Autotrail / Lithium set up

[Rockpool]

Advice please.
Have just installed lithium Roamer 230ah battery in our Autotrail Apache 700 (2017) and looking at disconnecting the Sargent smart battery charger PX300-12 as it does have a lithium battery setting. Have installed a separate victron blue smart charger to cover hookup.
So at the rear of the Sargent EC500 there is a 25amp fuse marked charger fuse… So have pulled it out and carried out a few tests to see if it is charging any of the batteries.
On hook up there is no sign of any power being feed back to the lithium batteries through the victron shunt or battery bms. There is no increase in voltage at the starter battery on hook up (swapped between the two batteries on the panel above the door)
The Epever mppt is charging the lithium and trickle feeding the starter battery fine.
The Victron DC-DC charger is working fine.
The fridge works on 12v when driving and the step is also working properly.
Is there anything else I should be looking at to ensure the Sargent system doesn’t charge the batteries or has anyone else used this method?
Thanks

 

[Diabalo]

Have you left the origanol Sargent split charging system in place? I believe it's built into the EC500

 

[Rockpool]

Actually forgot about that. Will look at it to see if it can be disabled?

 

[TCG]

have you physically unplugged the PX300 from the back of the sergeant EC500

We recently installed
Victron B2b, Victron BMV, victron mains charger and Victron Mppt. with two lithium's.... Bypassed the sergeant unit works a treat

 

[Rockpool]

Just unplugged the fuse the Sargent unit still plugged in.