Soundbuds Slim+ battery performance and long haul flight use

I thought it might be worthwhile posting my long term experience with the overall battery performance of the two pairs of Anker Soundbuds Slim+ earphones which I have been using for a year.

Both my pairs of Soundbuds Slim+ achieve 5.5-6 hours of listening time with volume set at approximately 50%. I’ve never attained the advertised 7hrs - I assume this might be possible if one was to use a lower volume of perhaps 35%. Full recharge time is about 90 mins.

I fly London-Dubai a lot and use the Soundbuds Slim+ as my main in-flight earphone since I’ve never been comfortable with over- or on-ear headphones. Flight time is typically 7 hours and I’ve always had to swap over to the second pair after 5.5-6hrs due to the battery running out. Hence my need for two pairs.

Passive noise isolation is very good, though admittedly not to the level of any decent active noice cancellation over-ear headphone, including the one provided in-flight by Emirates. The wired connection between the Slim+ earbuds is an advantage over “truly wireless earbuds” when flying since I don’t need to worry about them inadvertently falling out of my ears into the seat crevices when I sleep! The earpieces are comfortable for my ears to wear for 7hrs straight without soreness or fatigue. Your mileage might vary!

I’m usually a month between flights and recharge the Slim+ earphones fully on arriving home. I top them up the day before flying and even after 4-6 weeks turned off sitting in my travel bag, the charge level remains at 90-100%. That’s decent low bleed battery drain!


This are useful news for frequent flyers. When I was on duty, I traveled around the world - but such equipment was not available at that time. So I had to use the inflight program - which also was not too bad, because I detected some artists former unknown to me.

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You’re doing all the right things here. Yes Slim+ passive noise isolation is good, I use them for that on shorter flights but use Bose QC 35 for longer flights, these obviously very different in packing size. Swapping between 2 pairs and recharging the other, recharge time is less than usage time so you can keep going with 2 indefinately with a Powercore.

Newer Powercore with trickle charge would be a better fit for the buds to get them fully to 100% without having to repeatedly press the power button for the last few minutes.


My wife uses the QC35 II and ANC on those is outstanding. It’s a substantially larger form factor, but she’s got a carry-on that just about squeezes into the measuring rack! :sweat_smile:

Emirates has USB charging sockets on the seats, so a charging cable does the job. My preferred cable being a Powerline II in white - easily visible even when cabin lights are dimmed, and withstands all the abuses of a frequent traveller!

Good to see that the latest Powercores have “low current mode” to faciltate charging of low power devices like earbuds. Too bad that my favourite Powercore Slim 5000 has yet to be updated to provide this.

As an aside, Emirates is one of the most easy going airlines about the use of Bluetooth devices and mobile phones on board. No major surprise since they have mobile phone service on board most flights between Europe and Dubai. I connect up a small battery powered USB transmitter to the in-flight entertainment headphone jack so that I can use my Slim+ earphones for their vast on-board music and movie collection. Ahhh… wireless freedom! :grin:

The smaller the Powercore, the lower the current it turns itself off. So smaller Powercore get very close to trickle charge anyway. A small Powercore+ Mini turns it off not far off fully charged buds. The bigger Powercore need to be asked to do 2 things at once like be charging both tablet+buds to keep the buds charging. Both methods work. The trickle charge capability only appeared recently in very few Powercore. I don’t see a need to urgently invest to solve that problem, a Mini I owned for years solves it well enough.

The king of of the over-ear noise cancelling is currently Sony from all the reviews. That in no way criticises Anker as you’re comparing $300-$350 with like $21.

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Very clever. :grin:

No audio lag?

The Sony WH-1000 XM3 is without doubt the best ANC overear headphone on the market at the moment. Too bad I can’t use overears, so I’m content with the Slim+. It certainly does a fabulous job as a passive noise isolating in-flight earphone for £25!

Regarding the Bluetooth transmitter, I use one of these:

It has AptX as does the Slim+. No video-audio sync lag when watching in-flight movies. Maybe it’s the AptX, but probably not. I previously used the same set up with my Soundbuds Surge and there was no video-audio sync lag either. And the Surge does not have AptX. One notable issue is that the Surge has difficulty pairing with that Bluetooth transmitter. With the Slim+, pairing is quick and easy.

From time to time, I also plug that Bluetooth transmitter into my bedroom TV so that I can watch stuff whilst using the Slim+ for audio so that my wife can sleep undisturbed. :smile: :innocent:

I switched to the Slim+ from the Surge due to the Surge having comparatively heavier bass and recessed mid range and treble. I found the sound signature on the Surge too claustrophobic. The Slim+ has brighter mids and treble and a more “open” feel to the sound. Some others would probably prefer the Surge for the heavier bass!


Cool, thanks for the added detail.

Anker do similar products

The notion of BT transmitting the in-flight entertainment is intriguing. The Bose has cabled which I use for in-flight but yes prefer wireless because in most seats you do have to get out of your seat for a passenger to leave and all the wires can (and have in my case) cause some metal to get bent. Airline dependent I may just a tablet with my own media or the Bose corded to their media. Your method is informative, might give it a try!

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It’s worth trying BT transmission for the in-flight entertainment particularly if you use the QC35. ANC on the QC35 only works in BT mode. In corded, it’s passive noise isolation only. Give it a go, I think you’ll like it!

Obviously best to get the BT transmitter pairing to the QC35 sorted at home first. After that, it’s as simple as turning both on where they’ll pair automatically and then plugging the transmitter into the earphone jack.

Incidentally, the item which you linked is an Anker BT receiver only. What is needed is a BT transmitter. The Anker one is this:

It’s a little on the large size for travelling since it was made for use with home entertainment systems and has two SPDIF ports.

Sorry to correct you but noise cancellation is on as option for Bose in cabled mode too. The 3 modes are on BT ANC, cabled no ANC, cabled ANC.

But yes an option of BT ANC to in flight audio is a good idea.

I stand corrected! I had assumed that ANC does not work on the QC35 II in cabled mode because the ANC button toggle (in BT mode it controls ANC off/low/high) becomes inactive when the cable is plugged in.

Tiny change in the model II to add a few more modes.

Anker’s over-ear Life 2 has more in common with the Sony of being able to control ANC from the headset.

I had one of the old version and it was junk. They sent me a different one that was twice as expensive and was nice but it last about months before the plastic separated and eventually. So I would use caution when purchasing one of these.

Thanks for sharing your personal experience. I normally get about 6 hours at 80%. However, due to age and the mount I use to use them, they get about 5 hours now. I have recently retired them and use them as backup in my gym bag (for those days I forget to charge my other set of earbuds)

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Are you meaning your experience with a Slim+ is that it was junk? Mine appear to be holding up well. But they’re used about four times per month at most.

Sorry somehow TV reply to was moved. I was relying about the mpow receiver.

I have the slims and the slims+ and both versions are good but they are not my favorite soundcore earbuds.

I had one of the early Mpow receivers too and it wasn’t great. This present one which has a switch to choose between transmitter (needed for conversion of in-flight entertainment audio into a BT signal) or receiver mode is much better. Connects with speed and reliability, 10hr battery life, size of two chocolate squares and the audio quality is on par with typical AptX or A2DP BT audio. ie: does the job!