Charging issue

[deeezz]

I'm am having an issue using the charging function. The inverter started to charge and then errors saying ac feedback. My setup is off grid so I am using a generator to charge the batteries. Right now I only have L1 and L2 connected in my panel for the charge function. The generator is a harbor freight 8750/7000 watt generator. I did a test for ac feed back (shut inverter off measured for voltage on the out side of the inverter) and got 0v. I have a version 1 board I think (I paid for the air shipping). 

[Sid Genetry Solar]

1 hour ago, deeezz said:

The inverter started to charge and then errors saying ac feedback.

I'm wondering if your inverter still has the out-of-the-box firmware in it 😉.  I guess that because we don't have an "AC Feedback" error; might have at one point, but not anymore.

Can you check what firmware version your inverter is running?  (OUT page -> Diagnostic Info -> top 2 lines will show LCD version and CPU version.)

I'll work on/test 1.1r5 (current with fixes!) here this morning hopefully, and we'll get your inverter sorted out.

 

EDIT: Went through your user history, found you've updated it before.  Still, I'm curious to know what firmware version the inverter has.  Would appreciate a photo of the exact error message to be sure.

[deeezz]

I have 1.4 for the lcd and the cpu

[deeezz]

1.1r4

[Sid Genetry Solar]

Here's a complete list of all the possible error messages (apart from "??undefined??").  Which one is it saying?

(you won't be able to get the "FET Amp Limit" on anything except the newer Rev. C boards with a GS mainboard, so that's out!)

[deeezz]

It said ac backfeed I tried switching L1 and L2 on the charge side and got xformer polarity so I switched them back. Also I'm at work now so my responses may be delayed a little

[deeezz]

I can send pics of the lcd when I get home to night.

[Sid Genetry Solar]

2 minutes ago, deeezz said:

I can send pics of the lcd when I get home to night.

"AC Backfeed" definitely narrows it down then...that makes it sound like something is going out of spec during charge, and it's dropping back to inverter mode--but the timeout threshold must be a little short.

Will run tests on 1.1r5 today, see if I can get all the quirks worked out, then we can try an update later today.

Is the inverter also powering loads during charge, or is it just doing a standalone charge?

[deeezz]

It was powering a light load about 250w-350w. I tried lowering the charge % and it seemed like the inverter would charge for a few seconds and then stop then kick on again and then off. Then I would get the error code. 

[Sid Genetry Solar]

6 minutes ago, deeezz said:

It was powering a light load about 250w-350w. I tried lowering the charge % and it seemed like the inverter would charge for a few seconds and then stop then kick on again and then off. Then I would get the error code. 

Hmm...interesting.  Might want to look into this via video call or something if a firmware update doesn't resolve the issue.  "AC Backfeed" is a rather unexpected error--though it shouldn't be clicking on and off in the first place.

[BlackWaterPark]

Can the inverter normally charge at full function while also inverting at full output.

Also, is it more efficient/all-around-better to charge from a generator outputting 240v into the charger rather than 120v?

And if you are running a pair of 240v GS6 inverters with one in load assist (slave), would it be preferable to use that one as the charger?

[Sid Genetry Solar]

4 hours ago, BlackWaterPark said:

Can the inverter normally charge at full function while also inverting at full output.

Well, power can only go one way or the other way...not both ways at the same time.

For charge, the entire load has to first be "offloaded" onto the AC input, THEN the inverter can start to pull additional power from the AC input for charge.  "Charge" mode uses the exact same AC path, big AC transformer, FETs, and battery cables as "inverter" mode...they are not separate power paths.

A future firmware version for Rev. C boards will allow "hybrid" load powering, where the load is partially powered via the battery, and partially via AC input (utilizing AC input amperage limit functionality)--BUT unless the AC input is capable of FULLY supplying the output loads + charge power needs, you will still be pulling power from the battery.

 

5 hours ago, BlackWaterPark said:

Also, is it more efficient/all-around-better to charge from a generator outputting 240v into the charger rather than 120v?

Definitely will be able to run higher charge currents (due to transformer "AC" side wire amperage limitations...double the voltage = double the wattage).  Total overall efficiency will be slightly higher due to reduced losses in the transformer secondary.

 

5 hours ago, BlackWaterPark said:

And if you are running a pair of 240v GS6 inverters with one in load assist (slave), would it be preferable to use that one as the charger?

Again...unless the output load is FULLY offloaded to the grid/generator, you will still be discharging your batteries--albeit at a lower rate.

It would actually be easiest for the "slave" inverter to run battery charge as necessary--as it'll already be in "AC Mains" mode for parallel operation.  That inverter just has to change the FET drive setup and switch to battery charge functionality...

[Carlos]

Looking forward to the hybrid feature it’s basically the same as Victron power assist. This way if you as input ac cannot supply your peak load then it switches to hybrid mode and your battery provides that peak power. How fast will the switching be ?

[Sid Genetry Solar]

1 hour ago, Carlos said:

Looking forward to the hybrid feature it’s basically the same as Victron power assist. This way if you as input ac cannot supply your peak load then it switches to hybrid mode and your battery provides that peak power. How fast will the switching be ?

Inverter will already have to be in AC Mains mode (i.e. AC pass-thru) for "hybrid" functionality, as it's "AC Mains + battery assist."  Reaction time will depend entirely on the firmware: the CPU will be able to see an "overcurrent condition" within 1 AC wave, but then will have to throttle the FETs up to counteract the overcurrent condition.  Depending on the regulation algorithm used, it could be <0.25sec, or as long as 1sec.  (The issue with fast reaction is the tendency for the inverter to enter a regulation oscillation.)

Something for me to work on while everyone looks forward to it...the pressure 😉.

[dickson]

Reaction time will depend entirely on the firmware: the CPU will be able to see an "overcurrent condition" within 1 AC wave, but then will have to throttle the FETs up to counteract the overcurrent condition.  Depending on the regulation algorithm used, it could be <0.25sec, or as long as 1sec.  (The issue with fast reaction is the tendency for the inverter to enter a regulation oscillation.)

One AC wave  to react to an overcurrent is possible  and necessary  .   The CPU  regulation algorithm  must be less than  15 millisecond .   The invention of the moffets is one of the most usefull  device .    The starship  can  switch  on and off  the FETs  for a 3 millisecond  burst of it steering  rockets  so   15 millisecond  is a lot of time  to protect the inverter  from  destroying itself .  

[Sid Genetry Solar]

1 hour ago, dickson said:

One AC wave  to react to an overcurrent is possible  and necessary  .   The CPU  regulation algorithm  must be less than  15 millisecond .   The invention of the moffets is one of the most usefull  device .    The starship  can  switch  on and off  the FETs  for a 3 millisecond  burst of it steering  rockets  so   15 millisecond  is a lot of time  to protect the inverter  from  destroying itself .

I was referring to the original question about "hybrid power sharing", which works by a set current limit, thus the "overcurrent reaction" being slow.

FETs are being switched at a cycle time of ~42uS (0.042mS), with a variable pulse width minimum well under 1/500th of that, or 83nS (0.000083mS).  There's no lack of control ability, just a reaction requirement.

 

For FET amperage overload on the C board, reaction time is not limited by the CPU speed, as it is handled in hardware (not software). 

For system overload / AC backfeed (admittedly the latter being the most dangerous; I'm aware of at least 2 inverters being damaged by connecting their outputs directly to a "hot" AC panel), technically the CPU can see amperage readings (and polarity) approximately every 4uS (0.004mS).  The challenge becomes whether or not to take action based on a single sample.  If the code is too trigger-happy, it'll cause errors/shutdowns based on "dirty" or surge loads.  But if it takes too long to react, it won't be able to quit the FETs in time to prevent damage.  There may not be a happy medium here, unfortunately.

[Carlos]

I believe it’s better to sell the inverters as off grid only. AC should only be used for pass through or charging or both. Having an inverter that can back-feed or grid-tie can be dangerous if not properly installed. 

[dickson]

For system overload / AC backfeed (admittedly the latter being the most dangerous; I'm aware of at least 2 inverters being damaged by connecting their outputs directly to a "hot" AC panel), technically the CPU can see amperage readings (and polarity) approximately every 4uS (0.004mS).  The challenge becomes whether or not to take action based on a single sample.  If the code is too trigger-happy, it'll cause errors/shutdowns based on "dirty" or surge loads.  But if it takes too long to react, it won't be able to quit the FETs in time to prevent damage.  There may not be a happy medium here, unfortunately.

The  powerjack  rev 10.3 control board take too long to react  and blow the FETs .   The  rev 11.1  control board is too trigger happy  and I can not  get to max load  as I try many times  and   the inveter will shut down first .   I  have not try  to backfeed  grid  power to the  output of the inverter yet to see  if the  rev 11.1  control board will shut down and save itself  .   Maybe  one  day  I wiil  try and see if it will shut down  if grid power backfeed  with the inverter ON .   If not shut down in time then   all the  FETs will be no fire  and the  trace in the mainboard  will be shorted and crack  and the  LF driver  and control board will be  gone .   Powerjack  will make more money selling another  inverter  .   

[Sid Genetry Solar]

24 minutes ago, dickson said:

I  have not try  to backfeed  grid  power to the  output of the inverter yet to see  if the  rev 11.1  control board will shut down and save itself  .   Maybe  one  day  I wiil  try and see if it will shut down  if grid power backfeed  with the inverter ON .

I guarantee you that it will blow up.  0% chance of survival.

Why?

PJ inverters can't determine the direction of power flow. 

They also don't have an instantaneous overload trip built in.

[Sid Genetry Solar]

1 hour ago, Carlos said:

I believe it’s better to sell the inverters as off grid only. AC should only be used for pass through or charging or both. Having an inverter that can back-feed or grid-tie can be dangerous if not properly installed. 

I do agree.  Maybe I'm too much of an "off-gridder", but I don't like connecting AC mains to any important equipment.  There's some serious red tape for backfeeding into the power grid without the proper permits--these days with smart power pole meters, you're likely to get caught redhanded within seconds.  While it will be completely and totally possible on the Rev. C GS inverters to run backfeed/grid-tie functions, I don't have any immediate plans for exposing said functionality...simply because of the legal ramifications.

However, the "parallel" function itself by definition of current implementation in GS inverters, is a "frequency throttled grid-tie inverter."  This functionality will be integrated deeply into the upcoming Rev. C functionality--simply because so much can be done with it (including absolutely seamless return transitions from grid to battery.)

[Carlos]

I still think that a split-sync is much better than 2 inverters in parallel. Either split-sync or three phase setup. Here in Europe three phase setup are common even in homes unlike North America where it’s split phase system and 60hz.

[BlackWaterPark]

1 hour ago, Carlos said:

I still think that a split-sync is much better than 2 inverters in parallel. Either split-sync or three phase setup. Here in Europe three phase setup are common even in homes unlike North America where it’s split phase system and 60hz.

I'm starting to think this would be better for me as well.  The only thing that was making me consider the 240s was being able to charge @240v with a generator, but really, it sounds like id be better off with a dedicated external high efficiency charger designed for lifepo4 and just let inverters just be inverters. I've always used external chargers before anyway. Of course that would,( i presume?), render those cool genstart functions a moot point.

Edited November 30, 2021 by BlackWaterPark

[Sid Genetry Solar]

20 minutes ago, BlackWaterPark said:

Of course that would,( i presume?), render those cool genstart functions a moot point.

Well, this is Genetry Solar, so...not necessarily!

If you set the System Mode to "Inverter Only" (as opposed to the default "Normal"), the inverter will not switch to AC mains.  But the voltage genstart trip thresholds (and the generator start function) will continue to operate.  This is kinda a requisite, as the inverter has to be able to start the generator in order to get AC Input power to switch to in the first place.

[BlackWaterPark]

Well that's pretty cool then. 

[deeezz]

ok i have the rev.c board installed and just upgraded to 1.16r about 3 weeks ago. however i am still having charging problems. i have tried to calibrate the inverter and not having much luck. i am running 240v on the input side. this is whats going on  i can measure 1.6 amps on each phase of the input the screen says 1.6 on the main input. when i go into the calibration settings i can not adjust the amps to match what is going in or out of the inverter the closest i can get the input or output is about 2.6 amps (when my clamp meter reads 1.6 amps) and the inverter likes to charge and then kick off at any random time. i know i have mismatched hull sensors.  Is it possible that my sensors are to far out of spec. to calibrate the inverter correctly.  or am i just doing something wrong. i did the testing with the inverter in pass-through and about a 150w load on one phase.