Connecting solar panel with electron

I have an electron with asset tracker shield that i plan to run with lipo battery and solar panel. https://www.amazon.com/gp/product/B00HQXQOIQ/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 this is the solar panel i have. and i also got https://www.amazon.com/gp/product/B00JUFJ1GA/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 36v 24v to 5v 2amp regulator which i plan to connect to vehicle alternator so when vehicle is on i can be charging electron lipo. but my question is can i stick the solar panel directly to power input on asset tracker shield? will i have any problems when solar panel is not outputting full 5v ?

You can connect the output of the solar panel to the VIN pins of the Electron and it will charge just fine. Put a diode on the + output line of the solar panel to prevent the 5v input from feeding back into the solar panel causing it to possibly heat up.

You can feed the 5v output of the 5v regulator to the VIN pin also so it will charge from either source.

so i can have multiple vin and it shouldn’t have problem? even if both sources have different voltage?

Not if you add a diode to the solar panel or power the Electron via the USB port and feed the solar to the Vin pin.