Solar charge controller mosfet driver help?

[chand00786]

I am working on solar charge controller.I do not want to add a diode between solar panel and battery to avoid reverse current from battery to solar panel at night.I tried it with the following circuit but it is not working properly.it is always on whether the signal from MCU is low or high.If there is any problem in the circuit kindly rectify it.OR if any one has a batter design to solve this problem.

 

[betwixt]

I'm not exactly sure what that is expected to do but I will guarantee it won't work!

If I understand:
1. the battery is always connected.
2. the PV should be connected across it when the MCU tells it so. (both Q3 and Q4 conduct at the same time)

problems are:
where do you expect the gate to source voltages to come from to turn Q3 and Q4 on?
the BC548 does nothing, it has no collector current source.

Brian.

 

[Vbase]

A transistor that switches both negative and positive current hasn't been invented yet, and you can't do it with 2 transistors back to back. Use a relay or live with the 0.7V you lose on the diode.