Usb charging Board like the Dna 20 but for 7.4 volts????? HELP

[benda]

Want to make a OKR box mod or a box mod with a board that runs on 7.4 volt but i would like to use a charging board like the ones that are used in the Dna20 mods, I want to be able to seal the mod up and charge by usb, Im not apposed to making a 3.7 device but i would need to be able to get the power of the dna20 with out the dna20 price. That is whu I want to use the OKR board, but for that I need to stack batteries. Any info would be greatly appreciated. Thank you

 

[tmassey]

i dont believe such a thing exists, but lucky for you breaktru already figured out a work around. USB Charging 2 Li-Po Batteries.

 

[benda]

Thanks for the info. big help

 

[WarHawk-AVG]

it appears that it just switching from a series (stacked batteries) to a parallel charging circuit using a 3PDT switch...interesting

One of these wired up like the diagram, to the switch, and pow...like it says...down for parallel battery charging, up for stacked voltage
USB Li ion Charger 1A Lithium Battery Charging Module TP4056 DIY 18650 Charger | eBay

plenty to chose from 3PDT switches
Toggle | Newark | Results

very interesting!

 

[DrMA]

You can also do the same thing with a DPDT switch, which tend to be much smaller form factor than 3PDT. here's an example: http://www.instructables.com/id/SIMPLE-ParallelSeries-Select-Switch/step2/Wiring-the-switch/