Would like details on the differences between these two modes. Apparently Standard mode limits DOD to 50%, what does Performance mode do?
Thanks,
Pat
asked
Lynx Ion BMS Standard vs Performance Modes
@Pat Davitt When system is running with latest software release V1.16:
- default mode: 75% DOD, battery fans are enabled above 30 degree Celsius.
- Performance mode: 90% DOD, battery fans are enabled above 35 degree Celcius.
(battery fans are also enabled if inside plus(fuse) busbar temperature is above 52 degree Celcuis)
Note: with latest software release also SOC is automaticlly adjusted, so in default or performance mode the battery can be discharged until 0% SOC.
Thanks for the information. Just for fun I changed the setting to Performance mode and the SOC read 81%. When I changed it back to Default mode the SOC dropped to 75%. Looks like Performance mode primarily changes the DOD setting for the SOC calculation.
My assumption is that the different modes do not change the "allow to charge" and "allow to discharge" functions of the BMS.
Pat
Thanks also. I was told Performance was 100% but seems more like 90 going by Ah consumed. Have now left mine in Performance so the extra Ah is there if needed over Default. I also understand if it is used that cycle life will naturally reduce from that quoted in the HE datasheet. Does Performance mode alter the charge voltage?
I now have latest software so will check and see if I have the full 100% or rather 5kWh available from my 200 Ah HE.
Think I've got the BMS reported SOC behavior for the two modes figured out. The BMS reported SOC is not based on a 0-100% actual SOC but instead on 20-100% for the Default mode. So, when in the default mode, a reported SOC of 0% is actually 20%. In the Performance mode a reported SOC of 0% is actually 10%
Does that make sense?
Pat
So are you saying if a 200Ah HE then Default you should have 40Ah remaining at 20% SOC of actual stored energy and Performance 20Ah at 10% SOC of stored giving 4kWh useable in Default and 4.5kWh useable in Performance? And the SOC shown is therefore based on the useable energy subject to mode selected. That makes sense to me.
Normally with Li-ion batteries you don't use the top xx% to have a longer battery life, (this is different for LiFePO4). so it's likely you can charge to a higher voltage in this performance mode.
I don't think so. I charged my HE batteries in Performance mode and the constant amperage (Bulk) and constant voltage (Absorb) voltages were identical to charging in Default mode. I believe the two modes act more on the discharge side.
Unlike voltage and amperage, SOC is a mathematical estimate of the usable power remaining in the battery. My understanding is that the default mode is designed to conform to the published cycle life which is based on an 80% DOD.
Remember we are not dealing with hard facts here, only with observed behavior. We don't really know for sure.
Pat
In default mode the charged voltage is 28.0V (highest cell voltage 4.00V)
In performance mode the charged voltage is 29.05V (highest cell voltage 4.15V)
The discharged voltage is in both modes 21.0V (lowest cell voltage 3.00)
Thanks. I noticed it was marginally higher but wondered if that was to do with temperature, so I wasn't sure in fact if there even was a voltage difference between default and performance.
I'm not disputing your information. I am curious where you obtained it. Is there a document that goes into more detail about the HE Batteries and the Lynx Ion BMS?
If so, can you post a link. I just noticed you work for MG Systems, so I know, you know what you are talking about.
Thanks,
Pat
Because this chap seems to be one of the programmers, so for me it’s come from the horse’s mouth. https://community.victronenergy.com/users/2713/wilcop85.html
Yep, he is the real deal. Note the definitive answer to my post on a Lynx Ion BMS firmware update problem.
Pat
I saw that. For info here’s my max voltage in Performance at 100% SOC
@Pat Davitt @Wilcop85 I just switched back to Default mode as I’ve realised I have enough useable energy with that 75%, rather than the 90% with Performance, of the stored energy. I don’t know the expected cycle life at those percentages?
Although the Victron datasheet quotes 2,000 cycles @ 0.3C to 80% DOD ref:
https://www.victronenergy.com/upload/documents/Datasheet-Lithium-ion-HE-Battery-and-Lynx-Ion-BMS-EN.pdf
Just curious and in fact I don’t even use 0.3C (60A) discharge, so my 200Ah NMC HE will probably outlast me!
