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Old 02-18-2022, 01:11 PM   #1
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Safely disconnecting/reconnecting

Caveat: I bought this bus, regrettably so, and am trying to fix this guy's solar problems.

Ok, I can't seem to disconnect or connect wires without spark welding occurring. Am I shorting the batteries and damaging equipment?

Attached pic: I'm trying to reroute my inverter negative wire to the bottom left battery negative terminal. I was told this would charge my batteries more evenly.

Problem is, when I go to move said wire, it sparks repeatedly and spark welds whatever it touches. I thought repeatedly touching to the terminal would spark and dissipate energy, but it's every time and doesn't dissipate at all. What is causing this? I turned the inverter switch to off, but it didn't seem to do anything. All my outlets that run off 120V stayed on/live. None of my 120V things plugged in turned off. Why/how is the inverter not turning off? How do I turn off the inverter and de-energize it? Or are the batteries causing all this? How do I safely disconnect batteries?

How do I safely disconnect, move the inverter negative cable to lower left battery terminal, then connect, then turn system back on? This crap scares me and makes me think I'm gonna start a fire, blow up a battery, or destroy equipment.


Explain like I'm 5 haha. Still learning.

What are the safest steps to avoid sparking and damage?
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Old 02-18-2022, 03:00 PM   #2
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I don't know why the inverter would still be powering your 120v appliances if its turned off, that makes no sense. Nor can I see why you're getting sparks like that. Its been awhile since I put our electric in, so I'm a little rusty. Hopefully this'll bump the thread so it doesn't get lost in the shuffle. If you're not plugged into shore power, it's either the batteries or the solar panels causing this.
The things that stick out to me, are that there don't appear to be any disconnect switch between the batteries and the inverter. There should be a big honkin' switch on the POS wire, I think between the fuse and the inverter but I could be misremembering.

There should also be a breaker between the solar charge controller (I assume that's what that gray box is) and the batteries. The should be breakers between the panels and the charge controller as well. You should always switch batteries off before working on this stuff, as well as switching the solar off correctly (I think its panels first, then controller and reverse order when turning back on but we've been out of the bus for a year so I'm a little rusty on that too).
First thing I'd do is get some switches and breakers in there. There are lots of examples of electrical systems on various skoolie and van building blogs. One I used extensively was https://faroutride.com/electrical-system/ They have a pretty good overview in case you're not too familiar with how this all goes together.


Hopefully someone will chime in about your specific concerns.
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Old 02-18-2022, 04:43 PM   #3
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Something is drawing power, hence the sparking. This is what I would do....
1) Turn off or unplug everything the inverter powers and turn it off. If you can't turn it off (?), pull that fuse on the right side
2) Shut down all your DC loads and/or pull both fuses on the back of your converter (on the left)
At this point everything DC should be off and you can relocate your ground.

Both your inverter on converter should have circuit breakers or switches and fuses so you can shut them off, a Service Disconnect.
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Old 02-18-2022, 07:35 PM   #4
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As the others suggested, there's some cause to this sparking you should get to the bottom of. As a bandaid/fix to your sparking issue, put a master switch inline with the battery connections, in addition to any fuses / breakers.
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Old 02-19-2022, 12:11 PM   #5
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It's pretty clear, based on what you've described, that the inverter isn't actually turning off. How are you turning it off? Are you using the little I/0 rocker switch? Do you have the remote control cable plugged in? In the photo, I see a small gray cable...that looks like it might be the remote...so I'm guessing here. If you have the remote plugged in, maybe you could try unplugging that from the inverter in case it's taking priority over the rocker switch. If you don't have the remote plugged in, and the rocker switch is off...but the receptacles are still powered up...then your inverter is defective and I wouldn't consider it safe.

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Old 02-19-2022, 06:26 PM   #6
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Quote:
Originally Posted by rossvtaylor View Post
It's pretty clear, based on what you've described, that the inverter isn't actually turning off.
Nah, this isn't quite accurate. My, and I'd say most high-powered inverters are the same- you connect them on or off to a battery and you'll get weldy-sparks all over. The caps in the inverter are getting charged. This is why typically recommendations are that you connect the inverter negative only and then use a resistor on the positive until the caps are full _before_ connecting inverter positive, and also why when you want to service an inverter you discharge the caps somehow, typically by running a resistor between +/- on the inverter input.


I had this problem until I installed a master switch. Master switch = connect inverter with switch off, then switch on, no sparks.
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Old 03-05-2022, 07:05 PM   #7
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Inverter sparks

As previous post mentions the inverter capacitors are still charged and depending on battery and inverter size large sparks can be had. A power resistor of about 100 ohm will bring the current in a bit slow and resolve the spark issue.
If the resistor is used to temporarily make a circuit from batteries to inverter then after a couple seconds hook the connection up it will not spark. This is the same as hooking up a large charge controller.
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Old 03-06-2022, 02:02 AM   #8
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First, you mention solar.
Then, you mention sparks.
.
Could the photovoltaic array be doing their job?
Powering your wires?
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Old 03-06-2022, 11:47 AM   #9
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Well you’ve a little problem for sure. First start by ensuring shore power is off. Then shutdown all your AC loads, assuming you have a load panel. Then shutdown the inverter, either with its power switch or by disconnecting the DC Input. Then disconnect the batteries. You need to purchase a DC battery disconnect, which will isolate both the negative and positive. Solar systems are not like your vehicle 12 volt system which grounds the negative, so typically the the system “floats” and uses a ground detection system. These things are not required to make inverters work, rather they are to let you safely operate and shutdown. DC is super dangerous for fires as the arc from a spark is hard to stop. Let us know more. Also I see a couple small wires connected to the batteries without fuses, just a fire waiting to happen, please fix
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