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Author Topic: PowerJack LF Inverters - AC Coupling out of the box!  (Read 7157 times)
eabadger
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« Reply #30 on: April 29, 2017, 07:53:50 AM »

or that joint wasn't tight, causes heat which just gets worse and worse.
on these lower price inverters, i always used to do all the visible joints up, and tweak the fet clamps

steve
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1600w PV main array at 24v, excide 2v 1000a forklift cells now x 2, 320w PV secondary array at 12v. Enfield 1944 ex RAF 5.6kw diesel genset (now in pieces, big ends gone), Petter AC1 28v diesel charging set at 2.8kw.
1kw wind turbine.
26kw wood stove back boiler to underfloor heating and dhw
Scruff
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« Reply #31 on: April 29, 2017, 10:17:11 AM »

The green on the copper strands looks like entropy more than heat....maybe it's melted yellow insulation staining though.
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biff
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« Reply #32 on: April 29, 2017, 10:37:36 AM »

If you know what to look for,
                         Power Jack can be a good enough buy, Some lecky wizards buy these inverters from Old Jack Chang and then rebuild them properly because they say that the parts alone are worth 4 times the price of the inverters, however, in saying that, you do not know what you are getting until you open it.
It seems that they just stick in anything that is available off the supply shelves, so 5wk one might only have the max of 2.5 continuous, So it is a lucky or unlucky dip.
 There are at least 4 different videos of punters stripping these down and mocking their construction but they all agree that they had one thing in common, they were dirt cheap.
There could be really good parts in there but the whole lot was compromised by a few tiny stupid details that could have been easy corrected.
  Their control boards are supposed to be second to none and one guy was buying control boards direct for $40,00 a pot in bulk. The same guy is highly credible and very much respected.
So If you know what to look for and know how to put it right before you use it,,,,,,,,,,,Just like the bearings on my Y/S wind turbines,,open it up correct the silly fault and you have a good one.
                                                                Biff
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Nickel2
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« Reply #33 on: April 29, 2017, 10:52:34 AM »

There are many things from China that would work well if they were built properly. My workshop band-saw was cheap at 110, but soon showed it's flaws. Once the faults were found, the bullet was bitten, it was taken apart and re-engineered. Clamp-brackets at 87 degrees were machined to 90 degrees, holes plugged and bored straight, hinges aligned so that the arm comes down vertically. It's still good and doing it's job after 35 years. My pillar drill had the same treatment. If China ever raises the quality of it's builds and keeps the prices low, the rest of the world will go bust. If I buy anything Chinese, I take it apart and do a thorough final inspection before use.
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EpEver 4210A at 24v
24V 400 Ah battery. (4x200Ah FLA)
EpEver STI1000-24-230 pure sine inverter
Of course it'll work. (It hasn't caught fire yet).
eabadger
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« Reply #34 on: April 29, 2017, 11:56:53 AM »

not sure it is always their fault, i think the resellers and maybe us the buyers drive down the price?
i lost patience with chinese things as if they spent an extra 1% on most goods it would be brilliant.
i think the inverter above could have failed due to loose connection heat build up and then more loose connection with then a possible condensation or something else causing the verdigris.
are the fets ok after that? if you add the cost of them all up fixing doesnt become a viable option most times.
my iphone charger, genuine one made in china, poorly insulated and design cable made the charger overheat and cook, so maybe cost isnt the issue?
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1600w PV main array at 24v, excide 2v 1000a forklift cells now x 2, 320w PV secondary array at 12v. Enfield 1944 ex RAF 5.6kw diesel genset (now in pieces, big ends gone), Petter AC1 28v diesel charging set at 2.8kw.
1kw wind turbine.
26kw wood stove back boiler to underfloor heating and dhw
Scruff
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« Reply #35 on: April 29, 2017, 09:10:34 PM »

Apple neglect thermal management as a matter of course. It's good for business when the life expectancy of their products is a coupla years.

FFF probably worth cutting out the krusty cable and replacing it. If yer lucky it's just the resistance of the burnt one acting as an electron embargo.
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Tinbum
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« Reply #36 on: April 29, 2017, 10:28:25 PM »

On the 'good' one it looks as if the heat shrink is too long and trapped under the connection. Cry
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fourfootfarm
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« Reply #37 on: April 30, 2017, 10:24:05 AM »

Hi All,

Scruff, I tested it with some wholly inappropriate jumper wire and when it boots up no alarms and showing a healthy 230v rather than the 0 it had on the display before.. Will strip it back to the torroid connections and rewire with some tri-rated or similar. I'll see look what I've got lying around that can take the heat and I can squeeze through that ferrite ring.

My money is on loose connection too. Even taking into account that the connection would have eroded away, there was rather too much wiggle. It doesn't get much hard use so its probably been soldiering along for ages in that condition. Which would explain the lovely green hue too. It kicked the bucket when trying to start a table saw.

re: quality and price its a bit of column a and a bit of column b. We the dastardly consumer demand cheaper and cheaper products so the manufacturers have to squeeze more and more to make the margin. Its an ever downward spiral.

Been a bit busy so not tested the FETs yet. But if they're blown I might salvage salvage the torroid from this machine and add it to the other one I have. Might even get the full rating then! This one is nominally 5kw and I've had that out of it for about 10 seconds before it got too warm. The silicon can do the rating but torroid gets too warm. The other one is 7kw and will manage 4kw continuous mix of resistive and inductive loads. I ran out of things to turn on but it managed that for about 10 minutes quite happily.

Tinbum, you're right it does a little. I will unscrew it and cut the offending bit of heatshrink off.
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Outback FM60. EPsolar 30a MPPT and a bunch of Tristar 45's. Hodge Podge of solar ~ 4500w. Various generators and 1000ah 24v forklift battery.

Turkish Turnip
Scruff
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« Reply #38 on: April 30, 2017, 01:46:17 PM »

Happy Days,

I'd opt for tri-rated panel wire or flex in a silicone jacket much easier work in a tight space.

Yurp probably a loose connection, the heat cycles wouldov accelerated the oxidation.
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jonesy
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« Reply #39 on: April 30, 2017, 03:46:50 PM »

The other connection looks crimped.  If it had been soldered, they probably used a good dollop of flux as it's quicker than cleaning the cable.  That will lead to verdigris if not taken right off, or cross contamination?
I've heard of acid dip to de-oxidise cables prior to crimp. Acid burns if you lick it  Shocked
Make sure you clean the crud off the underside of that PCB just above the lug - bits of grot on the insulating paper.
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fourfootfarm
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« Reply #40 on: May 01, 2017, 05:40:00 PM »

I've got some rattle cans PCB cleaner and conformal coating on their way, will give the whole lot a going over before putting it back in service, then dismantle the other one and treat it to the same.

Tri-rated sees like the best idea, its just such a pig to crimp. Might have to invest in some of those bootlace things too. I have got some 70mm stuff lying around but not sure if I would get it round the ferrite, its very thin stranded but the sheer size of the stuff is an impediment.
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Outback FM60. EPsolar 30a MPPT and a bunch of Tristar 45's. Hodge Podge of solar ~ 4500w. Various generators and 1000ah 24v forklift battery.

Turkish Turnip
Scruff
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« Reply #41 on: May 01, 2017, 08:31:17 PM »

Conformal coating is a double edged sword. Increased reliability and horrendous serviceability. Unless you're fitting the inverters in a hostile environment I'd leave it be.

Silicone jacketed cable is super flexible.

Marine is high flex too but you're paying premium for tinned strands.
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fourfootfarm
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« Reply #42 on: May 01, 2017, 09:37:19 PM »

I think you're right on the conformal coat. The farm is about as far away from the sea as its possible to get in the UK so it's maybe uneccessary. I do remember reading that the older models use a ladder of very high rated resistors to measure AC volts, and that any moisture on them will affect the accuracy of the readings. I'm parroting now rather than working from actual results though.

I'll do some further dismantling and see if I can see the offending articles and might give them a bit of dab. The dump loads keep the power shed pretty toasty and condensation free anyway.
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Outback FM60. EPsolar 30a MPPT and a bunch of Tristar 45's. Hodge Podge of solar ~ 4500w. Various generators and 1000ah 24v forklift battery.

Turkish Turnip
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