Pre-Order Discussions

February 11, 2023:

Just in from the new transformer company:

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They matched the line drawings and specs pretty much perfectly.

Yes, I do notice that the hole looks a bit off-center; this would have to do with the winding of the 36/60v tap across the back, but not the front.  (Which the two main primaries don't wind over the front anyway.)  Not a problem.

https://www.copper.org/applications/electrical/busbar/bus_table1.html

here is a copper bar ampacity table which can be useful to you...

the toroid transformer picture is looking promising for the gs 48-volt inverter....

That looks like the bracket should fid now

A reason I decided to move up to the 12K

Side note the 6K has been running well at about max load

3 hours ago, Steve said:

Side note the 6K has been running well at about max load

We've got multiple customers literally holding them at redline all the time.

3 hours ago, Steve said:

A reason I decided to move up to the 12K

 

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Because your battery is low?  🤪

February 17, 2023:

• FINALLY beginning to make some progress.  It's difficult to have to reinvent yourself due to unexpected circumstances.  Painful, yes.  Worth it....in the long run, absolutely.  It truly would have been nice if the previous factory would have produced the inverters as promised and expected--this saga would long have been over.  But we're plodding forwards.
• Transformer spec/design has been confirmed, and the full order is ready for payment as I write this.
• Getting fasteners (all the nuts & bolts) all sorted out and quoted from a manufacturer right now; I'm expecting to have a resultant quote tomorrow.
• Started the ball rolling on main inverter filter capacitors made to our specifications by a dedicated capacitor manufacturer.  "Trading companies" can't provide datasheets--and they most certainly can't guarantee quality.  We're working with an actual manufacturer that can literally print the Genetry Solar logo on the side of the caps (pretty high MOQ though, so we won't be doing that at least for a little bit!
• I will be getting orders ready for the following items shortly:
  • cooling fans
  • busbars
  • miscellaneous parts and items (ferrites, terminals, connectors, etc.)

14 hours ago, Sid Genetry Solar said:

• Started the ball rolling on main inverter filter capacitors made to our specifications by a dedicated capacitor manufacturer.  "Trading companies" can't provide datasheets--and they most certainly can't guarantee quality.  We're working with an actual manufacturer that can literally print the Genetry Solar logo on the side of the caps (pretty high MOQ though, so we won't be doing that at least for a little bit!

That's interesting.  Why do you need custom capacitors?

24 minutes ago, JIT said:

That's interesting.  Why do you need custom capacitors?

Ideally, we wouldn't need custom caps--as this is a "standard" size (i.e. 10, 22, 27, 33, 47, 68, etc.)  However, it seems quite difficult to find 22,000uF 80v electrolytic capacitors with a ripple current rating >7A. 

The ones currently used in our prototype inverters were "old stock" from Mouser (and no longer produced).  Funnily enough, despite being official U.S. Chemicon caps purchased from an accredited distributor, the official datasheet does not list 22,000uF 80v caps in their spec tables.  (Seems to be all-too-common unfortunately.)

I've checked Chinese "trading companies" but none of them can provide a datasheet--indicating inferior / relabeled / counterfeit / junk quality.  We can easily find physically smaller (and cheaper!) capacitors rated 22,000uF 80v--but their ripple current will be closer to 3A: less than half of the AC filtration capability.  Especially considering that most capacitors are only rated for a 2,000 hour life, it's important to get the base specs up high for a long life expectancy.

Most inverters use the cheapest junk they can find "as long as it does not blow up immediately."  (I'm thinking of that Magnum inverter I dug into...using tiny cigar-sized 63v caps, but boasting a 68v maximum DC input voltage!)  But that's not what we're willing to settle for at Genetry Solar.  I've probably grossly oversized the caps--but that's because we don't want the caps to be a failure point.

I happened across an actual capacitor manufacturing company (an actual manufacturer, not a trading company) in my searches on Alibaba...and they quoted a decent price to manufacture.  The reason it's "custom" is because they have not made this size of capacitor before.  (This capacitor company actually sells capacitors on LCSC.com, so they're not a toy trading company.)  They will be able to provide a test datasheet of the capacitors after production...even if the big caps will have a sky-blue wrapper instead of a more "formal" purple, black or brown 😉.

Worth noting that these filter caps do not "improve surge ability" in the inverters, as commonly assumed.  They're there to try to absorb the inductive "kicks" from the battery cables (resulting from the SPWM switching methodology.)  They don't store enough energy to maintain the battery voltage for even a fraction of a single AC wave at full load.

Previous job we ran into some discontinued caps and found the original mfg was willing to sell them only as complete batches with lead time (Mallory if I recall correctly)

1 hour ago, Steve said:

Previous job we ran into some discontinued caps and found the original mfg was willing to sell them only as complete batches with lead time (Mallory if I recall correctly)

There's no point in us trying to source parts from a U.S. supplier, because THIS is what you run into:

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FORTY-SIX WEEKS lead time.  For a capacitor!

Oh, and our start order is going to be at least 150pcs.

I'm expecting a lead time of TWO weeks from this Chinese manufacturer.

February 18, 2023:

• I'm considering some minor spec changes to improve our inverters still further....
• Up to this point, we've used black ABS plastic connectors for the AC Output block.  (Which have been a huge upgrade over the connectors used on the very first production run.  And way better than the cheapo flexible ones that are all over the place.  I purchased some of those some time back, and they were garbage.  Cross-threaded and/or stripped-out screws...)
  <img class="ipsImage ipsImage_thumbnailed" data-fileid="2162" data-ratio="56.01" width="416" alt="conn1.jpg.bbc5d4ce29946a739bddd8c19ef7182b.jpg" data-src="/monthly_2023_02/conn1.jpg.bbc5d4ce29946a739bddd8c19ef7182b.jpg" src="/applications/core/interface/js/spacer.png" />
  • there's a problem with them: they only come up to 60A.  And I don't want to use a 60A terminal block on the 12kw inverter (despite it being only 50A continuous max).
  • We've found an 80A option that was a custom production run from a particular supplier.  But it has a major problem: the contacts tend to split when you tighten them down on a wire.  Between Sean and I, we've broken 2 of the 3 connectors we have.  Which doesn't exactly give us confidence that customers will fare any better....
    <img class="ipsImage ipsImage_thumbnailed" data-fileid="2163" data-ratio="153.22" width="342" alt="conn2.jpg.973db44a0717cbd2d939fc893bf9c39d.jpg" data-src="/monthly_2023_02/conn2.jpg.973db44a0717cbd2d939fc893bf9c39d.jpg" src="/applications/core/interface/js/spacer.png" />
  • once the brass insert breaks, the next step is pulverizing the plastic housing (done THAT too).  It's clear that the brass insert breaks due to the hole being too big through the center of the contact...but that's the only way to allow bigger wire gauges.  But bigger wire gauges require more pressure to secure...and the weakened metal...yeah, you can see where that goes...
     
• A few days back, I found these style terminal blocks.  They look considerably stronger:
  <img class="ipsImage ipsImage_thumbnailed" data-fileid="2164" data-ratio="50.23" width="880" alt="conn3.jpg.b2ad87081e264ff24a9bc4946faba079.jpg" data-src="/monthly_2023_02/conn3.jpg.b2ad87081e264ff24a9bc4946faba079.jpg" src="/applications/core/interface/js/spacer.png" />
  • this connector even has ribbing on the wire-gripping metal, so the wire won't slide out...
  • The only issue is that I can't seem to find these on eBay or Amazon for quick shipping to check one out in person/by hand.  But they sure look better--and are available in both 60A and 80A sizes.
  • they're about the same dimensions as the black ones.  I only need to adjust some case hole locations--and that's it.
• Sean wants rounded Allen-head screws for holding the case together. 
  • Can't say I relish the idea of "harder to field service" by not using Philips-head screws, but....whatever.

the hex head bolts work the best,,,,

screws tend to strip 

allen-head key screws will also tend to strip out....as do many allen head wrenches....

large connectors in quality breaker boxes have the main lug connection tighten down with large hex keys for high amperage connections

torx screws are good for construction as they do not cam out and strip as easily,,,, not sure if you could utilize that style of screw in a machine threaded version....

a hex head machine bolt for the case would still be the best simplest solution...for the case assembly

IMO

I use high amperage dinkle connector on din rails similar to your picture above so they are likely made with a bolt down version for the AC output.... I do not have any sources as I am not searching for that type of connector....

dinkle is a brand name but once you se them you will find the copy cat ones in other brands,,,,

dinkle is distributed out of Florida in the USA...

if the right type of screw driver is used in the above connector (pictured in Sid'd reply above) that fits the screw correctly at the proper 90 degree angle they will not strip (as easily), but some people will not use the right screwdriver of course....and they will strip that type of screw...

I bought special bits made for electrical screws....$5 for 2 of the special bits specific for the electrical screws...I think....

On 2/18/2023 at 9:08 AM, Sid Genetry Solar said:

Ideally, we wouldn't need custom caps--as this is a "standard" size (i.e. 10, 22, 27, 33, 47, 68, etc.)  However, it seems quite difficult to find 22,000uF 80v electrolytic capacitors with a ripple current rating >7A. 

The ones currently used in our prototype inverters were "old stock" from Mouser (and no longer produced).  Funnily enough, despite being official U.S. Chemicon caps purchased from an accredited distributor, the official datasheet does not list 22,000uF 80v caps in their spec tables.  (Seems to be all-too-common unfortunately.)

So, basically you are doing it for space reasons?  Otherwise, you should able to use multiple caps to get what you need.  Multiple caps has the benefits of lower ESR/ESL as well.  It just seems like adding supply chain risk with a single sourced custom caps.

I use high amperage dinkle connector on din rails similar to your picture above so they are likely made with a bolt down version for the AC output.

 This connector works good for my Powerjack .