Hello looking for recommended cable sizse to conect this charge controller and DC Coverter to my 48V system via Lynx bus bar. The Manuals do not give suggestions. It will be within 5 meters of the battery. Also any suggestions on MEGA fuse amp rating is appreciated. Thanks
Hi i would start here with Wiring Unlimited section 4.1
If you have any questions after reading please post back.
Which model is your charge controller?
150/60 online manual
Use at least 10 or 16mm² cable.
Orion TR manual pdf and datasheet
Fuse size is usually 1.25 x expected current and cable size to match amps. Maybe 6mm. But you are already buying at least 10mm for the mppt so may as well go with that.
I took a quick swipe at the cable size for the solar charge controller using the BayMarineSupply wire gauge calculator.
For my solar charge controller (150/35), Orion Tr (48-12/30) and Orion XS (12-12/50) I went with 6 awg. It’s overkill, but I had gobs of that size wire on hand.
VESCC115060211
SmartSolar MPPT 150/60-Tr
5m is a long way - i would be looking at the possibility of moving the mppt closer to the battery. Voltage drop over the solar cable will be insignificant compared to the battery cable, so the whole situation (cost and performance) will be better if you can get the mppt controller closer to the battery.
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Agreed distance matters. Usually means a switch to gauge or two higher.
I just read the manual and used the victron tool app. Is I understand it correctly the Solar Charge controller will take the 90+ volts I am feeding it from the solar array and convert and charge at max voltage of 64.8 volts (per the charger data sheet). The rated charge current is 60A. So for the tool I used current of 60Am voltage of 48 and distance of 1/2 meter. 6mm2 or 10AWG cable would show 0.7% vloss which is good. Fuse calculation 60a x 1.25 = 75m so an 70-80a mega fuse above 48v would work. Is this correct?
For the Orion-Tr 48/12-20A (240W) Isolated DC-DC Could not find a data sheet for but it appears by its name description that it will use 20A current from the battery bank to coverter at 48 volts so for the victron toolbox I have used 20A at 48v 0.5 meters suggesting that I could use 1mm2 or higher cable safely. Fuse would need to be 25A or higher. Am I doing the calculations correctly?
Thanks
This is incorrect. The amp rating on every DC-DC charger and converter that Victron sells is the OUTPUT rating, not the input rating. So it will be 20 amps going into your 12 volt system and between 5 and 10 amps on the input side coming from your 48 volt system.
Did you make a typo mistake in your first post. You wrote that the wire run was 5 meters. Now you’re using .5 meters. Which is it???
Sorry. Yes it was a typo. Run will be 0.5 meters.Thank you for catching this. How does one distinguish the direction between input vs output ratings? This is where I am getting caught up in my calculations. Thank you
The current rating is always on the output. Victron doesn’t provide a current rating on the input. Take a look at the datasheet for the Orion Tr in the link below. Nowhere does it provide a current number for the input. You have to figure it out for yourself. In order to achieve the requested output voltage and amperage, the device has to work with what is available on the input side. Voltage tends to be a fixed number, so the amperage has to go up (which often causes the voltage to go down due to voltage loss on the wire).
I don’t recall seeing any “rule of thumb” to determine the input current. When figuring the wire gauge size, I assume that the input current will be at least 20% higher than the output current.
The Orion XS is a bit different in that it gives you the ability to explicitly limit the input current.