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mitch184 avatar image
mitch184 asked

Orion XS amp draw from alternator

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

orion xsdc-dc chargermarine
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niels-mobers avatar image niels-mobers commented ·

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!

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Justin Cook avatar image
Justin Cook answered ·

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

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mitch184 avatar image
mitch184 answered ·

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?

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Justin Cook avatar image Justin Cook ♦♦ commented ·
Honestly what I'd recommend is tracking down the specs for the alternator and/or putting a clampmeter on it so you know what it puts out at idle; no point in guesswork really.
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mitch184 avatar image mitch184 Justin Cook ♦♦ commented ·
It's a new install so I can't measure it and the manufacturer only gives out specs down to 2000rpm.


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.

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matsekberg answered ·

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.

img-0523.jpeg


This is the XS drawing 32.7 amps from the alternator/battery:

img-0494.png


And here you can see the battery connected to the alternator being sucked of 2.19 amps.

img-0496.png


img-0494.png (227.6 KiB)
img-0496.png (183.7 KiB)
img-0523.jpeg (904.9 KiB)
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Related Resources

Orion XS product page

Orion XS datasheet

Orion XS manual (html)

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