home equipment that require that voltage for secure operation. There are a number of various kinds of inverters, however RVs with photo voltaic ought to boast a pure sine wave inverter. 

Pure sine wave inverters do the perfect job mimicking the facility you’ll get with a family 120-volt plug. They supply the cleanest vitality to cut back the danger of damaging delicate electronics inside your RV.

Moreover, RVs prepped for photo voltaic are outfitted with the correct electrical programs to assist use the vitality that your photo voltaic panels harness. These elements embody however aren’t restricted to a battery monitor, battery isolator, bus bar, wires, fuses, breakers, switches, and retailers.

Contact our efficiency and enchancment division in case your RV is not prepped for photo voltaic and also you need to discover your choices for including photo voltaic. 

RV Photo voltaic Calculator

Close up of solar panels on RV roof
Photograph by Tenting World

So, how a lot photo voltaic do you really want on your RV? It’s time to crunch some numbers. Get out a pen, paper, and a calculator. 

Report Wattage for Digital Home equipment and Units

Your first step is to record all of the gadgets and home equipment that devour vitality and file their working wattages. Your record ought to embody home equipment put in in your RV and gadgets you generally plug into energy retailers, corresponding to hair dryers, toaster ovens, and cellphone/laptop computer chargers. 

The wattage on your RV home equipment is often present in your proprietor’s guide, on-line, or on an identification sticker someplace on the equipment. 

If the wattage isn’t listed, you’ll be able to remedy for wattage utilizing this equation: 

Wattage = Amps x Volts

In case your air conditioner pulls roughly 15 amps when working on 120-volt AC energy, its working wattage is roughly 1,800 watts. It pulls extra surge wattage when beginning up, nevertheless. 

Surge wattage accounts for the extra wattage wanted to start out {the electrical} motor or fan in home equipment and mills. 

Right here’s an instance of RV home equipment and their respective wattages (yours will range): 

Equipment Watts
Air Conditioner 1,000
Microwave 600
Water Pump 60
Fridge 1,000
Espresso Maker 1,000
Hair Dryer 1,500

Estimate Every day Utilization Hours

When you’ve listed your home equipment and their wattage wants, revisit every machine/equipment and estimate what number of hours you’ll use them every day. Chances are you’ll run your air conditioner for 8-12 hours a day in the summertime, however you’ll most likely solely run your microwave for a complete of 5-10 minutes. 

Return via your record and add a column for utilization hours subsequent to every equipment. 

Let’s add to our desk above: 

Equipment Watts Utilization Hours
Air Conditioner 1,000 4
Microwave 600 0.25
Water Pump 60 1
Fridge 1,000 4
Espresso Maker 1,000 0.1
Hair Dryer 1,500 0.1

Choose AC versus DC Energy

Run again via your record and mark which home equipment run on DC and which require AC. AC home equipment require an inverter, as we talked about above, and it’s essential to consider a median 10% effectivity loss for home equipment that require an AC inverter. 

Meaning a 1,000-watt air conditioner will truly require roughly 1,100 watts when working on energy from an AC inverter. This comes into play later when calculating every day watt-hours.

We’ll amend our desk to point AC versus DC home equipment. Discover how the wattage modifications barely for AC home equipment: 

Equipment Energy Supply Watts Utilization Hours
Air Conditioner AC 1,100 4
Microwave AC 660 0.25
Water Pump DC 60 1
Fridge AC 1,100 4
Espresso Maker AC 1,100 0.1
Hair Dryer AC 1,650 0.1

Calculate Every day Watt-Hours of Vitality Use

It’s time to calculate the full watt-hours of every day vitality consumption you estimate on your off-grid adventures. This offers you the utmost quantity of energy you anticipate to make use of every day. For RVers that journey seasonally, sure climates require using extra home equipment like area heaters or dehumidifiers. 

Calculate your vitality utilization for all seasons to have essentially the most correct thought of how a lot photo voltaic you really want on your RV. Make the most of the very best estimate when designing the perfect photo voltaic setup for year-round RV journey.

Let’s add watt-hours for every equipment, in addition to a complete calculation: 

Equipment Energy Supply Watts Utilization Hours Watt Hours
Air Conditioner AC 1,100 4 4,400
Microwave AC 660 0.25 165
Water Pump DC 60 1 60
Fridge AC 1,100 4 4,400
Espresso Maker AC 1,100 0.1 110
Hair Dryer AC 1,650 0.1 165
Whole Watt Hours 9,300

Convert to Amp Hours

Together with your estimated watt hours recognized, you’ll be able to calculate what number of amp hours of vitality storage capability your battery financial institution should present. To calculate watt hours, you’ll divide watt-hours by voltage. 

Listed here are the outcomes of our calculation:

Equipment Energy Supply Watts Utilization Hours Watt Hours
Air Conditioner AC 1,100 4 4,400
Microwave AC 660 0.25 165
Water Pump DC 60 1 60
Fridge AC 1,100 4 4,400
Espresso Maker AC 1,100 0.1 110
Hair Dryer AC 1,650 0.1 165
Whole Watt Hours 9,300
Whole Amp Hours 775

Learn how to Select RV Photo voltaic Parts

Now it’s time to make use of our calculations to pick out properly-rated elements for our RV’s photo voltaic system. 

Select Your Battery Kind

Three RV Batteries sitting on a table
Photograph by Tenting World

Our whole amp hours are our information for choosing the proper battery. Our selection will differ primarily based on the kind of battery we wish. 

For lithium batteries, it’s suggested to keep away from exceeding a depth of discharge of 80%.

Meaning we should add 20% to our whole amp hours (775 x 1.2 = 930 amp hours). This converts to a lithium battery financial institution with a minimal of 11,160 watt-hours of energy (930 x 12 = 11,160).

If we select a 100 amp hour lithium battery, we’ll want 9.3 batteries to retailer all of the vitality consumed every day. You possibly can see how that might be prohibitive, each when it comes to space for storing and cargo weight. 

For AGM and lead acid batteries, we don’t need to exceed a depth of discharge of fifty%, that means we have to double our minimal amp hour threshold (775 x 2 = 1,550 amp hours). This converts to an AGM or lead acid battery with a minimal of 18,600 watt-hours of energy (1,550 x 12 = 18,600)

If we select a 100 amp hour AGM battery, we’d want 15.5 batteries to retailer the vitality we devour every day. As your depth of discharge will increase, you’ll require a bigger battery financial institution (i.e., extra vitality storage capability) to compensate. 

Select Your Inverter Measurement

Your optimum inverter dimension is predicated on the mixed wattages of the home equipment you intend to energy with it. The mixed wattages of our 5 AC home equipment above whole 5,730 watts. Nonetheless, it’s secure to multiply by 1.5 to permit for startup wattage necessities (i.e., surge wattage). 

So, on this use case, we’d advocate an inverter that may deal with a minimum of 8,595 watts. 

Estimate Hours of Solar Publicity to Get Photo voltaic Panel Wattage

RV with Solar Panels on the Roof
Photograph by Tenting World

Most photo voltaic specialists advocate utilizing 4 hours of solar publicity as a conservative estimate. Your precise variety of solar hours relies on your location and publicity to direct daylight. 

In additional southern areas like Arizona, you might obtain nearer to 5 to eight hours of direct daylight. You’ll additionally improve your solar hours in case your photo voltaic panels can tilt for an optimum angle because the solar strikes throughout the sky. 

To stay with a conservative estimate, let’s say you obtain 4 hours of direct daylight every day. To calculate what number of watts of photo voltaic panels you’ll want, divide vitality consumption (watt hours) by hours of solar publicity. 

9,300 watt-hours / 4 hours = 2,325 watts

Contemplating the truth that most moveable and roof-mounted RV photo voltaic panels seize between 80 and 440 watts, we’d want wherever from six to 29 panels. It’s uncommon that RV roofs have sufficient area for this many panels, which is why we would additionally think about a moveable generator or energy station to complement and recharge our RV’s battery financial institution. 

Even when we lowered our vitality calls for to three,500 watt-hours and we had been tenting someplace with eight hours of every day solar publicity, we’d nonetheless require 440 watts of photo voltaic panels. That will require the roof area to put in this entire photo voltaic equipment from Nature Energy.

Select Your Cost Controller

Your cost controller should be rated to deal with the wattage of your photo voltaic panels. A cost controller’s minimal amperage will be calculated by dividing your photo voltaic panel’s wattage by your battery financial institution’s voltage. 

Persevering with with our energy-intensive RV proprietor’s instance from above, we’d divide our required 2,325 watts of photo voltaic panels by 12 volts to calculate a great cost controller amperage of 193.75. This implies we’d want a minimal 190-amp cost controller to deal with this type of demand. 

Our extra energy-saving instance would nonetheless require a minimal of a 35 amp cost controller (440 / 12). 

How A lot Photo voltaic Do You Actually Want for Your RV?

In case your RV is prepped for photo voltaic, however you don’t have any panels but, seek the advice of your producer for his or her suggestion. The elements utilized in your photo voltaic prep will let you know what number of watts of photo voltaic panels you’ll be able to fairly add. 

On the whole, it’s really helpful to have about 300 watts of photo voltaic panels for each 100 amp hours of battery financial institution capability. That equates to a minimal of 600 watts for RVs with a 200 amp-hour battery capability and a minimal of 1,200 watts for bigger motorhomes and fifth wheels with 400 amp-hours of battery storage capability. 


Whether or not your RV is prepped for photo voltaic otherwise you’re on the lookout for a whole photo voltaic set up, our licensed efficiency and enchancment technicians are at your service. Contact our group to schedule an appointment at present.

What questions do you will have about including photo voltaic panels to your RV? Tell us within the feedback under.


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