I recently overhauled my boat’s electrical system with the following components:
- Quattro-II 12/3000/120-2x50 2x120
- 2x XS1400 DC-DC chargers, each connected to Port/Starboard engine starting banks, served by 105A alternators each.
These are connected to 4 x Series/Parallell Lifeline AGM 300AH 6CT - 600AH bank that I installed about 18 months ago.
Overall the system is working amazing, really no complaints. I am running into one issue though. When the AC load on the inverter exceeds ~1500W, the DC-DC chargers immediately start throttling back. As soon as the load goes away, they return to full output.
The video here shows my house battery bank at 80% with both DC-DC chargers putting out ~47A each. As soon as I start the HVAC system, the DC-DC chargers throttle back and won’t return to full output until the load goes away. I have run loads as high as 1200W and don’t have this problem. I’ve replicated this with other loads - such as the microwave - and the consistent pattern is above 1500/1600w, the chargers reduce output. I have run lower loads around 1200W and the DC chargers maintain full output. My theory was that this is due to battery voltage dropping under load, but you can see in the video the battery bank is still at about 12.5v under load.
I do have DVCC enabled.
Here are the settings for the two XS1400’s - I verified both are identical and both show up as ‘slaves’ in the system.
Any ideas anyone may have to resolve or things to try to further test this would be super appreciated 
