Polar pro case Fits 2 extra and slimmer than the original case
Controller joystick guard You can probably find a cheaper one.
Gimbal guard Extra protection while in the bag.
This is my set up if I'm going outdoor. They don't take up that much space so. You can fit it in any size of backpack you want.
Hydration backack The quality is ok for the price. I dont use the bladder when I have my spark inside.
I have an anker 10000mah one, pretty good and compact. https://www.amazon.com/gp/aw/d/B01CZV9FUW/ref=mp_s_a_1_2?ie=UTF8&qid=1468580985&sr=8-2&pi=SY200_QL40&keywords=anker+powerbank+quick+charge&dpPl=1&dpID=31gCZcX7ZgL&ref=plSrch - this is the one with quickcharge 3.0, the normal one is only 19$
https://www.amazon.com/gp/aw/d/B00Z9QVE4Q/ref=mp_s_a_1_2?ie=UTF8&qid=1468581011&sr=8-2&pi=SY200_QL40&keywords=anker+powerbank&dpPl=1&dpID=31rGxoDUwpL&ref=plSrch - 13000mah one, no quickcharge.
That I don't know.
I have no experience with the VR power, check older reviews. One of these types of battery accessories was a low quality repurposed headlamp battery pack.
That anker is wider and taller than mine, and only slightly heavier so mounting it may be tougher. I believe people have had good luck with this one:
https://www.amazon.com/Anker-PowerCore-13000-Portable-Charger/dp/B00Z9QVE4Q
Normally I would recommend one that has usb-c and supports 18w power delivery as it kept my Quest 1 topped off. But with the Quest 2 the battery drains slowly when using USB PD, so the 13000mah should work.
I would link my 10000mah PD anker redux battery but can no longer find it on amazon, the 13000 or 15000 mah size may be your best bet to hit 8-10 hours.
This is the one I used https://www.amazon.com/gp/product/B00Z9QVE4Q/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
It does not have USB-C, it just uses usb, so I'm not sure if that would be an issue or not. i assume with most chargers being USB-C lately they may have made a more updated version.
Solar doesn't work like how you think it works. Solar is like using a dripping faucet to fill a bucket. If you think you're going to charge a phone placing it in the sun for 5 mins you're in for a huge disappointment.
If you plan to basecamp awhile you can get an Anker 21w panel system and a two 13,000mah battery packs.
How this works is... During the day when you're out hiking you position the solar panel in the sun at your base camp. It will roughly take a full day to fully charge a 13aH portable battery if the conditions are good. Now you have 13Ah of power or enough portable battery to charge your phone at least 3 times. You put that in your backpack.
While you're carrying one of those 13,000mah battery packs you put the other on the solar charger at camp so it's fully charged and ready to go when you get back in the evening. When the one you're carrying is dead, you swap it for the charged one.
You never actually plug a phone directly into a solar charger as that's insanely inefficient. Same as houses with solar power, they are not powered by the solar panels they're powered by battery banks that are recharged by the sun.
If you're going on a thru hike without a basecamp or stopping during the day? Solar is not for you. Carry some high capacity portable batteries and limit phone use.
Before anyone pulls the trigger on that one, I actually just got a 13000mAh Anker for $29, free shipping. So if you want to dish out $2 for another 2600mAh, might be worth it. [LINK]
Yup, my wife likes the 5k version. I do prefer the 13k over the 10k though.
https://www.amazon.com/Anker-PowerCore-Ultra-Portable-VoltageBoost-Technology/dp/B00Z9QVE4Q
Too bad though, a bunch of these were on sale in the last week or two on amazon.
This is the one I have. Looks like the price went up a few dollars, but still worth it IMO.