I would like to top up both of my batteries (start and house) with a SmartSolar 75/15 controler, while engine is not running. Since Orion Xs doesn’t have bi directional charging, I was thinking using the configuration above, where the SmartSolar would be connected to the start battery, instead of the house battery. When engine is off, energy would be supplied to the Orion Xs by the SmartSolar. When engine is on both alternator and the SmartSolar would provide energy to the Orion Xs.
House battery is a LiFePO4 150 Ah battery.
Start battery is a regular lead-acid battery so SmartSolar would be set to:
absortion mode: 14.6 V
float mode: 13.5 V.
The alternator is a regular one (not smart), with 150 Amp max output. Orion Xs would be set on engine shutdown to:
Yes the proposed configuration can work. During solar charging of the house battery there will be efficiency losses via both the MPPT and the Orion XS and power lost to the starter battery (it will draw an amp or so even when in float or storage mode). So, for example, 100W of solar input is likely to supply only around 80W to the house battery.
Your starter charging voltage of 14.6V may be a bit high for a conventional flooded lead acid battery but will be ok for an AGM. Both the MPPT 75/15 and Orion XS have built-in profiles for these battery types so start with those .
The MPPT 75/15 cannot put out more than about 220W to a 12V battery system so your PV capacity should be limited to around 200W .
The XS can potentially draw up to 50 A from the combination of PV and start battery when the engine is not running so you may want to dial back its charging current to balance the loads.
This will unfortunately constrain the current drawn when charging from the alternator.
If you have the space, a bigger MPPT and PV capacity would be a better fit for the Orion XS
But since Orion would be set to a shutdown voltage of 13.30 V, would 50 amps be a problem, when engine not running?
What I understand is that the starter battery and Smartsolar can potentially deliver 50 amps, but when voltage drops below 13.30 V, Orion would cut connection, to the house battery. Am I right?
That would be great, and would sort my problem. In that case I would connect the Smartsolar to the house battery directly, avoiding losses through the Orion.
Do you know when will it be available?
Good to know its coming. My old CTEK D250 could do this and it is the only feature missing from my new Victron setup which otherwise performed perfectly during a recent 10 day holiday trip.
Just a small sidenote, may or may not be relevant to you:
If this setup is in a vehicle with regenerative breaking (usually combined with Euro5/Euro6) it is best to not charge the starter battery outside of the car itself. Not solar, not trickle, not XS reverse.
The car’s controller will want to keep the starter at 70%~80% to keep room for the breaking energy, and if the car’s controller finds the battery is getting energy “out of nowhere” (out of its control) and gets too full, it gets rather confused and starts doing weird stuff.
In my case, it refused to charge completely, causing my entire engine based battery charging (both start and house) to simply never work.
I even spotted (before I replaced disconnect relais with XS) that the house battery (charged with solar or shore) was usually back-charging the starter upon engine start, causing yet more “mysterious energy” for the car controller, extending the cycle indefinitely.
Only after I replaced the disconnect relais with the XS as well as unplugged the camper’s trickle charger, did the system start to behave predictably.
Of course, if you have a classic alternator, or maybe even Euro6 without regenerative breaking (if those exists) then ignore above.
Once the Orion starts if the voltage falls to the shutdown voltage the Orion reduces the charge current to maintain the starter battery at the shutdown voltage so it matches the power coming in.
From the manual.
If VIN ≤ Vshutdown, the charge current will be reduced to prevent VIN to drop below Vshutdown.
So, should I match the float voltage from the smartsolar with the shutdown voltage of the Orion, and make both set to 13,50 V? Or make it as, float voltage of the smart solar set to 13,50 V and shutdown voltage of the Orion set to 13,30 V.
Set the Orion shutdown voltage below the float voltage of 13.5V and above the full battery voltage of 12.8V. 13.2 or 13.3V is fine. You need it below float voltage so the MPPT is forced to output power.
