LV6548 and Knowing Your Battery Percentage

[priorityelec]

I have a new LV6548 and 2 EG4 batteries hooked up. The battery percentage is all over the place and is clearly not accurate but the batteries are able to fully charge just fine but the bms is stopping charge. I really want the inverter to stop charge just a little before the BMS. And I want the inverter to shut off the batteries and switch to utility power on its own...not wait for the batteries to die.

In the watchpower phone app I have the following settings:
--Bulk Charging Voltage 56.8
--Battery Cut Off Voltage 47.0
--Float Charging Voltage 54.4

Right now my batteries are fully charged up and sitting at 54.4 volts but the app on my phone says they are 72% charged. The actual inverter battery percentage bars show they are charging at 3 bars. The batteries themselves show 4 solid SOC lights.

Also, as they're charging, the batteries make their way up to 56.8, the app shows 100%, then they settle down to 54.4. If i turn on an air conditioner the voltage drops and my battery percent will start showing somewhere in the 60% range...but I know they're fully topped off.

What am I doing wrong?

 

[Zwy]

I have a new LV6548 and 2 EG4 batteries hooked up. The battery percentage is all over the place and is clearly not accurate but the batteries are able to fully charge just fine but the bms is stopping charge. I really want the inverter to stop charge just a little before the BMS. And I want the inverter to shut off the batteries and switch to utility power on its own...not wait for the batteries to die.

In the watchpower phone app I have the following settings:
--Bulk Charging Voltage 56.8
--Battery Cut Off Voltage 47.0
--Float Charging Voltage 54.4

Right now my batteries are fully charged up and sitting at 54.4 volts but the app on my phone says they are 72% charged. The actual inverter battery percentage bars show they are charging at 3 bars. The batteries themselves show 4 solid SOC lights.

Also, as they're charging, the batteries make their way up to 56.8, the app shows 100%, then they settle down to 54.4. If i turn on an air conditioner the voltage drops and my battery percent will start showing somewhere in the 60% range...but I know they're fully topped off.

What am I doing wrong?

Move Float charging voltage up to 56.0V and see if it holds there.

 

[priorityelec]

I've seen on posts that it's not good to force lifepo4 above resting voltage when at full charge so I have my float low. Can anyone chime in on that one?

 

[houseofancients]

I have a new LV6548 and 2 EG4 batteries hooked up. The battery percentage is all over the place and is clearly not accurate but the batteries are able to fully charge just fine but the bms is stopping charge. I really want the inverter to stop charge just a little before the BMS. And I want the inverter to shut off the batteries and switch to utility power on its own...not wait for the batteries to die.

In the watchpower phone app I have the following settings:
--Bulk Charging Voltage 56.8
--Battery Cut Off Voltage 47.0
--Float Charging Voltage 54.4

Right now my batteries are fully charged up and sitting at 54.4 volts but the app on my phone says they are 72% charged. The actual inverter battery percentage bars show they are charging at 3 bars. The batteries themselves show 4 solid SOC lights.

Also, as they're charging, the batteries make their way up to 56.8, the app shows 100%, then they settle down to 54.4. If i turn on an air conditioner the voltage drops and my battery percent will start showing somewhere in the 60% range...but I know they're fully topped off.

What am I doing wrong?

this would be the one of the reasons you'd want your bms to "talk" to your inverter.
i dont think the eg4's can talk pylontech of rs485 to the mpp's, however, there is solar assistant running on a rasberry pi that can communicate with both your batteries, and inverter and should be able to do what you want..
atleast report proper soc, and take action based on that, and charge parameters on the mpp's

 

[Zwy]

I've seen on posts that it's not good to force lifepo4 above resting voltage when at full charge so I have my float low. Can anyone chime in on that one?

Actually, Andy at Off Grid Garage did a test and found it actually led to more Ah capacity using a voltage for absorption for charging to full charge.

56V gets you to 3.5V per cell. I think many here think they will extend the service life of their pack by some method of not fully charging the cells. The problem will be calendar again will affect lifespan way more than charging into the lower knee area. Then we get into cell balancing and if the BMS doesn't see a high enough voltage, then cell balancing won't occur.

As to why I suggest this, the reason is that if you look at your current settings, the float is where the SCC will turn back on charging the battery, it also is where the SCC will begin supplying PV power thru the inverter. I have found this is how GW runs their units.