Lug holes too big
- Thread starter Dicey2024
- Start date
sunshine_eggo
Victron's little biatch
No. Get smaller ring terminals. By sandwiching with washers, you increase the resistance with the washer between the terminals.
timselectric
If I can do it, you can do it.
- Joined
- Feb 5, 2022
- Messages
- 25,718
If that washer is tin coated copper, yes.
If not, it will make for a bad day.
If not, it will make for a bad day.
silverstone
Solar Enthusiast
- Joined
- May 3, 2022
- Messages
- 1,148
Using washers is NOT an issue if they are NOT in the main current path (e.g. when torquing the cable lug from above with a nut / bolt), and where the tinned copper cable lug is in direct contact with copper posts / tin-or-nickel plated aluminum posts. Make sure to clean the posts especially if they are pure aluminum !!!
If the washer is in the current path like you illustrate (I am referring to the BOTTOM washer), then IT IS an issue. The bottom washer, if steel, will get red hot. The top washer and nut is not the issue. THE ISSUE IS THE BOTTOM WASHER.
If the washer is in the main current path, galvanized steel / carbon steel has approx. 10 times more resistance than copper ... It will glow red and melt your plastic. If stainless steel it's maybe 4-5 times even more worse (40-50 times worse than copper) ...
Your plastic will melt and most likely start a fire ...
You could in theory cut a small piece of copper bar (e.g. square) and drill a hole in it to put as an interface material between the posts and your cable lug. But it's probably going to be more work, complicated, less good of an electrical connection, compared as to getting the proper cable lug in the first place.
If the washer is in the current path like you illustrate (I am referring to the BOTTOM washer), then IT IS an issue. The bottom washer, if steel, will get red hot. The top washer and nut is not the issue. THE ISSUE IS THE BOTTOM WASHER.
If the washer is in the main current path, galvanized steel / carbon steel has approx. 10 times more resistance than copper ... It will glow red and melt your plastic. If stainless steel it's maybe 4-5 times even more worse (40-50 times worse than copper) ...
Your plastic will melt and most likely start a fire ...
You could in theory cut a small piece of copper bar (e.g. square) and drill a hole in it to put as an interface material between the posts and your cable lug. But it's probably going to be more work, complicated, less good of an electrical connection, compared as to getting the proper cable lug in the first place.
Last edited:
pollenface
Solar Wizard
make your own out of crushed copper pipe 
crossy
Solar Wizard
As above, the correct size lugs should be readily available.
For high-current connections there really is no viable alternative.
EDIT one of many, many. https://www.amazon.com/Ga-Stud-Copper-Lugs-Pack/dp/B00O7S7PM2
For high-current connections there really is no viable alternative.
EDIT one of many, many. https://www.amazon.com/Ga-Stud-Copper-Lugs-Pack/dp/B00O7S7PM2
Last edited:
chrisski
Solar Boondocker
If that is a Blue Sea ST blade fuse block, it is a not 1/4” stud. Specs make it look like a #10.
www.bluesea.com
The block is rated for 100 amps total, 60 amps per circuit.
I fused mine for 50 amps and used 8 AWG 75 c wire with this stud
ST Blade Fuse Block - 12 Circuits with Negative Bus and Cover - Blue Sea Systems
Compact ATO® / ATC® fuse block consolidates branch circuits and eliminates the tangle of in-line fuses for electronics and other appliances.
www.bluesea.com
I fused mine for 50 amps and used 8 AWG 75 c wire with this stud
Last edited:
Steve_S
Emperor Of Solar
Better to use the "Best Fit". Selterm makes some of the best HD Tinned lugs out there.
These can be had off Amazon/Ebay as well... Selterm has stores in both.
selterm.com
These can be had off Amazon/Ebay as well... Selterm has stores in both.
Marine Grade Tinned Copper Battery Cable Lugs | SELTERM
Explore our range of tinned copper battery cable lugs, designed for superior conductivity and corrosion resistance in diverse electrical setups. Shop today
selterm.com
silverstone
Solar Enthusiast
- Joined
- May 3, 2022
- Messages
- 1,148
The hole of the fuse terminal seems also quite big compared to the stud though.
There seems a lot of surface inside the hole of the busbar/fuse that you just installed that is NOT used around (or under) the stud.
This means that the electrical connection will maybe only use 10% of the rated cross-section or so. Thus similar problem as the washer IMHO.
Steve_S
Emperor Of Solar
1AWG, #10 Stud, Tinned Copper Battery Cable Ends, Wire Lugs, Marine Grade, MD0110P
1AWG, #10 Stud, Tinned Copper Battery Cable Ends, Wire Lugs
SELTERM Marine Grade Wire Lugs are made from 99.9% pure annealed tinned copper, providing a high degree of conductivity for maximum current flow. This particular variant is generally suitable for use with 1 Gauge Battery Cable & # 10 (M5) Stud.
selterm.com
No fuse can take stresses, most especially T-Class which can separate. Fuses do require proper holders.
Checkthisout
Emperor Of Solar
- Joined
- Nov 14, 2021
- Messages
- 5,444
No. Put the fuse in a holder.
And no, that big fuse needs to be where the conductor connects (or as close as possible) to the battery.
Checkthisout
Emperor Of Solar
- Joined
- Nov 14, 2021
- Messages
- 5,444
Also, in your original photo, when the terminal hole is too big you're losing contact area.
It's just catching the edges of the terminal.
That cable is also unnecessarily large for feeding that fuse panel.
It's just catching the edges of the terminal.
That cable is also unnecessarily large for feeding that fuse panel.
Checkthisout
Emperor Of Solar
- Joined
- Nov 14, 2021
- Messages
- 5,444
make your own out of crushed copper pipe
No, don't do this.
I have multiple fuses. I have a fuse on the battery, this one is for the fuse box - the fuse box says to use a fuse less than 125amp
The fuse box is rated for 100amps and it said to use 1/0 cable
Thank you I used your link to find #10 lugs for 6awgIf that is a Blue Sea ST blade fuse block, it is a not 1/4” stud. Specs make it look like a #10.
The block is rated for 100 amps total, 60 amps per circuit.ST Blade Fuse Block - 12 Circuits with Negative Bus and Cover - Blue Sea Systems
Compact ATO® / ATC® fuse block consolidates branch circuits and eliminates the tangle of in-line fuses for electronics and other appliances.
I fused mine for 50 amps and used 8 AWG 75 c wire with this stud
Checkthisout
Emperor Of Solar
- Joined
- Nov 14, 2021
- Messages
- 5,444
That fuse box will not do 100 amps. Trust me on that.
Just calculate your actual loads and use wire big enough to carry those amps.
It will be a much easier install with smaller wire.
It also needs to come straight out of the bottom or you won't be able to get the clear lexan cover on.
HighTechLab
AKA Dexter - CTO of Current Connected, LLC
- Joined
- Sep 23, 2019
- Messages
- 1,967
1/0 AWG 1/4" ring terminal lugs:
www.currentconnected.com
Tinned Copper Battery Cable Lugs - 10 Pack
Experience superior conductivity and durability with our Tinned Copper Battery Cable Lugs. Customizable options for a secure connection.
www.currentconnected.com
Thank you I found some1/0 AWG 1/4" ring terminal lugs:
Tinned Copper Battery Cable Lugs - 10 Pack
Experience superior conductivity and durability with our Tinned Copper Battery Cable Lugs. Customizable options for a secure connection.
TomC4306
Solar Obsessive
Or just buy proper copper washers..make your own out of crushed copper pipe
The Blue Sea is rated at 100 amps, however if you remove the back cover and have a look, most people with any common sense would be reluctant to run 50 amps total load. I’ve purchased the Blue Sea fuse block and the other one seen on Amazon, both have the same rating but I like the construction of the Blue Sea better, still de-rate it and avoid exposure to weather! Just nickel plated steel.
AlpineJoe
Solar Enthusiast
- Joined
- Jun 13, 2022
- Messages
- 300
I got a knockoff on Amazon for free to review, and the quality sucked. Metal was folded brass and the fingers to make contact with the fuses would loosen up after only 1 insertion. Tossed it in the trash.
How long is your run of 1/0?
1/0 is probably needed for chassis install of say 20’, if your cable length isn’t excessive you can save that 1/0 for other projects.
Similar threads
