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Xringer · 11-28-11, 11:01 PM

I was amazed to find these (this cheap) at 40 amps. Must be a pretty good sized MOSFET in there.

I think you can find these without the weird heat-sink,
but this one had a good price and was in the right amps range.

I saw some 20A versions a bit cheaper, but I wanted it to be 4X over-rated..

When it turns on, it's discharging the 3500 uF cap which could be up to about 145 vdc.
145v / 10 ohms =14.5A (a very short pulse).
Depending on the sun.

Since the max power point of the array is 115V, I'm going to set the
frequency so the rapidly firing SSR will keep the cap right around 115v.
Hopefully, that will send an average of 7 amps to the load. (800w)!
It's sorta a PWM heater driver..

It will be interesting to see if this hack can hot-rod my system to near 800w.
Which is it's rated power. It if does a good job in bright sunlight,
I'm wondering what the performance will be during poor sunlight condix.?.
Will the high output freq be useful at all when it's partly cloudy??

11-28-11, 11:01 PM	#3
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	I was amazed to find these (this cheap) at 40 amps. Must be a pretty good sized MOSFET in there. I think you can find these without the weird heat-sink, but this one had a good price and was in the right amps range. I saw some 20A versions a bit cheaper, but I wanted it to be 4X over-rated.. When it turns on, it's discharging the 3500 uF cap which could be up to about 145 vdc. 145v / 10 ohms =14.5A (a very short pulse). Depending on the sun. Since the max power point of the array is 115V, I'm going to set the frequency so the rapidly firing SSR will keep the cap right around 115v. Hopefully, that will send an average of 7 amps to the load. (800w)! It's sorta a PWM heater driver.. It will be interesting to see if this hack can hot-rod my system to near 800w. Which is it's rated power. It if does a good job in bright sunlight, I'm wondering what the performance will be during poor sunlight condix.?. Will the high output freq be useful at all when it's partly cloudy?? __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less.. Last edited by Xringer; 11-28-11 at 11:04 PM..