Busbar and huge battery terminals

[Sooz52]

Solar summary
Busbar and large battery terminals

Hi, hoping for a ping moment...
Basically I would like to know if anyone has an easy fix to connect wires to extra large battery terminals - I’m struggling to find connectors endings large enough for them so I can cable up.
I had to increase to mate for the move from AGM to LiFePO4. That was hard as no local DIY shops stocked them, I went to a car mechanic and got his largest ones, but the ends for the wire are so big it’s hard to press smallish cables in.
Now I bought myself a Victron BMV monitor and the Busbar terminals are even bigger, maybe M9 but the manual doesn’t say. It looks like I have to run a new single cable from the battery -ve to the Busbar, then put all the 4 or 5 cables which currently are in the battery -ve on the Busbar. So that means I need around 6 or 7 huge connectors.

In the photo you can see the progression - originally AGM on the left, LiFePO4 middle and a ring from the new Busbar on the right.

Anyone got any bright ideas.

Thanks

 

[Kannon Fodda]

I too was a bit surprised by the larger bolt sizes on the Victron shunt thingy when I went to fit it to my already installed Lithium and B2B. I think 10mm dia compared to the terminals on the battery, I think 8mm.

I ended up finding a specialist car electronics shop, fortunately reasonably local to me, that did radio, sat nav and all sorts of stuff, and they had a drawer full of connectors. Not cheap at £4 a go, the 1m length 25mm2 cable off the rainforest proved cheaper. I tried to drill out a 8mm dia terminal, but there wasn't enough metal left.

Making the joints, apparently you should have the special hydraulic crimper tool. I cheated and was able to squeeze it all up in a small vice. I'm sure the professionals will say my method won't have been adequate.

 

[Two on Tour]

I made up a 25mm2 link cable between my Victron shunt and an earth block that I used as a bus bar. I terminated all of my negative circuit on the earth block and mounted in a plastic junction box.

Toolstation

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[Revolvor]

The Victron Shunt terminals are 10 mm diameter.

THIS is one source of Crimp connections - lots of combinations of wire size and lug diameter. Also available on eBay. You will need a crimping tool though.

 

[pappajohn]

That's an easy one...... 'tin' all the wires or solder the lot together as one then solder the soldered wires into the crimp.
Crimping is quick.... Solder is secure.

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[Revolvor]

I made up a 25mm2 link cable between my Victron shunt and an earth block that I used as a bus bar.

I did the same!

 

[autorouter]

For thinner wires onto large terminals, you can use red/blue/yellow insulated eyelet terminals. The colour shows the wire thickness it is suitable for. Red = up to 1.5mm2, blue = up to 2.5mm2, yellow = up to 6mm2. They are available for terminals from 3mm to 13mm. Minimum pack size is 50, unfortunately, but they're not massively expensive.

BLUE PRE - INSULATED RING / EYELET TERMINAL

BLUE PRE - INSULATED RING EYELET TERMINAL Suitable for cable sizes 1 10mm2 - 2 5mm2 17 - 14 AWG Available hole sizes - 3 2mm 3 7mm 4 3mm 5 3mm 6 4mm

www.altecautomotive.co.uk

Bigger than 6mm2 you'll have to use the uninsulated crimp terminals like the centre one in your picture. You can use heat-shrink tubing or wrap with insulating tape. You'll need large crimp pliers unless you can get a friendly auto-electrician to do the crimping. Select the cable size and the terminal (stud) size.

"Small" Battery/Starter, Tin Plated Copper Tube Ring / Eyelet Terminals 6mm2 -50mm2 (Packs of 4) | Altec Automotive

"Small" Battery/Starter, Tin Plated Copper Tube Ring / Eyelet Terminals 6mm2 -50mm2 (Packs of 4) from Altec Automotive. Our range covers cable sizes from 6mm2 to 50mm2.

www.altecautomotive.co.uk

 

[autorouter]

I had to increase to mate for the move from AGM to LiFePO4.

If you don't put a space between M and 8, the spell-checker converts it to 'mate'

 

[Gizmouk]

Firstly that's a shunt, not a busbar.

The lugs can be bought from any decent electrical wholesaler, who normally stock up to around 95mm. Bigger, and they'll normally have to be ordered in, or for really big lugs bought from cable suppliers.
We used to use up to 630mm CSA

To order, you'll need two figures:
1. The CSA of the cable
2. The diameter of the stud

Then order the lug as, e.g:
Stud / Ring lug 70-12 (each lug should have the size stamped on it)

Use the correct crimp tool and die set - rent or borrow if needed.

Example:

Non Insulated Crimp Lugs for Crimping

www.tlc-direct.co.uk

Let me know if you need any help with cable sizing / calcs

 

[eddie]

I did the same!

View attachment 446140

You'v left your packed lunch in there!

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[Revolvor]

You'v left your packed lunch in there!

. A cheap and cheerful cover over fuses and relays!!

 

[paddymcc]

Hi autorouter
On the link for altec automotive they had a cheap crimping tool for bigger cables:

Do these work ok?
I have a hand crimper that does up to 6mm2 and don't really want to spend £30 on something l will rarely use...

 

[autorouter]

I have one of those cheap crimping tools, and I think they work OK if they are standing on something solid and are hit with a big hammer, preferably a lump hammer. More like a solid squeeze than a massive squash. That's OK if you are making up new cables, but can be a bit problematic if you are crimping a new terminal on an existing cable.

I prefer to use it in a big metal vice rather than a hammer. Of course many people, especially funsters, do not even have a small vice let alone a serious one

I've since got some big crimping pliers (non-hydraulic) which I now use instead.

 

[Sooz52]

Loving the answers. Blinking spell correct with M-8, haha.
Well I like the idea of pressing all 4 wires into one. My worry would be missing a connection due to my apparently appalling soldering skills (wtf, I used to be good at this!).
I’ll try a battery supplier for some M-10s and I’ll remember that I have to hammer the buggers before attaching to the battery. Still..... can’t they make this easier???? Why do we have to become frigging experts? Sigh.

 

[Sooz52]

That's an easy one...... 'tin' all the wires or solder the lot together as one then solder the soldered wires into the crimp.
Crimping is quick.... Solder is secure.

Yes, this is what I need to do thanks. Just got to get a couple of M—-10 rings

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[Podney]

I thought crimping was something you did to your hair??????? No???????
Im confused.

 

[Sooz52]

Why oh why do Victron do this? If big batteries don’t need such big terminal? And why can’t they include some connectors to help us? Humph.

 

[Sooz52]

I thought crimping was something you did to your hair??????? No???????
Im confused.

That was my youth...

 

[Two on Tour]

Why oh why do Victron do this? If big batteries don’t need such big terminal? And why can’t they include some connectors to help us? Humph.

If it is going to take near it's rated 500 amps, then you will need some pretty hefty connectors and a big bolt to hold them down.
Just because your batteries are not big ..............................

 

[Podney]

That was my youth...

I’d do it now.............if I had any hair.

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[Raul]

Just a correction in regards cable lug size for the shunt. It’s 12mm ring for sure, I’m doing a inverter upgrade as we speak and I’m relocating the shunt. The bolts are m12 with a 17mm hex. So you will need 12mm by whatever the cable you are using. I’m making a extension in a 8mm brass bolt to use it as a buss stud. That saves my wiring as I can use lots of existing crimps. For the lugs I use hydraulic crimper with hex dyes.

 

[Revolvor]

Just a correction in regards cable lug size for the shunt. It’s 12mm ring for sure

No it's NOT. For the 500 Amp Victron SmartShunt it is M10, as confirmed by me just measuring the Crimp, and also this: 17mm A/F spanner is correct.

 

[Revolvor]

Sooz52 I think I may be incorrect in my post above. From your picture, I see that it is a BMV 712 shunt. I was referring to the Victron SmartShunt, so maybe Raul is correct after all. I am sure that the correct information will be on the full manual that you can download.

 

[Raul]

This is what fits perfect my shunt. It’s a bmv 700 , the bmv 712 is the same. In my case I use a 70mm cable, the 12 is the ring in mm.

 

[Revolvor]

Jim Maybe this thread is a good advert for your idea of making sure that posts with "correct" answers are elevated to the top of the thread! See posts #21 to #24

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[TinaLes]

Just finished watching a video of a guy fitting his Lithium batteries, plus the Victron shunt & other large cables all of which needed massive crimps, plus DIY busbar clamps between the individual battery cell, insulated with heat shrink sleeving in the middle etc.

His admirable solution was to buy a length of standard 15mm copper tube from a plumbers merchant, cut into length required for each crimp, squeeze one end in a vice to form the flat lug, place cable in the other end and using a hand hydraulic crimp, clamp up on the bared copper wire.
Drill out the appropriate size hole in the flattened end for the battery terminal bolt size.
Job Done.
LES

 

[Raul]

I’m not a advocate of those practices. The gauge will be wrong and improper crimped. The purpose made lugs have the right gauge for the dyes and once crimped, air is removed between strands becoming a solid core. No chance of that with hammer crimp or vice.
Lugs are cheap and lasts a lifetime, why skimp?

The interconnects for the cells you seen in the clip, are purpose made to allow for expansion, if he used the right ones. If he’s used homemade, they will be rigid and if cells swell it will rupture around stud. The cells needs packing tight with band or metal clamp.

 

[Lenny HB]

Lugs are cheap and lasts a lifetime, why skimp?

Agree I only need to do 5 or 6 crimps well worth the £25 for a hydraulic crimper to do the job properly.

 

[Raul]

This is what fits perfect my shunt. It’s a bmv 700 , the bmv 712 is the same. In my case I use a 70mm cable, the 12 is the ring in mm.

Correction to my post, I was wrong the bolt is 10mm indeed. For some reason I got mixed up with the lugs. A 10mm should fit. See photo.
I apologise if I threw a spanner in the works. Revolvor is right.

 

[TinaLes]

I used to hire a hydraulic crimp from my electrical wholesalers when I was doing very large cable for 3 phase installations as a sparky. It came in a box with different die sizes & shapes, worth it if only using it once in a blue moon.
LES

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