First let me say I love this mod!
I used "coolpixs4" battery test method from page 2 on this thread (http://forum.xda-developers.com/show....php?t=2330300
). I've quoted his method here:
Use Battery Monitor Widget pro to diagnose your current battery conditions. Discharge untill the phone auto turnoff then continous charge to 100%+2hours more (when you see 0mAh on BMW widget) go to Calibration Tab to check your battery condition. The measured xxxxmAh +/- ?% is your answer.
In that Battery Monitor Widget app I also set the battery perameters to fully charged at 4201mV and empty at I think I chose 3350mV or 3250mV. Please note the default empty on a Desire HD is to shutdown the phone at 3500mV. In general when I read the product spec sheets, quality Li-ion batteries such as 18650's produced by Panasonic, Samsung, Sony & LG often say do not dischage below 2.5V absolute minimum (which is often done in company stress tests) and normally it seems standard practice to not discharge below 3.0V (where the protective circuit will often kick in, turning the battery off). Discharging below this can potentially result in crystals forming on recharge that can make the battery unstable and explode. Interestingly enough is that when I set the battery to discharge below the stock 3500mV it seemed to drop off (die in the arse) in the mV extremely fast only resulting in a very small advantage of the amount of additional power/phone usage gained till it was empty and shutdown.
I found after testing a number of Chinese ebay Desire HD batteries were no better and sometimes worse than my original battery that came with the phone which was 5 yrs old and had been well used! Original HTC Desire HD batteries are actually Printed as SAMSUNG on the metal under the battery wrap incase you wanted to know. Some so called "original" Desire HD batteries are cheap and nasty knock offs and don't have any print on the metal once you remove the wrap.
So grad I got your advice/ideas, guys and did this battery mod. I got the AKKU POLARCELL 1800mAh for the EVO 3D from ebay which came from Germany. Damn it was a tight fit even after removing all plastic wrap but testing with above method confirmed it is indeed around the 1800mAh and I really notice the difference!
So I cut the battery housing to fit and used some copper tape to replace the combined Wi-Fi & bluetooth antenna that gets cut out when you chop the battery housing. I simply cut bits of thin copper tape to fit close to the same length as original Wi-Fi antenna and tacked a little solder to bridge the copper tape at point where needed to make it all electrically connected as one piece of wire would be. Reception works great!
I have not personally tested but I've read aluminium isn't the best for antennas and so I used copper tape. Measurements of copper tape shown in pic below but almost any thin copper tape should do the trick when cut to size.
I have bought a replacement battery plastic housing to keep with my old Desire HD battiers. So when I'm out camping, if needed I can pull out the EVO 3D battery when it's empty and replace with one of the old Desire HD batteries and just throw the unmodified plastic housing on to hold it in place.
I've also done the GPS antenna mod with great results to feel free to have a look at my other post on that with more pics and details if you are interested on page 38 of the GPS antenna mod this thread here: http://forum.xda-developers.com/show...8#post66098522
The silicone case nicely protects and holds these mods in my phone. There is only a little bulging most noticeable in the silicone case from the front of the phone along the sides. Here are some pics of my mods: