PowerJack 30000Watt 48volt LF SP PSW 2 box inverter 2021 model 189 pounds

You don't need to.  If you count the number of strands of wire per winding (primary, secondary), I can estimate the maximum wattage the wire can handle before overheating.

I  screenshot  Sean latest  GS 12kw  youtube .   Look at the size of the red positive  input cable  and  the black  primary winding  look like it has  ten strands  .   

the large PowerJack inverters all have 2 positive and two negative posts to connect the DC cables from the battery.... I only use one but may run a second set of 4/0 cables on the larger battery.... I always use 4/0 hydraulically crimped cables with tinned copper lugs to the inverters with a 400 Amp class T fuse....

GS12 only uses one for positive and one for negative DC connection post, so that will be a cost savings...at least in their prototype design on YouTube...

one question in the back of my head???

they always say one should pre-charge  the capacitors in the inverters with a resistor or some use something as simple as a light bulb......if the inverter is turned off,,,,, do you need to pre-charge the capacitors again before turning the inverter back on????

I have used a resistor a time or two....but I have also just made all connections with a switch to disconnect and then turned on the breaker on the inverter as the switch.

I see in some YouTube videos where they build a special pre-charge circuit....for capacitor pre-charging....in the inverters....

so is it a requirement for every time one turns the inverter on and off to prevent problems or is it just for the initial connection to the batteries??? the need to pre-charge the capacitors in the large LF inverters????

this is a nagging question in the back of my head to understand or avoid problems with these inverters>>>

thanks for all the replies! 😎👍👍👍

hate to make a catastrophic error!!!

PowerJack 30000 watt LF PSW SP inverter capacitor precharge or any PowerJack LF inverter for that matter???

I have seen Sean in his old Gentry solar YouTube videos just connect them with a big spark and others on YouTube connect them with a spark without a pre-charge resistor applied 1st...

is there a potential damage to the inverter if one does not do the pre-charge of the capacitors in the inverter with the resistor 1st???

and if it had already been hooked up and previously charged the capacitors but then shut off for a time, will the capacitors drain down or will they hold the charge from the previous connection and thus not require an additional pre-charge via the resistor method???

have a great day! 😎

It is always a good idea to precharge the caps--as otherwise you have a zap of several thousand amps when the inverter's connected.  That "zap" can easily cause a surge on the battery lines, potentially wrecking havoc with the rest of the system.  Not to mention not being that great for the caps in the first place.

I used to use LM3414HV chips for LED drivers direct off the 48v battery bank.  They've got a 65v absolute maximum voltage, no prob, right?

Well, flipping the breaker on my inverter ("zap charge") would instantly blow those chips (and then the LEDs) out with overvoltage.

I ended up switching chips to ones rated for significantly higher voltage--solving at least the issue of my lights getting blown out.

Depends on the inverter's design.  GS inverters will self-discharge back to zero in a matter of minutes.

That is not a cost savings when the single terminals cost at least 5x that of PJ's terminals.  This is a case of purposely choosing a higher quality item instead of trying to be absolutely as cheap as possible. 

Which I guess is kinda how I've designed most of the inverters.  Our power button costs roughly 10x that of PJ's--but I just like the RGB button so much better.  The busbar costs considerably more than the wire PJ uses--but it's a design requirement due to the FET amp limit.  Our relays cost well past 30x what PJ's do--but they're considerably better.

We at Genetry work to make the inverter as cost effective as possible--but WITHOUT sacrificing quality.  And that's the defining difference.

so then essentially every time the PowerJack inverter is shut off, it would likely need a pre-charge to the inverter capacitors to be safe and nice to them.... never had anything blow up yet with the PowerJack LF inverters but needed to know the best practice... 

yes, I have had vendors of busbars not be able to say they were rated at 48 volts...so I think there are quality issues with some chinesium products and their copies.

 I could replace wire with better quality higher AWG copper wires for a small expense,,,, that would be easy to upgrade with a small bit of time & effort.

I probably would not go to the effort to bend and fit solid copper busbars inside the 30000 watt PowerJack control board case,,,,that would take too much time for me at the moment! 🤔

not sure about the quality of the DC posts on the 30000 watt PowerJack inverter,,, but as you indicate they may be a lot  cheaper one....than you are buying...

I have never noticed any problems with the DC posts on the PowerJack LF inverters,,,,but there may be some???

Just always wondered why there were 2 positive and 2 negative DC posts for connection to the battery...

thanks for the reply...😎👍👍

DC battery connection posts on large wattage LF inverters????

there would be a lot more amps going through a 12 volt one vs a 24 volt one vs the 48 volt DC post....the 48 volt DC post would have the lower amperage draw so correct me if I misunderstand but the 48-volt version would not need as beefy of a DC battery connection post as would a 12 volt one pulling the same amount of power ???? (volts x amps = watts)

but thicker is better>>>less resistance>>>less heat....increase the electrical transfer efficiency....

I can picture the thicker copper wire having less resistance than the same size aluminum wire.... so thicker aluminum wire  is required there...this why the diameter of the windings of enamel coated aluminum along with the number of strands is important as it takes more aluminum to do the same as the copper wire or a copper busbar can do....

example:  say they were a pulling the same 5000 watts with the same but different jumpers within the respective inverters...

thanks as always for the replies....😎

they indicate about 90 percent overall efficiency in the cheap LF inverters....but I do not know...🤔

34 minutes ago, pilgrimvalley said:

so then essentially every time the PowerJack inverter is shut off, it would likely need a pre-charge to the inverter capacitors to be safe and nice to them.... never had anything blow up yet with the PowerJack LF inverters but needed to know the best practice... 

Battery connections, ideally.  Main power switch, no.

19 minutes ago, pilgrimvalley said:

 I could replace wire with better quality higher AWG copper wires for a small expense,,,, that would be easy to upgrade with a small bit of time & effort.

I probably would not go to the effort to bend and fit solid copper busbars inside the 30000 watt PowerJack control board case,,,,that would take too much time for me at the moment! 🤔

not sure about the quality of the DC posts on the 30000 watt PowerJack inverter,,, but as you indicate they may be a lot  cheaper one....than you are buying...

I have never noticed any problems with the DC posts on the PowerJack LF inverters,,,,but there may be some???

None of these things are worth the time/money as far as upgrading a PJ.  The busbar serves a specific purpose on the GS inverters, but would be a complete waste of time and money in a PJ--the wires they use are OK.

DC posts on the PJ are the cheapest on the market.  But it's not like there is anything wrong with that.  I just want something a bit fancier/better.

21 minutes ago, pilgrimvalley said:

Just always wondered why there were 2 positive and 2 negative DC posts for connection to the battery...

Copying other companies' inverters.  Reasoning being that for higher amperage, it would help reduce resistance if there were 2 sets of input wires. 

In theory, it's noble.  In the actual practice...it's questionable at best.

23 minutes ago, pilgrimvalley said:

yes, I have had vendors of busbars not be able to say they were rated at 48 volts...so I think there are quality issues with some chinesium products and their copies.

Busbars won't have a voltage rating unless there's insulation to be concerned with.  Voltage rating on wires is determined by the insulation on the wire, not the wire itself.

6 minutes ago, pilgrimvalley said:

they indicate about 90 percent overall efficiency in the cheap LF inverters....but I do not know..

PJ specifications mean nothing.  You should know that by now 😉.

1 hour ago, Sid Genetry Solar said:

Busbars won't have a voltage rating unless there's insulation to be concerned with.  Voltage rating on wires is determined by the insulation on the wire, not the wire itself.

i think it was when i was buying a busbar with multiple connection points that was attached to a plastic base where they did not know if it was ok for 48-volts but that may have been the vender not knowing..

<img alt="Blue Sea Systems 100 Amp Mini BusBar" data-ratio="57.23" width="166" data-src=" https://encrypted-tbn3.gstatic.com/shopping?q=tbn:ANd9GcSatO96g3Q1AxqWeYFSwglL8ShKbCoQ95O9vzZysXmmIVTD-WT6k6pZWUEgqK8f&usqp=CAc" src="/applications/core/interface/js/spacer.png" />

so I bought 1/4 x 7 inch x about 1.5 inch busbars with separate insulators and separate Stainless steel bolt down brackets so that part is ok with the busbars to attach many things... I also bought some 4 inch x 12 inch x 3/8 inch tinned copper busbar to make a bigger battery....in the future...

busbars and wire have ampacity ratings so it requires a thicker wire or a thicker busbar to carry more amps..., but for some reason that particular vendor would not sell the busbar mounted in a plastic base for 48 volts as it was only rated for up to 24-volts...

and aluminum requires a lot thicker material than copper for the same ampacity,,, but copper is more expensive....copper kind of doubled and tripled in price from just a few years back...🤔

thanks for the reply.... still trying to understand their reasoning better....

better wire insulation is its ability to withstand higher temperatures ..... i understand that part........thanks for your replies..😎👍

I tend to use the thicker wire of higher ampacity...

the problem always arises as to the different lugs ends that do not fit so have to buy other lugs for some vs others... absolutely no uniformity....metric vs standard >>> 2 sets of tools...

have a great day...

Higher temps is only part of it.  The wire insulation also has to prevent arcing--and THIS is what gives a wire/conductor a voltage rating.  If the voltage is too high, electricity will just arc right through the insulation.

 I also bought some 4 inch x 12 inch x 3/8 inch tinned copper busbar to make a bigger battery....in the future

That  look like a  copper plate that you will cut into strip .     I  buy a 10 foot i/2 inch copper water  pipe  from home depot  and  flatten  with a hammer  and  bend  and drill holes  for all my busbar  and a lot cheaper .  
 

so then essentially every time the PowerJack inverter is shut off, it would likely need a pre-charge to the inverter capacitors to be safe and nice to them.... never had anything blow up yet with the PowerJack LF inverters but needed to know the best practice... 

Battery connections, ideally.  Main power switch, no

Since your inverter is  connected to the battery  24/7  nothing will blow up .     Pre-charge  mean  connecting  your  negative awg 4/0  cable   from battery to PJ inverter  input negative  and  NOT  connect the  red 4/0 pos cable  until  you pre-charge by  touching a  resistor 50watt  8 ohm between the battery positive and the positive input of the PJ inverter for one second  and  maybe a little spark .   Now remove the resistor and  connect the big 4/0  positve cable  and  then  you can turn on  PJ  switch  or main power switch  as many time as you want    but if you ever  disconnect  either  4/0  cable  then need to pre-charge  again .    All ev car has  automatic  pre-charge  when the ignition is turn  on  and to not damage  all the  electonics and computer in the  car  .     I  watch Sean old youtube  where he think  it was funny to see the sparks fly and a  bang like a shotgun  and  then he  did it again and again and  it was it  was a funny video  .  

A  picture of my  pre-charge  resistor and alligator  clip .     

An appropriate voltage and wattage (watts will determine amps which sets how fast the capacitors charge up) incandescent light bulb can also be used to precharge the inverter and it gives a handy visualisation too, ie when it goes dim / out you are OK to turn on the breaker.