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Installing an Orion XS on a boat to charge my lithium house battery. I also have an AGM starting battery hooked to the alternator. If the max output of the XS is 50 amps, what happens when the motor is at idle and the alternator is not putting out 50 amps? Will the XS pull back the amperage to what is available, or would it continue to pull 50 and potentially pull amps from the starting battery? Or is it possible to program something?
Thanks
Hi Mitch,
With "Engine shutdown detection" enabled, the Orion XS will reduce the current based on input voltage level, this is set by "Vshutdown". See: https://www.victronenergy.com/media/pg/Orion_XS_12-12-50A_DC-DC_battery_charger/en/operation,-configuration-and-monitoring.html#UUID-7cb1b674-5e2b-c9d8-2c36-5af41989f186
So you can keep the max current at 50A, when the alternator voltage drops to Vshutdown (typ. 13.1V for a smart alternator) the current is reduced to prevent the alternator voltage from dropping below Vshutdown. This prevents current draw from the starter battery. So what you want is already there! Isn't that cool!
If you only have a low-output alternator, would definitely recommend turning down the XS to ensure you're not pulling too much from the start battery/overloading the alternator. That is possible in programming, see the manual for details: https://www.victronenergy.com/media/pg/Orion_XS_12-12-50A_DC-DC_battery_charger/en/index-en.html
Thanks for the reply. It's a 150 amp alternator at high rpms and 80 amps at 2000 rpm. However, I don't think it puts out 50 at idle. I've looked all through the programming and am still kinda stumped. I see where you can turn down the input/output but then I would lose out on some charging while running. DO you think putting in a longer delay before the charger starts charging would be the direction to go?
Additionally, there is an auxilliary motor that only puts out 5-16 amps that I use when I'm trolling. I don't think there is any DC-DC that would work for that small of an alternator. Perhaps just hooking that directly to the Lithium house battery? Wasn't sure if one of the MPPT would work.
You state the manufacturer only gives rpm down to 2000rppm and 80Amps, I am assuming that this is the alternator datasheet. This is for the alternator rpm not the engine rpm. Typically you will have the alternator geared around 3:1 from the engine, so if your tickover is 900rpm the alternator will be doing 2,700rpm and more than 80A. If you have a slower tickover engine you need to gear the alternator higher.
You must clarify this before you go further because your concern about low appears wrong.
I have a similar issue in my RV but it cannot be solved by tuning the ”engine start voltage” setting.
I have a smartshunt on the starter battery so I can measure if current is going to or from the starter battery.
My problem is when the engine is running at normal RPM the Orion xs draws current from the starter battery, 1-3amps. The alternator is good for 110-150 amps so it should work.
Sure I could turn down input max amps on the XS but that will limit the ability to use the max 50amps from the alternator.
An idea for the Victron folks is to use the VE.smart networking to read the smartshunt current from the starter battery smartshunt, if it is negative then limit the current drawn so that the start battery isn’t emptied.
Hmm it seems as if the XS is actually reading the current from the input battery, see image.
This is the XS drawing 32.7 amps from the alternator/battery:
And here you can see the battery connected to the alternator being sucked of 2.19 amps.
