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Issue #60



60      48      36      24      Ah      60      48      36      24
512     382     318     219     10      0.85    0.80    0.88    0.91
693     533     423     308     15      0.77    0.74    0.78    0.86
905     658     518     378     20      0.75    0.69    0.72    0.79
1385    1053    811     545     30      0.77    0.73    0.75    0.76

                                min/max 0.69    0.91    $/Wh    

Antennes et MB




Panneaux solaires

  • 20150216 ev-power
    Solar panel SCHUTTEN Poly 300Wp 72 cells EUFREE (MPPT 35V)
    Solar panel SCHUTTEN Poly 300Wp 72 cells EUFREE (MPPT 35V)
    Art.No.: GWL/Sunny-300P
    186.19€    1     21%    225.29€    
    Total Products (without VAT):    186.19 €    
    plus 21% VAT**:    39.10 €    
    Total Products (with VAT):    225.29 €    
    Shipping (net):    52.76 €    
    plus VAT 21% Amount:    11.08 €    
    Weight of shipment: 31.20 kg        
    Grand Total:    289.13 €    

Photovoltaique amorphe


Remote Power Control


Piles a combustible

Piles au methanol pour les caravanes avec un modele en vente (ebay & boutiques meme sur Toulouse) autour de 2000 euros pour 25W (12V * 2A) de capacité, petite boite 43,5 x 20,0 x 27,6 cm / 6.5 kg et 0.9 litre de methanol par kWh produit. A 10W cela fait 45 jours d'autonomie pour 40 euros la recharge de 10 litres.




Ultra capacitors
Mass, typical 5.51 kg Usable Specific Power, 2,700 W/kg Specific Energy, E max 3.2 Wh/kg Stored Energy 17.8 Wh

Q = C * V
Q = I * T
C = 20F
V = 5V
Q = 100C
With discharge current say 1uA:
T = 100C / 1uA = 100,000,000 seconds
T(seconds) / 60 / 60 / 24 / 7 = 165 weeks to discharge to 68% of max capacity.
At current draw 100uA the value is 11 weeks.

Alright, first I’m no math wizard really…
(couldn’t get through calculus…)
I just looked at datasheets.
I don’t know the MSP430, but his datasheet say
With internal oscillator @1Mhz = from .2ma – .3ma
(change with / voltage) so let’s guess .25ma
Yeah, there the lcd module that would be easy
To measure since consumption is steady.
Let’s say it take 100 clock to get a task done
(assuming a more complexe task is done) = ~100us @ 1Mhz, which give 100us/1s = 0.01% duty cycle = 0.01 * .25mA = 2,5uA average
or ((2.7+1.8)/2)V * 2,5uA= 5.6uWatts

Capacitor leakage :
We dont what it is, it seem to change wildly from
One 10F from another :
Nichicon = .5 * C at 2.7volt = .5 * 10 = 5mA…
They say it’s after half an hour.
Maxwell = 0,03ma after 72 hours
So duuhh it must be reduced when voltage drop…

Here you also have to take into account ESR
(Equivalent Serial Resistor) so it’s like a resistor .
Nichicon = .3 ohm
Maxwell = .075 ohm
We take that in account in the capacitor
Discharge formula ( as R)

Q = C* V * (1-e^(-t/(RC) ) )
Where Q= is the charge Amp/s?
C = 10F
V = 2.7 at start, 0 or with our mcu 1.7V
e = natural number = ~ 2.71828…
t = time in second
R= in this case, ESR + mcu load (V=RI)
Then you need to consider the leakage of both cap.

So it’s not impossible, it took like 10min to get these info,
Take 20 more and you might have some approximation

I did my part.


Solutions radio


Cell Type: The type of silicon that comprises a specific cell, based on the cell manufacturing process. Each cell type has pros and cons. Monocrystalline PV cells are the most expensive and energy intensive to produce but usually yield the highest efficiencies. Though polycrystalline and ribbon silicon cells are slightly less energy intensive and less expensive to produce, these cells are slightly less efficient than monocrystalline cells. However, because both poly- and ribbon silicon panels leave fewer gaps on the panel surface (due to square or rectangular cell shapes), these panels can often offer about the same power density as monocrystalline modules. Thin-film panels, such as those made from amorphous silicon cells, are the least expensive to produce and require the least amount of energy and raw materials, but are the least efficient of the cell types. They require about twice as much space to produce the same power as mono-, poly-, or ribbon-silicon panels. Thin-film panels do have better shade tolerance and high-temperature performance but are often more expensive to install because of their lower power density.
Sanyo’s "bifacial" HIT panels are composed of a monocrystalline cell and a thin layer of amorphous silicon material. In addition to generating power from the direct rays of the sun on the panel face, this hybrid panel can produce power from reflected light on its underside, increasing overall panel efficiency.
Cells in Series: Number of individual PV cells wired in series, which determines the panel design voltage. Crystalline PV cells operate at about 0.5V. When cells are wired in series, the voltage of each cell is additive. For example, a panel that has 36 cells in series has a maximum power voltage (Vmp) of about 18V. Why 36? Historically, panels known as 12V were designed to push power into 12V batteries. But to deliver the 12V, they needed to have enough excess voltage (electrical pressure) to compensate for the voltage loss due to high temperature conditions. Panels with 36 ("12V") or 72 ("24V") cells are designed for battery-charging applications.
Panels with other numbers of cells in series are intended for use in grid-tied systems. Due to the increased availability of step-down/MPPT battery charge controllers, grid-tied panel


Il faudra sans doute 50 a 100W de panneau photovoltaique pour un relai, on trouve du 90W amorphe pour 121 euros livrés :

20kg de batterie (100 euros) + panneau (121 euros) + regulateur (50 ?) + matos wifi et antennes (300 ?) ~ 600 euros.
MIMO et dual 2.4/5.5

Une solution alternative :

- un routerboard a la place du switch
- un cable pieuvre power jack 1 femelle vers 8 males
- une alimentation de portable 19V 3.42A
- un splitter PoE passif
- des injecteurs PoE passif

L'avantage du routerboard est qu'il accepte 9 a 28V DC en alimentation donc a peu pres comme les ubiquity et que ses temperatures de fonctionnement sont tres larges de -40 a +55C.
La doc du routerboard n'est pas tres claire sur la taille du power jack est-ce 5.5/2.0 ou le plus standard 5.5/2.1 ?