Multiplus ii 12/3000/120 230v tripping supply MCB

Q&A and troubleshooting
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1

Hi all,

Can someone confirm if the following is normal behaviour (I didn’t expect it)…

I’ve just received a new Multiplus ii 12/3000/120 230v and connected it to main on my bench, no other connections at all, in order to upgrade to latest firmware and configure it before installation. So at this stage, no battery connection. I turned it on to switch position ii by mistake (as this is charger only) and it basically made what sounded like machine gun fire and proceeded to trip the 32 amp MCB on the mains supply. Is this normal and expected behaviour?

Thanks

2

Just to add that the mains supply MCB does not trip when it’s switched to position i (on) and i proceeded to modify settings as needed.

I’m just really surprised that it tripped the mains supply MCB in charger only mode with no battery connected.

3

No Batterys connected ? Why ?
The batteries must always be connected first for the system to function properly. So please connect the batteries first and then continue

4

Hi Steffen,

So, this is an upgrade to a Multiplus 12/1600/70 230v so the batteries are still in my campervan, and as I say i was just powering it up from mains to do some configuration and firmware update.

I don’t expect it’ll ever be used in a scenario where it’s in charger mode only with no batteries connected (ie isolated). But as i say, I didn’t expect it to trip a 32 amp MCB, I’d have expected it to just not energise the 12v terminals.

5

It is sufficient to simply supply the connection terminals with 12V. So there is no need for batteries. But then it just can’t charge. But it is sufficient for configuration.

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6

I had the same issue, and made a warranty claim only to discover that they have to be powered initially on the low voltage side. I use a lab/bench switched power supply for that so firmware updating is somewhat easier.

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7

There is massive in rush for the power bank capacitors to fully charge up. So yes tripping is normal.

FYI the installation manual says to connect the battery first.

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8

That’s a good idea. I don’t have an alternative 12v supply but if I did then that’s what I’d do too.

9

Thanks - something I don’t get though. Hypothetically then, if I had a lifepo4 battery in low SOC protection mode that needed waking up it would effectively be the same as no battery connected. How then would you be able to charge it if turned the Multiplus ii on charge mode cause too much in rush and trips the MCB? I hope to never be in that situation, but if I were I’d like to know for sure that the Multiplus ii could cope with that.

10

From what I under its not the inverter that’s not coping it is the MCB…?
Ideally you would program the inverter to shut itself off before the battery protection is triggered.