MKR1000 Charging capacity

Hi people, I'm trying to use the MKR1000 with a 3.7V/2000mAh battery and using a solar panel to charge it. I have 14hs without daylight so I need 14hs*120mA = 1680mAh , but I want to have some buffer so I decided to use the 2000mAh battery,

Now the problem is that the battery charger, charges at 350mA only during 4hs so the maximum charge is 1400mAh, so never reach the 1680mAh I need.
So if those calculation are Ok I couldn't never run the MKR1000 with a solar panel.
Is this correct ?
Is there any way to increase the charging time, or power?
Thanks in advance for your help.

If I read the datasheet of the MKR 1000's MCP73830 battery charge management chip correctly, no. It is a fixed 4 hours.

Power is programmed by the RPROG resistor on the PROG pin of the MCP73830 (R3 on the MKR 1000). You can see the equation in section 5.4 of the datasheet:

IREG = 1000 / RPROG

So you could solder another resistor in parallel to R3 to get a higher IREG

Thank for you answer, very clear.
What happens if you add a charger in parallel to charge more time?