I have a (2017) Swift Select motorhome, complete with Sargent EC500 system, including the PX-300 charger/power supply.
As the PX-300 is a low-tech charger (wasn't designed to meet the needs of modern AGM batteries etc) I want to replace the PX-300 with a suitable Victron unit. Current preference is the 25 amp BlueSmart IP67 charger (the PX-300 is also 25 Amp). As an alternative I could fit the BlueSmart IP22 - however this is only available in 20 and 30 amp outputs. (30 is too much, but I think the 20 would be fine.
The crux of my question relates to the 12v 'mains on' trigger feed I need to send back to the EC500. Sargents PX-300 PSU has a 12v output which is used to tell the EC500 that the mains is connected so the system knows that mains is available. How could I achieve this with a Victron charger? (data sheet/manual is on this link: https://sargentltd.co.uk/shop/product/px300_charger/152)
I'm considering:
A: buying the 20A BlueSmart IP22 unit with 3 outputs, and using one of these as the trigger for the EC500 'mains on signal'- however this seems like overkill and means I lose 5amps of power (as Victron don't do a 25amp version of this charger, and 30A would be more than my 130Ah leisure batt could take)
B: buying the 25A BlueSmart IP67 unit and using some sort of diode arrangement so that the 'mains on' signal would work when 12 is flowing from the charger to the battery, but not when power is flowing only from the battery - however this would be a real faff to set up and wouldn't be particularly elegant.
I've noticed on the pictures of the IP67, there's also a small orange cable - however it isn't clear what this is for and the manuals don't mention it. Is it possible this is a 12v trigger feed - or is this a temperature probe or similar?
Any thoughts would be very welcome. I'm confident others will have done this - so please share your experience.
Kind regards, Richard
