Series parallel switch ?

[theinnocuousgender]

Hey guys, I'm building an unregged dual 18650 box mod thats using a mosfet. I love the small form factor of a dual 18650, but like both series and parallel setups. Is there a circuit or switch I can set up which would allow me to switch between a series circuit and a parallel circuit with the simple flick of a switch?

I know a DPDT would work, but I can't find on that can carry a high enough current and am confused about the wiring. Any help?

thanks!

 

[SupplyDaddy]

SIMPLE Parallel/Series Select Switch

Replace "motors" with "batteries" (step 2)

As to the switch.. There are 25 and 30 amp switches. Don't think you're going to get any better than that.

If you're looking to incorporate charging into this, forget it. The feedback when switched to series will fry the charger.

 

[dc99]

David4500 (on here) had a board on oshpark just for this. I believe he took down his shared projects though. Its tiny since it uses SMD parts. I would try to contact him and ask if he has any boards. Ive used quite a few of his other boards with great success.

 

[EverPresentNoob]

when using a mosfet you dont need a 25-30 amp switch... a standard mitec switch at 3 amps is plenty. the mosfet is carrying the load, not the switch. Think of the mosfet as a relay used in your cars electrical system.

 

[SupplyDaddy]

when using a mosfet you dont need a 25-30 amp switch... a standard mitec switch at 3 amps is plenty. the mosfet is carrying the load, not the switch. Think of the mosfet as a relay used in your cars electrical system.

Wrong switch. Not a firing switch, but a power source switch.

 

[EverPresentNoob]

Wrong switch. Not a firing switch, but a power source switch.

oops... My bad.

 

[david4500]

The board mentioned by @dc99 which did indeed switch between series and parallel.
Unfortunately, it was based on a flawed schematic. There was an imbalance issue I wasn't originally aware of.

 

[dc99]

The board mentioned by @dc99 which did indeed switch between series and parallel.
Unfortunately, it was based on a flawed schematic. There was an imbalance issue I wasn't originally aware of.

Sorry David. The others Ive used were awesome.

 

[rochi]

I'm getting mad for that. Did u find out how to do this? MOSFETs or what?

 

[innertwist]

david4500, what sort of imbalance issue did you run into with that board? Leakage current? Cell leveling? Did it blow transistors?

 

[david4500]

This Parallel to Series circuit everyone is using, is flawed. • /r/OpenPV

 

[david4500]

New schematic in TINA-TI circuit simulator. Was playing around with something with the intent of switching a series mod to parallel for the purpose of USB charging. The pfets in the diagram are suitable for charging currents, not a full current load at a 510/atty. This circuit hasn't been constructed in the real world.