Conext XW Pro refusing to Charge Lithium Ion Battery

[RicoWarner]

Hi all - so have had Conext XW Pro running for a couple months no problem, using flooded lead acid batteries. Generator would connect via manual transfer switch, Conext would qualify w/blinking green LED, and it would switch to charging mode w/solid green LED. Great.

So switched over to the Discover 130Ah AES lithium ion battery w/integrated BMS. It runs on the Xanbus and propagates the settings automagically. Plug and play. Yes, saw there is a forum for plug and play...but that is not per se where the prob shows up.

The problem is when I try to charge the battery with my backup generator. I flip the manual transfer switch, and...wait for it...nothing. No blinking green LED while it qualifies the elec-TRICKITY.

It is like charging mode is disabled. Thinking it has to do w/battery in some way, as is 1st time I tried charging since it went online, have had no problem charging before. Unlikely the ATS relays died, as is a new system. Probably an auto-populated setting from the battery.

Any ideas how to make charging work? Maybe a hint, the battery is probably fully charged, but I need aux power source so can run some power tools.

 

[GXMnow]

Do you have the generator going into the AC1 or AC2 input? My system is on grid, so my AC1 is the grid connection, and I connect my backup generator to the AC2 input. The qualifying limits on AC1 are pretty strict, but you can adjust the AC2 to tolerate more frequency and voltage fluctuation. My old Coleman generator is having an issue with the governor, so the rpm is bouncing a bit and it keeps disconnecting, but each time it stabilizes, I see it trying to qualify again. Do you have a decent volt meter? I would check to make sure you are getting your proper line voltage at the input of the XW-Pro. If you can, also check the AC frequency from the generator. That also needs to be pretty close for it to see it as good power.

I am using Lithium Ion batteries, but my BMS does not talk to the XW-Pro, I have it set to "Custom" and I entered the cell properties manually. That is one thing I would try in your case. Just manually set some safe limits for your batteries in the Custom battery menu and see if that takes care of the problem with the generator.

The BMS communication shouldn't directly change how the generator qualifying works, but if that was the only change you made, it is sure worth looking into it. Even if the battery is reporting completely full, the XW-Pro should still qualify the incoming power and be able to switch to that to keep from using the battery to run the loads. Grid support and Generator support settings can alter how it will use the generator power or assist running the loads, but even here, it should still qualify the incoming power.

 

[RCinFLA]

Don't know why you have an external transfer switch but that is not likely your charging problem.

Do you have consistant AC passthough to AC_out from generator verified by ACin2 current reading? This would verify generator lock-on by inverter.

As mentioned, AC1 input is intended for utility grid and has a much tighter AC frequency tolerance than AC2 input which is intended for generator input and has more AC frequency range.,

Do not interpret AC input frequency range spec as rpm wobble variability range by generator. The generator output frequency must be within the specified range but also must be stable in frequency. The phase locking and tracking by the inverter is very slow and can only tolerate a variability of about 0.3 Hz per second. It cannot tolerate a wobbly generator rpm govenor control. Listen for smooth constant engine rpm speed. No wha-wha sound. It is doubtful any DVM frequency measurement will show varying generator frequency since the count period averages out the frequency variance.

Secondarily, verify the charging float and absorb settings in the inverter. If too low settings it will think an LFP is fully charged. Even if it changes battery type automatically to lithium batteries it might not change float and absorb setting values. I think lithium battery type may also default to no charge float.

XW inverters and 'plug and play' is a bit of an oxymoron. They have many inter-dependent settings that the user interface or manual does not do a good job of explaining.