From Chris at Off Grid Ham, An Introduction to AC Inverters. Even if you’re already happily running all of your ham radio equipment off grid, at some point you might wish you could run something that wants 120V AC. If you’re not a ham radio operator, and you’re looking into running some household stuff from a battery/solar system, then you also are probably interested in learning something about AC inverters.
AC inverters are like other technology in that during the early years they were very expensive and didn’t work particularly well. Over time they were tweaked and improved and today inverters are better and less expensive than their ancestors. I suggest including an inverter in your off grid plans even if you don’t think you need one because the day may come when it will be an essential asset. Furthermore, if you have any intentions of owning a larger solar energy system to power common household devices, then a familiarity with AC inverters is a must…There are three basic types of AC inverters on the market: Square wave, modified sine wave, and pure sine wave. Which one will work for you depends on what you plan on powering and of course your budget…
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Chris Warren over at Off Grid Ham has a nice article up, How Much Battery Do You Really Need? The article discusses how much radio time you can get from a battery, or conversely how much battery do you need to run your radio.
It’s always some variation of “How big of a battery do I need to run my (fill in the blank) radio?” It comes up a lot, not just in my email but also on the various forums and blogs I visit. The question is too open ended and comes with too many variables to give a definitive answer, but there are some basic battery concepts that will help you sort through this confusing topic.
Before asking the question, provide some answers.
It certainly does not help that many of the answers floating around the internet are based on guessing, hypothetical conditions, and overly generous manufacturer data. Before you can know how much battery you “need”, first find out how much power all your stuff consumes and what you plan on doing with it in the real world. Off Grid Ham reader James (whose question was the inspiration for this article) asked about going off grid with his Yaesu FT-450 radio. The official Yaesu specifications state that this radio consumes maximum 22 amps/304 watts on transmit, and 0.55-1.5 amps/8-21 watts on receive depending on the audio level (these numbers are rounded).
James wants to run his radio with a 35 amp hour AGM battery and charge it with a 2 amp plug in charger. He plans on adding a solar panel at a later time. So what can he realistically expect from this setup?
A 35 amp hour battery can provide 35 amps for one hour. This is known as the C-rate or 1C-rate. The 2C-rate would be 17.5 amps for two hours, the 3C is 11.66 amps for three hours, and so on. Following the math, the 35 amp-hour battery should push James’ 22 amp transmitter for a little over ninety minutes. In the receive only mode, assuming an average of 1 amp, the battery will go for 35 hours.
But let’s deconstruct this…
Read the entire article at Off Grid Ham by clicking here.