blocking diode

[hughconley3]

What size blocking diode should I use for a 147 watt, 46 volt solar panel

[Mike90250]

Well, for that voltage of a panel, you realize you will need a MPPT controller ($250), to get your 147Watts ? If you just use a PWM controller ($70) to charge a 12V battery, you will only get about 50 watts, or about 100W into a 24V battery.

Here's an article about charge controllers

http://www.windsun.com/ChargeControls/ChargeCont.htm

So, your panel can only put out about 3.2 amps, and you should use a Schottky diode of about 6 amps to block reverse current. But nearly every charge controller has the blocking function built in, and you don't need a separate diode.

Good Luck

What size blocking diode should I use for a 147 watt, 46 volt solar panel

[hughconley3]

Blocking diode

Oh, so a charge controller replaces a blocking diode? I was already planning on getting a 48 volt mppt charge controller for my 48V system because I read that mppt charge controllers are for higher voltage systems.

[Mike90250]

EVERY MPPT controller has internal blocking diode function. Stick with a name brand, Rogue, Blue Sky, Morningstar. Don't bother with chinese imports on ebay, many do not work well, the ones I listed are 90-98% efficient, ebay is unknown.

Actually, better double check the max voltage inputs on solar side, 46 may be high for the Rogue :
"The MPT-3024 will operate with an input voltage from the PV array
of up to 60 volts. If the array produces more than this voltage at any time,
the controller will suspend operation and a fault will appear on the LCD
display (see Section 14). The user must power down the controller and
correct the situation before the controller will resume normal operation. A
24-volt nominal array, which may produce more than 45 volts open-circuit
on a cold sunny day, is the maximum recommended array configuration to
be used with this controller. A 36-volt nominal array will normally have an
open-circuit voltage of greater than 60 volts, which will exceed the
operating voltage of the MPT-3024. Use of arrays greater than 24 volts
nominal is therefore not recommended. The absolute maximum input
voltage for the MPT-3024 is 75 volts. Above this voltage damage to the
controller will result"