Power measurement on LUX/EG4 6000xp

[rnehrboss]

I'm testing new 6000xp inverter. Tied to 4 LifePO4 12v 280ah. Batteries connected in serial for 48v (no communications). As has been discussed in other threads, I set the battery type on the inverter to lead acid (Is that why the percentage read 82% full in this snapshot when the batteries reported 100%?)


Question: Inverter says I'm pulling about 20 watts continually. If I look at the BMS on each, they read about 12-19 Watts each. Here is one of the batteries show 15 watts. Also batteries now show 82% which means I've used 18% for 0.9kw (in the battery discharge above). Doesn't this mean I'm only looking at getting .9kw/.18%=5kw out of the batteries when I should be getting 280ah*12*4=13440?

Thanks

 

[shvm]

(Is that why the percentage read 82% full in this snapshot when the batteries reported 100%?)

Yep. The inverter has no way to know the SOC reported by the BMS unless you set up BMS comms.
Which is cheap but can be easy or not depends on your BMS make, BTW.

Also batteries now show 82% which means I've used 18% for 0.9kw (in the battery discharge above). Doesn't this mean I'm only looking at getting .9kw/.18%=5kw out of the batteries when I should be getting 280ah*12*4=13440?

Highly likely your BMS SOC counter is not calibrated fully.
I'd give it few more charge-discharge cycles and see what happens.

 

[rnehrboss]

thanks for quick reply. how woud you run discharge. high draw like space heater, or low draw?

re battery com: I havent see any proucts to do that, but it would be great. I have CHINs smart batteries: https://www.amazon.com/CHINS-Bluetooth-Temperature-Charging-Monitors/dp/B0CDSG56HD/
with internal bms, I'm guessing its a big NO.

 

[rnehrboss]

I imagine the battery voltage indicated on the inverter is accurate (which shows 81%)? That alligns with this SOC table:

 

[shvm]

I imagine the battery voltage indicated on the inverter is accurate

53.6 V is ~99% for any 16S LFP.
The inverter is in Lead Acid mode anyways. Wait till you see it reporting 70% at 51.2V

how woud you run discharge. high draw like space heater, or low draw?

Depends on the cells and the connection wire used plus connection quality.
For LFP, you are very safe until 0.5 C .
This wouldf be 140 Amps. More than enough to run entire house at once on 48V.

Your 6000XP is the bottleneck here, not batteries.

 

[EG4_Jared]

I'm testing new 6000xp inverter. Tied to 4 LifePO4 12v 280ah. Batteries connected in serial for 48v (no communications). As has been discussed in other threads, I set the battery type on the inverter to lead acid (Is that why the percentage read 82% full in this snapshot when the batteries reported 100%?)
View attachment 202990

Question: Inverter says I'm pulling about 20 watts continually. If I look at the BMS on each, they read about 12-19 Watts each. Here is one of the batteries show 15 watts. Also batteries now show 82% which means I've used 18% for 0.9kw (in the battery discharge above). Doesn't this mean I'm only looking at getting .9kw/.18%=5kw out of the batteries when I should be getting 280ah*12*4=13440?

Thanks

View attachment 202991

As pointed out by shvm, without BMS communications, the inverter cannot determine the State of Charge reported by the BMS and will charge/discharge base off the voltage reading.