question

Albert de Jongh avatar image
Albert de Jongh asked

Multiplus II battery terminal bolt snapped / sheared

I was tightening the negative terminal tonight, using a Gedore 5 - 50 Nm torque wrench set to 10 Nm (the manual says tighten to 12 Nm). The bolt inside the inverter snapped off :-(

And this is what the other half of the bolt looks like - kind of powdery inside?

I am a little bit unhappy, since we have regular power failures in South Africa at the moment, and I have no idea how long this will take to have fixed (the inverter is less than a year old).

Multiplus-II
1581882327254.png (4.6 MiB)
1581882895466.png (731.1 KiB)
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6 Answers
Rob Duthie avatar image
Rob Duthie answered ·

Hi

Note these are only 6mm tinned brass bolts, just go an buy another one and fit your self.

Note: 6mm brass bolts torque range from 5 to 8Nm range depending on the friction coefficient.

Regards

Rob D

NZ

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·

Only the very first batch of MP-II has M6 bolts. Now they have M8.

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Albert de Jongh avatar image Albert de Jongh commented ·

I don't think I'd even try to replace the bolt - it is behind that little circuit board, and probably also soldered to it or something. I looked from the bottom of the inverter, and can't see how it is kept captive.

I see M.Lange mentioned below M6 vs. M8 bolts - mine has the M6 bolt, and my paper manual says max torque is 11Nm. The manual on the internet says 12Nm (but in brackets behind it M8 bolt). Could easily create some confusion!

And I was even more conservative with the torque wrench at 10Nm.

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Rob Duthie avatar image Rob Duthie Albert de Jongh commented ·

Hi Albert

As us kiwis do, we call it the number 8 wire method, just do it!! the inverter is simple in design and construction. Other wise if you stuck out in the boon docks, you can wait for ever.

Note: I do have one myself with 6mm bolts.

Regards

Rob D

NZ

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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Apologies for the inconvenience, but the thing to do in this case is start the warranty claim process.

Please contact your dealer, or fill in the form above. It might be able to be resolved quickly.

That torque setting is the maximum, in the future if you are going to use torque wrenches, find one with a range closer to the target, eg 1-15 Nm. In this case it could be a fault in the metal part, or the low end of the torque wrench. It is much easier to feel the natural point of tightness with a smaller tool.

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Albert de Jongh avatar image Albert de Jongh commented ·

Thank you @Guy Stewart (Victron Community Manager). The inverter has been handed in at the supplier here in Cape Town and they will liaise with Victron to have it resolved. I hope for quick resolution as the inverter keeps my business running during our regular rolling blackouts.

The Multiplus II documentation could perhaps be improved in two ways:

  • Note the actual torque values, not the maximum ones.
  • The manual on the internet is for the latest inverter - hence the max torque there is different to the older version (which I have). It is not immediately obvious that you should be using a different value since the manual is for a "Multiplus II". I have now gone and checked that it does actually specify the HW revision on the second page at the bottom, but it is easy to miss that. Perhaps I am nit-picking :-)
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Rob Duthie avatar image
Rob Duthie answered ·

Hi

Is that a brass bolt? if so they have lower torque values anyway than steel bolts, also is the torque wrench being calibrated and checked not a cheapy? as thay can be a long way of in calibrated readings.


Regards

Rob Duthie

NZ

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koos avatar image
koos answered ·

Victron posts torque values of 12Nm for DC terminals and 1.6Nm for AC terminals in the manual

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Rob Duthie avatar image Rob Duthie commented ·

The 1.6Nm is for the AC screw terminals not bolt type as the bigger units have.

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Robert avatar image
Robert answered ·

Hello,

my brand new phoenix had the same Problem.

Victron replaced it without problems.

Best regards Robert


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solarpete avatar image
solarpete answered ·

The picture of the broken M8 bolt does not appear to be brass or copper. Why is the bolt not solid? (having the center filled with some non structural material) The Victron 12Nm torque spec seems very high (even if for a brass solid bolt) compared to the steel grade 4.6 torque spec of 11Nm.

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