Bringing your idea to life takes energy, and we’re not just talking about the caffeine you and your team drink during a long working session. In order to make your tech idea into a product that people can use and enjoy, you’ll need to think through an efficient and appropriate way to power it.
In this article, we’ll cover the fundamentals of power management and what you should consider when building your tech product.
What are the basics of power?
Let’s start with the fundamentals: Voltage, current, and resistance. Voltage is measured in volts, current is measured in amps, and resistance is measured in ohms.
The first thing you’d learn in any entry-level class about electricity is Ohm’s Law. Ohm’s law states that V=IR or voltage = current x resistance. It’s critical to your tech product because it defines how everything works. Using this formula, you can understand the amount of voltage you have, the resistance of the object you’re applying it to, and the current you’ll need for your device.
You can use water to understand how electricity flows. Pretend you have a giant bucket of water. The water represents your electrons in the system. If you pour the water into a pipe, the flow rate is like current, any pipe restrictions act as resistance, and the pressure difference between sections of the pipe are analogous to voltage. Make the pipe smaller, and you increase the resistance to flow (increase resistance) and subsequently decrease the water flowing (or lower the current). Increase the water pressure (higher voltage) and the water flows at a higher rate (current increases) for the same resistance.
Here’s how it applies to your tech product: Your battery voltage will vary by chemistry, so start by thinking about what battery you’re going to need. (Avoid choosing nonstandard chemistries if possible — it’ll save you a lot of headaches down the road.)
What is power consumption and why is it important?
Power consumption is how much power you’re using in your devices. Keep in mind that power consumption is becoming more and more of a critical consideration for customers. Your users could be unhappy if they do not have enough power to keep their device running for long periods of time. As consumers demand more eco-friendly devices you’ll need to think more about power consumption even with products that are plugged into outlets to prevent unwanted power usage.
Take some time to understand the limitations of your options:
Home/industrial systems. If your device is going to require a lot of energy and if portability isn’t a concern, then your device is probably best being plugged into a wall. Hair dryers and kitchen appliances are great examples of tech products that work best when plugged in, because of the large power requirements of these devices.
Household voltage varies depending on your region. In North America, household voltage is 120 volts. But in much of the rest of the world, it’s 220v. For anything that requires more voltage, or power, you’ll need to incorporate transformers directly from your utility company.
Battery. You have two major choices for batteries: rechargeable and non-rechargeable. Your typical double AA batteries would be a great example of non-rechargeable batteries. Your users would have to replace the batteries themselves, which means the products design will have to include access to the battery pack. Keep in mind that many consumers are pushing for rechargeable batteries and with advancements in lithium battery chemistries, it’s becoming increasingly cost effective to give them that option.
For most portable devices, rechargeable batteries are the way to go. There are lots of ICs (integrated circuits) that are currently set up for most battery chemistries. You can look up reference designs or you can get modules that allow you to power up the rechargeable pack in your device. Your device will get the needed power from a battery, but you’ll still need to be mindful of power consumption to give your users a longer battery life.
Solar. Your number one question for solar should be: Is the device able to collect enough sunlight? If it’s primarily going to be used indoors, it’ll only gather small amounts of energy through windows or from lights. Also keep in mind where your device will be used. If it’s going to be used in rainy or dark climates, it will have far less solar energy available.
Generally solar energy is best reserved for situations in which you have a system that needs energy in a remote location where a normal power line can’t reach it, and where charging or replacing batteries regularly is difficult. Remote communications, remote monitoring, portable power packs, or even toys are good examples of applications for solar power. Solar can function as its own power system, but remember the energy isn’t necessarily consistent and the power level is typically lower.
Best practices for building your power design
Power conservation is the name of the game. For any device that consumes a large amount of power, you should dedicate several functions to power savings. Here are some ways you can cut down on power consumption in your device:
Battery monitoring system. A lot of chips come with a battery monitoring system built in. Its job is twofold: First, it can help ensure consistent power levels to your device using it within your product design. As a battery discharges, its voltage will change slightly. You need to make sure you monitor that voltage, because the rest of your system is built around having a set voltage. A battery monitor will monitor voltage to help improve battery life.
Second, a battery monitor will protect your battery overall. It will monitor your battery to ensure it isn’t getting too hot even if it’s drawing large amounts of power or operating in a warm environment. A battery monitor can prevent thermal runaways so that batteries don’t melt or explode. It can also prevent damage by telling your circuit when to disconnect the battery and shut off the device if the voltage is too high or low. There are many reliable partners in battery technologies, but we would recommend looking at Analog Devices (ADI) first. They have a wide array of battery and power management devices that should fit your need
Sleep mode. If battery-operated IoT devices were constantly sending data, they’d run out of power quickly. So to save on power, most IoT devices are set up to connect and communicate with their networks only when necessary. You don’t actually need the device to be active all the time to be effective.
You can program devices to limit certain functionality when they do not need to be transferring data to their networks or simply need limited portions of their circuits to run in order to reduce power consumption. When necessary, the device can jump into active mode, perform its task, and then go back into sleep mode. It’s similar to a cell phone: You press a button to activate the circuit, it performs its necessary actions, and then it might go back to sleep after a period of time.
Selecting the correct chips to minimize power draw. Any time a component is consuming power it’s creating heat, which is wasted energy. Keep in mind that not all components are created equal. Some components will consume more power to perform the same function, leading to wasted energy and compelling your customers to charge their devices more often. Find manufacturers that focus on making efficient components with lower power draws that can save battery life and inherently be more eco-friendly.