diodes

[deep denial]

I want to wire in some diodes - one to block back-flow into a solar panel charger at night, and a couple to allow running the compass light from either nav lights or tricolour. I went onto Maplins site, and of course there are about a billion different types of diodes available. Which sort/spec do I need? thanks for any advice.

 

[savageseadog]

Any diode that will take the current will do, with at least double the current rating than you will actually need. There are Schottky diodes which have a lower forward voltage drop which could be useful for your solar panel.

 

[VicS]

For the solar panel one of the "rectifier "diodes. You dont say what current /power the panel will deliver but one of the 50 V ones will do. Pick one that will handle the max current you'd expect. IN4001, IN5400 or P600A (1,3, 6 amps respectively)
Will have to look further if the panel is more than 72W or use two in parallel.

For the compass light a switch so you can switch it on independently of the lights, but if you must (assuming your light is not more than 12W ) IN4001.

EDIT:
On reflection I should have asked if you are sure the panel needs a diode. If it has been supplied for battery charging I'd expect to have one buit in.

BTW I'd not be too worried about the volts drop with the solar panel, their EMF is quite high so it'll only be if trying to squeeze the last fraction of an amphour out at low light levels that it will matter.

 

[deep denial]

thanks for the answers