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marchoffman avatar image
marchoffman asked

Continuity and DC Voltage on inverter input

Victron Inverter 48/8000/110

Attempting to connect 53.2v battery puts battery into fault mode.

Once battery is disconnected completely,

• I am testing 32v on inverter's DC input terminals

• Continuity on inverter's DC input terminals

(Yes, getting these readings with absolutely nothing connected to inverter)


Please advise

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2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

What batteries do you have?

The inrush current (charging up the capacitors) of the inverter can cause a overload or short circuit cut-off at some batteries.

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marchoffman avatar image marchoffman commented ·

BSL Battery

B LFP51.2v 125Ah


2 batteries in parallel.

Also tried each battery by itself as master.

Problem persists

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wkirby avatar image wkirby ♦♦ marchoffman commented ·
Like Matthias said, there is a large capacitor bank at the DC input front end.

Did you pre-charge the capacitors as part of the battery connection procedure?

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nickdb avatar image nickdb ♦♦ wkirby ♦♦ commented ·

The 125AH BSL's are rated to 90A continuous each, 105A peak. With 2 in parallel, the probability of a surge activating BMS protection is low.

My post seems to have disappeared.

I posted the setup link for this specific battery for the OP to review his configuration, so it matches the tested config for this specific model:

bsl_6_4_manual_v1.pdf

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

An empty capacitor is like a short circuit.

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nickdb avatar image nickdb ♦♦ Matthias Lange - DE ♦ commented ·
True, but the BMS will log a SCP event and display an LED error state, and this is not such a common problem nor should it be a continuous issue for the OP.
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marchoffman avatar image marchoffman wkirby ♦♦ commented ·
Where can I find more information about pre-charging the capacitors?

Alternatively, could you give me a run-down?

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kevgermany avatar image kevgermany ♦♦ marchoffman commented ·
The usual way is to make a temporary connection through a resistor that will keep the current below the cut off value. Then remove the resistor and make the permanent connection straight away. A low wattage light bulb matching the battery voltage can do it and handle the current.
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bobybayo avatar image
bobybayo answered ·

Is this why I'm reading 20v on the busbar while the battery and PV are disconnected on my 24v system? Once I connect the battery, voltage reading matches that of battery.

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wkirby avatar image wkirby ♦♦ commented ·
Yes, any component of the system with capacitors at the front end, like inverters, will store a charge for a while if there is no loads to consume the energy in the capacitors.
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bobybayo avatar image bobybayo wkirby ♦♦ commented ·
Thanks
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