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.
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But since Orion would be set to a shutdown voltage of 13.30 V, would 50 amps be a problem, when engine not running?
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As soon as your solar MPPT starts charging, the starter battery voltage will rise above the Orion’s start threshold during its absorption mode.
The Orion will switch on and try to satisfy the house battery charging demand. If the current draw exceeds the MPPT output the start battery will supply the excess for a short while until its voltage drops below the 13.3V shut-off threshold. The MPPT will continue charging the start battery until the voltage rises and the cycle repeats. This is the reason why I was advising to balance the loads to match the PV capacity. This will slow the cycling effect. More PV capacity could make better use of the Orion’s potential.
