Lithium MS2812 Conversion from Lead Acid

[WinePress]

I have successfully converted from lead to lithium. I used information from this forum (Thanks Richpatty) and others to arrive at the settings for the non existent lithium profile of the Magnum MS2812. I am trying to now fine tune the settings. I have no issues with bringing the batteries to 100%, My issue is trying to maintain the resting levels at less than 100%. When set up on shore power I would like to have the batteries set at about 80%. My understanding is that will allow the batteries to have a longer life. This seems to be elusive with my current settings. Once the bank is fully charged I bring down the voltage and the bank will begin to discharge down to about 80%, then a couple of hours later it back will be back at 100% then slowly begin to discharge down. So it is this constant back and forth that I can’t figure out.
I am unfamiliar with the Magnum feature CC/CV and was wondering if anyone has used this setting to manage their Li bank. It seems like this may be a possibility but I’m not sure what the settings should be.
The Chinese manufacturer, Chin is of no help. They only offer to say charge to 100% and don’t worry about it as the internal BM will keep the cells from overcharging.

Here is my settings currently-
Batteries- Two 12 v 280 amp LiFePO4 batteries Mfg. Chin
Charge profile for Full Charge-
Absorb- 14.2
Float- 13.6
EQ- 14.2
EQ Time- .1
Absorb done- 5.0 hrs
Charge rate- 100%
Max charge time- 8.0 hrs
Final Charge- Silent
Re-bulk Voltage- 13.2

Charge profile for 70- 80 %Charge- (Will not stay at 80, creeps back and forth from 70 to 100)
Absorb- 13.0
Float- 12.9
EQ- 13.0
EQ Time- .1
Absorb done- 5.0 hrs
Charge rate- 100%
Max charge time- 8.0 hrs
Final Charge- Silent
Re-bulk Voltage- 13.0

Any help and experience is greatly appreciated.

 

[Richpatty]

This is a great point... I believe there is a way to do this... This is from page 13 from the ME-ARC remote (which is an upgrade from the one that comes with the MH.).
I have NOT tested this.

SOC Connect – Incoming AC only connects when the battery bank State of Charge (SOC) falls below the Connect SOC setting in the SETUP menu’s 02E AC In - SOC menu item. Disconnects from incoming AC when the battery bank SOC rises above the Disconnect SOC setting, also from the 02E AC In - SOC menu. This feature requires the optional ME-BMK (battery monitor) to be installed. See SETUP menu 02E for more information on the Set Connect SOC menu settings.

You do need to make sure you get to 100% at least monthly to ensure all the cells in the batteries get balanced.

Also there is some good videos on this topic from Will Prowse.




I don't travel as much right now and my RV is covered when stored, so I shut down as much as I can and let the batteries drift down in charge, They take a full month to get low...and by then it is time for either a trip or the RV's 30 day "exercise" where I get the batteries back to 100%.

I hope this helps ...

 

[WinePress]

Thanks Rich,
I will make these changes and see how the system reacts.

 

[newmarokie]

Wine,
You might consider adjusting the rebulk voltage and let the batteries cycle up and down