I have a 5V 1000mA solar cell which I have connected to two 18650 3.7V 3400mA batteries in parallel. The solar positive comes in through a 1N4007 diode (cathode toward battery)and then a latching relay before going to the positive of the batteries. The latching relay disconnects the solar cell when the battery is charged to 4.2V and reconnected when the battery discharges to 3.4V. The batteries are connected to a 5V boost regulator, powering an Arduino Pro Mini which for most of the time is in sleep mode. Every two hrs the Arduino wakes up and performs some tasks for about 3 minutes. During this time the batteries also power an ESP8266-01 through a 3V voltage regulator for about 2 minutes. When not connected to the solar or at night the power drain is about 1/420V in 2hrs. However when exposed to sunlight (in Tucson, AZ in April) sunlight is about 30º off directly overhead it only gains 1to2/420V in a 2hr. period. It used to get more, about 4/2hr period. I am at my whits end as to why it is not charging more. It should be. I am attaching a schematic of my wiring. (sorry I'm not an electrical engineer so schematic might not be that great.) Can anyone see where I have done something wrong keeping the solar from charging more or some way I can get it to charge more?