Blocking Diode Recommendation

So I want to charge some rechargeable batteries with some solar cells I bought and I heard I should use a blocking diode to prevent the batteries from discharging at night. I have 3 6V, 50mA solar cells in parallel for a 6V, 150mA total. Does anyone have a recommendation for the model number or kind of diode I should use? Preferably one with a very low voltage drop. Or is my solar setup too small to require a diode? I have never done this sort of thing before, so any help would be greatly appreciated!

Posted by msh21 8 years ago