question

Paul Carmichael avatar image
Paul Carmichael asked

VS with pylontech

Hello again all.

Tomorrow is the big day. Going to change over from FLA to 6 pylontech us3000c.

Quick question: do any of you use virtual switch with lithiums? I have a connection to another house which I've used as a backup for when we don't get much PV. If I want to do the same with the new batteries, what should the settings be? It's currently set for detecting voltage drop, as that is the obvious trigger using the FLAs.

Pylontechvirtual switch
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2 Answers
nickdb avatar image
nickdb answered ·

Why not use conditional AC control from victron connect?

Can connect on SOC which is more relevant with lithium, given the flatter voltage curve.

screenshot-2023-06-25-at-125913.png

screenshot-2023-06-25-at-125930.png


9 comments
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Paul Carmichael avatar image Paul Carmichael commented ·

Looks remarkably similar to the VS. I presume those settings are the default, rather than suggested for me?

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nickdb avatar image nickdb ♦♦ Paul Carmichael commented ·
Yip, default from "demo mode". Allows you to fiddle.
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Paul Carmichael avatar image Paul Carmichael commented ·

Just looked. Isn't victron connect the mobile app? I have to use ve configure to change the Quattro settings.

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nickdb avatar image nickdb ♦♦ Paul Carmichael commented ·
Can use it from a mobile device or laptop etc, with the mk3 usb. You can configure most things on a ve bus system apart from assistants with it, and unlike veconfigure many changes don't require a restart of the inverter.
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Paul Carmichael avatar image Paul Carmichael commented ·

Cheers. I'm sort of used to making changes with veconfigure, but I'll take a look at this other setup. What is the recommended SOC to trigger connection?

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Alexandra avatar image Alexandra ♦ Paul Carmichael commented ·

Something before 10%. With virtual switch though you can't do it on soc only on voltage.

You may have to disable VS and use AC ignore assistant instead if you want SOC switching.

All other information you might need is on this page, although i am sure you saw it.


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Paul Carmichael avatar image Paul Carmichael Alexandra ♦ commented ·
Can I disable VS etc. using victron connect? I will have to disable assist as well.
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Alexandra avatar image Alexandra ♦ Paul Carmichael commented ·
@Paul Carmichael

No, you will have to use ve config to use assistants.

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nickdb avatar image nickdb ♦♦ Paul Carmichael commented ·
Really depends what your use-case is. Pylons run happily down to 10% so it really depends what you want left in the tank and making sure they get a regular opportunity to balance at full charge.
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Paul Carmichael avatar image
Paul Carmichael answered ·

Thanks both. I live in the south of Spain, so not a massive issue. The FLAs have been a big headache though. Although I have 910ah, the battery has never gone below 80% because of the voltage drop. So I'm guessing, I should actually get more usable backup from the lithiums.

3 comments
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Paul Carmichael avatar image Paul Carmichael commented ·
An update on FLAs. I've installed and commissioned the new pylontechs and disconnected the FLAS. It turns out that 2 of them are completely dead. I'm guessing they were letting current through so the other 22 cells were always being over charged. That would account for the noisy, and cloudy cells. I'm going to try to sell the good ones, although I don't know how long they might last.
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rithym1964 avatar image rithym1964 Paul Carmichael commented ·
Interested to know how long the FLA's had been in service before failing especially as you mention the bank has never gone below 80%, is that SOC or DOD?
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Paul Carmichael avatar image Paul Carmichael rithym1964 commented ·
Eight years. But when I dismantled the bank, I measured all cells. One was completely dead and I suspect it always was. It must have been short circuit so I've been overcharging all the rest all this time. One other had dropped to about 1.5v, but I'm guessing that was a result of the overcharging. I'm going to try to sell the "good" cells, but I don't know how long they'll last. At 50€ each, who cares? New ones cost 400€.
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