Replacing a FiiO E7 battery - simple! (Photos)

I've had a FiiO E7 headphone amp for a few years and it's recently gained a new lease of life -- as an audio interface! However, the OEM battery got a bit long in the tooth, so I set about replacing it. It's much easier than you might think. Click through for photos and step-by-step instructions, plus a list of components to buy. (Warning: magnifying glass and hot glue gun are advantageous!)

I've had a FiiO E7 headphone amp for a few years and it's recently gained a new lease of life -- as an audio interface for my LG G3! Sadly, the has G3 shockingly bad audio quality from its onboard 3.5 mm output - riddled with noise, fuzz/hiss and audible aliasing and distortion. This is likely due to poor design from LG in an effort to power save, combined with a latent bug in Android relating to how it scales audio samples, the latter sounding like it's aliasing audio in a certain range of gain due to it internally resampling or something stupid like that. My old Galaxy S3 LTE running Cyanogenmod 10 (4.2.2) sounded amazing, I wish it hadn't died!

ANYWAY! Recent builds of Android (I'm running 5.1) include a provision for audio-via-USB, enabled by default on most devices, so hooking up a micro-to-mini USB cable between the phone and the E7 gives you blissfully great audio quality.

So, I dug mine out of a cupboard - with a flat battery, of course - and charged it up. Soon after, the battery got fat and decided to push the front of the screen out... Ok, time to replace the battery! 

As Tek Syndicate documented, it's pretty darn easy to do this, and they recommended also fitting a JST connector to simplify future battery swaps. And if that wasn't easy enough, they even recommended some SparkFun components (a 1000 mAh LiPo cell, and the 2 mm JST connector!) to purchase.

So, some sleuthing later - and it was surprisingly hard to find the JST connector with any of SparkFun's UK distributors - I had my components delivered from Kirkcaldy-based Proto-PIC. I photographed the installation (novice soldering skills and everything!)...

(These photos also on my Google+ page, click here to view.)

Although the replacement battery is noticeably smaller than the original (even taking into account the swell of the old cell), it's still a snug fit. With some appropriate cable routing, it sits snugly in the space over the components - no adhesive velcro or double-sided sticky tape required, though I might use some just to stop it shimmying by tiny amounts (which it would only do if you shook it).

All in all, really easy to do, even if you only have beginner soldering skills. Proto-PIC came through quickly, shipped the items thoughtfully packaged in a plastic tub... And ended up being pretty much the cheapest supplier of all I researched.

They also had that magical JST connector in stock, so there was no contest. All other UK SparkFun distributors sadly were out of stock - the next quickest shipping quote I had was that it'd be ordered on the 19th with their other SparkFun orders, then shipped from the US...!

Kudos also to FiiO who really sensibly designed their unit with small Allen key screws holding the backplate on, and a really neatly designed and configured circuit. I look forward to many more years of happy listening ๐Ÿ™‚

14 thoughts on “Replacing a FiiO E7 battery - simple! (Photos)”

  1. Awesome project! My Fiio just got bloated and i was searching the net for similar cases.
    It will be around 1 week plus for my new battery to reach me.

    Question: can it work without batteries? I mean, technically, it should still power up using USB power right?

    1. I thought it should, but mine didn't. Its charging circuit got REALLY confused when it attempted to charge a nonexistent battery! It sorta fired up with USB charging disabled, but it wasn't too happy. Didn't actually attempt passing audio through it, should have tried!

  2. Thanks a million! I just replaced the battery on my E7, which wouldn't hold its charge. I wouldn't have known it was possible, or where to get the battery, without your article. Fwiw for anyone else reading this, Proto-Pic were out of stock of the JST connector, but they can also be obtained from CPC Farnell.

  3. Hi - this post was of great interest to me since I recently pulled out my E7 and it also had a dead battery. I found the replacement battery you mention on Amazon, and I'd like to try and swap it in. Is soldering actually required? I don't have a soldering iron and have never used one. My question is whether it is possible to simply snip the wires connecting the old battery, then strip those wires and the wires on the new battery, tie them together, and wrap with electrical tape? Skipping the JST connector obviously. Would this work? Thanks a lot.

    1. I suppose you could, I've no idea as to whether it would hold after being thrown around in a bag for a while ๐Ÿ˜‰ perhaps hot gluegunning the twist joins could work, or some heat shroud?...

      Insulating the wires from the board components was my biggest concern.

      Don't be scared about getting to grips with a soldering iron. I'm still a relative novice at soldering (my common complaint is that I don't have the three hands soldering apparently requires), but this was very easy to do. Oh, and don't grab the iron by the hot end, I've absentmindedly done that before. 

  4. I have a question regarding the battery that you used, it says in the description on the website (Lithium Polymer batteries require special charging circuits. Do not attempt to charge these with anything but a specialised Lithium Polymer charger.), does this mean you cannot charge the fiio as normal with usb lead to pc.

    1. Hopefully the photos I took of the battery include the incorporated charging circuitry at the top of the battery - no particularly special charging circuitry on the FiiO board. I just soldered it back onto the board in place and I charge it from my USB port on a daily basis without worry. ๐Ÿ™‚

  5. Hi Chris,

    I stumbled onto this website while trying to figure out how to replace the battery of the E07K.

    First off, thanks!

    Now two things:

    1) Is the clear blob hot glue at the connection into JST connector?

    2) The link to Tek Syndicate is not working. 

    Thanks again!

    1. Sorry about the TekSyndicate link 404ing. Looks like their old forums are dead and buried and I didn't snapshot it beforehand. (mutters something about URIs and the web supposedly being permanent...)

      The clear blob is just that, a dab of hot glue. Doubling as a makeshift insulator (due to my slapdash soldering skills) as well as securing it in place.

  6. hi. I have an E7 that might have battery issues too - I am looking for some advice. mine doesn't stay on even when plugged in. I use it with an E9 which has a dock that provides mains power to the E7 (I suppose) but the E7 barely turns on, the screens flicks a "bye bye" message then turns off again. i would try to change the battery but I'm not sure it would solve it; not sure but I think it shouldn't rely on the battery if it's plugged in via the E9 dock - what do you think? Is this a battery issue or something else?
    Thanks a lot!

    1. @dan:

      Definitely sounds like the battery is dead. Or the charging circuit is gone, so it's essentially flat. Mine did the same thing if I disconnected the battery while it was connected via USB. I don't think it's clever enough to take direct DC power, it has to pass-through charge.

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