diy solar

diy solar

Bad connections

Daddy Tanuki

Daddy Tanuki

Solar Wizard
Joined
May 11, 2021
Messages
2,491
Location
Flanks of Mount Fuji
So lo and behold enven the Magnificient Daddy Tanuki can have issues gather round younglings and learn.

So last week finished commissioning two new 400 aH banks to bring the total to 1300 aH or 70kWh depending upon your calculations. While wiring everything in I had to remove the cable from solar in breakers/bussbar to the main DC buss-bar. guess what Daddy missed while closing up? Yeah forgot to put on a ferrule on new wire and torque to spec….

So popped up again today (Saturday) (one week later) and was like why is my 70kWh bank at 75%??? Manually hit my solar controllers to go into equalization mode (turbo boost) and a couple of seconds later noticed smoke coming out of my midnight solar inverter mounting panel????


IMG_1948.jpegYes my precious… feed on the ring/dark side/muggles!!!! @sunshine_eggo (& Smurfs) and guess what I saw…. “Oh no, it’s the smoke!” Turns out I did not double check nor ferrule nor check torque on one of the replaced cables….

IMG_1949.jpegThank god I caught this bone headed mistake in time….
 
just glad it did no more than cook the wire a bit. that was a wire in a bussbar socket that was not tightened down at all. it just sat in the bussbar socket quietly arcing when it wanted and heating up the insulation. scary stuff! I saw that puff of smoke and smelled that unmistakable smell of arcing and damn near shit my britches.
 
Daddy Tanuki said:
If you new how closely i watch this stuff. this system is a cost avoidance measure for the future when i can no longer cut firewood nor pay exorbient electric bills.
Click to expand...
I wonder if it would be best if you loosen a connector that you pull the wire out as a visual reminder?

Did your smoke detector go off? Do you have another spare SCC?
 
Brucey said:
I wonder if it would be best if you loosen a connector that you pull the wire out as a visual reminder?

Did your smoke detector go off? Do you have another spare SCC?
Click to expand...
sadly no smoke detector yet... I know stupid answer... being in the shop i have been a bit negligent in so far as a smoke detector goes.

SCC that was the agregate total of three SCC's. I have two more as spares. Roughly 30 amps apiece I need to reset them as currently they are limiting total output of the arrays to 100 amp max as originally i was running them into one BMS for the original pack and it had a limit of 200 amp charge so I set the SCC's to send no more than 100.

no that I have the two new winston packs on line I need to let figure out a way to set its limit higher but still keep it at 100 amps per BMS (now three) the only time I ran them unfettered they maxed out at 150 amps so even though thats below the rating of the DALY bms's i want to look at that carefully before I make any rash decisions.

Edit: I did pull out the wire as I was replacing it with a thicker cable. I routed it cut it to length test fitted it again and then got interrupted and did not put the ferule on nor did i tighten either end.
 
<SIGH>

I should have picked up on this . . . Died two days ago I was returning from out of town, charging stopped working. This connection was a little loose. Was running the EV charger, 32A continuous. I really think you should re-torque screws after you run a few cycles. I found a couple other connections that were not very tight, a loose connection will heat. This melted the plastic that held the contact in the rotator. Not sure if it was from the inside or the outside connection heating. I have spares so it was just a 30min swap. Not sure what the U-shaped metal pieces are for that are encircling, but not touching the contact. EV charger kept reporting a ground problem from time to time. Exact same unit is running my primary panel / 100A, I see no indications of heating on it, temp gun shows no anomolies.

1710957160525.png



1710957615447.png
1710958553028.png
 
ksmithaz1 said:
<SIGH>

I should have picked up on this . . . Died two days ago I was returning from out of town, charging stopped working. This connection was a little loose. Was running the EV charger, 32A continuous. I really think you should re-torque screws after you run a few cycles. I found a couple other connections that were not very tight, a loose connection will heat. This melted the plastic that held the contact in the rotator. Not sure if it was from the inside or the outside connection heating. I have spares so it was just a 30min swap. Not sure what the U-shaped metal pieces are for that are encircling, but not touching the contact. EV charger kept reporting a ground problem from time to time. Exact same unit is running my primary panel / 100A, I see no indications of heating on it, temp gun shows no anomolies.
Click to expand...
I have one of those and have loaded it pretty good while watching it with a Flir camera, never warmed up at all. I found some crimp ring terminals that are a snug fit on 6AWG and used those to make connections.
 
I've never seen the guts of this, what is the purpose of the braided copper instead of just connecting the terminals to the circuit board directly?
 
Phoenix and other direct wire terminals are an ongoing problem even in well designed systems. I wish we could move away from the eventuality to all lugs for DC. If my system has a weak spot for heat, it will be my charge controller's battery terminals.

Breaker people, you can follow the light and join the Fuse and Contactor Crew today if you want to. Renounce the air and quench your DC in gas.
 
hwy17 said:
Phoenix and other direct wire terminals are an ongoing problem even in well designed systems. I wish we could move away from the eventuality to all lugs for DC. If my system has a weak spot for heat, it will be my charge controller's battery terminals.

Breaker people, you can follow the light and join the Fuse and Contactor Crew today if you want to. Renounce the air and quench your DC in gas.
Click to expand...

Have you got a link for a good post or resource so I can deep dive the subject? I've been reading some things where it comes to anti-islanding and using time delay AC contactors for that purpose, but I haven't run across a really good explaination of how they work in DC land and maybe some wiring examples?
 
robbob2112 said:
Have you got a link for a good post or resource so I can deep dive the subject? I've been reading some things where it comes to anti-islanding and using time delay AC contactors for that purpose, but I haven't run across a really good explaination of how they work in DC land and maybe some wiring examples?
Click to expand...
Yes! Here's some:

www.te.com

Electrical Contactors for High Current Load

TE's electrical contactors are engineered to handle high current loads and are perfect for use in a wide variety of applications. Learn about the various types of contactors that TE offers.
www.te.com www.te.com

Digikey pdf download: https://www.digikey.com/Site/Global/Layouts/DownloadPdf.ashx?pdfUrl=F701E7505DAA4BA09F698AFD4D3B00C8

My contactor switch box: https://diysolarforum.com/threads/hwy17s-battery-build.72380/page-7#post-1021346
 
robbob2112 said:
Have you got a link for a good post or resource so I can deep dive the subject? I've been reading some things where it comes to anti-islanding and using time delay AC contactors for that purpose, but I haven't run across a really good explaination of how they work in DC land and maybe some wiring examples?
Click to expand...
Just replying to this again to add something that occurred to me: Contactors are generally operated by a DC power source. It is tempting and more common in DIY solar to use pack voltage 48v for this operation, and there are contactors with 48v coils. However, I think anyone using contactors should consider setting up an auxiliary 12v power supply with a small lead acid battery, as is common in the DIY EV scene, for a 12v controls circuit. That way you don't have to worry so much about the controls wires getting too sloppy or crowded.

Orion and Nuvation are the two BMS I am interested in that can operate on an all 12v controls circuit. I have done Orion so far, and I want to do a Nuvation next.
 
Brett V said:
I have one of those and have loaded it pretty good while watching it with a Flir camera, never warmed up at all. I found some crimp ring terminals that are a snug fit on 6AWG and used those to make connections.
Click to expand...
I put the T-gun on my primary several times, specifically when I noted the load was really high, and the room ambient was also very high. This unit was intermittently used (Only while charging the cars). I don't think I ever hit it with the gun while in use. I had one other of these fail, it was a 60A 2-pole unit but the failure was on the relay not actuating, not the primary contacts (It still worked manually).

This unit was in play to switch EV charging from the inverters to the grid if my load exceeded 95-100A. I now have a smart EVSE, that floats the charge current based on SOC. Once I hook in a current selector to the algorithm to float it down based on load, I might just eliminate it completely.

For now, I have several spares, and they started making a 120A version. I downgraded the breaker on my panel to 100A, to match the relay, so long term I'll bump it back as I re-wire for the solar outbuilding.
 
You must log in or register to reply here.

Similar threads

R
Portable Solar Charger
Replies
14
Views
1K
RV8R
R
Tex
Daly BMS Woes
Replies
0
Views
1K
Tex
Tex
Back
Top