It seems that bike-powered battery chargers do exist: http://t3.gstatic.com/images?q=tbn:ANd9GcRhAnAGE38vKDupFRBvagyVB2kgTCUZUygKHq0phUMFSx1OIGP12w&t=1 http://www.phonedog.com/2008/12/30/seriously-green-mobile-tech-the-bike-powered-battery-charger/
Thanks. Paul Olivier On Fri, Aug 31, 2012 at 4:29 AM, Paul Olivier <[email protected]>wrote: > Crispin, > > On Thu, Aug 30, 2012 at 10:22 PM, Crispin Pemberton-Pigott < > [email protected]> wrote: > >> Dear Friends of Fans (FoF) >> >> Thanks Frans and Phil. I think the fan power can be reduced on Paul O's >> stove by increasing the length of the outer sleeve providing secondary >> air. >> > > I have experimented with changing the length of the burner housing, > and this is such a delicate undertaking. > > >> There is little flow resistance to secondary air flow and it can be used >> to >> draft primary air flow to a certain extent. >> >> The vertical height of a stove directly affects the requirement to provide >> primary air pressure. As the fuel packing also affects this, several >> solutions are available to reduce the need for pressure. My point is that >> 2 >> watts is a lot of power for a stove fan and it is worth looking at the >> overall design to see if it is needed at all, and when. For example, it >> may >> be required for 5 minutes in the beginning but not after that, or 15 >> minutes, or for 1/2 the burn etc. This need impacts the battery life >> requirement. It may be that a 'fan powered stove' only needs fan power >> part >> of the time. That being the case, a super capacitor might be a worthy >> candidate because it can be charged in a few seconds. >> > > In the case of rice hulls, very little power is required at the beginning > of the burn. > But toward the end of the burn, the power requirement at least doubles. > Rice hull biochar provides far more resistance to the flow of air than > rice hulls. > Thanks. > Paul Olivier > > > >> >> Regards >> Crispin >> >> >> >> Phil, >> >> 3x LiION =3,7Vx3=11,1V Charger needs 4,2x3=12,6 maximum or EXPLOSION >> RISK >> 2W motor at 12V-------->0,1666 A 8h xO,166A =1,8Ah Laptop cells are 3,6 Ah >> and more Sun cell 15,6V---------> 12,6 V +3V for charging regulator LM317 >> >> PC uP fans exist at 5V x0,2A=1W you could power with 2 cells; Also a dual >> fan of 2x 1W >> >> Regards >> Frans >> >> I see Paul Oliver's work to be excellent and appreciate how a variable >> speed >> fan can offer excellent control over TLUD operation. My reservation is >> that >> there are many places where even the small power requirement (Paul says >> 1-2 >> watts) just isn't available. Lots of people here in Nicaragua are totally >> off-grid and don't have reasonable access to a way to charge a battery. >> So, >> I am been thinking about options. Being, among other things, an >> electronics >> geek, here is what I have been thinking about. >> >> >> Running the TLUD 8 hours a day at "average" fan speed means 12 watts per >> day. At 12 volts that's one ampere hour. I have been thinking about a >> couple >> of approaches. One is "higher tech" but may be a better solution at an >> equivalent or lower cost. In both cases I am just thinking of a >> photovoltaic >> panel to charge the battery. The difference is the battery voltage. >> >> Small PV panels are pretty common on the surplus market. For example, >> Electronic Gold Mine (http://www.goldmine-elec.com/) offers an >> assortment. >> The specifications vary from 7 to 35 volts open circuit with output power >> in >> the range of 1-3 watts. Prices are from $4.50 to $15. As this is quantity >> one retail price information, it is likely the could be found at >> significantly lower costs. >> >> >> As any PV-based system will need some sort of charge controller for the >> battery and what PV cells (in particular, what voltage) will be available >> at >> the best price point, I am thinking that using a single-cell Lithium Ion >> battery (3.7 volts nominal) would make the most sense. Units with a >> capacity >> of 2.2 ampere hours and more are commonly used in laptop computers. They >> offer reasonable life, low cost and the possibility of finding them on the >> surplus market. The cells can be paralleled if higher capacity is needed. >> >> A switching "up-converter" would be needed to supply the 12 volts needed >> for >> the fan. The speed control could be incorporated into the up converter >> which >> would reduce the cost and increase the efficiency. >> >> The alternative would be to use a more or less 12 volt battery (three >> Li-Ion >> cells in series) so that the up-converter could be eliminated. My initial >> guess is that the reduced electronics cost would not be as much as the >> increased battery cost but it is a viable alternative as long as higher >> voltage surplus PV panels are available. >> >> While this sounds like a lot of electronics, this is all very common stuff >> that you find in, for example, cellular phones. There is some design work >> needed but the actual component costs will be very low. >> >> Comments? >> >> -- >> Phil Hughes >> [email protected] >> >> >> >> _______________________________________________ >> Stoves mailing list >> >> to Send a Message to the list, use the email address >> [email protected] >> >> to UNSUBSCRIBE or Change your List Settings use the web page >> >> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org >> >> for more Biomass Cooking Stoves, News and Information see our web site: >> http://www.bioenergylists.org/ >> >> > > > -- > Paul A. Olivier PhD > 27C Pham Hong Thai Street > Dalat > Vietnam > > Louisiana telephone: 1-337-447-4124 (rings Vietnam) > Mobile: 090-694-1573 (in Vietnam) > Skype address: Xpolivier > http://www.esrla.com/ > -- Paul A. Olivier PhD 27C Pham Hong Thai Street Dalat Vietnam Louisiana telephone: 1-337-447-4124 (rings Vietnam) Mobile: 090-694-1573 (in Vietnam) Skype address: Xpolivier http://www.esrla.com/
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