For low power solar charging of lithium ion's, its not necessarily a better way to charge. For information on why we did not design it as a true MPPT, read our design notes!
For large multi-watt solar arrays that are charging lead acid batteries, you will want to get an MPPT charger. For small cells, its not necessarily more efficient. For information on why we did not design it as a true MPPT, read our design notes!
Use any rigid, flexible, monocrystal, polycrystal, etc panels with 6V to 10V rating (12 to 20 'cells') for the best performance
5.5V panels sometimes work, 6V to 9V is really the best!
This is a fault condition detected by the charger. Most often it is a battery problem or voltage input problem. This can happen if the battery is allowed to discharge completely. The protection circuits on some LiPo cells require the battery to be disconnected in order to reset the circuit after an over-discharge cutoff event. Often just disconnecting and reconnecting the battery will allow it to charge again.