MPPT charge control Project - LT3652

[Arash]

I am doing a Solar powered power bank as my dissertation project. It's based on LT3652 charge control, a Lithium-Ion battery (4500mAh) and 2 boost converters (3.3-5V and 3.3-12V).

I am using a 21W, PV panel with a maximum voltage of 7.68V. I need 4.2V and 2A output to charge the battery.
In calculations I did set minimum voltage in, as 6V and float voltage as 4.2 and followed the datasheet.

My design is based on Sparkfun Sunny Buddy MPPT. I changed the inductor (SDE0805A-100M) and diodes (RBR5LAM30ATFTR) and also sense resistor.
Unfortunately I'm not getting what I need out. Pictures speak better than words.
1.My schematic.
2.The actual prototype board
3.The open circuit voltage out. (7V in, 4.2V out)
4.Voltage out with 4.7ohm load.(6V in, 1.5V out . If i change the input voltage any higher and lower than 6V output voltage drops!)
5.Current out with 4.7ohm load.(6V in, 220mA out It goes up to 240mA at 7.6V in).

I appreciate your thoughts and advise as my deadline is reaching and i have been all over the place but i couldn't find the fault. as you can see I have changed the calculated 3.2uH inductor with a 10uH one but it didn't make much of a difference!

Ps. Sorry for the long post, I just wanted to give you as much as information as i can.

 

[WHONOES]

At first glance, it looks as though you feedback resistors R3 , 4 and 5 are incorrect. Have a look at the datasheet schematic and text.

 

[Arash]

At first glance, it looks as though you feedback resistors R3 , 4 and 5 are incorrect. Have a look at the datasheet schematic and text.

I only followed the data sheet. here my calculations. please take a look and let me know where the error is.

 

[WHONOES]

I forgot to ask what the range of the reference voltage coming from the potentiometer is.

 

[Arouse1973]

The charger IC checks to see if the battery voltage is within limits to begin charging at full current. You don't have a battery so it's probably this that is causing the issue. The IC will only give you 15% of the programmed current if it senses a low battery voltage, which is about what you are seeing. This feature is common to most of the battery charging ICs I have seen, it's to protect a very discharged battery initially.
Thanks
Adam