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f9cme avatar image
f9cme asked

Dump Load; SOC; LFP; 7/2022 gear

Hello.

I've been lurking on the blog and looking at videos and PDFs. Figure it's time to send up a flag.

Where do i find any or all info specific to dumping safely and correctly using SOC and Li for multiple Quattros, Cerbo GX, MPPT RS 450/100, etc? Preferably detailed info.


As for me:
Im a 14 yr off-gridder using a Pb BESS looking at switching to LFP and Victron gear. Even an AC/DC couple system with Fronious if it made sense in the end. Again... no grid for miles.

Ie p 15 thru 18 of:

https://www.victronenergy.com/upload/documents/Brochure-Off-Grid-backup-and-island-systems_EN_web.pdf



Looking for succinct material... (or at least what to read and watch) in regards to using the latest victron gear, LFP, and best (safest way) to dump into large water tanks to pre-heat infloor mix. I never used a dump before as unfortunately I've always been underpowered. Thats all going to change.


Again, where do i find any or all of that info specific to dumping safely and correctly using SOC and Li for multiple Quattros, Cerbo GX, MPPT RS 450/100, etc?

I'm using USA 240v Split phase.



Basically, in my humble opinion, a small commercial install in regards to power usage due to amount of PV for pre-heat.

I don't want to destroy the delicate LFP with hysteresis... and or goof up something that i could have avoided by simply learning first from others as "the book" and real world don't always jive.


I want to be an educated consumer, not an installer's nightmare pita.... or the guy relying on the salesman "expert" on every turn.


Respectfully.... and Thanks in advance,
F9cme
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nickdb avatar image
nickdb answered ·

Hi @F9cme welcome to the community, there certainly is plenty of reading and learning to be done, and it is great to see someone wanting to RTFM before diving into the deep-end.

In case you haven't seen it already, there are a lot of resources and info available for you at https://professional.victronenergy.com/online-training/


I am sure someone will chime in shortly around the core of your query.

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f9cme avatar image
f9cme answered ·

Thanks!


Will look at that.


Was just reading:


P 8. 2.1.3. Fronius Zero Feed-in
of/from:
https://www.victronenergy.com/upload/documents/Energy_Storage_System/ESS_design_and_installation_manual-en.pdf


Leads you to page 13


Maybe the ac/dc is my best bet.


Cheers,

F9cme

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JohnC avatar image
JohnC answered ·

Hi @F9cme And welcome to the true offgridder's search for the holy grail. Yes, it can be elusive even if it sounds simple. The following just random stuff..

You mention hysteresis as a concern. Hard to avoid if your dump load is of higher power than what excess solar is available. And there's nothing to tell you what that excess actually is until it's switched in. Experience with your own system can help, but even then passing cloud makes it tough.

You're looking at ESS, but Victron don't recommend it for offgrid. It comes with little annoyances that you might find too much. But it does show that hysteresis may not be of such importance as you think, as many grid-connected users may be moving power back and forth all day long. Without adverse effects on their batts.

Your Quattro though can be a great place to switch your dump load, using the onboard ACOut2 relay. Controlled by onboard 'Assistants', and you could look up how to work with them.

The Victron website Downloads section has a massive amount of info, but specific stuff about setting up a dumpload is likely scarce, as this is a fairly personal thing, Even try typing Dumpload into the searchbar here.


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f9cme avatar image
f9cme answered ·

4c674eee-a7d3-4bf4-8372-1c42ff933b01.jpegHello.

Appreciate the input.

I've used the search engine here and outside the chat room with very little success.


Im on a mini vacation at my buddy's place; so, im going to jump back into this next week.


In addition to the Victron gear/comm logic, Has anyone used an ammeter sensor on the inbound line from the PV AC output (ie Fronious, etc) to create an and/or logic tree.

I.e. If it sees a minimum of XYZ amps for at least ABC minutes, then it closes a relay. Allowing power to get to dump load (water heater). And vice versa to open the circuit.

Safe & fun weekend to all.

F9cme


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nickdb avatar image nickdb ♦♦ commented ·
wrt implementing logic/automation in general.

If a little light dev work doesn't scare you, Node Red is implemented in the GX large OS image (it is more seamlessly integrated in the upcoming 2.90 release). With the supplied nodes it is quite straight forward to start controlling devices, relays etc.

This can be coupled with functions of your own creation to have the system behave in ways which aren't easily done through the default interface.

For example, I've been fiddling with functions that track the average available PV on a rolling hourly basis so that this can be used, along with SOC, to adjust operating limits and enable/disable external smart devices.

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f9cme avatar image
f9cme answered ·

[moderator note: removed offer to sell used equipment]


Fwiw... Mouser has 200w resistors that work for the two Quattro set-up. Same for fusing and switching.

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Justin Cook avatar image Justin Cook ♦♦ commented ·
@F9cme this is not a sales/classifieds forum; you might try creating a listing on your local FB Marketplace, eBay, or sites that do have for sale sections like diysolar.com and other places.
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