Go Back   EcoModder Forum > EcoModding > Fossil Fuel Free
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 05-20-2013, 12:11 PM   #11 (permalink)
Master EcoModder
 
Join Date: Sep 2010
Location: Saskatoon, canada
Posts: 1,474

ChargE (not yet running) - '92 Mazda MX6 LX
90 day: 33.89 mpg (US)

Ford Prefect - '18 Ford F150 XLT XTR
Thanks: 745
Thanked 541 Times in 436 Posts
MPPT Charger

Quote:
Originally Posted by MPaulHolmes View Post
All you do (during the bulk charging phase) is adjust the PWM duty to maximize the output current! You don't need to maximize the product of the input current and input voltage (input power)! Just the output current!
I'm not quite following ... do you have a fixed output voltage, and that's why the output current is the only thing that you need to maximize?

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 05-20-2013, 12:39 PM   #12 (permalink)
PaulH
 
MPaulHolmes's Avatar
 
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,832

Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
Thanks: 1,368
Thanked 1,119 Times in 734 Posts
DISCLAIMER: This made sense to me last night, after being in the sun all day, so I could be wrong. haha:

Yes, since it's feeding a 48v battery bank, the voltage is approximately constant. Well, higher current into the batteries causes the battery bank voltage to go up slightly because of the internal resistance. Am I thinking about this wrong?
__________________
kits and boards
  Reply With Quote
Old 05-20-2013, 12:50 PM   #13 (permalink)
Master EcoModder
 
Join Date: Sep 2010
Location: Saskatoon, canada
Posts: 1,474

ChargE (not yet running) - '92 Mazda MX6 LX
90 day: 33.89 mpg (US)

Ford Prefect - '18 Ford F150 XLT XTR
Thanks: 745
Thanked 541 Times in 436 Posts
MPPT Charging

Quote:
Originally Posted by MPaulHolmes View Post
DISCLAIMER: This made sense to me last night, after being in the sun all day, so I could be wrong. haha:

Yes, since it's feeding a 48v battery bank, the voltage is approximately constant. Well, higher current into the batteries causes the battery bank voltage to go up slightly because of the internal resistance. Am I thinking about this wrong?
I guess charging a battery bank is close enough to constant output voltage. It will be a narrow range of output voltage ...

So maximizing output current ... will maximize the input V * I for the buck converter ... that follows!

I don't know how you have the PV arrays wired. Do you need a buck/boost circuit for cloudy days ... wait ... you said Arizona. Never mind!
  Reply With Quote
The Following User Says Thank You to thingstodo For This Useful Post:
MPaulHolmes (05-20-2013)
Old 05-21-2013, 12:21 AM   #14 (permalink)
PaulH
 
MPaulHolmes's Avatar
 
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,832

Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
Thanks: 1,368
Thanked 1,119 Times in 734 Posts
My wife had made the pictures set to private. dang it. But she has some pictures of her nursing on there too, lol, so I guess I understand. Here's one picture anyway:


I was up at 3:40am, and worked until around 8pm. And it was like 95 degrees outside today. But it's getting close to done:




Two 3/8" x 3" lag bolts to connect the "superstrut" from home depot to the 4x4:
__________________
kits and boards
  Reply With Quote
Old 05-21-2013, 12:47 AM   #15 (permalink)
NightKnight
 
NachtRitter's Avatar
 
Join Date: Dec 2008
Location: Placerville, CA
Posts: 1,594

RippinRoo - '05 Subaru Legacy Wagon 2.5 GT
Subaru
90 day: 21.16 mpg (US)

Helga - '00 Volkswagen Jetta TDI
TEAM VW AUDI Group
Diesel
90 day: 53.91 mpg (US)

Olga - '03 Volkswagen Jetta Wagon
90 day: 46.24 mpg (US)
Thanks: 303
Thanked 311 Times in 186 Posts
Quote:
Originally Posted by MPaulHolmes View Post
I was up at 3:40am, and worked until around 8pm. And it was like 95 degrees outside today. But it's getting close to done:
Still rather cool there, eh? Don't you have another 20 - 30 degrees to go?
  Reply With Quote
Old 05-21-2013, 01:00 AM   #16 (permalink)
PaulH
 
MPaulHolmes's Avatar
 
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,832

Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
Thanks: 1,368
Thanked 1,119 Times in 734 Posts
hahaha. Yes. We moved here in December, and I was dying from the heat by the time February hit. It just keeps getting hotter!! And it's MAY!
__________________
kits and boards
  Reply With Quote
Old 05-21-2013, 09:12 AM   #17 (permalink)
Master Novice
 
elhigh's Avatar
 
Join Date: Jan 2008
Location: SE USA - East Tennessee
Posts: 2,307

Josie - '87 Toyota Pickup
90 day: 27.96 mpg (US)

Felicia - '09 Toyota Prius Base
90 day: 52.87 mpg (US)
Thanks: 421
Thanked 606 Times in 445 Posts
I was thinking that if you're up to it - and you certainly appear to be - you could mitigate a lot of the heat load your house experiences by shading the house with the solar panels.

That would sharply reduce how much air conditioning you need. Sure, you give up a lot of power generation by foregoing tracking, but I think you get it back in reduced weathering on your roof, reduced cooling load, etc.
__________________




Lead or follow. Either is fine.
  Reply With Quote
The Following User Says Thank You to elhigh For This Useful Post:
MPaulHolmes (05-21-2013)
Old 05-21-2013, 09:02 PM   #18 (permalink)
Human Environmentalist
 
redpoint5's Avatar
 
Join Date: Aug 2010
Location: Oregon
Posts: 9,103

Acura TSX - '06 Acura TSX
90 day: 28.24 mpg (US)

Lafawnda - '01 Honda CBR600 F4i
90 day: 47.32 mpg (US)

Big Yeller - '98 Dodge Ram 2500 base
90 day: 21.82 mpg (US)

Prius Plug-in - '12 Toyota Prius Plug-in
90 day: 57.64 mpg (US)

Mazda CX-5 - '17 Mazda CX-5 Touring
90 day: 26.83 mpg (US)
Thanks: 3,173
Thanked 3,487 Times in 2,600 Posts
I would think the clay tiles would reject more solar heat than the PV panels since they are lighter in color and do not conduct heat as well, but I'm no expert on the subject. I'd use landscaping to provide shade on the house, as it appears there is none at the moment.

Tracking is absolutely crucial to getting the most performance per M^2 out of a PV array. However, the pictures of the rack don't suggest a method of adjusting the vertical tilt seasonally, and they certainly don't pan east to west.

Still, I'm sure the setup is more efficient than if I were to install the same M^2 PV on a tilt and pan tracker in the Pacific NW. It seems insane to me that people install PV up here, when there would be a better return by installing it in AZ. Essentially leasing out the PV system to those that can better take advantage of it.
__________________
Gas and Electric Vehicle Cost of Ownership Calculator







Give me absolute safety, or give me death!
  Reply With Quote
Old 05-22-2013, 01:17 AM   #19 (permalink)
PaulH
 
MPaulHolmes's Avatar
 
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,832

Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
Thanks: 1,368
Thanked 1,119 Times in 734 Posts
A solar tracker would be much better. It's actually really simple. You can have a photo diode that only has a small slit for light, and each time it gets dark, a motor turns on until the peephole gets sunlight again. One hard thing was making the mounting strong. We get CRAZY winds around here. My neighbor used to have 21 chickens, and after the monsoon season in July/August, he only had 1 chicken left. haha. So, I was just afraid it would break if I tried to get tricky on the first draft. (My son wanted to click the face with the tongue sticking out)
__________________
kits and boards
  Reply With Quote
Old 05-23-2013, 07:43 PM   #20 (permalink)
PaulH
 
MPaulHolmes's Avatar
 
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,832

Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
Thanks: 1,368
Thanked 1,119 Times in 734 Posts
OK I went with photobucket. I think they'll show up now...





I just used some square washers that are 1/4" thick to squash each panel down at 4 different points. I should get a picture of that part.

There were about 15-20 mph winds today and there's not even a hint of wobble. I think they will be fine in really really fast winds, at least I hope.

__________________
kits and boards
  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com