I love my new Phonak M70 hearing aids but my word, it’s now 3pm here in the UK and already my battery is at 14% and I’ve barely been on my iPhone.
Is it a common thing that iPhone batteries don’t last as long with Bluetooth hearing aids?
I didn’t have this issue with my Phonak ComPilot.
I am due to get a new iPhone in August but my battery health is still at 92%
I would have to think it’s your iPhone battery @Zebras…. Mine is an iPhone 12 Pro, they are excellent phones, 6 months old now, and battery health @99%, I have had it on all day, made 1 phone call, and surfed the net a couple of hours or so, played a card game, battery charge sitting at 82%…. Cheers Kev 
@kevels55: Yes, Kev, but if the HAs have not been trying to communicate with the Mother Ship, of course there will be no battery drain! It’s only logical!
They are constantly connected Jim, as soon as I switch my aids on they automatically connect to my iPhone…… And stay connected till I switch the aids off, doesn’t matter if I am in the kitchen, and my iPhone is in the bedroom, I can still answer a call…. Cheers Kev
Thank you for clarification Jim… Although, I should know better, as its difficult for you to avoid satire 
in many ways that is a blessing, having the ability to laugh at ourselves, our predicaments, and our shortcomings, is perhaps the gift of understanding… And maybe, not to take life too seriously. Cheers Kev
I have Phonak P90s and use my iPhone nearly continuously to connect iPhone playing audiobooks to my HAs. I have listened to over six hours today and my iPhoje battery remains at 75% after an overnight charge last night. That requires a continuous Bluetooth connection.
I will say that using Bluetooth as I do requires more frequent HA battery change; but that is understandable. You can’t operate two-way radio communications, sometimes continuously, without consuming battery power.
80% of the value of my HAs rests with the Bluetooth connections to my iPhone’s audiobook player. FWIW, Clif
I think I must of just had bad luck that day with my iPhone battery or maybe because I was at the hospital most of the day at medical appointments for myself, I get very little signal so my iPhone was continuously trying to find signal, so drained my battery more.
Spoke to someone on FB who’s part of the Deaf Group that I admin. She has the Sky M70 M so uses size 312 batteries and Altho she’s listening to her phone for around 20 hours a day, she only has to change her batteries every 8 days. She says she loves to stream and also use her Roger System. I was quite shocked at how long her batteries were lasting
What phone? How many Apps does she have on the phone and that run in background? How much ‘Screen On’ time does she have?
All of which will affect battery usage and other things (WiFi/Bluetooth). I keep analysing what is using my battery to get more out of it.
It’s me who had bad luck with my iPhone. I have no Apps in the background and most of my Apps notifications are turned off. I was barely on my iPhone that day as I was at the hospital all day. I haven’t been on my App Store for years (apart from recently downloading the Phonak App) as I’m not a fan of playing around with Apps.
iPhone SE 2020.
I’m still using my first set of batteries on my M70 SP so couldn’t tell you how long my batteries last.
I don’t know what iPhone the lady has. My iPhone does last 2 days quite often even when listening via my Phonak ComPilot for most of the day/s.
Quite likely being in the location without signal. The phone expends a lot of processing trying to find signal. If I am going to be out of coverage but still want the phone for GPS or camera I tend to go to Airplane mode.
I am an Android user, - My P90s will generally run low on battery before my phone if I have been making a lot of calls, or it is a long day.