I charge Lithium batteries and set the charging algorithm to Lithium. When I change the charging parameters on my MPPT 100/50 to user defined to change the charging end voltage I noted that the algorithm change as I would charge lead acid batteries. At a charging state of appr. 90% the charging amps will be reduced until the battieres are full (like it should be for lead acid batteries). Is there any setting in user defined in which the charging algorithm stays for lithium to get 100% charging power until the batteries are full?
Thanks for advice.
Alfred
Usually lithiums would slow the charge down after 90% (pylon, byd etc all do that) it is so they don’t overshoot the end voltage.
You can’t really go full amps to the end voltage even with active balancing in practice.
I checked the charging algorithm and it does not went down at 90% when you select lithium batteries. I got full amps until the end voltage. The standard end voltage is 28,4 volt, my batteries end voltage is 29,2 volt.
Not fully understanding you here.
You have programmed 28.4v and the batteries reach 29.2v?
So your batteries are overshooting their charged voltage?
What batteries/bms do you have? The batteries i refer to have can communication with the system.
No misunderstanding. Victrons end voltage if you select Lithium batteries is 28,4 Volt. The end voltage of my batteries for fully charged is appr. 29,2 Volt. The charger keeps the full power until it reached 28,4 Volt, the charging power was not reduced until it reached the 28,4 Volt.
When I change the charging settings to user defined for and end voltage of 29,2 Volt the charging power will be reduced at appr. 90% of end voltage which is for lead acid batteries.
I assume when you change the charging settings to user defined, you no longer have the charging algorithm for lithium batteries. Due to this algorithm the charging time is longer then necessary.
I think that you are misunderstanding the charging process. With lithium batteries the battery voltage is fairly constant up to 90% charge and then it increases. When you charged your lithiums to 28.4V they did not get completely full so stayed on the flat part of the curve. When charging at 29.2V they will have got fuller, the voltage increased higher so the current would fall over the last part of the charge. Lithium does not maintain full current to the end, it tapers off. The final part of charging is constant voltage, reducing current, the controller is simply maintaining voltage regardless of lithium or lead acid, it just supplies what the battery can accept.
