Go Down

Topic: Battery charging switch (Read 702 times) previous topic - next topic

boylesg

How do you implement, using transistors, a switch mechanism that switches off the circuit powered by the battery and connects the battery to the power source?

I can immediately see how I might do this with a single relay, but am not sure where to begin with transistors.

outsider

#1
Feb 06, 2018, 03:38 pm Last Edit: Feb 06, 2018, 03:43 pm by outsider
You want to switch the battery from the load to a charger, or the load from the battery to another power source?
Draw me a pitcher picture.  :)

boylesg

#2
Feb 07, 2018, 12:14 am Last Edit: Feb 07, 2018, 12:16 am by boylesg
You want to switch the battery from the load to a charger, or the load from the battery to another power source?
Draw me a pitcher picture.  :)
The former - switch from load to charger.

Picture....difficult because I am unsure where to begin.

TonyWilk

Not quite sure what you mean...

I can immediately see how I might do this with a single relay, but am not sure where to begin with transistors.
Draw and post your relay circuit, then we could look at converting it to transistors.

Yours,
 TonyWilk

boylesg

#4
Feb 07, 2018, 02:41 pm Last Edit: Feb 07, 2018, 02:42 pm by boylesg
Had to improvise a relay in Multisim - no relays that match the type I have.




TonyWilk

#5
Feb 07, 2018, 05:11 pm Last Edit: Feb 07, 2018, 05:12 pm by TonyWilk
Using a P-Channel MOSFET for example this one: FQP27P06 from Sparkfun
you can switch the +V rail. There's two of them to switch the charger-to-battery and battery-to-load, I've added the NPN transistors so they can be controlled from the output of an Arduino for example.
Diagram:


Of course, whatever circuit is driving those transistors has to have power - so I'm not sure how you see this operating.

Yours,
  TonyWilk

boylesg

Are there any purpose made ICs for doing this type of switching?

As an alternative to that bulkier than necessary relay.

Go Up