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the gs went from the 6 plus fan hype wifi board to 2 fans to cool the toroid, and extra windings on the choke was supposed to help, but that was in Sean's YouTube video of old... the extra jet engine noisy fans were not practical in use or expense...evidently .
That is what I thought 3 years ago so I put 7 Delta fans on my PJ 15kw and found the transformer still overheat in one hour running a 4 ton heat pump at temperature of 120 degree F . The inverter suppose be in a room with 72 deress F temperature . A test of the Sandi 20 kw show a 10 to 20 percent drop in output for every 10 degree temperature increase . At 100 degree the Sandi 20kw output will drop 30 percent and 6 kw due to heat so now it is a 14kw inverter with copper windings . A GS 12kw with aluminum windings at an impossible 120 degree F will drop 50 percent at least and 6 kw due to heat so now it is a 6 kw inverter . Only need 2 Delta fans as one blowing at the transformer and one blowing at the FETs . I can run at night with 2 fans and less noise .
it seems to say they have no manufacturing knowledge and very poor quality control....after some 12 years of selling powerjack inverters...?
I hope PJ buy a machine that can crimp 10 wires and not come loose and cause a fire inside the 12kw inverter . When my PJ AWG 0 cable crimp came loose the inverter shut down because the voltage drop . I shut that AC breaker and the DC breaker but the fire is still there and starting to spread and I did not know why . I put the fire out with a fire extinguisher and the wire insulation must be made of low temperture plastic . No more PJ parts for me .
the competition's LF inverter with copper wound iron-core transformers don't require as much cooling as the aluminum wound transformers to prevent the saturation and overheating problems. that is why they (the LF inverter competitors)use copper windings...along with the ease of assembly that Sid talks of routinely...
The material of the windings (copper or aluminum) makes zero difference for "saturation" (which BTW I have never experienced in any inverter tests). The ONLY practical differences between the 2 materials are the following:
- electrical resistance
- weight
- cost
If you scaled the wire sizes appropriately for the different metal resistances, and manufactured a copper-wound and an aluminum-wound transformer to the same specifications...you will find no functional difference. (There will be significant cost and weight differences, however.)
The surge capacity is not determined by the transformer. More often than not, the true surge capacity limitation is the maximum amperage of the FETs...before they say bye-bye and go up in smoke.
(The one exception I'm aware of is the GS 6kw inverter, where the transformer's DC resistance DOES limit the maximum wattage simply by a result of voltage drop. But that's at 600A DC * 48v = 28kw, which is almost 5x the continuous rating. Betcha you won't find a 'copper-wound' inverter with more than a 3x surge rating!)
A GS 12kw with aluminum windings at an impossible 120 degree F will drop 50 percent at least and 6 kw due to heat so now it is a 6 kw inverter .
50% losses is impossible. There is no way any sizable inverter can dissipate that much heat.
What DOES happen is that the finite "maximum" temperature (180F in the GS inverters) does not change regardless of ambient temperature. And the higher the ambient temperature, the LESS headroom there is to dissipate waste heat--resulting in a reduced maximum load to avoid exceeding the max temperature limit.
At 100 degree the Sandi 20kw output will drop 30 percent and 6 kw due to heat so now it is a 14kw inverter with copper windings
So no, that's not how it works. Copper or aluminum, that's simply not how transformers work.
If at 100 degrees Fahrenheit, the Sandi is rated at 14kw continuous output, you will NOT have 6kw of losses. (That's one quick way to literally melt down the entire system.) Again, what happens is that the less temperature headroom the inverter has (i.e. max temp - ambient temp), the SMALLER the allowable losses are. Since the losses are fairly fixed, the output power must also be limited in order to limit losses and continue operation.
In other words, if at 100F you try to push more than 14kw through the Sandi, it'll overheat and shut down. But there is absolutely no way you will ever get 6kw of losses out of the Sandi. (Or any other inverter of similar size, for that matter, REGARDLESS of whether it's wound with copper or aluminum.)
the gs went from the 6 plus fan hype wifi board to 2 fans to cool the toroid, and extra windings on the choke was supposed to help, but that was in Sean's YouTube video of old... the extra jet engine noisy fans were not practical in use or expense...evidently
OK, OK, OK...we started out trying to improve PJ inverters. They happened to have spots for 6 fans in their big chassis of the time, and Sean thought "the more fans the better." But testing eventually proved that more fans didn't help.
After we started specifying our own transformers, we found that huge numbers of fans were completely unnecessary--and like I said, not helpful at all. We're using a smaller number of fans simply because "more" aren't needed nor are they helpful.
18000 divided by 53 volts = 339 amps....
Sean video today said his proto type gs12k was doing 18000 watts so it was definitely pulling more than 339 amps out of the pouch cell battery....and the breaker or safe fuse size would need to be 1.25 times the amp draw to prevent a fire....
to do 18000 it was likely pulling close to 20000 watts from the battery (I did not calculate that part)
20000 divided by 53 volts = 377.36 amp then times that by 1.25 for proper DC fuse or dc breaker would be 377.36 times 1.25 = 471.70 rated DC circuit breaker or an big Axx class T fuse to prevent a fire and also a lot larger than a 4/0 copper cable....between the inverter and the battery....
a 500 amp class T fuse is the next size up in DC fuse holders and a lot more expensive as will be a 500 amp DC rated breaker...
it would be best to recalculate the DC rated breaker and or DC rated fuses to prevent a fire....
trying to prevent the mosfets from overload, but the weak point will be the wire and fuse or DC breaker between the inverter and the pouch cell battery he uses...
the large copper wound transformers(18K Sigineer for example) I seen use a flat enamel coated winding not exactly an enamel coated wire as the aluminum wound toroids powerjack produces.......the transformer is not an apples to apples comparison but those designs use only one fan to cool the e-type transformer that is copper wound...
the high voltage Sandi inverter mikeg showed in his YouTube video was almost a one to one and hardly a step up transformer at all.....
It just caught my attention the claimed continuous 18000watt output at 53 volts????of the prototype gs12k....
heat is the enemy for sure... at high amps🤔
In other words, if at 100F you try to push more than 14kw through the Sandi, it'll overheat and shut down. But there is absolutely no way you will ever get 6kw of losses out of the Sandi. (Or any other inverter of similar size, for that matter, REGARDLESS of whether it's wound with copper or aluminum.)
Sorry I should not say heat loss . The Sandi 20kw transformer reach the shut down of 170 degree probably at 14kw load at 100 degree F . The GS 12kw will shut down at 120 degree F running 12kw load for maybe 1/2 hour but not continuous . From the youtube it look like the GS 12 kw can run continuous with 12kw load at 100 degree F.
1 hour ago, pilgrimvalley said:It just caught my attention the claimed continuous 18000watt output at 53 volts????of the prototype gs12k....
That was not a continuous output claim. Sean simply noted that the output had reached 18kw...for a few seconds.
The inverter has been tested to do 12kw continuous without overheating at ambients around 80F. We have not tested it at higher temps yet.
super robkar 12000 watt amg powerjack commentor utilize a different approach to increase/tame surge output vs a choke below: a long 12awg extension cord acts as the choke essentially????
Sean simply noted that the output had reached 18kw...for a few seconds.
I just watch the youtube by Sean . 4/0 cable and 400 amp fuse should work if continuos limit is set at 16kw . Sean say 36kw for surge limit is good enough since the FETs is 40kw . I have whole house surge protection and extra surge outlet on heat pump and TV and garage opener and wifi router for double protection and it works . I seen days where there are continuous lightnings and little rain . The continous thunder sound like a war zone outside .
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That was not a continuous output claim. Sean simply noted that the output had reached 18kw...for a few seconds.
well it would be a definite concern to not allow it to run at that high of an output without large dc rated fuse and properly sized dc breakers which will cost a lot to install properly....if it would only do 12000 continuous then 4/0 may or may not be sufficient >>>>.but at 18k and shutting down due to battery sag,,,,what would happen if the pouch cell battery did not sag....???wires and small breakers overheat for inadequate sizing????
he (Sean) now always says he is not an electrician so installer be advised to do it safely....
what size inverter cables will be required for a 12k that can surge to 36k as Sean stated and you say briefly was doing over 18k?????
what about fuse and breaker size.....????? for the 12k
I am not an electrician....😢
he said it could surge to 36k....correct??? 🤔
16000 divided by 53 volts = 301.88 amps but would still have a pull from the battery of somewhere near
301 x 1.1 = 332.075 amps and so the dc protection would need to be 125 percent at least above 332 .075 amps or 415.09 amps...
a 400 amp class t fuse seems too small for 16000 watts???
4/0 Welding Cable carries 310 Amps for 600 volt in-line applications. 4/0 Welding Cable is an extremely flexible cable with pure fine stranded copper. It contains an abrasion-resistant rubber EPDM jacket.Apr 29, 2021
perhaps i should watch his youtube video again....
he said it could surge to 36k....correct?
Surge is less than one second . A well pump may take 5 seconds of surge . The fuse and breaker takes 8 seconds to trip and the wire takes 20 seconds to catch fire . Set the surge limit to 36kw is SAFE unless you buy PJ wires .
bet they don't include the powerjack inverter cables for liability issues.....too easy to make liability claim within the USA and GREEDY LAWYERS lurking everyplace. 🤣
I will have to see about DC breakers but I have been using 400 amp class T fuses with 4/0 copper cables on all my inverter to battery connections🤔🤔
bigger wire is better, but I have never bought or used any larger than 4/0 copper🤔
humid out today after the rain..😎
a 400 amp class t fuse seems too small for 16000 watts?? it would be best to recalculate the DC rated breaker and or DC rated fuses to prevent a fire....
A 400 amps fuse will blow for sure but may take 20 seconds and hopefully the inverter will already shut down . IF the fuse blow then 80 dollars gone but cable bigger than 4/0 cost too much . 4/0 Welding Cable carries 310 Amps for 600 volt in-line applications and that is not going to work . Two 4/0 welding cables in parallel is needed to be safe from fire .
Sean's useage of the word continuous in his YouTube video yesterday implies more than a second of surge at or around 18000 watts..... but sid says only a second or so,,,,which means a surge at which point the software shut down the inverter to protect the mosfets which are supposedly to be rated to 40k....
one can get 1000 volt 4/0 cable for about $10 per foot delivered....i am not sure it would safely handle the approximate 20000 watt draw from the batteries in any real amount of continuous draw.... a 1 second surge probably is not enough time for it (the copper cable) to heat up much...at 20 seconds or any real use at a real continuous load not likely to be big enough for the calculated amp draw >>>> 20000 divided by 53 volts equals 377.36 amps...
the NEC (national electric code) indicated the fuse or breakers should be sized at 125 percent of the load for safety...so a 377.36 amp load would need a (not larger than) 471.69 amp fuse or breaker that is rated at DC between the battery and the inverter...
the 400 amp class T fuses I have are rapid blow fuse so would likely blow before 20 seconds....
if it (the inverter) shuts down at 12000 watts then 12000 divided by 53 volts is only 226 amps but again it would take more like 12000 times 1.1 or 13200 watt draw from the battery to produce 12000 watts continuously out of the inverter; so then the 13200 divided by 53 volts equals 249 amps draw from the battery and 125 percent of 249 amps equals 311 amp fuse or dc breaker is the maximum size allowed by the NEC in the USA to prevent fire....
make me wonder if you would be restricted to a 387.5 amp class t fuse??? 310 amp rated 4/0 copper cable times 125 percent is 387.5 amps....it does get confusing....as to what would be code legal to prevent a fire????
if two 4/0 cables were used then a 400 amp fuse would need to be installed on each 4/0 cable....to be code legal....or would the fuse be required to slightly smaller???
altE site says 400 amp dc fuse for 185 amp draw using a 5500 watt 48 volt inverter with 4/0 copper inverter cables
you can use a smaller DC rated fuse/ DC rated breaker but then they may blow sooner to protect the 4/0 wire at less than 310 amps. the DC rated fuse or DC rated breaker is to protect the wire from overheating and starting a fire....that is my understanding...
I am not an electrician and only use my inverters off grid.....
very few places get into the NEC DC fuse or DC breaker requirements of inverter cables....need more study/research by me so please forgive any questioning safety thoughts in my ramblings....🤔🤔
but the again a non UL approved inverter will not likely pass an electrical inspection in most places in the USA...and may void your house insurance also???? better put it outside in a cement/steel fireproof enclosure...
have a great Monday and thanks in advance for your replies....
big dc rated breakers are very expensive but would likely be chump change to prevent a fire in one's living quarters....