Hi folks,
Does anyone out there know the voodoo behind the charging algorithm or what, other than temperature, could be causing Quattros and MultiPlus's to not reach their maximum charging currents?
Problem
The inverter/chargers are not reaching their maximum charge rate. A cluster of 6 x Quattro 15000 can theoretically push 1200A. There are 45 flow batteries which can each accept up to 50A during charge.
However, test results on this system showed a maximum of 1050A reached which after 5 minutes reduces to 900A which is then sustained. This is only 150A per Quattro. This results in 9 hours to charge rather than 6 hours which should be possible. This impacts the business case for some clients. This was the same on both a 35 degree day and an 18 degree day (Celcius).
The system is running the ESS module. The tester commented that charging fewer batteries and/or with ESS not running he has observed the 200A charging on other systems, but for some reason, it has not been able to be reached in this system.
Ideas
The comparatively high internal impedance of the flow battery being 80 to 100 milliohms (all connected in parallel) may be causing the algorithm to not adjust the voltage high enough to push enough current into the batteries.
What does the "lithium batteries" checkbox in the charger page actually do/change? Again, I imagine this would change some characteristics of the charging algorithm, even if lithium battery is not chosen from the list of battery defaults. Li
Questions
How does the charging algorithm work for the charger in Multiplus II and Quattros?
Is it possible that the charging algorithm would not raise voltage enough either due to high impedance?
or the ESS module somehow altering behaviour?