Crap ~ Both my 225 amp Class T Fuses Blew

[time2roll]

Since these are DIY batteries can the max amps be reduced to maybe 20 just to see if the inverter will idle or power a small load.

 

[rodrick]

Can you run some 12 volt lights in series

 

[TacomaJoe]

For a quick test the water heater element should work. You don't want to have it energized too long without the tank of water. While energized, if you measure close to your battery voltage across the element, you pretty much know the inverter is shorted.

Going forward, if the inverter is shorted, I'd suspect something with the move. Maybe a loose nut or screw shorted something inside.

 

[Quattrohead]

Got it.

Now to find a 48v load.

Would a standard water heater element work?

A regular tungsten filament 120v home lamp would work just fine for this.

 

[MrM1]

I left the site, but I've got plenty of flood lights (non led). I can make up a "tester" early next week.

But on arriving home, I tested a 350w 12v inverter across the +/-. No beEp

I then tested my Conext SW 4024 across +/-. No beEp no OHM. meter read nothing.

I'm not optimistic.

 

[MrM1]

Going forward, if the inverter is shorted, I'd suspect something with the move. Maybe a loose nut or screw shorted something inside.

NOTE : when the trailer was moved, It was only moved about 40 ft and slowly. So it's not like they drove it across town. Still could be though

 

[MrM1]

if you measure close to your battery voltage across the element, you pretty much know the inverter is shorted.

So once connected in series, if I get close to battery voltage across the 2 element screw connections the inverter is shorted?

So if I use a light bulb,
- if it lights up is that good or bad? Bad I guess.

What if I connected the inverter and turned my switch only to pre-charge. (just not to the on position). I have a resistor in the switch pre charge.

- What would I be looking for is this scenario?​

- would the inverter try to power up?​

- will the cap start to get hot?​

- Voltage across either side of the cap?​

 

[MrM1]

OK ... just an update from the folks who moved the trailer. Here is the steps that happened

1. Turned off PV breakers
2. They disconnected the PV input Anderson connector cables that connect the Array to the trailer
3. Disconnected the 60 amp 240v AC power cable from the trailer to the building
4. Turned off the AC breaker in the trailer
5. Left the Inverter Powered ON in the trailer move (there is a sub panel, some lights and 4 receptaclesf in the trailer)
6. Moved the trailer about 40 feet to prep for the pouring of a concrete pad
7. Reconnected the trailer AC out to the Building AC in via the 240v 60 amp cable
8. The building powered up for about 10 minutes
9. .Then it all went dark

Loads at the building right now (and could not have exceed)

• it is still under construction
• there is a well pump on site connected. Max 2000 watts running . 240v AC split phase
• there are 3 ceiling fans
• the workers are using sanders and compressors
• thats it ... I could not get more than a total of 4000 watts +/- of AC split phase (mostly) 120v ac load on site last week
• This load (less surge) is only about 40% of inverter capacity.

 

[TacomaJoe]

In your series if you get the battery voltage across the heater element screws or the light bulb, that's bad, meaning that your inverter is shorted.

The resistor in the pre-charge will also get the battery voltage across it if the inverter is shorted. Current is limited by the resistor and is probably not to enough to power up the inverter (if it was good). The capacitor won't get hot. It acts like a short at first, but quickly charges to battery voltage and the current drops to zero (no current, no heat). The capacitor voltage goes from zero to the battery voltage when the pre-charge is connected. You can work ohm's law on your pre-charge resistor to see how much heat it will generate. A 25 ohm resistor will dissipate about 50 watts with your battery voltage.

 

[MrM1]

In your series if you get the battery voltage across the heater element screws or the light bulb, that's bad, meaning that your inverter is shorted.

The resistor in the pre-charge will also get the battery voltage across it if the inverter is shorted. Current is limited by the resistor and is probably not to enough to power up the inverter (if it was good). The capacitor won't get hot. It acts like a short at first, but quickly charges to battery voltage and the current drops to zero (no current, no heat). The capacitor voltage goes from zero to the battery voltage when the pre-charge is connected. You can work ohm's law on your pre-charge resistor to see how much heat it will generate. A 25 ohm resistor will dissipate about 50 watts with your battery voltage.

Thanks. I think it is a 25 or 30 ohm. I built it a year ago

 

[timselectric]

Actually, when I put the meter across the inverter positive and negative it starts at 0.2 then drops to 0.1 and then to 000 across inverter +/-

Across the busbar with inverter DISCONNECTED and scc connected I get no reading.2.Just DL on the meter

View attachment 136683

That's the capacitors.

 

[MrM1]

That's the capacitors.

OK ... then I need to try the Light / Load or Pre- charger and voltage across the terminal test

 

[DougfromdaUP]

In your series if you get the battery voltage across the heater element screws or the light bulb, that's bad, meaning that your inverter is shorted.

The resistor in the pre-charge will also get the battery voltage across it if the inverter is shorted. Current is limited by the resistor and is probably not to enough to power up the inverter (if it was good). The capacitor won't get hot. It acts like a short at first, but quickly charges to battery voltage and the current drops to zero (no current, no heat). The capacitor voltage goes from zero to the battery voltage when the pre-charge is connected. You can work ohm's law on your pre-charge resistor to see how much heat it will generate. A 25 ohm resistor will dissipate about 50 watts with your battery voltage.

Not that it matters too much, but battery voltage is 53, so power dissipated in 25 ohm resistor accross output is 112 watts…

 

[timselectric]

There's a built-in fuse, just above the battery terminals.
If it was internally shorted, it would have blown.

 

[MrM1]

There's a built-in fuse, just above the battery terminals.
If it was internally shorted, it would have blown.

Thanks. I did not want to open the case before reaching out to SS because of the seal on the case .... " Do not Break Under Penalty of Law" ... or something.

 

[MrM1]

Thanks. I did not want to open the case before reaching out to SS because of the seal on the case .... " Do not Break Under Penalty of Law" ... or something.

But if the fuse inside blew, wouldn't that mean I would not have the continuity BeEp across the +/- battery terminals?

 

[LydMekk]

Old style lightbulb will work.

 

[timselectric]

But if the fuse inside blew, wouldn't that mean I would not have the continuity BeEp across the +/- battery terminals?

Correct
That's why I'm saying it isn't shorted internally.
If it was, that fuse would have blown.

 

[TorC]

Any big capacitor will initially look like a dead short to an ohm meter, and in continuity mode will show a short at first. This short is illusory, and fades as the capacitor charges up. From the outside, a capacitor is kind of like a near-infinite-C rating battery that has a very high self-discharge, typically not over a few tens of minutes for full discharge. The ohm meter works by generating a low voltage DC signal, and looking at how much current flows. Although it's an open circuit to DC, charging the capacitor up fools the ohm meter initially.

 

[MrM1]

Well replaced the Growatt 12kW Inverter with a new one, and the whole system powered up, charged and preformed as expected.

Stress tested with
Water heater = 1200w
Well Pump = 1900w
1 ton mini split = 1200w
Table saw, chop saw, circular saw, and small compressor. Lights fans

Total over 8000 watts no problem. Growatt handled loads no issues.

So the old Growatt 12kW inverter failed ... For some reason? Signature Solar believes we have a warranty claim. All paper work is filed. Thanks Signature Solar and everyone who helped me trouble shoots here.

Mike