SOC drift and calibration

[Olive2Roam]

Hey all, I am 2 years into our Ollie ownership and have yet to calibrate the SOC (State of Charge) for our batteries (12V, 130A Lithionics). It is clear that the SOC displayed in the app, and the actual SOC are out of sync, so I am planning to calibrate tomorrow. The only question I have is that in the Lithionics document (attached), number 5 says "As time goes on observe the SOC value going down until eventually the BMS will reach the NeverDie reserve mark and turns off the power. Turn off your loads and press the BMS On/Off/Reset button to wake up the BMS."

Is the On/Off/Reset button referred to simply the power button on the top of the battery? I assume so since the batteries have an internal BMS. 

Also, do you have a preferred (quick) method for draining the batteries from their full charge to the cutoff?

Thanks in advance!

 FAQ What is SOC Drift RevA.pdf

Edited 19 hours ago by Olive2Roam

[Rolind]

I have found that often a “full” discharge to the shutoff is not necessary to reset the state of charge. Usually discharge to 70-80% will do it once you charge the batteries back to 100%   I do however sometimes discharge my batteries to shutoff, usually while camping on shore power in the summer. I shut off shore power and run the air conditioning. Sometimes when I get very  close to the shutoff SOC, the inverter will disconnect and I will have to complete the discharge using the lights or other non  loads. 
The switch on the top of the battery is the switch they are referring to.

Edited 17 hours ago by Rolind
Added info

[Snackchaser]

5 hours ago, Olive2Roam said:

the SOC displayed in the app, and the actual SOC are out of sync, so I am planning to calibrate tomorrow 

Hey!  I'm pretty sure all the Lithionics 130 amp batteries have the "internal BMS" without that reset function.  That procedure is for batteries with a "external BMS" and it won't reset the SOC as described, although the full charge part is the best fix for the internal BMS too.  Mine sometimes takes a while for that last 1% from 99% to 100%.  Also make sure the charge parameters are right.  I assume you are charging from shore power with a Xantrex inverter/charger, so look at the Xantrex app. and check/set the absorption charge volts to 14.4 and float to 13.4.  I have mine set a little hot at 14.5 and 13.5 and have never had any drift in 4 years... not recommending -- just sayin!.  

Cheers!  Geoff

[Olive2Roam]

9 hours ago, Rolind said:

I have found that often a “full” discharge to the shutoff is not necessary to reset the state of charge. Usually discharge to 70-80% will do it once you charge the batteries back to 100%   I do however sometimes discharge my batteries to shutoff, usually while camping on shore power in the summer. I shut off shore power and run the air conditioning. Sometimes when I get very  close to the shutoff SOC, the inverter will disconnect and I will have to complete the discharge using the lights or other non  loads. 
The switch on the top of the battery is the switch they are referring to.

@Rolind, Thanks for the info. I can't run the AC off our 260AH battery bank, but I have a small space heater that may do the trick. 

Thanks!

[Olive2Roam]

5 hours ago, Snackchaser said:

Hey!  I'm pretty sure all the Lithionics 130 amp batteries have the "internal BMS" without that reset function.  That procedure is for batteries with a "external BMS" and it won't reset the SOC as described, although the full charge part is the best fix for the internal BMS too.  Mine sometimes takes a while for that last 1% from 99% to 100%.  Also make sure the charge parameters are right.  I assume you are charging from shore power with a Xantrex inverter/charger, so look at the Xantrex app. and check/set the absorption charge volts to 14.4 and float to 13.4.  I have mine set a little hot at 14.5 and 13.5 and have never had any drift in 4 years... not recommending -- just sayin!.  

Cheers!  Geoff

Thanks, @Snackchaser. I'll check those parameters. 

[Olive2Roam]

The process went pretty much exactly as planned. All seems to be well as we are charging up. Hopefully the accuracy of the SOC will improve. (I recently had a battery shut down when the app was indicating a 35% SOC.)

Thanks for the assist.