Greatest GoPro accessory ever?

We all love our GoPro cameras. They are the camera all other sport cameras are measured against. I have a number of GoPro cameras, including the GoPro Hero and the GoPro Hero 3. I have a vast amount of mounts as I use them in many different situations. This includes under the sea, in a car and on my bike. However, as every GoPro owner can testify to, I also have a large number of batteries. For the GoPro Hero and the GoPro Hero 2, this was fine. The internal and external batteries were the same battery. Taking extra batteries with you on long trips wasn't a problem. With the GoPro Hero 3, everything changed. The battery usage far exceeded the previous models and the different internal battery just played havoc. Officially, the new external batteries were no longer battery compartments with a battery slotting in. So the new external batteries became incredibly expensive. Unless you had a previous model external battery compartment and batteries. They were compatible. However, the internal batteries still had a problem, they were useless. 

I put up with the problem of battery charge being useless for quite a while. After a while, due to age and the number of charges, some of my external (and internal) batteries started swelling. Never a good sign with rechargeable batteries. So I started looking online for some replacements. I was stunned. If you could find batteries for the Hero 1&2, the cost was ridiculous. It was even worse for the external batteries for the 3. I would not be deterred. Then I stumbled across a game changer. The Brunton All Day Battery. It claimed to run your GoPro for about 10 hours. Yet the cost was the same as an external battery for a GoPro 3 which only added an extra hour (total 2.5 hours) if you're lucky. Yes, fine tuning the settings could get me close to 4 hours runtime with existing batteries. This is nowhere near 10 hours though. I had to have one. 

I bought mine from AbSafe (Australia) http://shop.absafe.com.au/products/Brunton-all-day-battery

As of the date of this write up, it is being listed as AUD$69.95 plus shipping. 

Now, the first thing that is not obvious. I have a GoPro 3, not a GoPro 3+. The camera sizing is identical. The housing is not. So I purchased a cheap GoPro 3+ copy housing. It will not fit the the 3 housing but the 3 camera will fit into the required 3+ housing. 

I have a 64GB card in this camera. So testing the battery was not going to be a problem. The largest ride I went on (including coffee shop breaks) was six hours. I left the camera running the whole time and I still had to power it off when I got home. With all of the settings tuned for minimum battery usage (720, 30fps, etc) I managed to just reach 10 hours non-stop recording. This is not a real test as I left it inside a window recording. I say it's not a real test as there was not 10 hours of daylight and it was recording night time. Recording at 1080p, I get about 8 hours of recording in the same environment. 

As I said, this is possibly the greatest GoPro accessory ever. I now have a problem though. My GoPro3 has developed a fault, it can no longer record audio. So I am looking at the GoPro4. This accessory is obviously not compatible as GoPro in their wisdom changed the internal battery yet again. From everything I am reading, it appears as though Brunton will release a 4 version but it may require a cable from the outlet to the GoPro charging input. I am not thrilled with this idea as water ingress becomes an issue. The GoPro 4 Session looks great but 1 hour of battery life? I no longer have to put up with it now I have the Brunton All Day Battery. If you have a GoPro 3/3+, you need this accessory.