Momax EXPower 2700mAh Battery

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Hello!

I bought this battery from eBay and it just arrived.
I know the first thing that anybody wants to know when they hears "extended battery" is how it looks...
So, here are some pictures
(YES, they are shot with an iPhone 4 and the phone is on an iPad... My brother has bitten the forbidden fruit!)







7/3/2012 UPDATE:

Originally Posted by iridaki

OK, after almost a full week with it, here are my observations:

1. The battery is indeed of extended capacity and the cells appear to hold the charge better than stock battery so far. I do not have the equipment to confirm that it is 2700 mAh as it is claimed, but there is no doubt that it is almost twice as lasting as stock battery.
I've been in between changing ROMs at this point, but I will upload screenshots of Battery Usage in the coming days. I've been able to stay away from charger for more than 50 hours, which is an immense improvement over stock battery.

2. Battery cover is of OK quality, feels a bit loose at times, but it is not falling out of its place. Of course, I haven't dropped the phone, so I can't guarantee on the durability. Certainly sub-par to OEM battery cover, but not bad either.
The kickstand is purely awesome! Phone stands on a perfect angle. I am concerned about its durability too though.

3. Here comes the tricky part:
The phone seems to be unable to display accurate readings of the battery.
It drains from 100% to 1% approximately the same way stock does and then I have to pull it an re-insert it and when the phone boots it displays 65%. Same way, every time it hits 1%, I have to do the same and the percentage rises.
I looked into /sys/class/power_supply and found a folder called semc_battery_data. I searched further and realised that the capacity (1500) and type (Li-Pol) are actually hardcoded on kernel level. HTC developers have already addressed similar issues on kernel level.
I talked to Bazoocase (the developer of the 0% battery issue work-around, so pretty much the expert on the Arc battery gauge!)
about it and he confirmed that this is really the case:

He was kind enough to prepare a test kernel for me, with increased battery capacity, from 1500 to 2700, and I am testing it right now.

____________________

All in all, my personal opinion is that this battery is long-lasting and reliable, a huge improvement over stock.
Whoever wants the extra juice and is ready to compromise the thinness of the Arc, could go for it.
I will certainly keep using it, as it has freed me from the "looking for a power plug" plaque.
Even if the kernel patch turns out not to be working, inaccurate readings are not an issue, at least for me,
when I can safely go through the day without charging and can reach up to 2 days of battery life.
As far as my usage goes, I could get 18-20 hours average from stock battery, which is not bad at all,
since the easiest thing to do is plug your phone before you go to bed. However, I do appreciate not necessarily having to do that too.

I will keep this thread updated should I have further findings.

iR¡D@k!*™ via Tapatalk Pro

its not an Arc anymore <whers the sexiest of our Phone

Originally Posted by migsguerra

its not an Arc anymore <whers the sexiest of our Phone

It certainly deprives the Arc of its slimness but it doesn't look half as bad as I thought it would!

Originally Posted by iridaki

It certainly deprives the Arc of its slimness but it doesn't look half as bad as I thought it would!

How much backup are you able to make out of it?

It being thicker looks like it'll handle better. Does it feel any easier to hold?

Originally Posted by doomed151

It being thicker looks like it'll handle better. Does it feel any easier to hold?

Yes, it is not slippery anymore in fact!
I am going to make a video, should be more indicative than pictures.

Originally Posted by abrarabbu

How much backup are you able to make out of it?

When it arrived, it had 8% battery in it, I drained it and that took approximately 6 hours (5 hours screen on, music, youtube, browsing, emails).
I plugged it in overnight and today when I woke up, took the phone off charger. It's been 3 hours and still @99%.
So far seems really good, but to be honest, I have to monitor battery life for 2-3 cycles before I can tell if it's that good.
I'll keep you posted.

Originally Posted by iridaki

Hello!

I bought this battery from eBay and it just arrived. I will update this thread with my observations after a few days of usage. Meanwhile, here are some pictures.


iR¡D@k!*™ via Tapatalk Pro

I wish we could have one battery like razr maxx.slim and powerful...

good

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Looking good... eagerly awaiting the results

OK, after almost a full week with it, here are my observations:

1. The battery is indeed of extended capacity and the cells appear to hold the charge better than stock battery so far. I do not have the equipment to confirm that it is 2700 mAh as it is claimed, but there is no doubt that it is almost twice as lasting as stock battery.
I've been in between changing ROMs at this point, but I will upload screenshots of Battery Usage in the coming days. I've been able to stay away from charger for more than 50 hours, which is an immense improvement over stock battery.

2. Battery cover is of OK quality, feels a bit loose at times, but it is not falling out of its place. Of course, I haven't dropped the phone, so I can't guarantee on the durability. Certainly sub-par to OEM battery cover, but not bad either.
The kickstand is purely awesome! Phone stands on a perfect angle. I am concerned about its durability too though.

3. Here comes the tricky part:
The phone seems to be unable to display accurate readings of the battery.
It drains from 100% to 1% approximately the same way stock does and then I have to pull it an re-insert it and when the phone boots it displays 65%. Same way, every time it hits 1%, I have to do the same and the percentage rises.
I looked into /sys/class/power_supply and found a folder called semc_battery_data. I searched further and realised that the capacity (1500) and type (Li-Pol) are actually hardcoded on kernel level. HTC developers have already addressed similar issues on kernel level.
I talked to Bazoocase (the developer of the 0% battery issue work-around, so pretty much the expert on the Arc battery gauge!)
about it and he confirmed that this is really the case:

Originally Posted by Bazoocaze

I had read the bq27520 datasheet, and indeed the fuel gauge must auto-detect and adjust it's parameters automagically from the battery usage, so you must let it charge from 0% to 100% and discharge from 100% to 0% a few times without using heavy consumption to let it learn the new battery impedance/capacity.

However, looking at the sony driver source (battery_chargalg.c, among others) it looks like Sony have hardcoded the battery capacity in code, and then this will explain your usage issue with the extended battery.

Searching deeper in the kernel sources I found the constant value that seems to represent the hardcoded battery capacity:

file: arch/arm/mach-msm/charger-anzu.c

struct device_data device_data = {
        .limit_tbl = &limit_tbl,
        .battery_capacity_mah = 1500,
        .maximum_charging_current_ma = 1050,
};

He was kind enough to prepare a test kernel for me, with increased battery capacity, from 1500 to 2700, and I am testing it right now.

____________________

All in all, my personal opinion is that this battery is long-lasting and reliable, a huge improvement over stock.
Whoever wants the extra juice and is ready to compromise the thinness of the Arc, could go for it.
I will certainly keep using it, as it has freed me from the "looking for a power plug" plaque.
Even if the kernel patch turns out not to be working, inaccurate readings are not an issue, at least for me,
when I can safely go through the day without charging and can reach up to 2 days of battery life.
As far as my usage goes, I could get 18-20 hours average from stock battery, which is not bad at all,
since the easiest thing to do is plug your phone before you go to bed. However, I do appreciate not necessarily having to do that too.

I will keep this thread updated should I have further findings.

Good work

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Thanks 4 sharing this, very helpful!