On Sat, Jun 4, 2011 at 6:26 PM, Al Shinn wrote: > Perhaps of interest and perhaps on topic > > I just opened up 3 different solar path lights. > > 1) $1.00 from dollar store has 1 amorphous solar cell on glass (in > circuit V =3D~ 1.3V in bright light), 1 IC (pn ANA618) w 4 leads 1 large > button cell (the tag on the lamp says NiMh 1.2V/60mAh), 1 white LED, 1 > inductor, and a switch. At first I thought that the inductor was a resis= tor > but that did not make sense so I approached it with a magnet, not only wa= s > the magnet strongly attracted (not really proof) but the light got bright= er > - proof to me. > This unit's tag says from L'Image Home Products made in China > > 2) $2.00 from orchard supply has 4 small crystal solar cells potted in > plastic, 1 IC (pn 6N06) w 4 leads 1 aaa NiCd cell 1 white LED 1 inducto= r > and a CdS cell. same inductor story. This one blinks when the battery ge= ts > low. > > 3) $2.00 from orchard supply - has 1 amorphous solar cell on glass (1.3= 3 > in circuit w bright light, 1 IC (pn 5252F) w 4 leads 1 aa NiCd cell 1 > white LED 1 inductor. same inductor story. > Tag says made for Orchard Supply in China > The circuit in this one is as follows: > pin 1 of IC has Sol+ > pin2 B+ and L > pin3 B-, Sol-, Led- > pin4 Led+, and L > > Can't find any such chips on Google. But if you could, it might be a good > thing for the solar guitar tuner, I bet (at least $0.25) the chip has a > boost current source that could be a voltage source with a bit of tweakin= g - > diode + cap + Zener?. You could go to OSH for the chips and all for $2. > > Note the NiMh button cell in #1 (a solution to some size objection to Ni= Cd > s by the OP.) > Note - none of these have visable diodes in series w the solar cell - a= nd > the cell V was too low to allow one in #1 and #3 (1.3V in circuit, perhap= s a > fet is used to block reverse current to the solar cell? > > But > > Thanks! That sounds interesting, but it seems that you can't do a constant voltage charge on Ni based batteries. Lithium ion seems really good. I'll stick a a 2xAAA holder on there as well, but will probably not be needed. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .