EcoRenovator - View Single Post - A7 AirTap install (ASHP hot water heater)

Xringer · 04-19-14, 03:21 PM

Since I have a dry contact from the controller (closed with calling for heat, open when the tank is hot enough),
I could use it to switch +12V into the Rin..

When the contact opens, Rgs would pull the gate down to Zero volts...

I'll check out the specs on the FETs to see what resistors will be needed to
develop the gate voltage needed for full turn-on..

The PV panel array can't deliver any more than 8Amps. It impossible for
PV to exceed it's amperage rating, since it's limited by sun light.

Only when you get certain solar-cloud-effects, will you get more power..
And that will be on the order of 2 to 20% more..
It would take a supernova to get much more than 20%..

I can short out the PV inside the house and never blow the 10A fuse on the array..
Which is why it's a waste of time to put fuses on solar panels..

Not sure why those DC SSRs suck so bad. I think it might be the DC signal source I'm using. Spikes maybe..

I'll have to think about a way to pull down the DC signal level quickly in case of a grid failure.
Don't want the gate voltage to drift down slowly, after the power supply input dies.. Need to load it down..
I figure the (AC powered) controller contact will fall out fast enough to prevent much over-heating of the SSR, if the AC failed..

04-19-14, 03:21 PM	#382
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Since I have a dry contact from the controller (closed with calling for heat, open when the tank is hot enough), I could use it to switch +12V into the Rin.. When the contact opens, Rgs would pull the gate down to Zero volts... I'll check out the specs on the FETs to see what resistors will be needed to develop the gate voltage needed for full turn-on.. The PV panel array can't deliver any more than 8Amps. It impossible for PV to exceed it's amperage rating, since it's limited by sun light. Only when you get certain solar-cloud-effects, will you get more power.. And that will be on the order of 2 to 20% more.. It would take a supernova to get much more than 20%.. I can short out the PV inside the house and never blow the 10A fuse on the array.. Which is why it's a waste of time to put fuses on solar panels.. Not sure why those DC SSRs suck so bad. I think it might be the DC signal source I'm using. Spikes maybe.. I'll have to think about a way to pull down the DC signal level quickly in case of a grid failure. Don't want the gate voltage to drift down slowly, after the power supply input dies.. Need to load it down.. I figure the (AC powered) controller contact will fall out fast enough to prevent much over-heating of the SSR, if the AC failed.. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..