Discharging Lithium Battery

[FL-Guy]

I just installed a new 200Ah lithium battery. I am discharging the battery to reset my WF3785 AD converter to lithium and to calibrate the battery shunt monitor.
How low do I take the voltage to reset the battery monitor to 0?
Currently at 11.6V
Battery info say BMS will cut off at 10.8V

[xrated]

You didn't mention what brand/model shunt you have, and since there are several of them out there, it may vary between brands/models. The procedure I use (Victron BMV 712 is to wait until the battery is fully charged and "sync" the monitor to read 100%. Your percentage of remaining battery AH will then depend on the battery size in AH. The BMS of the battery is responsible for cutting off current flow from the battery when it reaches a predetermined level of voltage. Mine is set to 2.6V per cell or 10.4 volts at the battery. That low of a setting would likely show that you have maybe 7, 8....maybe 9 percent of the battery left. Hope this helps

[Soundsailor]

I just installed a new 200Ah lithium battery. I am discharging the battery to reset my WF3785 AD converter to lithium and to calibrate the battery shunt monitor.
How low do I take the voltage to reset the battery monitor to 0?
Currently at 11.6V
Battery info say BMS will cut off at 10.8V

For the WFCO chargers, try to get below 11V to get the auto-detect to work. That would also be an excellent time to set your shunt monitor's discharge level.

[FL-Guy]

For the WFCO chargers, try to get below 11V to get the auto-detect to work. That would also be an excellent time to set your shunt monitor's discharge level.

Got everything to work. A little tricky with the converter. I spoke with tech support and interestingly he told me that if the wires to the battery from the converter were over 10 feet the converter might have trouble recognizing the lithium battery. Our converter is in the back of the 17' trailer so there is at least 15' to the battery in a straight run. When I dropped the coroplast to run my wires into the space below our Murphy bed I found the wires were anything but a straight run.
Anyway, I had to restart the converter 3 times once it started the bulk charging in order to get it to go into lithium mode. The tech support guy (Larry) said there is an upgraded software version for the controller that they can flash if you send it in, covered under warranty. I couldn't find the label he mentioned that had the version number on it, but since it switched to lithium I really don't want to remove the entire thing to send it in for them to check. Apparently, they are also can put a jumper on the board to make it stay in lithium mode. He hinted that they are working on a kit of some kind they can send out for this.
Also got the shunt zeroed out at 11V

[Soundsailor]

Got everything to work. A little tricky with the converter. I spoke with tech support and interestingly he told me that if the wires to the battery from the converter were over 10 feet the converter might have trouble recognizing the lithium battery. Our converter is in the back of the 17' trailer so there is at least 15' to the battery in a straight run. When I dropped the coroplast to run my wires into the space below our Murphy bed I found the wires were anything but a straight run.
Anyway, I had to restart the converter 3 times once it started the bulk charging in order to get it to go into lithium mode. The tech support guy (Larry) said there is an upgraded software version for the controller that they can flash if you send it in, covered under warranty. I couldn't find the label he mentioned that had the version number on it, but since it switched to lithium I really don't want to remove the entire thing to send it in for them to check. Apparently, they are also can put a jumper on the board to make it stay in lithium mode. He hinted that they are working on a kit of some kind they can send out for this.
Also got the shunt zeroed out at 11V

Great news on getting the blue light to come on and setting up the shunt. Keep us updated on what develops. I'd love to get my hands on one of those kits if they're ever released. And putting a jumper on the board sounds interesting also.

[FL-Guy]

Even though the blue light is still on (lithium charge) my battery seems to top out at 90.7% 187amps. That reading comes from the shunt. Possible the battery wasn't down far enough to zero the shunt? I did set the shunt to 210Ah as "full" Although the battery is a 200Ah I've seen several videos where the testers say this battery actually is 225 to 230Ah. Even at 90% its still better than the 81Ah flooded battery I replaced.

[xrated]

Even though the blue light is still on (lithium charge) my battery seems to top out at 90.7% 187amps. That reading comes from the shunt. Possible the battery wasn't down far enough to zero the shunt? I did set the shunt to 210Ah as "full" Although the battery is a 200Ah I've seen several videos where the testers say this battery actually is 225 to 230Ah. Even at 90% its still better than the 81Ah flooded battery I replaced.

I asked before in my previous post....what battery monitor do you have? and unless I overlooked it, I never did see an answer.

[FL-Guy]

I asked before in my previous post....what battery monitor do you have? and unless I overlooked it, I never did see an answer.

Sorry. I did neglect to mention its a Furrion that came factory installed. I can't figure out why they put the status screen in the passthrough on the wet wall instead of next to the One Control console inside. It's got all the wire it need all coiled up behind the wall.

[xrated]

Sorry. I did neglect to mention its a Furrion that came factory installed. I can't figure out why they put the status screen in the passthrough on the wet wall instead of next to the One Control console inside. It's got all the wire it need all coiled up behind the wall.

No problem, but I am not familiar with the Furion shunt. What I was going to say, on the Victron shunts, the phone app that you use has a way to "sync" the shunt to show 100% when the battery is fully charged, not sure if Furion has that feature or not.

Something else to think about...you said that you have set the battery capacity to 210AH.....why not set it to the actual advertised number of 200AH and see what you end up with as far as percentage SOC that way. Another thing to remember, total length of the run is whatever your distance is.....say 15' times two =30'. You have one wire coming and one wire going, to the overall length of the circuit is 30'.....or whatever the actual distance length is. If the wire/cable is 6ga, you are likely getting some voltage drop at the higher current flow that LFP batteries normally have...vs. Lead Acid batteries. Another thing to remember, the charger is going to start charging in CC mode or constant current mode, then when either a time period of charging OR the tail current drops to a certain level (10% for example) the charger will...or at least should switch into CV or Constant voltage mode. That last little bit of charging that is left will take a bit of time, compared to how fast the battery will be charging in CC mode. What it boils down to is that the voltage of the battery is just slightly less than the applied voltage from the charger, so the current flow is at a much smaller rate.

[FL-Guy]

Thanks for the explanation. Furrion shunt only lets you set the zero point when the battery is as low as you want it to go and then the Ah. Says to use the actual or a "reasonable amount" over that. Then you can view Ah, amps and voltage in or out and SOC as a percent. Pretty basic