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Following scenario: I have a bunch of Sunpower C50 unprocessed single solar cells. I'm trying to make a panel out of them for hiking. According to the datasheet each cell has 0.574 Vmpp an 5.65 Impp or 3.24w power. Since cutting the cells is hard I want to put 4 of them in series so that I have around 2V and 12w output... I want to utilize this as much as possible and therefore charge a single cell Li-ion battery directly with maximum power point tracking.

But I'm struggling to find an IC that fits the purpose. All energy harvesting ICs like the CJMCU-25504 with solar input are low power or not rated for 2V, and most solar battery charger ICs like a CN3791 are mostly buck converters.

I once designed a MPPT circuit myself, so I know that the output voltage of a PV panel is mostly constant, so one simple MPPT algorithm which the CN3791 for example uses is, to just keep the input voltage constant. So I was wondering if I might find a way to design a boost converter that controlls the input voltage ratehr than output? Or maybe there is just the right IC for it, I just can't find it.

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  • \$\begingroup\$ too low voltage. you have also better ic from linear technology. lt8490 \$\endgroup\$ – Marko Buršič Apr 5 at 15:41
  • \$\begingroup\$ LTC3105 has your voltage within spec but it can’t handle that much current. It may be a good start for your search tough. \$\endgroup\$ – winny Apr 6 at 7:02
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The CN3791's MPPT pin voltage is regulated to 1.205V, so you could connect it directly to the panel through a voltage divider to set the max power point. Then drive the CN3791's VCC pin with a boost regulator to get your charging voltage.

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