JY Power is the first mobile audio-based battery company to publish a comprehensive power chart and spec sheet. Why did we do that? Simple. Calculating the right combination of amps, alternators and (of course) batteries is a hell of a lot harder without it. No hiding numbers. No B.S. ratings. Just the facts.
Today, we’re going to check out the Power Chart.
The first thing to ask is actually NOT the power capacity of the battery; it’s the efficiency of your amplifier.
Amplifier efficiency tells you how much power is really getting to the subs. Every amplifier converts a certain amount of power into heat. That heat is wasted energy, that never gets to the subwoofer. Most Class D amps are around 75% efficient. Some are more. Some are less.
If you have a multimeter and clamp, you can calculate your amps efficiency. If you want truly accurate info, don’t rely on the spec sheet – measure it on your own. Manufacturers almost never deliver that info on every individual amplifier, as long as the amp falls within certain tolerance it simply “passes.”
Here is the quick math:
Wattage / Draw (Battery Voltage x Amplifier Draw)
1000 watts / (14 Volts x 100 Amps)
1000/1400 = 0.71
So this amplifier is 71% efficient. Now that we know that, we can figure out how much power the battery will actually deliver to the amplifier(s). Simply divide the power the battery will support by the efficiency of the amp. If the amp is 71% efficient and you are using an HP-40 standalone (no alternator), your subs should need about 3,834 watts (71% of 5,400).
For the sake of not making this article very, VERY long we are assuming you know how to calculate and measure battery voltage, amplifier wattage and current draw. Contact us if you want the entire calculation from scratch.
You: “So Travis, how long will my battery last?”
This is important. No one – and I mean no one – can tell you exactly how long the battery will play before it needs recharging. If you remember The Cube, we routinely played that system non-stop for six hours straight or more, full send. That was 60,000 watts.
The music you play varies note by note, which means the amount of power it requires will change literally thousands of times every single second. The volume level you play it at, the type of music you play, etc… all makes a difference. The only way to know is to watch the volt meter and determine your own personal “normal”.
Since most people have at least a factory alternator connected to the battery, the chances are very high that you will never completely discharge the battery. Since your alternator is probably running while you are playing your system, the battery is recharging as you play. The bigger the alternator – the faster it will recharge, and the harder it is to drain.
Not to repeat what it says on our main web page (but I’m going to), this is one of the massive advantages a Lithium battery has over AGM. They can recharge from completely dead to completely full in 15 minutes. If a comparable AGM battery dies it will take about 20 hours to recharge.
Another is weight. To get the same kind of power from an AGM battery, you would need about six Group 31 batteries. That’s over 400 pounds. The HP-40 is 15 pounds. Essentially the AGM guys are literally adding over 28 times the weight to their vehicle.
The last is, of course, money. Each one of those AGM batteries is about $400. So, to get the power of one HP-40, you have to pay about $2,400. That’s roughly 2 ½ times the price of our battery. The advantages are clear – which is why we came back to the lanes with the strongest battery we have ever made.
See you soon, and please comment – either here or on the JY Facebook page!