My First 48V 6.5KWh Li-Ion Powerwall 🥰

Could put a pre-charge button next to the breaker that bypasses the breaker while pressed, but there's the 30Ω 200W resistor in series with the connection. Press the button for a few seconds for the pre-charge, then flip the breaker afterwards.
If wanting to get really fancy, add in a few extra bits of circuitry to detect voltage differential on both sides of the resistor. When they are different, red led on, when equal, the led turns green. Or use a current sensor with flow turns on the red one, zero flow turns on the green.
 
Wolf said:
Yes and no. The reason you got a spark is that the instant you hook up the neg cable the capacitors on the inverter want to charge and they like to do it fast. So the best way to "pre charge the inverter" is to use a resistor to trickle the voltage and amps into the capacitors. For a 48V system a 30Ω 200W resistor will do just fine making the connection for about 10 seconds. If you have a high quality MCB like ABB you can get away with hitting it once or twice as it will reset because of the amps. 3rt time should hold. ABB MCB will take that punishment but many others won't.
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Good to know. I don't have such big resistors. Maybe my MCB was lucky this time!
 
italianuser said:
Maybe the manuals should say anything about this stuff
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Well they dont and thats a big failure on their part.
Even Victron which is the "Rolls Royce" of solar equipment only mentions a spark.
Ha if I where to connect my 832Ah batteries to my inverter without a precharge I would send so many amps through the wire it would melt the connectors in a millisecond.
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Here is a website that explains it and shows you different ways to achieve this.
climbingvan.co.uk

How to pre-charge an inverter easily | nohma.com, off-grid electrics ⚡

In this mini-article, we will explain why you need to pre-charge some inverters, when it is required and how to do it.
climbingvan.co.uk climbingvan.co.uk

Wolf
 
Thanks all for this precharge stuff. Following your suggestions I ordered 2x 100W 60ohm resistors (AliExpress 4.62€ incl.shipping, ~5.00USD) and I'll use a 3-way switch, I bought a couple of those some years ago. So now the control panel is getting more and more filled up with stuff, will look great.
 
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