We are creating a solar device that locates the optimal position to gather sunlight, and then stores the light in an AGM battery that we have. We have a 6v battery and we ordered 4 6v solar cells. Unfortunately the 6v solar cells did not come in. There are 4v solar cells in one of the labs at school (2 cells 4.2V .18mA No load). Assuming we wired them in parallel: Could these be used to power the 6v battery up to 4v? What would happen after the battery hit 4v?