A camping trip in your RV sure brings about a lot of fun for the whole family. However, the complexity of the electrical systems can feel a bit intimidating for some people.
The good news is, it doesn’t have to be that way! You can learn some basic stuff that should help you leverage your RV’s potential.
Today, we’ll discuss the battery. You’ll know what you can run off RV battery and how you can calculate its capacity. Let’s get going!
Most, if not all, RVs have two electrical systems. The first one operates via a 110V AC power, and the second works with a 12V DC power.
The alternating current (AC) system is the one connected to the wall outlets, just like what you have at home. This powers any “luxuries” like the TV, air conditioner, coffee machine, toaster, laptops, and similar devices.
With such a heavy load, your AC system primarily depends on shore power at communal campsites. If you’re into dry camping, you can still derive a similar amount of power from a portable or a built-in generator.
On the other hand, the direct current (DC) supplies appliances that don’t require that much power. The water pump, lights, and propane fridge are among the components that run on this line.
This system can flawlessly operate on your RV’s house batteries. This is clearly different from the chassis batteries, aka starting batteries, that power your RV engine.
Whenever I discuss the electrical systems of RVs, some people think that the AC and DC systems run independently of each other. But nothing could be further from the truth.
When you hook up your RV to a shore cable or a generator, a small part of that power goes to a special component called the “converter.” If properly connected, the converter should transform the 110V AC into a 12V DC. This way, it’ll automatically charge your house batteries and chassis batteries, for that matter.
Generally speaking, I don’t recommend running a portable generator while driving. The toxic carbon monoxide fumes can build up and cause serious respiratory damage. Nevertheless, that doesn’t mean you’ll have to forget about watching TV and making coffee on the road.
With the right “inverter”, you can transform the 12V DC output of your battery into 110V AC.
Based on the previous sections, your house batteries can directly power minor devices like the lights, water pump, propane fridge, and your RV’s warning systems.
If your circuit has an inverter, you can ramp up the battery power to run basically any device. However, it’s important to know that bigger devices will deplete your battery faster than usual.
That said, I always recommend keeping tabs of the amperage used by your devices. This way, you can do the math to know how many hours your battery would last.
Before calculating your RV’s amperage, you must understand the technical jargon behind your battery.
The most basic parameter that describes the battery’s power is the amperage per hour (Ah). As the name implies, this should tell you how much amperage the battery can give for how many hours.
For example, a 100Ah battery should be able to give 1 amp for a total of 100 hours. With a more realistic rate, it can also give 10 amps for about 10 hours. However, these estimates are just theoretical. The battery discharge can’t be considered as a linear formula with only two variables.
To put things into perspective, let’s say you’re simultaneously running several devices that use about 20 amps in total. The formula would predict about 5 hours of runtime. But in reality, the actual duration may be way shorter.
As you’re draining more current, more heat will be generated by the battery’s internal components. Without getting into technical details, the extra heat will negatively affect the chemical reactions, thereby accelerating the discharge rate.
The Reserve Capacity (RC) is another parameter that measures a battery’s capacity. Unlike AH, it describes the discharge rate in a logical environment. RC denotes the number of minutes a battery will give 25 amps at 80 °F before it drops below 10.5 volts.
For example, a 125RC battery will supply 25 amps for about 2 hours if the temperature remains at 80 °F.
Here’s where things may get a bit tricky. To know how much amperage every device uses, you’ll have to go through a somewhat meticulous process. I’ll assume we’re considering a coffee maker to make things easier.
At the bottom of your device, you should find the watts and volts used per hour. Coffee makers are generally rated at 1425 W and 120 V. To calculate amps, divide watts over volts. Now we know that this device uses a bit less than 12 A per hour.
However, unless you’re a coffeeholic, it’s not typical to use this machine for a whole hour per day. If you prepare 4 cups daily, that should add up to around 12 minutes, which translates to about 2.5 A.
After carrying on with that process for all your RV devices, you should compare the total to your battery’s AH and RC ratings to find out how much it’d last.
Like I said earlier, you don’t have to be an expert to enjoy your time in an RV. If the previous process seemed too complicated, ignore it. To be on the safe side, I’d recommend investing in the highest capacity you can find. You’ll be sacrificing space, but you’ll enjoy more TV and coffee before your battery dies!
When comparing two batteries together, make sure you’re comparing the same parameters together. Theoretically, a 100AH battery giving 25 amps should last for 4 hours. A 100RC battery, on the other hand, will last for an hour and a half with the same usage rate.
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