What's going on here?

Author	Message
phil99 Guru Joined: 11/02/2018 Location: Australia Posts: 3273	Posted: 09:57pm 17 Jun 2025       Only a guess, perhaps the ideal diode doesn't turn off until there is some reverse current flowing. The rebound would then be when that reverse current stops. Or it could be due to a change in temperature. The terminal voltage of the cells is affected by temperature, falling as the temperature rises. When the cells are almost full much of the charging current can no longer be absorbed so goes into breaking down water in the electrolyte, making hydrogen and oxygen. As they recombine the energy is dissipated as heat. Note how the battery voltage is falling faster than the solar voltage toward the end. Perhaps that indicates the cells are full and heating up. When charging stops the cells cool down and the voltage rises. Some high rate chargers use the drop in cell voltage to switch to trickle charge. Edited 2025-06-18 09:00 by phil99