Author Topic: LT3652 Efficient Solar charger. Example schematic from datasheet - weird  (Read 837 times)

0 Members and 1 Guest are viewing this topic.

Offline rowifiTopic starter

  • Contributor
  • Posts: 37
THE DATA SHEET HAS A SCHEMATIC DIAGRAM FOR : 2A Solar Panel Power Manager With 7.2V LiFePO4 Battery and 17V Peak Power Tracking.
The input comes from a solar panel and is specified to be lower than 40V,
The battery is 7.2V
There are two diodes in the schematic, one from the battery and another from the solar panel both connected to the LOAD.
As I see it the higher voltage will make it to the load, so if the load is requires 7Volt and the solar panel supplies 10v to 40v that higher voltage will likely destroy the load.
I can't work out what is the intention for this schematic am I missing something.
Thanks
 

Online Peabody

  • Super Contributor
  • ***
  • Posts: 2405
  • Country: us
Re: LT3652 Efficient Solar charger. Example schematic from datasheet - weird
« Reply #1 on: January 02, 2024, 02:41:07 pm »
It looks like that's right.  And the lighter the load is, the more likely it will be toasted.  You would need a regulator before the load - either a buck or a buck/boost depending what voltage you need for the load.

This circuit also has a diode drop in the battery line.  That's not a huge problem in a 2S circuit, but not ideal.
 

Online magic

  • Super Contributor
  • ***
  • Posts: 7571
  • Country: pl
Re: LT3652 Efficient Solar charger. Example schematic from datasheet - weird
« Reply #2 on: January 02, 2024, 03:02:02 pm »
You could omit direct connection to the panel and power the load from the LT's buck converter, but doing so interferes with Li-ion charge termination logic: when battery voltage reaches 4.2V per cell the charger enters CV mode and is supposed to stop charging when battery current drops to 10%, allowing the battery to rest and fall below 4.2V. This may never happen if there is extra load in parallel with the battery.
 
The following users thanked this post: rowifi


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf