Battery charging and wifi resource are always the trouble. Upper than 25000mAh is great. If there's some other gadgets, will be appreciated.
Any suggestions and answers?
25000 mAh external battery? I reviewed 20000 mAh from Anker before: http://forum.xda-developers.com/show....php?t=2578443
You have to be careful with high capacity external batteries because a lot of shady ebay/amazon companies claim high numbers but lie about it. Or the efficiency of the battery is so low, 25000 mAh will end up being 10000 mAh after conversion Stay away from eBay when buying batteries, and read all the comments and number of reviews on Amazon. Some reviews could be exaggerated, but if you have hundreds of positive reviews/comments - its a good sign you are dealing with a company you can trust. Also, make sure they are offering 12-18 months warranty with a product.
For other accessories, visit a link in my signature, I reviewed hundreds of different gadgets on XDA.