question

Mahey Márquez avatar image
Mahey Márquez asked

Electrical spark every time I turn on a 48V Quattro and reset the lithium battery

Hello I am connecting a quattro in its first connection to a lithium battery, it gave me the normal spark but it was very large, I checked the fuse and it has continuity, I made a second, third and fourth connection and it gave a great spark again and the batteries The lithium batteries were restarted, I did not leave the inverter connected because the batteries would restart with some possible equipment failure and damage the batteries.


I have turned on many multiplus and quattro and had not missed this big spark. the polarities and wiring are well checked.


I would like to know if I continue with the startup or do I need to do some other verification.


After removing the fuse to check the continuity of the fuse, I measure the voltage at the Quattro terminals (positive and negative terminal) and the capacitors do not remain charged, they reach 2.2V, they do not charge at the battery voltage of 50V.

MPPT ControllersMultiPlus Quattro Inverter ChargerLithium Battery
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3 Answers
Kevin Windrem avatar image
Kevin Windrem answered ·

I recommend you precharge the Quatro capacitors. You can use a resistor between the positive bus bar and the cable going to the Quatro for a few seconds. If the Quatro charges to battery voltage, it can then be safely connected directly to the bus bar without sparking.

Use a 50 ohm 50 watt resistor. That will limit the inrush current to 1 amp and the capacitors should charge within 10 seconds or less. If the Quatro's voltage doesn't rise quickly to battery voltage, something is wrong.

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oxy avatar image
oxy answered ·

How long should the capacitor hold the charge? I.e. if you disconnect from battery, how much time can pass to not get a spark again when reconnecting?

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Kevin Windrem avatar image
Kevin Windrem answered ·

Total discharge is on the order of 10s of seconds or longer.

Note that the LONGER you wait, the bigger the spark when you disconnect the battery.

The spark is big enough to damage terminals and bolts so you really need to precharge when reconnecting.

It's also a good idea to discharge the caps after disconnecting the battery. A short on the terminals can be as damaging.

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nickdb avatar image nickdb ♦♦ commented ·
Turn the inverter switch on and off a few times once disconnected, drains them pretty quickly.
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