When it comes to powering your boat or RV, understanding the difference between watts (W) and volt-amperes (VA) is crucial, for ensuring your systems run smoothly without any unexpected hiccups, especially when choosing the right inverter or inverter charger. For anyone not familiar with these concepts it can be very confusing. Unfortunately, what you don’t know can hurt you. This blog will simplify these concepts, helping you make informed decisions when selecting power equipment for your adventures.
Imagine you’re at a bar, and you order a pint of beer. The bartender hands you a glass full to the brim, but as you lift it to drink, you notice a thick layer of foam on top. The beer in the glass is what you really want, while the foam is just taking up space.
Watts (W): The beer itself represents the real power—this is what powers your devices.
Volt-Amperes (VA): The combination of beer and foam represents apparent power. While the glass looks full, not all of it is useful beer; some of it is just foam.
In technical terms, watts measure the actual power your devices use, while VA measures the total power that the inverter supplies, including both useful power and power lost in inefficiencies.
Why Focus on Watts for Inverters and Inverter Chargers?
When selecting an inverter or inverter charger, especially for a boat and RV applications where space and efficiency are at a premium, you should focus on watts rather than VA. Here’s why:
Real Power Consumption: Devices onboard your boat or RV consume real power (watts). To ensure that your inverter can handle your load, you should match it to the watts, not the VA.
High Operating Temperatures: Inverters often operate in high-temperature environments, like inside an RV on a hot day or in the engine room of a boat, where temperatures can reach 40°C or more. At these temperatures, inverters may need to be derated, meaning they can’t produce their full rated power. Watts gives you a more accurate measure of what the inverter can handle under these conditions.
Derating Concerns: As the temperature rises, the performance of electronic components decreases. Focusing on the watt rating ensures you’re considering the actual power your inverter can deliver, even when conditions aren’t ideal. VA ratings might not give you a true picture of performance in hot environments.
Efficiency Matters: When you choose an inverter based on watts, you’re prioritizing efficiency. An inverter with a high VA rating but low watt output is like a glass with more foam than beer—looks good, but it doesn’t deliver when you need it.
When you’re out on the water or on the road, what matters most is the real power that’s running your devices. Selecting an inverter or inverter charger based on watts ensures you’re getting the power you need, especially in high-temperature conditions where performance can drop.
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