EcoRenovator - View Single Post

Xringer · 11-03-10, 11:50 PM

Hi Ryan,

The MTM tracker uses relays. I have found (as well as one other poster here) these relays are okay
for a short demonstration or school science fair project, they don't last very
long in actual use on a solar array.

Due to shadows, clouds, your actuator's motor, gear box and the mechanical backlash of the parts, the relays take a beating.
Contacts clicking open and closed many thousands of times a day.

I found the photocells provided with the kit, would not operate at higher
temperatures, and could even be permanently damaged by solar heat.

When the MTM board was working, it was extremely accurate, way more
precise than is actually needed in a polar mount tracker.

I have no pictures of the bottom side of the board, and I was asked by the vendor, not to disseminate the schematic diagram.

I really can not recommend using this board on an array that's going to be
moving a heavy load (my array is about 150 pounds).
The relays just don't seem to be able to take the wear.
If I ever do repair my board, I'm thinking of replacing the relays with
a power MOSFET 'H' driver circuit.

I have been using the RedRock board for a while now, and so far it's working
very well. All I'm worried about now, is the actuator wearing out.

Last week, I measure 507 watts at the load!! Which isn't bad for a 500w array of some poor looking panels..

11-03-10, 11:50 PM	#165
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Hi Ryan, The MTM tracker uses relays. I have found (as well as one other poster here) these relays are okay for a short demonstration or school science fair project, they don't last very long in actual use on a solar array. Due to shadows, clouds, your actuator's motor, gear box and the mechanical backlash of the parts, the relays take a beating. Contacts clicking open and closed many thousands of times a day. I found the photocells provided with the kit, would not operate at higher temperatures, and could even be permanently damaged by solar heat. When the MTM board was working, it was extremely accurate, way more precise than is actually needed in a polar mount tracker. I have no pictures of the bottom side of the board, and I was asked by the vendor, not to disseminate the schematic diagram. I really can not recommend using this board on an array that's going to be moving a heavy load (my array is about 150 pounds). The relays just don't seem to be able to take the wear. If I ever do repair my board, I'm thinking of replacing the relays with a power MOSFET 'H' driver circuit. I have been using the RedRock board for a while now, and so far it's working very well. All I'm worried about now, is the actuator wearing out. Last week, I measure 507 watts at the load!! Which isn't bad for a 500w array of some poor looking panels..