How We Test the Quality of Batteries We Sell at iFixit

Our in-house battery analyzer, testing a set of MacBook Pro batteries for quality and consistency.

When you buy a replacement battery for your phone or laptop, it’s crucial that the components be well-made—not just for the battery’s performance and longevity, but also for safety. We take quality very seriously here at iFixit, and go out of our way to ensure we’re selling the best parts available.

Our journey to source the best batteries starts with an exhaustive market survey to understand where they are made. Original replacement batteries can come from a supplier sourced by the original equipment manufacturer (OEM), an aftermarket factory, or from devices that have been taken apart. All of these sources can range in quality, which is why it’s important to test and have good standards in place. 

Why Don’t We Always Sell OEM Batteries?

Getting parts from the original manufacturer isn’t as common as it once was. “Apple used to have user-replaceable batteries they’d sell in their stores, but after redesigning their laptops with batteries glued to the inside, they stopped selling replacements for new models,” explains Daniel Demeter, our in-house battery expert. “They won’t sell you the battery, so you have to pay for their service, which costs more.”

Apple’s approach is increasingly commonplace. With the exception of Motorola, manufacturers don’t sell their OEM parts outside of their approved repair providers, so you’d have to buy them from the grey market, which could include factory rejects, refurbished parts, or flat-out counterfeits (aftermarket batteries with the OEM brand stamped on them). Batteries have a limited shelf life as well—we’ve investigated some poorly performing OEM Apple batteries that turned out to simply be old. You’re better off with a new aftermarket battery than an OEM battery that’s been sitting on the shelf for five years.

A high-quality iPhone battery from iFixit, side-by-side with its OEM counterpart from Apple.

Apple, Microsoft, and other major electronics companies don’t make their own batteries. They source batteries from factories the same way that we do. As battery chemistries improve, newer devices include better batteries.

In our experience, that aftermarket battery may be just as good as the original battery that came in your machine. Some aftermarket batteries are higher in capacity than the original components, since lithium ion batteries have improved—however slightly—over time.

Our Quest for the Best Battery

We spend a lot of time making sure we’re selling the best batteries out there. Some might call our attention to detail obsessive, but we couldn’t imagine doing it any other way.

“It starts with an understanding of where the batteries are coming from in the first place,” says Scott Head, Operations Supervisor at iFixit. You can buy batteries from the grey market, or from middlemen vendors that buy product from an aftermarket manufacturer. But when we can, we go straight to the source. “We try to work directly with manufacturers for our core products, so we monitor quality and make improvements to the product,” Head said.

A man pointing to a laptop in a factory.
Our QA team reviews testing data with the suppliers’ engineers to ensure the highest quality possible.

For example, we recently found that our 15- and 17-inch MacBook Pro Retina batteries had a higher return rate than their 13-inch counterparts. We worked with the manufacturer of these aftermarket batteries to determine the cause—and discovered internal cabling, unable to handle the additional voltage of those larger capacity batteries, to be at fault. The manufacturer adjusted their assembly process to utilize more heavy duty cabling on those models. (Of course, all of our battery products are backed by a 1-year warranty.)

When we seek out suppliers for specific products, we’ll often take a visit to the factory ourselves, so we can observe their testing and QA procedures. “The quality of workmanship is really important,” says Head. “For example, If you open up a battery and see how well the soldering is done and how precisely things are assembled, you can get a better sense of how good a battery is. If they’re not doing a good job—if they’re bridging joints, or re-using older battery cells to save a couple bucks—there can be some safety issues.” 

Rigorous Standards and Testing

When dealing with aftermarket products, it is also quite common that some manufacturers aren’t able to achieve the capacity of the original batteries. In those cases, we’ll typically pass and find someone who can meet a higher standard. To make things even more confusing for consumers, resellers will sometimes lie and say a battery has a certain capacity when it’s actually much lower. We have equipment in our labs to test individual batteries. We frequently pit different factories against each other, testing not only capacity but consistency in quality from one shipment to the next.

Our battery analyzer can test up to 48 batteries at once.

We work with battery engineers from around the world to constantly raise our quality bar. We recently upgraded to more advanced testing equipment, enabling us to test a far wider range of battery products. This equipment can test up to 48 batteries simultaneously, and can handle batteries for any mobile phone, tablet, or laptop. Increasing our testing volume not only allows us to compare quality between manufacturers, but allows us to test a sample of batteries from each shipment to ensure they’re providing the same quality over time. (The good manufacturers have this same equipment in this factory, and are testing the product thoroughly—but we’re so committed to the quality of our products that we want to do our own spot testing and make improvements.)

Not every battery seller you find online goes to these lengths. “iFixit has a reputation and a standard to uphold,” says Head. “A discount seller on Amazon is just going to get the cheapest thing they can to move as much product as they can. We’re always responding to customer feedback on battery quality, making adjustments, sourcing the best quality parts we can, vetting factories in Asia, and doing final testing right here in the USA.”