Our 12th kickstarter is launching soon!
To get the earlybird goodies, click "notify me on launch" HERE.
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education skip experiences global resources cider press projects digital market permies.com pie forums private forums all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Anne Miller
  • Pearl Sutton
  • r ranson
  • Nicole Alderman
  • Leigh Tate
  • paul wheaton
  • Greg Martin
master gardeners:
  • Carla Burke
  • Jay Angler
  • John F Dean
  • Nancy Reading
  • Beau Davidson
  • thomas rubino
  • Edward Norton
Posts: 114
Location: Val d'Espoir, Quebec, Canada, zone3a at the bottom of a valley
forest garden rabbit books chicken composting toilet food preservation bike bee building wood heat homestead
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Edge case submission
Note1: oops, did'nt see it was only the battery energy for the 100watt for 6 hours. Will connect one of my house trojan agm battery, 102ah@10hr, and get a new picture as soon as i can.

My submission for bb small dc system.

Took a car battery and a reused system that i had stored. I didn't have the info on the ah of the battery, but searching on the net, i found the calculation about the reserve capacity (RC)  tagged on the battery on the calculation to use it.

source: Calculator academy web site

AH = BR *60 *25 / 3,600
   Where Ah is the amp hours
   BR is the battery reserve capacity (minutes)

My BR is 90 minutes, so
90*60*25  / 3,600 = 37,5ah usable energy

37,5ah * 12v = 450w, missing 150w

The panel is rated for 2,2a and 17v
2,2a *17v *6h =  224,4w

So with a full battery and a bright sun and perfect angled solar panel, i can achived 100w for 6hours.
450w+224w= 674w

For a regular 100w consuption of energy, i would install a bigger panel or battery.
panel info
panel info
battery info
battery info
panel installed
panel installed
system installed
system installed
view on the 12v cig plug and 5v usb outlett
view on the 12v cig plug and 5v usb outlett
cell phone charging
cell phone charging
Staff note (gir bot) :

James Alun approved this submission.
Note: You've achieved the technical ability for the construction of the system. In the future, I would like to see the wiring tidied up please. And a quick point aboit your calculation, multiplying by 60 and then divig by 3600 converted minutes to seconds to hours, (90*25)/60 would have been sufficient.

Staff note :

Discussion is ongoing behind the scenes about this BB submission...  Unapproving it for the moment...

Staff note (gir bot) :

Someone flagged this submission as an edge case BB.
BBV price: 0
Note: Sorry. A 100 watt bulb requires 8.333 amps at 12 volts.  8.333 x 6 hours = almost exactly 50 amp hours. It appears your battery is a little too small to meet this posted requirement "Explain how the battery(s) will put out 100W for 6 hours." Using an inverter would introduce losses that would increase the overall power needs even more.

My cellmate was this tiny ad:
Work Trade for the 2023 Garden Master Course
    Bookmark Topic Watch Topic
  • New Topic