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jomugu avatar image
jomugu asked

Looking for someone interested in testing an excess energy management system for off-grid systems.

Hi all,
Looking for some kind of tester/partner interested in an excess energy management system for off-grid systems.
I’m a Victron (also Fronius and Lorentz) official installer. During the last years, I’ve been developing a system to use all that PV power excess that we are just losing when our batteries are full (or our charge capacity is smaller than the available PV power).
At the beginning, I designed this system to be used with AC-coupled Fronius -Victron. As a matter of fact, the actual prototype, which has been working for the last two years with excellent results, has this set-up with a 24/3000 and Primo 3.0. I chose this configuration for many reasons, one of the most important, it’s the one who allows you to oversize your PV field and, then use the excess power in a more efficient way.
The system can manage up to six loads ON/OFF (also implemented but not tested yet a seventh variable load). Based on a stablished priority and parameters, the different non-critical loads will be switched on when is energy excess. When there is no excess energy anymore, the system will shut down load by load, again following priorities. Energy excess is calculated in a very cost-efficient way, working really fine.
For the actual prototype, all loads are AC, with two AC units, a 1200 W water heater, a small water treatment plant and a couple of pumps. Loads can be switched on/off by a dry contact, 0-10V signal or IFTTT (this last one preferred). The system can be connected to Alexa (private sketch by now). Also, monitoring is possible via Blynk, as well as manual function for switch on/off loads and set of most system parameters).
As I’m aware that AC coupling is not the most popular coupling method, I decided to adapt the system to work with DC-coupling (as long as everything is Victron in the system, it will be easy).


What I’m looking for is someone who is interested, professional Victron installer preferable, with a DC-installation medium size (PV 4-6kWp, Inverter Multiplus 3, 5 or Quattro, single phase), internet connected, with an IFTTT and similar non-critical loads as described, to test the DC-coupling version and, eventually, be associated for future development or more interesting things.
I forgot to say I’m in Spain, but nowadays I don’t think this is making any difference.
I attach some pics of the App that monitor the system.



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167987660-4038743092850536-2505993867862361476-n.jpg

MPPT ControllersoffgridFronius
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2 Answers
markt avatar image
markt answered ·

Hi @Jomugu

It sounds like you have achieved some of what I am looking to do in my off-grid house in Spain. Sadly I am still about 2 years away from completing the build and solar installation so can't offer to test a DC coupled version.

My direct solar experience is with SMA equipment in the UK, although I am familiar with the Victron range and have yet to decide what to use here. I will need to include an electric car charger, bore hole water pump and both domestic and pool water heating in my diverted power system.

Diverting a variable amount of power into a resistive load does seem to be a challenge off grid, with phase angle regulation causing a lot of disturbance to the inverter. I believe it may be possible using the PWM technique as used by the 4-noks Power Reducer. I have yet to work through the detail of this.

Keep up the good work and posts on your progress.

Mark

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mtthhrs avatar image
mtthhrs answered ·

Are you still working on this system or need someone to test it? I might be interested. I have a mostly offgrid solar installation company in the United States. In the last half year we started using mostly Victron Stuff.

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