robertilles95 avatar image
robertilles95 asked

Can I run DC|DC chargers in parallel using a mini distributor?

image-67201281.jpgI plan on running up to three 12|12 30A Non-Isolated DC to DC chargers in parallel in one of my systems and I just want to verify that the way I'm doing it is safe.

I plan on running 2awg cable from the alternator connection to a "LittleFuse" 1-3 way fused distributor (image attached), then from the distributor to each charger via 6awg cable. I'm not certain stepping down from 2awg to 6awg is the best idea, but if that's ok, please let me know.

wiringorion dc-dcdc isolators in parralell system
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1 Answer
Kevin Windrem avatar image
Kevin Windrem answered ·

Wire size depends on both ampacity (the wire's current carrying capcity) and voltage drop.

#6 is fine for 30 amps as long as the voltage drop isn't significant. If the runs are short then this too will be OK. Keep in mind, the DC-DC chargers need an accurate sample of battery voltage and any voltage drop in the wire between the two might cause the charger to enter absorption too soon.

The connection between alternator and DC-DC charger is more tolerant to voltage drop. Again if the lines between the fuse block and the chargers is short, you should be fine with #6. Your use of #2 from the alternator to the vicinity of the chargers is the best way to minimize voltage drop.

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kevgermany avatar image kevgermany ♦♦ commented ·
I don't know the US wire sizes, but I think you missed the 90A input current.
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robertilles95 avatar image robertilles95 commented ·
What I'm worried about is that, cumulatively, the three chargers will be drawing 90 amps of power from the alternator. The fuse block is acting like a bus bar, therefore I should be fine running three separate lines of #6 from the block to my chargers?
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kevgermany avatar image kevgermany ♦♦ robertilles95 commented ·
Line from alternator needs to handle the full 90A.

Fuse block to Orions, one line per Orion, must handle the 30A.

Orions are designed to work in parallel to increase output current. Eachust be programmed with identical charge parameters.

How big is the alternator? Drawing this current, with other vehicle loads, like lights, may burn out the alternator. There's a Victron video about this on YouTube.

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robertilles95 avatar image robertilles95 kevgermany ♦♦ commented ·

The alternator is a standard 140 Amp. I read that keeping draw under 100 amps is safe enough, but will shorten the life span of the alternator.

According to my calculations the #2 awg (35mm^2) should be sufficient to get to the fuse block, and then #6 awg (16mm^2) from the block to the chargers.

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Related Resources

Victron Wiring Unlimited PDF

Victron Wiring Unlimited Online

Victron DC to DC Converters Product Range


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