question

maxwhitby avatar image
maxwhitby asked

LYNX SHUNT SOC WILL NOT RESET TO 100%

I have a MultiPlus II 48/8000 connected to a Lynx Shunt and a Cerbo GX running firmware 2.92.

I have charged my 280 Ah LiFePO4 battery to 100% (as reported by the BMS) but the Lynx Shunt is only displaying ~ 70%. Previously the Lynx was measuring in agreement with the BMS reading, but after a few weeks this discrepancy has arisen. My problem is that I am unable to reset the Lynx SOC (via the setting in the remote console "synchronise state of charge to 100% - press to sync"). When I click on the interface button or use the keypad nothing happens.

Any suggestions please? I have tried resetting the Lynx to factory defaults. Thank you for your help.

regards from Northumberland in the UK

Max Whitby

lynx shunt
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

2 Answers
pwfarnell avatar image
pwfarnell answered ·

There are 3 key settings in the Lynx shunt for synchronisation to 100% which should occur just as the battery gets to 100%.

"Charged voltage", "Tail current" and "Charged detection time".

When the actual voltage is above the charged voltage AND the actual current is below the tail current FOR the charged detection time then the shunt will reset to 100%.

Therefore, set the charged voltage 0.1 or 0.2V below your absorption voltage, set the tail current to something like 2% (equates to 2% x 280Ah = 5.6A) and if you have no solar you could reduce the charged detection time to 1min. The bit you need to be careful of is the tail current, look back over your logs to make sure that the current does go below 5.6A when charging stops. If it doesn't, set the tail current a bit higher than what it does fall to.

You should also check that the "Peukert exponent" is 1.05 and the "Charge efficiency factor" is 99%.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

maxwhitby avatar image
maxwhitby answered ·

Many thanks for your prompt and detailed answer. I will adjust those settings as you advise. But is it not also the case that pressing the "press to sync" button should immediately reset the SOC to 100% without these parameters being involved? When I try to press it nothing seems to happen?

regards from Northumberland

Max Whitby

2 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

pwfarnell avatar image pwfarnell commented ·
I must admit that I have never tried that button because my system reliably synchronizes most days and does not drift much. Therefore, I can not answer, but I agree it seems like that should be the case.
0 Likes 0 ·
kevgermany avatar image kevgermany ♦♦ commented ·
Yes, it should synch the way you expect. You need to return it under the warranty.
0 Likes 0 ·

Related Resources

Lynx Shunt VE Can online manual


Additional resources still need to be added for this topic