I'm planning a set up for charging a Victron Smart Lithium 12v 200ah battery from the alternator of my van (a 2012 Mercedes Sprinter 313cdi).
I will have Dometic Freshwell 3000 air conditioning unit in the back of the van which I would like to be able to use while driving and on hookup. The plan is to run it through a Multiplus Compact 12 2000 as it requires 230v AC - 4.2amps to run.
4.2a @ 230v = ~1000W, the Multiplus will need maybe 1250W supply when considering losses?, more losses in getting the power to the multiplus, through the leisure battery, from the charger/alternator means maybe working on the basis that 1500W is required from the 12v alternator?
125amps required from the alternator - is that a fair estimate?
I need to check the alternator I have fitted but could look at upgrading if it is not 180a+
What is the best way to ensure that the supply of power from the alternator/starter battery to the leisure battery is enough to offset the demand of the multiplus/aircon and not result in flattening the battery(s) on long journeys?
Options that might work:
- Multiple Orions in parallel - seems over the top to have 4+ orions in parallel just to achieve 120amps
- 1x BMS CL 12/100 for 100amps, in parallel with 1x orion for 130amps total - benefit of BMS included and the voltage controlled charging from the orion to help top up the Lithium battery.
Any suggestions on how to make this work are much appreciated.