Solar Battery Charger Tips Request

Thread Starter

HRN88

Joined Jul 21, 2020
24
Hi guys, I hope you are fine.

I want to design a solar charger for 2 Li-Ion batteries to power a system using the LTC3652 I.C. My doubt is: can I use this I.C in a system that needs to be powered all the time? I've read the datasheet and It doesn't mention that has a some thing like "Sharing Load" to automatically switch between the batteries or the solar panel to power the system. But I want to use this IC due to its MPPT.

Another thing is that In the datasheet says:
"An auto-recharge feature starts a new charging cycle if the battery voltage falls 2.5% below the programmed float voltage"

So, If I program 8.4V for the Output battery voltage through the voltage divider pin Vfb (3.3v), and my battery falls below the 2.5% (8.4v- 8.4v(0.025) = 8.19V) then the charge cycle will be triggered. But with that level the battery still have a lot of energy, why the IC trigger the charge process with only the falling of 2.5%? and maybe this leads to reduce the battery lifecycle. Usually a Li-Ion battery is discharged at 3.0-3.2v (6.4v for both)...

Are there something with experience using this chip?
Ty guys,
 

Ya’akov

Joined Jan 27, 2019
6,275
The reason the chip would start the charge cycle is because it is anticipating a time when the sun will not be available and while there is sun it wants to maximize the advantage.

If the charge didn't start until the battery was depleted the risk is the sun would become unavialable and charging would be impossible.
 
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