Hi tomnickell,
Welcome to Apple Support Communities. We understand that you're having an issue with battery usage on your iPhone being used by apps that aren't currently active. We'd like to help.
When you checked your Battery Usage, were you able to click Show Activity above the % of battery usage? This will give you a good ideas of the amount of time each app was using your battery while on the screen and in the background. To view that, please follow these steps:
- Head to Settings
- Choose Battery
- Scroll down to Battery Usage by App
- Click Show Activity
Do you see the apps you mentioned in the list over the last 24 hours? If not, choose to view the last 10 days and see if they're visible then. You can check if the battery usage was just for those apps or also other ones.
Then, we'd like to point out a good resource that addresses iPhone Battery and Performance - Apple Support
This can help with tips on maximizing battery performance and other tips:
How to maximize battery performance
“Battery life” is the amount of time a device runs before it needs to be recharged. “Battery lifespan” is the amount of time a battery lasts until it needs to be replaced. One factor affecting battery life and lifespan is the mix of things you do with your device. No matter how you use your device, there are ways to help. A battery’s lifespan is related to its “chemical age,” which is more than just the passage of time. It includes different factors, such as the number of charge cycles and how it was cared for. Follow these tips to maximize battery performance and help extend battery lifespan. For example, keep iPhone half-charged when it’s stored for the long term. Also avoid charging or leaving iPhone in hot environments, including direct sun exposure, for extended periods of time.

If you are still having issue with your battery usage after checking out those steps, it would be best to contact Apple Support for additional troubleshooting steps. They may be able to view specific details on your device that may need to be adjusted.
You can start that conversation with them here: Contact - Official Apple Support
Hope that helps.
Take care!