What is your Current Setup?

Basically, the low-side FETs are driven by a totem-pole transistor method.  Their idea of "level shifting" the 5v CPU outputs to the +12v FET drive...is to put a pullup resistor on the output of an LM339 (open-drain comparator).  And then hang an LED from one of the pullup resistors.  Totem pole transistor drivers can't exceed the input signal voltage...so that clamps the top.

Both high-side FETs are driven by a floating power supply (separate tap on the main switching transformer).  Really great idea...just poorly executed ;-).

Sure thing, GS inverters run ~15v on all 4 sides...it doesn't take much to spike +2v past 18v and start blowing the FET gates out.  This sort of failure usually results in very random FET failures--usually a day after a load test, under no load...the FETs will randomly fail and blow themselves up.

If you wanted to adjust the voltage for the high side drivers, you would adjust the bias on the LM431 chips on the driver board.  Those control an NPN transistor that's a series regulator to drop the power taps to the regulated voltage (instead of a total loss zener circuit).

Well, that "spacer" also carries the FET drive signals from the CPU to the FET drivers...so you'd really have to know what you were doing there 😉

Not as hard as you might think.  Hardest part is unbolting the transformer so you can push the wires back through the center hole.  The "battery" side winding is wound on top, so it's really trivial to remove a turn or 2.  Risk being the reduced resistance coupled with the poor FET drive (and crosstalk) can cause the inverter to blow FETs with a surge load.  Always something 😉.

That's the GS trick anyway...but PJ doesn't bother with this.  The reason for the multiple bundles...is because they can only get a maximum of 10 wires in a crimp at a time.  If you check with an ohmmeter, you'll probably find that the strands are randomly mixed between the crimps--in other words, anything but separate windings.

To me, anyway 😉.  As I've detailed elsewhere on the forum, the firmware does not have a "0-state" regulator output.  In other words, each loop through the regulator MUST either increment OR decrement the throttle.  This results in a constant stream of +1/-1/+1/-1 on the throttle--which as it runs at 120Hz means that one pair of FETs is going to run noticeably hotter than the other.  It also means that the inverter can get into an oscillation with itself (i.e. +1/+1/-1/-1/+1/+1, etc.) and cause LED lights to flicker pretty badly.

Have to say that I actually decreased no-load current on a PJ inverter by increasing the dead time in the firmware 😉.

On 2/3/2022 at 6:01 AM, Jnjvan said:

Yep. I'm using the Power Jack right now as a load to do some battery testing. When that task is done, I may try to "improve" the unit. It appears that PJ only put output filtering on the L1 output winding. There is a lot of 24KHz hash on the L2 side. It doesn't show up when using the two windings in parallel, but split phase is not so good. My unit has the fuses on the N1 and N2 connections. It makes more sense to me to have them on the L1 and L2 sides. I have also looked at the gate drive signals on the upper and lower FETs. Looks like there is room for improvement there too. Even with a relatively easy load (800 watts, mostly resistive), there was some ringing that could lead to cross conduction. The transformer is kinda noisy, even with no load. I am impressed with the low idle consumption. I measured less than 13 watts at 13.6 volts battery.

Sid, I've been browsing this forum over the last couple of days. Thank you for all the time you spend fielding questions. I'm new to the Power Jack world. It looks like you are all too familiar with their ins and outs. I may pick your brain a bit if I decide to delve into some of these changes (especially the FET drive stuff). 

John Van

I also interested in the inverter and found this thread while searching for info.  Can you confirm if the inverter can run at least 2000W/240V (or 1000W each 120V leg simultaneously) continuously?

Thanks

9 hours ago, JIT said:

I also interested in the inverter and found this thread while searching for info.  Can you confirm if the inverter can run at least 2000W/240V (or 1000W each 120V leg simultaneously) continuously?

Thanks

I have not tested higher than about 1.5 kW continuous, as my batteries are on their last legs. It did fine at that load for 20 minutes or so, no overly hot components, and the transformer was barely above ambient temp. The cooling fan did turn on intermittently.

I did notice that the resistance of the L2-N2 secondary winding is higher that the L1-N1 winding (0.399 ohm vs 0.345 ohm). This leads me to believe that the L2 winding may be smaller gauge than L1. The secondaries are two in hand aluminum wire. I presume the primary wires are aluminum also. The good news is that the output voltage is identical across the two windings. At least PJ used the same number of turns for both secondaries!

I destroyed one of the high side FETs when my probe shorted drain to gate. Fortunate that the damage was limited to that FET and G-S resistor. I removed the FET and the unit is back in operation. I will not be doing any further high power testing until I replace the failed part (one of four in parallel). The FETs are NCE80H15, which are only available from sketchy Chinese sources (Aliexpress, etc). The photos that I have seen on said vendors' sites make me think counterfeit. Not sure what I'm going to do yet.

Thank you for the info.  Do you remember the rough AC voltage drop when running 1.5kW continuous?

Not surprised to hear aluminum transformer windings.

Sorry to hear about the blown FET.  Based on everyhing I have seen about PJ it's probably a good idea to have a good supply of spare FET's around.  I hear you about fake FET's especially given the supply chain issues.  I hope you can repair the inverter soon.

Thank you for the info.  Do you remember the rough AC voltage drop when running 1.5kW continuous?

What cause the AC output to drop from 119vac to 106vac ?    Is  that from the design of the rev 11.1 or rev 11.3  control board ?    Do anyone  notice the AC voltage with a kill a watt meter ?    PJ  require an  output AC choke for waranty is  what remind that they have no real  design engineer .     The market people want to wiggle their way out of paying for anymore repair .   I  know PJ  have  manufacting engineer   and production  engineer  and good marketing people .   

I didn't record AC voltage drop with the 1.5kW load, but don't recall it being too drastic. My batteries were sagging pretty badly at that time.

I did some measurements this morning. Measurements are at inverter input and output terminals. Load power measured by kill-a-watt meter. Load is on L1 winding only (115V).

No Load: Vin=13.58 Vdc, Iin=980mAdc, VoutL1=114.7Vac, VoutL2=114.8Vac

585W Load (electric heater): Vin=11.89Vdc, Iin=57.9Adc, VoutL1=114.2Vac,VoutL2=116.4Vac

Observations:

No load (idle) power is 13.3W, not too shabby.

Efficiency at 585W is 85%

Voltage drop on L1 winding is not too bad. Voltage feedback is only on L1 winding, hence the rise in the unloaded L2 winding.

Note that output voltage is adjustable on the front panel. I returned it to the factory setting, but  was able to adjust up to 120, and down to 110 volts.

 I  did some measurements this morning. Measurements are at inverter input and output terminals. Load power measured by kill-a-watt meter. Load is on L1 winding only (115V).

No Load: Vin=13.58 Vdc, Iin=980mAdc, VoutL1=114.7Vac, VoutL2=114.8Vac

585W Load (electric heater): Vin=11.89Vdc, Iin=57.9Adc, VoutL1=114.2Vac,VoutL2=116.4Vac

Your  L1  and L2  voltage are equql and can be adjusted to 120vac .   The inverter price is very low  so I  can get  6  inverters to get  12000 watts   at the 120vac outlet for less than  1200 dollars .   This is the lowest price for 12000 watts total on ebay .    Thank you  for the information  .   The parts is more than  180 dollars  from  each inverter .  

It looks like many things could be improved but the base numbers don't look too bad.  For the price it seems worth the gamble.  Thanks for making the measurements. 

Current setup 20 240W panels bought used 

12 100AH 12.8v batteries 300AH 54V

8000W (4KW) power jack LF AMG running 230V split phase

Will be running GS inverter 6K as soon as I get one 

We're workin' on it!  I'm keeping a thread up-to-date with the latest info/updates we have from the factory.  Unfortunately, it's quite literally out of our hands at this point 😉. 

<a href="/topic/459-pre-order-discussions/" rel=""> https://forums.genetrysolar.com/topic/459-pre-order-discussions/

I have the same inverter, and ran it in 114° F temperatures. I live in California and went off grid during the last heat wave. Typically, it would stop once, about a half hour after I started it. The green light would stay lit, and if the fan was running, that would continue. I would have to manually  switch it off, then on, and it would then run reliably until the end of our Flex Alert.

Only time mine does that is if I overload it

It's doesn't take much to do that

Also Cali flex alert/peak day off gridding 

So, when you overload it, the green light stays on (no red light)?