These are Ni-cd or Ni-mh batteries so you can charge them without charge controller.
most solar lamps use them without any charge controller. add diode to block reverse voltage. ( like stock board has)
Another possibility (which is seen with MANY solar lights) is to use LiFePO4 rather than Nicad/NiMH. The advantage here is that the battery produces 3.2V rather than 1.2V. This results in simplified circuitry and higher output due to not being limited by a boost driver.