Adding USB outlets to 75/10 controller

Sagiller
Sagiller Member Posts: 8
in Battery/Electrical & Solar
We have two solar panels in our system: standard rooftop using Victron MPPT 75/10 controller and an added Renology suitcase using separate 75/15 controller.  We also have a Victron smart shunt, all connected into one network.  It has been working wonderfully so far.

We want to take advantage of the DC load connections on the 75/10 controller to power 12V usb ports.  It is our intention to use this to charge various 12V batteries, phones etc.  we want to be able to leave something charging while we’re out of the trailer and not have to worry about draining the camper battery if the sun goes away all day.

We know how to physically do this, but we’re not sure about some principles behind this.  So I have some questions that I hope the whiz kids on here can explain.

1.  If nothing is plugged into the USB port, will there still be a small current draw from the camper battery, just like the other 12V usb ports do? We believe the power from the controller would only come from the solar panel.  So no Sun, no power drain on the battery.  Is this correct thinking?

2. if we start charging a 12V battery via usb port, will this draw excess power from the solar panel, not from the battery?  I’m quite confused by the instructions in the Victron manual for the charger.  It implies that there could be a draw on the camper battery down to some preset values before it shuts off charging the 12V battery.

3. I’ve seen diagrams for setting up the various wire pairs for a controller that shows a fuse for all three pairs (pv, batt, and load).  Do we need a fuse on the load pair as well?  If so, what size fuse.

4. The Victron directions talk about configuring for using the load output in multiple sections: leave a jumper in, take it out, configure various low/high readings from camper battery to regulate on/off output from the controller.  Given our goal as stated above, what would be the best configuration for us: leave the jumpers as is and take default low battery shutoff?  Or remove jumper and set battery values via Victron Connect app?  Can we set things so wrong that we toast either the controller or the camper battery?

Any insights into this would be greatly appreciated.


2020 T@B 320 BD u / Toyota Tacoma / Flagstaff AZ
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Comments

  • pthomas745
    pthomas745 Administrator, Moderator Posts: 4,542
    edited September 2023
    I looked this over a few weeks ago, and I think I always made this much more complicated than it really is.
    The "load terminals" are seemingly simple to set.  The manual says to just pull whatever jumper is inside the "VE Bus" port, and then configure the load terminals in the load settings on the Solar Controller.  Seems you can set the Load to be "always on" or set it to one of the "algorithms" that prevent the load output from depleting the battery below a certain point.
    If the solar is producing power, it would charge the battery, and the battery would provide power for the load output.  If the solar is not producing power, the load would draw power from the battery. 
    The "USB/12V" ports in the trailer and most vehicles are fused at 15 amps. In paragraph 3.8, the section about the Load terminals,  they say the "Current Rating" is 15 amps or 20 amps, depending on the controller.
    This is paragraph 5.1.2 in the Load Settings section. Pull the jumper, and use the Settings of the Smart Solar in the Victron Connect.
    5.1.2. Settings via the jumper link
    If the load output algorithm is configured via VictronConnect or the MPPT Control display the jumper link is
    not used and it needs to be removed. Configuration via the jumper link is only needed in case the load output
    algorithm cannot be configured by any other means.
    Section 5.2.2 is where they discuss the settings for when the Load is on and off.  There are several choices: Always On, or Always Off.  There are 'Algorithms" that don't seem to make much sense. Algorithm 1 says "Off when the battery is less than 11.1V and on when greater than 13.1V."
    There is also a setting for you to choose the low voltage and high voltage cutoffs.  This is probably the setting to work with. 
    In the "Specs" on paragraph 9-1, they state the "Self Consumption" of the Victron is: 20mA at 12V.  That would seem to be for the entire unit. 
    Victron makes great stuff, but seems to find it impossible to describe how they actually work.  50 percent of all their manuals are incomprehensible, it seems.
    Here is the online manual I used for this info.  I'm sure you can make this do what you want as far as running small devices of less than 15 amps.  Might take a bit of playing to get the configuration right.
    2017 Outback
    Towed by 2014 Touareg TDi
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  • Sharon_is_SAM
    Sharon_is_SAM Member Posts: 10,061
    @Sagiller - have you used the Victron Community board for finding answers?  Lots of info here:  https://community.victronenergy.com/search.html?c=&includeChildren=&f=&type=question+OR+idea+OR+kbentry+OR+answer+OR+topic+OR+user&redirect=search%2Fsearch&sort=relevance&q=MPPT+load
    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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