Overload fault on MultiPlus 24 5000 120

[jillete]

Hello everyone,

I wanted to share my situation to see if anyone can help me with the problem, or whether it could be a fault with the inverter.

I currently have an off-grid system consisting of the following components:

Solar panels
Victron MPPT 150 85 -tr

Victron Energy Multiplus 24 5000 120

Turbo Energy Lithium Series 24V 2.24kWh battery

*As a note, until 2 years ago, there were lead-acid batteries connected in series, but these were replaced with a lithium one, which is the one listed above. I think the inverter and MPPT settings were never changed.

Right, the problem is that the inverter did not cause any problems until 2 months ago, but we have now noticed that when it has normally been running for 3 or 4 hours, the overload LED on the inverter comes on. After that, sometimes the low-battery warning comes on as a result of these faults.

What I did was update the inverter to the latest version (2614556), and update the charge and generator settings to the values specified by the battery manufacturer.

After several days of testing, I think it now lasts a little longer, but eventually the overload still comes on. Another test we carried out when it starts to fail is to disconnect the entire domestic network by removing the OUT cables directly from the inverter so that it cannot supply any kind of power, but the overload still comes on.

I have also noticed that, before the overload LED comes on, the inverter starts making a strange noise.

The MPPT is almost always in FLOAT, and when I set it to Charge only, none of the LEDs on the left-hand panel comes on. I seem to remember that they used to before.

Finally, I should add that the battery is always at 100%. On some occasions when the inverter trips, the alarm LED on the battery also comes on until you restart everything, at which point it switches off.

The photos were taken with the equipment switched off.

Could this mean that the inverter is knackered, or is it a programming issue?

I would be very grateful for any help you can give me.

Kind regards!!

[Karl-Heinz]

What voltage is the battery at? 100% doesn’t tell you anything: if low currents have been flowing for an extended period, the BMS won’t detect it, and the battery may be discharged while still displaying 100%.

If you’re seeing readings of around 12 V when measuring directly at the battery terminals, the battery is flat and needs to be charged immediately. However, charge the first 20% at a very low current to prevent damage (charging at approximately 10–15 A maximum).

[chrigu]

@jillete

As a note, until 2 years ago, there were lead-acid batteries connected in series, but these were replaced with a lithium one, which is the one listed above. I think the inverter and MPPT settings were never changed.

@jillete

What I did was update the inverter to the latest version (2614556), and update the charge and generator settings to the values specified by the battery manufacturer.

Using an LFP with old lead-acid settings is never a good idea. You’ve been possibly overcharging or overdischarging your LFP for almost two years. You’re lucky it even worked that long, and didnt end in a fire. Also given how poorly the system is installed. A wonder it worked that long.

The battery case looks like it got hit by water spray. Its also resting on a piece of wood on the floor. Very likely that theres corrosion involved.

I hope you are not pushing 85A out of that MPPT, those cables look way too small for that.

Since you have a managed battery, you need a GX in your system, to allow the BMS to control the charge sources over DVCC. You can then also see some more details of the battery like individual cell voltages. At least the battery should provide that, i dont know this exact model. Looks like a Pylontech clone, but that does not mean it actually works the same way.

@jillete

the overload LED on the inverter comes on. After that, sometimes the low-battery warning comes on

@jillete

I should add that the battery is always at 100%.

Check the connections for looseness, overheating and corrosion. Its possible that the battery outputs good voltage but the voltage at the inverter terminals is too low regardless due to high resistance somewhere.

The connection between MP and battery is also too thin for the size of the inverter. Victron recommends 2x 50mm2 per pole. At full load you are pushing around 200A through those cables, which appear to be only 25mm2, maybe 35mm2.

@jillete

The MPPT is almost always in FLOAT, and when I set it to Charge only, none of the LEDs on the left-hand panel comes on. I seem to remember that they used to before.

You cant set the MPPT into charge only, thats the only mode it has. But you can put the MultiPlus to charge only. However, since you are offgrid, there is no mains. So setting it to charge only will simply mean it will turn off.

Lastly, that schematic is worth nothing. You cant trust AI to generate something comprehensive. Rather draw it yourself.

[M_Lange (Matthias Lange - DE)]

Sounds like a power pack failure.

Disconnect the AC IN and OUT then try again, if you still get the same error the device is defective and you need to contact your seller/installer to get it repaired/replaced (if it is still within the 5 year warranty).

[jillete]

Hi everyone,

Just an update: it turns out the inverter is faulty, and I’m waiting for the supplier to process the matter.

Thanks to everyone for the help.