CHARLOTTE, N.C. -- The Defenders team uncovered glitches in hundreds of police body cameras at the Charlotte-Mecklenburg Police Department.

New numbers showed almost one in ten cameras have malfunctioned. Most are battery-related, according to the department. Now, groups advocating for police transparency want answers.

Police said none of the malfunctions have happened while officers have been using them during a call or responding to a scene. However, NBC Charlotte asked if that’s a risk.

Body camera videos have brought some answers in the aftermath of officer-involved shootings.

“At the end of the day, we need them to work every single time there is an incident,” said Corine Mack, President of the local NAACP.

Mack wanted answers about reliability after the Defenders' discovery. Nearly one in ten body cameras malfunctioning over the past two years translated to 271 of the departments 3,052 cameras.

“That’s a huge number when we're talking about lives,” says Mack.

It was an emotional issue for Meko McCarthy with the advocacy group, Safe Coalition. Her son, Lareko Williams, died after a police Taser in 2011. At the time, CMPD didn’t have body cameras.

“Then to have to rely on the entity itself that has stolen that life from you to tell you a story that in your heart doesn't sit right,” said McCarthy.

NBC Charlotte reached out multiple times for an on-camera interview with CMPD, but they declined. In a written response, a spokesman told NBC Charlotte all the battery issues were caught before the cameras were deployed.

“It’s like saying I'm going to get in my car today, knowing I have a battery hoping today the car is going to work,” said Mack.

In fact, just last year Houston’s police chief suspended the rollout of additional body cameras because of battery-related issues. It’s important to note; it was a different manufacturer that supplied that department.

According to CMPD, Charlotte’s malfunction rate, about nine percent, should not be a cause for concern. They recommended NBC Charlotte check with the manufacturer, Axon, about the failure rate.

The Defenders team reached out to Axon, but they did not get back to us with that information after repeated requests.

“One camera would be a problem, but now we're talking about 200,” said Mack.

Each camera costs roughly $575. However, CMPD said a malfunction does not cost taxpayers extra because the manufacturer has agreed to replace the cameras free of charge. The department also said there are enough backup cameras to cover any that have been sent back.

It’s meant to add a higher level of police transparency. Mack said the community’s trust depends on it.

“When we don't have that footage, it brings the question can we truly trust CMPD?” said Mack.

Mack said she plans to discuss the issue with CMPD Chief Kerr Putney, and then she will determine the next step.