[Power] Haiti power questions

[forster at ozonline.com.au]

Scott

> Full charge for XO1 measured at 156 minutes at 7.75 amps DC, but the voltage was a bit low

sorry I meant 0.775A

> 
> So that gives us, @12V, 93Wh per XO delivered over a period of 2.6h, or
> 35.77Wh per XO per hour, to achieve a full charge on the XO.

9.3 Wh per hr or 24.2Wh per charge?

> Our total load of 50 XO's for 2.6h is 4650 Wh.
1209 Wh? 
> We must deliver 1788.5Wh per hour for the 2.6h charging period, 

465W?

assuming 
> all 50 XO's a) started in a completely discharged state and b) 
> were connected and charging simultaneously.  The latter is tough on your 
> batteries.  If the school day is 6 hours, and two "shifts" of student 
> charging can be accomplished, then the LA batteries will last MUCH longer, 
> and our wiring can get much smaller.
> 
> According to the wunderground.com solar calculator:
> http://www.wunderground.com/calculators/solar.html
> 
> a hypothetical deployment of 1.4kW of solar panels in Matelgate, Haiti
> would produce an annual average of 7.3kWh generated per day, with a 
> december minimum of 6.44kWh/day being collected. Similarly, 
> 1400Ah of battery will provide 3 days of backup.  I would consider these 
> to be bare minimums for a system of this scale.

4 hrs per day equivalent is a good rule of thumb

> 
> Apart from the panels, other components include combiner boxes, where each 
> panel is individually breakered, a few charge controllers in parallel, a 
> main breaker enclosure with busbars, breakers, lightning suppression, etc, 
> batteries of course, all the cabling and interconnects, and some output 
> bus bars with terminations that the XO's can be connected to.
> 
> Cheers,
> Scott
> 
> >
> > Done with an XO1.5 running Turtle Art
> > http://wiki.sugarlabs.org/go/Activities/TurtleArt/Using_Turtle_Art_Sensors#Measuring_DC_Amps
> >
> > Tony
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