Dear,

By using a solar cell & rechargable battery (initial 0V),
1. Do you know how to provide a quick power up?
(under strong spot light,providing 0.8mA, start MCU within 1 min)
2. protect the cicuit from overcharging?

Problem facing:
I have tried to "parallel" like the followings:

solar cell // (0.1u Cap):schottky diode:recharge battery//MCU

: = in series
// = in parallel

But the MCU cannot power up, 'cos the battery consume
0.8mA ~ 0.9mA. It will drop the voltage level to ~1.2V
MCU need 1.5V to power up reset.

Here is the background:
using 1.5V MCU (5uA, no load)

solar spec.:
open circuit voltage Voc= 2.6V,
Short circuit current Isc=5mA,
Operating Voltage = 2V,
Operating Current = ~15uA(indoor) to ~2mA (outdoor)

Lithium-ion rechargeable battery:
(1.5V)
max. charging current = 6mA
nominal capacity = 5mAh