How I got a Large wire size to fit on the + POS battery out terminal !!

[CDN-VT]

90 amps max needs a better system I thought & the PV in is much higher Voltage so less amps & wire size is normally from the combiner (that in my mind should be close to the classic as to string watt drop checks ).

I'll type it out and paste it when it's done , than add pix , I wasted time on this forum  software already today.
It will come in bits .


My Classic has Imperial thread on the four terminals for PV in & out & Battery IN & OUT . It’s the + POS battery out that is my issue of having a wire size that won’t get hot or warm. Area is tight for larger wire that will not offer a voltage drop .
So my Classic is both metric & Imperial sizing of threads . For the Metric world I’ll include the sizes ,For the backwards or mixed up places (Like Canada [apples 4.99/lb but the till is 260/kg]) I’ll make sure all sizes are in both formats. My classics are 2015 vintage & I did 3 so I can have NO voltage drops or warm.

Pinch screw (remember on MINE were ¼-28 ) That is one quarter inch and 28 threads per inch Unified National Fine , the hole size for the wire is drill size #2 = .221 as # 1 Drill offers .228  inches  and .007 larger hole with less thread flanks .

This thread is very close to M7x1.00 mm  SI (System International )  but the M7 is loose in a ¼-28 nut , So it will give you only metric folks  a clue .. I’ll post a few links so our 10X10 metric folk can understand the madness . 7X1.00 mm works as well metric , but the tap into the terminal only gives 10% crown thread bite while a # 2 gives 75% thread crown(top of male thread) and a #1 drill hole gives 40% of thread bite .

My pos terminal is bore size for the wire & 2 drill or .221” and I can tap it with a Butterfield  tap & a bottoming tap so I get 75% thread bite In the terminal on ¼-28UNF .

Now the bolt I used had 1” /25mm of grip (unthreaded area under the head) , I used a die & smashed in a crude thread , since it’s only used to hold the spacer / transfer collar (just so the bolt by itself wont get warm @ 90 amps.)


I then got a dowel of brass rod & made stand offs & machined them with holes of # 1 drill size due to it’s not needed to hold , but transfer & remain tight , wrench grip areas of 5/16-8mm & the ¼-28 thread  (7x1.00MM could work also) internal hole .


Now the LUGS are in wire size & bolt hole size  , ¼ is a standard in AME & 8mm is another in metric , but using Stainless steel washers also helps the transfer & as with chemical Stabilant -22 .


I  Insulated with rubber fuel line of 8mm-5/16 and cut it so It can flip over the top & be tie rapped  up to lessen the bump factor.


VT

Luckily I tried to post a pix & it killed the upload , but not the text .
Bill Gates wrote this forum software !

[CDN-VT]

On second try One Pix was killing the upload & wiping up posted text.
2016 & it's like a Win3.1

Compressing pix to be small was the problem ,most forums use compression software to auto-correct the upload.

So Im sure with pictures , it should be under stood .
The pinch screw is snug but not crushing the threads , it's the bolt & brass threaded spacer will make the connection tight.

VT

[ralph day]

I kept reading POS as piece of something...not positive.  Gahhkk.  Can't be lack of caffeine, I lack it all the time.

Hey Nige, any one getting any use out of my old Xantrex 4048 yet?

Ralph

[CDN-VT]

Yes , It's on the Back of Elly :
http://kb1uas.com/mnsforum/index.php?topic=3142.0
VT

[boB]

Well, I guess that is ONE way to skin the cat !



boB

[australsolarier]

hey, connecting the thick wire in the midnite classic looks very nice.
the way i connected a 50mm2 wire:
from the 50mm2 down to 35mm2 wire with a compression fitting. i used a half inch copper tube. the 50mm2 fitted in nicely, the 35mm2 needed some short bits of wires to fill in. then used the hydraulic pliers for lugs to clamp it together. the 35mm2 has a bend in it.
to fit the 35mm2 wire into those ridiculously small holes i had to pinch off  half the strands from the 35mm2 wire.


concerning the heat created in the wire at 96 ampere:
i found most of the heat was from the cheap china dc breaker. the heat conducted out the wires for quite a long way. i changed  that to a  dual pole non polarized breaker, 63amperes, so total 126 amps paralleled up. it still gets a bit warm. but nothing like 54 degrees celsius like with the old breaker.

non polarized breakers are compulsory here in australia now (i suppose new zealand as well). one of the reasons was many solar installer connected them the wrong way round. also in multi string installation, each string needs their own breaker. so if you have a short in one of the strings, the currents from all the other strings will flow into the faulty string, triggering the dc breaker, but with the current flowing in the wrong direction . you then have a possible fire. i do not agree with all the australian solar regulations, but the non polarized breakers make sense.

[CDN-VT]

So I walked in today hearing fans running at MAX & a yellow LED bottom left side on & off for a bit & then back on !!

OK Crap , im digging in 1k feet of 6" ditch pipe & i'm still in the dirt , shedding dirt & sand as i go , don't touch squat , the SUN just came out from behind the storm clouds.
Quick strip off & wash me as quick so im not leaving brown dirt/sand all over (outside pool heated wash) grab a robe & then go see what this yellow led is all about !!
96 amps it's on !! WOW !!

SO to check my temps & joints etc. ALL were cool & tight !!!

96 AMPS & im liking the fan noise , from all the units .
Can't wait to have the classic & it's 3 in follow me up next year !!!

VT 

[sigp2101]

I strongly suggest replacing those SS washers with copper washers which have way less electrical resistance then SS.
Or at least eliminate bottom washer entirely to ensure direct contact of brass extension with plated cable lug.

[australsolarier]

sigp2101,
could you do a calculation what the difference in the losses of the ss washer and the copper washer would be, say at 90 A?
just out of curiosity.
greetings urs

[CDN-VT]

I strongly suggest replacing those SS washers with copper washers which have way less electrical resistance then SS.
Or at least eliminate bottom washer entirely one to ensure direct contact of brass extension with plated cable lug.

You have made a VERY GOOD point & I already had , It has two thick copper washers (crushing the crimp lug )with a smaller ss washer now on the bolt head , I dropped the small SS "fender" wasters in lieu of that problem .
Trying to find stuff you really need in Kanada , & on a .GOV island is a pain. Many items I need to make or buy tools to make .


Good spot sigp
VT

Edit add :
I never took any more pix or time on this thread etc & kinda thought it was swept under.

So to find & treat copper (squish / crush factor ), first all you will ever find is soft copper , , so re torques is a MUST . ( I pre abuse torque & wack it once so it compresses while it's easy) . I also tin the copper after the crushing / torquing as Im ready  to install for the LAST time .. Brass or bronze (better)  is out there also BUT hard for me in stores that are trained in NO or They never made those !!  Glad im OLD & KNOW !!


I didn't take any pix of the tinned units , but I have a unit I will be repairing & fixing burnt wiring  in a few weeks , I fixed the classic , but don't trust the rest from pictures (3 islands away job , sailboat time) , i'll take pix.

Here is the un-tinned copper as i change up into . I'll get a shot when I open up for filter fan cleaning , had a woodpecker making dust  last month . !!!


VT