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jem avatar image
jem asked

16x US3000c dead BMS - what next?

Hello,

My electrician (Victron specialist) came back this week to finalize an upgrade of my home's solar setup (adding a smart solar and wiring panels). He's the same person who installed the original system last summer, and it's been working nicely since.

As he turned on the master battery to finalize the installation, it made a loud "pop" sound, followed by a slow blinking green led. Nothing else. Voltage at terminals is 0 volts even though the battery is turned on.

He started testing the other batteries separately, and after testing a few batteries, another one popped. That made him stop to avoid further, useless damage. The 6 batteries he tested had the same green light blinking and 0 volts situation.

We're impatiently waiting for Pylontech's follow-up.

Has anyone experienced anything similar already? How is this sort of issue addressed? I can't imagine how to ship back the batteries to my supplier... the electrician thinks it's the BMS that died, suggesting that a power surge happened in a battery and fried all the other batteries' BMS (and let's hope it didn't burn other devices on the V.CAN bus).

About my electrician - I fully trust the guy's expertise, he's made dozens of similar setups before - I'm sure he didn't do anything wrong. See his work below as it illustrates well his state of mind and quality orientation.

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Pylontech
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4 Answers
daza avatar image
daza answered ·

Sounds like in rush of voltage to the caps means the BMS has seen this as a dead short, normally you gets a resistor or incandescent bulb in line so it can precharge the Multiplus caps so it doesn’t give any of the popping. Try resetting the BMS and use precharging to connect the batteries. Or the other case could be a polarity issue check that the polarity is right for every battery if it’s not that it’s most likely the in rush.

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jem avatar image jem commented ·
Hi, thanks for your input. How do you reset the BMS? You mean it might not be burnet, and could simply need a "reset" ?
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jem avatar image jem commented ·
Polarity check and first boot were ok. The technician shut down the entire system (can't say why) then re-started it all, then it popped.
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Craig Chamberlain avatar image Craig Chamberlain commented ·
@daza I believe the Pylontech batteries have soft start functionality as long as you have the inverter isolator(s) closed when powering up the batteries in the correct way. This means powering on the rocker switches and then pressing the red start button on the master battery. On a larger installation like this one it might involve multiple groups. You only get an inrush if you power the batteries up fully first and then close the inverter isolator(s).
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nickdb avatar image
nickdb answered ·

It is impossible to tell remotely. Did he check polarity of the new charger? What startup procedure was used? A pre-charge routine should have been used, the easiest way is to start the system from the original MPPT's before bringing the batteries online. With such a large system this is fairly important to do.

I see you opted for laying the packs on their back, I am not sure if this will be sanctioned by Pylon, hopefully that doesn't affect any warranty but, I think they may claim this is outside of warranty and an installation/configuration fault.

Nasty thing to have happened, hope you come right and get it sorted.

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ejrossouw avatar image ejrossouw commented ·

Acceptable if on their back.1693693698432.png

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nickdb avatar image nickdb ♦♦ ejrossouw commented ·
Thanks for confirming.
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jem avatar image jem commented ·
Interesting you mention a pre-charge routine. I'll ask him, I have no idea. The technician said this position was ok, as well as horizontally. He preferred this approach as to not stack them, as well as to avoid buying a rack.
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jem avatar image
jem answered ·

Pylontech staff just answered me - and ask for logs. Apparently some USB-RS232-RJ45 wire is needed. They sent me a wiring diagram, but I hope I can get a pre-built one. I'm not qualified for making those wires.

I'll keep updating the topic as the events happen.

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nickdb avatar image nickdb ♦♦ commented ·
Yip, if you look around there are cables available online.
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daza avatar image
daza answered ·

@Jem a quick Google found this

To reset the Pylontech batteries do the following: Turn OFF all the rocker switches on the left-hand side of the batteries Turn ON all the rocker switches Press and HOLD the red SW button on the master battery (battery with the CAN...

but don’t fire the inverter up again without doing the preacharge PS make sure the battery is isolated from the inverter to see if they power up again. let us know either way. Interested as I’ve got my batteries coming tomorrow but I’ve built in a precharge circuit and I’ll just put a clamp meter on the cables to the inverter to see when the caps are at 48volts

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jem avatar image jem commented ·

Thanks @Daza.

I forgot to mention that the battery popped before the Multiplus were turned on (MP's 3-way rocker switches were still on middle position "OFF").

I'll turn on one of the batteries and try that HW switch press like you mentioned from the Solis Service website you found. Thanks for the tip, I'll keep you posted.

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nickdb avatar image nickdb ♦♦ jem commented ·
Yes, the internal caps in the multi don't need the power switch to be on to charge.

The quickest solution is to leave the batteries off, turn on the mppts, give them a little time to work their magic, then turn on the batteries.

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seb71 avatar image seb71 nickdb ♦♦ commented ·
Yeah, but on the other hand it is not recommended to have only PV connected to an MPPT.
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nickdb avatar image nickdb ♦♦ seb71 commented ·
Well, it is one of the recommended methods, for the 10 or 15 seconds it takes you can't break anything. It is one of the most common methods, providing the sun is shining.
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daza avatar image daza nickdb ♦♦ commented ·
@nickdb correct, I did say to the OP to isolate from the inverter, from further looks there looks links no isolator on the inverter from the batteries which is why I believe it’s the caps that shut down the BMS, OP if you do what @nickdb said with a clamp in place to see it get to 48volts then turn it all on. get who ever done it to put switches on the inverter to break the battery connection to inverters each getting there own would be my advice. But I’m new to this game another seasoned member might be be able to better a advise
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Craig Chamberlain avatar image Craig Chamberlain daza commented ·

Yeah, looks like an absence of DC isolators from bus bars to inverters which isn't ideal. Also, I don't see any DC isolators for the solar arrays unless they are somewhere else. Even if there are isolators nearer to the PV panels I would still have expected additional isolators next to the MPPTs.

Hopefully the batteries are fused inside the Lynx Distributors to protect the cables.

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jem avatar image jem daza commented ·

Can't do this without the electrician sadly. It'd mean unplugging the 3 Multiplus from the batteries. Wouldn't it be more simple to simply disconnect the batteries from the Lynx?

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daza avatar image daza jem commented ·
It would be but more potential of shock and if you need to change an inverter you need to disconnect all the batteries also for precharging you won’t be able to do that.
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