MrM1
I'm Here, But I'm Not All There
Yes, brass bar, nickle plated
Growatt 12kw Help ~ JK BMS Throwing "Discharge Short Circuit Protection"
- Thread starter MrM1
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John Frum
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Sorry too hard to parse this.
MrM1
I'm Here, But I'm Not All There
The Plot Thickens.
Today I noticed a spark / arch coming out of the main switch when I turned on the batteries to power on the SCC (not the inverter). The trailer was pretty dark inside, which is why I had not seen a spark before. Odd. I open up the switch to find it had been arching. There is a burn mark where the switch first makes contact to close the DC connection of the 48v battery positive. The first position goes to a resistor, so this should have been limiting any call for large amount of current. Is this where/why the BMS is reading the short? Probably. But why is the switch arching?
So more testing.
HERE'S WHAT'S WEIRD:
I remove all battery cables from the battery terminals. I connected a DVM to the battery positive and connect the common of the DVM to the frame of the trailer. Only millivolts. BUT ... if I touch my finer to the negative battery terminal, I get 52.9vdc from the battery positive to the frame. Why? The floor of the trailer is wood. If I stand up with my shoes on and touch the battery negative there is only millivolts between the battery positive and frame. IF I take my shoes off and stand bare foot on the wood and just put my finger on the negative battery terminal, there is 52.9vdc between the battery positive and the frame. (Note: there are NO other cables connected to the 16s battery, just the busbars from cell to cell. )
Surely someone understands this?
But more importantly, Is this why I am getting an arch in my switch when the battery negative is grounded to the frame?
Today I noticed a spark / arch coming out of the main switch when I turned on the batteries to power on the SCC (not the inverter). The trailer was pretty dark inside, which is why I had not seen a spark before. Odd. I open up the switch to find it had been arching. There is a burn mark where the switch first makes contact to close the DC connection of the 48v battery positive. The first position goes to a resistor, so this should have been limiting any call for large amount of current. Is this where/why the BMS is reading the short? Probably. But why is the switch arching?
So more testing.
HERE'S WHAT'S WEIRD:
I remove all battery cables from the battery terminals. I connected a DVM to the battery positive and connect the common of the DVM to the frame of the trailer. Only millivolts. BUT ... if I touch my finer to the negative battery terminal, I get 52.9vdc from the battery positive to the frame. Why? The floor of the trailer is wood. If I stand up with my shoes on and touch the battery negative there is only millivolts between the battery positive and frame. IF I take my shoes off and stand bare foot on the wood and just put my finger on the negative battery terminal, there is 52.9vdc between the battery positive and the frame. (Note: there are NO other cables connected to the 16s battery, just the busbars from cell to cell. )
Surely someone understands this?
But more importantly, Is this why I am getting an arch in my switch when the battery negative is grounded to the frame?
Last edited:
OffGridIdaho
Hobby Farm in N Idaho
Here was the fix on mine when it did this.
Shut down for 30 minutes to clean the inside of the inverter (dust)
Turned JK BMS back on and instantly get the short circuit protection fault.
Went into advanced password settings and turned off discharge slider in the bms.
SCP counts down from 60 seconds and doesnt blow another error.
Turned on discharge slider and BAM SCP blows again.
OK I think I have this figured out.
30 minutes down time was enough to drain the caps on the inverter (see where Im going?)
Turned slider for discharge off again. BMS reset to GTG at T MINUS 60 seconds and its happy.
Flipped main breaker to inverter OFF, turned slider inside jk bms to on or discharge again, no error.
Sooooo I took a small wire and ran it from the neg side of the battery (not other side of neg bms) to the neg terminal of inverter. FLASH-SPARK it starts charging caps slowly. Slow enough not to have a huge in-rush and trip SCP in the jk bms.
I wait 60 seconds and remove wire and re-touch, no spark. I quickly flip the breaker back on ito the inverter
AND HOLY FLEEPIN BATMAN it doesnt blow the SCP error.
It was the massive in-rush to the inverter caps blowing the SCP fuse inside the jk bms.
Shut down for 30 minutes to clean the inside of the inverter (dust)
Turned JK BMS back on and instantly get the short circuit protection fault.
Went into advanced password settings and turned off discharge slider in the bms.
SCP counts down from 60 seconds and doesnt blow another error.
Turned on discharge slider and BAM SCP blows again.
OK I think I have this figured out.
30 minutes down time was enough to drain the caps on the inverter (see where Im going?)
Turned slider for discharge off again. BMS reset to GTG at T MINUS 60 seconds and its happy.
Flipped main breaker to inverter OFF, turned slider inside jk bms to on or discharge again, no error.
Sooooo I took a small wire and ran it from the neg side of the battery (not other side of neg bms) to the neg terminal of inverter. FLASH-SPARK it starts charging caps slowly. Slow enough not to have a huge in-rush and trip SCP in the jk bms.
I wait 60 seconds and remove wire and re-touch, no spark. I quickly flip the breaker back on ito the inverter
AND HOLY FLEEPIN BATMAN it doesnt blow the SCP error.
It was the massive in-rush to the inverter caps blowing the SCP fuse inside the jk bms.
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