One of the chief differentiators with the Samsung Galaxy S 4 versus other current flagship Android devices is the continued support for user-replaceable batteries. Although removable batteries are becoming increasingly scarce as industrial designers prioritize aesthetics and thinner profiles, being able to swap batteries or substitute in a larger one is still an added convenience if you absolutely need it.

I’ve been carrying the Samsung Galaxy S4 Google Play edition (henceforth SGS4 GPe) alongside the HTC One GPe since getting the two devices, and while I have a Mophie Juice Pack for the HTC One, I didn’t really have a bigger battery solution for the SGS4 GPe. Probably my biggest use case for extended batteries is when I’m traveling, where having a bigger battery often is the difference between being able to relax and searching for an outlet in a terminal. When I saw the ZeroLemon 7500 mAh battery mentioned on Reddit’s r/android and instantly knew I wanted to give it a try and put it through our battery life and charge test routine.

First, the ZeroLemon 7500 mAh battery is considerably bigger than the stock SGS4 battery, which came in at 2600 mAh. Both are 3.8V nominal chemistries, so that works out to 28.5 Whr for the ZeroLemon, and 9.88 for the stock one, a scaling of 2.88 in battery capacity. Because energy density doesn’t change between the two (fundamentally it’s still the same 3.8V Lithium-Ion polymer), the extended battery achieves its larger capacity by increasing volume. As always, this is the tradeoff that industrial designers have to make – increasing battery capacity at present necessitates more volume dedicated to it.

The extended battery is really two pieces. The first is shaped like the stock battery and fits inside the housing, the second seems to be two larger cells above it which protrude from the back of the SGS4. As a result, the extended battery requires a different kind of battery cover entirely.

The ZeroLemon’s battery cover isn’t so much a door as it is a rubberized case that fits on and wraps around the SGS4. It covers the volume rocker and power buttons, and imparts a somewhat squishy feel to them. There are also holes for the microphone, headphone jack, IR Tx/Rx port, and at the bottom microUSB and speakers. The rear facing speaker on the SGS4 gets covered up somewhat, although sound still leaks between the battery and chassis and out the grille at the bottom. The far bottom of the battery does somewhat occlude the lower primary Tx/Rx antenna on the SGS4, although I haven’t seen a dramatic change in RF performance.

Obviously the weight and size of the SGS4 changes with the case and extended battery installed, the question is how much. The tradeoff with the bigger battery is that the SGS4 gets considerably bigger, but not unwieldy so. It’s a big phone for sure though.

Samsung Galaxy S 4 Extended Battery
Battery Stock 2600 ZeroLemon 7500 mAh
SGS4 Thickness With Door 7.94 mm 17.0 mm
Battery Mass 43.5 grams 132.3 grams

I ran our normal smartphone battery life test suite on the SGS4 GPe with the big battery installed. This is the same test we’ve run for a while now with the display set to 200 nits exactly and loading through a number of pages on a schedule, over both WiFi and cellular (in this case for consistency with the previous GPe test, still T-Mobile LTE). Obviously the results speak for themselves here, runtime with the big 2.8x size battery is huge.

AT Smartphone Bench 2013: Web Browsing Battery Life (3G/4G LTE)
AT Smartphone Bench 2013: Web Browsing Battery Life (WiFi)

On the cellular test, we see a 2.7x scaling, very close to the expected 2.8x scaling given the increase in battery. On the WiFi test, we see just over 3x scaling, even better. I previously had no issues getting through a day with the stock SGS4 battery, I’d expect with the nearly 3x scaling you could possibly get 3 days of use out of this combo.

Device Charge Time - 0 to 100 Percent

The other tradeoff is of course an increase in charge time. Samsung is in a better position here thanks to the availability of 2 Amp (10 watt) charging using their supplied charger which includes proprietary 1.2V signaling on D+/D- pins. Unsurprisingly charge time goes up as well with the ZeroLemon, and even with that Samsung 2 Amp charger, it takes 7.5 hours to charge the ZeroLemon battery from completely empty. With this much charge time, it’s clear to me that without increased charging current this is effectively the maximum practical battery size for the SGS4, given the expectation that you can plug your phone in dead when you go to sleep and wake up with it fully charged (and sleep 8 hours a night). If you use the wrong charger (USB BC 1.2 compliant), a full charge could take just over 12 hours given this same scaling.

If you’re willing to make the size and weight tradeoff and want an absolutely huge extended battery for the SGS4, the ZeroLemon 7500 mAh battery seems like a pretty good choice.

Source: ZeroLemon (Amazon)

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  • beginner99 - Wednesday, July 24, 2013 - link

    Agree. This extra battery makes the phone way to bulky and heavy. I mean I think 5" phones are to big already without extra battery. Of course if you are hip hopper with huge pocket it might work for you but never ever forget to tighten that belt or you will literally get caught with your pants down...oh no, they are already down anyway...
  • frypan - Wednesday, July 24, 2013 - link

    it's like people saying phablets are too big and once they use it, they get used to it.

    this battery is meant for intensive phone user. you looking at function over form if you are using this
  • Krysto - Wednesday, July 24, 2013 - link

    I wonder if Snapdragon 800's Quick Charge 2.0 will help with that in future devices. It's supposed to charge 4x faster, but I'm not sure what corners it has to cut to do that, or what negative effect it has on battery life, if at all.
  • glugglug - Wednesday, July 24, 2013 - link

    You can get 3A car chargers pretty cheap, instead of the 1.5A USB BC1.2 standard (and I'm sure if you look you could find a 3A wall charger as well), so you could reduce that charge time to under 4 hours.

    The ones I've seen interfere with FM radio, but you can put the phone on Pandora while its charging.
  • solipsism - Thursday, July 25, 2013 - link

    That seems like a horrible solution. I don't want to turn my phone off, take it apart, put it back together, then turn it back on just to add a little more juice if my battery happens not to make it full day.

    I'd rather get an external battery that I can plug into phone's port. I use my phone a lot but there is certainly enough downtime to stick it on there for a couple minutes to charge it up. Remember, we're talking about getting through the day so any claims that it would take too long to get to 100% is foolish.

    An external battery comes with its own charger, can use the same micro-USB as the phone, be cheaper than what Samsung offers, and sometimes be used in line to charge both at night if you happen to have used both that day. The external battery also isn't limited to what fits inside the phone.

    It's a much more elegant and convenient solution all around.
  • jimweda - Saturday, August 31, 2013 - link

    My only issue is carrying the power pack and cable everywhere I go. I've gone that route before and its always been a hassle or inconvenient. I constantly run around at my work, always on my feet so an external battery doesn't work for me which is why I prefer the extended battery. The drawback is finding a great fitting belt holster for it. I personally think the S4 is too thin anyway and with my current Otterbox Defender case/holster I like the feel much better. Always felt like I would drop the phone without it.
  • thinhsonys - Wednesday, August 7, 2013 - link

    Manual Installation Purelook HD v8.0 ROM, PureXAudio for Music Lover, for Galaxy S3, S4
  • pancakes - Tuesday, July 23, 2013 - link

    I've had the ZeroLemon 7500mah battery on my GS4 for a week starting today, and I've plugged it in to charge it only twice since the first time I charged it. I'm getting about 2 to 2 and a half days on a charge so far, and I don't mind the added bulk the battery gives. Makes it nice to not have to worry about getting to a charger if I plan on going out without enough time to charge for a bit.
  • Shadowmaster625 - Tuesday, July 23, 2013 - link

    Yeah but it is still going to give you a good solid 10 hours of use after charging for only 3 or 4 hours. Just like any battery I'm sure this one goes from 20% to 80% in a flash. And I would much rather have this thing at 80% than a stock battery at 100% anyway.

    It is products like this that make Samsung #1. 17mm and 4 oz isnt that big or heavy. I've used bigger, and heavier in the past.
  • flyingpants1 - Tuesday, July 23, 2013 - link

    Agreed, 17mm is large but not totally ridiculous. It's the same size as other 2x batteries for Samsung, except this one is 3x.

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