EcoRenovator - View Single Post - Solar PV MPPT board for Hot Water heating

Xringer · 02-19-13, 10:20 AM

It's partly overcast today, and as usual, my back-up system is in float mode.

I'm thinking maybe I should use that 500w tracker PV to heat some water..
Since it's not being used, why not heat up some water?

The 800w fixed array is doing a pretty good job with helping keep the new GE DHW heater up to temp..

So, if the 500w Backup system PV float voltage is up around 85V (and it's cloudy right now),
that means the charge controller is ignoring the panels.
I could connect a water heater element to that 85V and the charge controller wouldn't even know it.
It would think some heavy clouds came over..

Just need a simple voltage level detector for the pack, (to see float level)
and a good DC switch to connect the 85V PV to a heating element (in parallel with the charge controller)..

An average of 300w off that tracker array would give me about 1,000 extra BTUh..

I'm wondering where that spare power should be connected.?.
To the old boiler, or to the upper element of the new GE (well insulated) tank?

I like the GE, it seems to have very low losses..
With both arrays connected, we could be getting around 1kW of power-to-the water,
during the sunny part of the day.. That's 3412 BTUh..

The technical term for this is, Dump Load..

02-19-13, 10:20 AM	#7
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	It's partly overcast today, and as usual, my back-up system is in float mode. I'm thinking maybe I should use that 500w tracker PV to heat some water.. Since it's not being used, why not heat up some water? The 800w fixed array is doing a pretty good job with helping keep the new GE DHW heater up to temp.. So, if the 500w Backup system PV float voltage is up around 85V (and it's cloudy right now), that means the charge controller is ignoring the panels. I could connect a water heater element to that 85V and the charge controller wouldn't even know it. It would think some heavy clouds came over.. Just need a simple voltage level detector for the pack, (to see float level) and a good DC switch to connect the 85V PV to a heating element (in parallel with the charge controller).. An average of 300w off that tracker array would give me about 1,000 extra BTUh.. I'm wondering where that spare power should be connected.?. To the old boiler, or to the upper element of the new GE (well insulated) tank? I like the GE, it seems to have very low losses.. With both arrays connected, we could be getting around 1kW of power-to-the water, during the sunny part of the day.. That's 3412 BTUh.. The technical term for this is, Dump Load.. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..