Hello,I have a problem getting the LTC4015 Charging the battery. It is initially configured to charge 12.2V Lead Acid Battery(CELL2 - L; CELL1 - H; CELL0 - Z; // CHEM1 - H; CHEM0 - L // 6 cell, Lead Acid Programmable) MPPT Pin - Low. NTC is simulated with two 10k resistors. The gerber and Schematic of LTC4015 on my board is equal to demo board DC2039A and RsnsI is equal to 3 mOmh instead RsnsB is equal 8 mOhm. During the charging, the current reaches 4 A, Absorb CC, but, often, when Vbatt reaches to 13.2 Volt, the current falls to zero and LTC4015 misses the last phases (Absorb CV charge and CV_CC_Charge). I try to reset the charger, removing Vin, but this problem reappears. However, Max_ABSORB timer is not equal to zero but is 5400 s and Charger_status, when the problem appears, is in Absorb phase.
What could be my problem?
Thanks in Advance.
Are you changing any registers or are they all at defaults?
If you put a load on your battery - maybe 1A - during charging, does this still happen? I'm wondering if it is entering CV mode but the battery is not pulling current for some reason. That would cause it to instantly exit CV mode.
If you have the equipment, try emulating the battery with a power supply in parallel with a load (make sure the power supply has a current capability greater than the load draws). We commonly use electronic loads, but you can use a power resistor if you don't have an electronic load. With this setup, you can quickly dial the voltage up to emulate the battery's voltage increasing during charging, so you can replicate this behavior without waiting for a full charge cycle.
First of all, I thank you for your answer.
The registers are all at defaults. I will try to put, during charging, an electronic load ( 1 A) on battery to see if this problem happens.
I already tried to test my board with electronic load and Power Supply after that the problem manifested. During this test, the board showed the problem only the first time but with next tests the problem no longer manifested itself. So, I decided to try again with battery, without electronic load and power supply, but the problem showed again. I would like to find and to understand the problem L but I cannot to find it.
Just to be clear, the procedure with electronic load and power supply is executed by C# Software (windows form) and is the following:
In your opinion, Is this procedure right? What could be the nature of my problem? components' tolerance or battery or possible welding problems? However, not all boards, just some, show the problem but I want to find it and resolve it.
Thank in advance,
Waiting for an answer,
Why is the load current and power supply relevant in your test description? It seems like all that should be relevant is the battery voltage/current. The load is powered from a different path, essentially directly from the power supply. I must be missing something.
Generally, that sounds right though: slowly increase the battery voltage to the target voltage, then slowly decrease the current.
Since that works, I'm wondering how the battery could be different. I do recommend that you try the test using a real battery but with a small load on it. I want to know if the battery is still drawing any current once the charger enters CV mode. If you add a small external load and this stops happening, that might be indicative that the battery is prematurely full. Could it be an old battery? Are you using the same battery between boards, some of which behave as you expect?