When you connect batteries or power sources of the same voltage, in series, the voltage adds together. When in parallel the capacity of the two add together.
Ive seen a few usb>sata cables in which there are two usb cables at one end. One for data+power and one for the extra power that larger HDD 3.5inch needs.
So my question is. If I treat the usb ports on my external battery as seperate sources of power, if i join the positive of port 1 to the positive of port 2 and then to a Micro usb cable. The same with the negative. This puts both sources of power/ports in parallel. This is confirmed by the face that if one port breaks the circuit is not broken.
By connecting them in parallel I should increase the capacity. In micro usb battery bank or whatever you want to call it. Capacity is measured in Ah or mAh. 1Ah is 1 solid amp for 1h. So by joining these two ports in parallel, I cant increase the total capacity as they are both the same battery. But should this increase the current.
The above was just to get the idea going, what im planning to do is below
Another mod I have is to take a usb hub, with ONLY a Usb cable with a usb male connector on it. Slit the cable open half way, find the red and black wires and make a T junction out of both. connecting the extra cable I just added to a male usb port that will go to my battery (usb power bank). Im joining 5v to 5v, whats the problem, the power system is working in parallel (because the hub can take it from a pc or the battery) and the data pins are unaffected. Allowing me to take a LOT more current when nessesery. Meaning I could hook up like 12 Hard drives or charge a few phones quickly. This being current each device will only take what it needs?
Any thoughts or issues spotted. What im aiming to do in total is that I have a windows tablet, but it only has a micro usb 3 port, im gunna use an adapter to make it into one female usb3 port. then give it some power by making a t junction to my power bank (it will be fixed to the back of the tablet) and then will go to a usb3 hub also on the back of the tablet:: http://www.amazon.co.uk/gp/product/B00Y25XFGK/ref=ox_sc_imb_mini_detail?ie=UTF8&psc=1&smid=A2PGPJL0BBLHLX
Not important but the power bank is "Anker® 2nd Gen Astro Pro 15000mAh Triple Port "
Im also using its 9v port to extend my windows 8 tablets battery to about 16-20 hours by my estimate
just to check and reduce peoples time that I waste (apologies in advance) Im only touching power pins, so I do not think I need the processing chips in smarthubs or whatever Its current so it does not matter how much I supply, each device "Should" take what it needs. The voltage is identical from both sources. Only the current is different as the pc provides 0.5A and the charger 1A and 2A ports.