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jamesmcclatchey asked

DC Charger output

I have an isolated DC-DC Charger connected with 4 AWG wire from a tow vehicle to trailer. There is little to no voltage drop in the wiring. I have 400 watts of rooftop solar connected to a Smart Solar MPPT 100/30. Batteries are 2 Battleborn 270 AH GC3 Lithium. Please review the attached iPhone screen shots taken while underway on the highway in partly sunny weather. One is from VRM and the other from near simultaneous Victron Connect. I think I have gotten more from the Orion in the past. Now its maximum appears to be no more than 200 watts where I have seen 300 in the past. Why is the difference of 13 V from the DC-DC charger so different from the 13.83 volts from the solar charger? Are these 2 units conflicted with each other? Is there something I can do to increase the charger output?


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MPPT SmartSolarorion dc-dc
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kevgermany avatar image kevgermany ♦♦ commented ·

Guessing.

Looks as if the Orion isn't getting enough input power and there is load on its output which drops the voltage. Might be resistance in connectors/fuses as well.

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Bob K avatar image Bob K commented ·
An Input Voltage of 12.9v indicates you have a smart alternator. Please post your Engine Shutdown Detection settings. If those settings aren't correct for your vehicle, the Orion will automatically decrease its load as the Input Voltage drops (because of the smart alternator dialing back its output).
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jamesmcclatchey avatar image jamesmcclatchey Bob K commented ·

Engine shutdown detection

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ jamesmcclatchey commented ·

The Orion starts reducing the charging current if the input voltage gets near the shutdown voltage.

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Bob K avatar image Bob K Matthias Lange - DE ♦ commented ·
I hit enter at the exact same moment, and learned this from you last year, so thanks.
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Bob K avatar image Bob K jamesmcclatchey commented ·

Your Shutdown Voltage is set to 12.95. As your smart alternator reduces its voltage output down toward 12.9v, the Orion will reduce its load (i.e. amperage output) in order to attempt to keep from falling below the Shutdown Voltage. That's why you're seeing lower amperage output from the DC charger.

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Try reducing your Shutdown Voltage down to 12.8v. A fully charged lead acid battery sits at about 12.78v, so you won't want to go below that in order to prevent discharging the starter battery after you turn off the vehicle.

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1 Answer
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jamesmcclatchey answered ·

Thanks for the responses. This makes sense. I will give it a try!

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Bob K avatar image Bob K commented ·

If adjusting the Shutdown Voltage downward doesn't make your alternator play nice with the DC Charger and output higher amperage, your next option is probably to wire up a Remote On-Off switched circuit (which will let you set your Shutdown Voltage even lower without discharging your starter batter when the vehicle is off). See my comment a few down in this thread: https://community.victronenergy.com/questions/229390/engine-start-detection-by-orion.html?childToView=229826#answer-229826

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jamesmcclatchey avatar image jamesmcclatchey Bob K commented ·
Just to tie things up, I reduced the Engine Shutdown Voltage to 12 V on the DC-DC Charger. A bit lower than the recommendations here, but it still detected the engine shutdown. I am getting full output now. Yesterday driving in full sun through west Texas, I was getting 350 watts from the DC Charger along with 150 watts from the solar. 500 watts into 2 Battleborn GC3 270 Amp-Hr Lithium batteries at 50% charge. Pretty cool!
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