Nishi 18650 pack building kit

spinningmagnets

Moderator
Staff member
Joined
Dec 21, 2007
Messages
12,952
Location
Ft Riley, NE Kansas
I just recieved a kit from Nishi in Mumbai India. It took a while, but anyone in the USA who orders from them in the future should be able to get them much faster.

the standard kit is shoebox sized, contains 108 end caps, enough to build a 54 cell pack. Ordering direct from India was $25 for the kit, and $25 to ship to Kansas...

The bus strips are copper-core and equal to 13A round wire. 7.6mm X 0.4mm = 3mm sq

The anti-corrosion plating is silvery looking, and reported to be zinc...
 
its basically a different iteration of that vurzend crap.

prehaps it's fun to play with but friction fit connectings should never be used in batteries. period.
 
  • Like
Reactions: AGS
If using the Nishi style, I would add an outer set of two compression side-panels over the entire pack. I would not rely on a friction fit to hold the end-caps onto the cells.
 
spinningmagnets said:
If using the Nishi style, I would add an outer set of two compression panels. I would not rely on a friction fit to hold the end-caps onto the cells.

That still might not work. If you apply too much compression to the cells they may just cave in a bit and make the connection unreliable anyways.

I've accidentally dented in some positive terminals by pressing too hard with my spot welder (back when my electrodes were quite solid and had no spring).
 
I was also planning on adding standoffs that prevent the panel attachments from being "overtightened". I may even add a thin layer of poron foam to add some cushion. The Nishi style Incorporates an over-cap that transfers external forces to the shoulders of the cylinder. But thanks for that heads-up about potential concerns.

I suppose that it might be better for me to comment less, until I can show pictures. I'll have a day off from work soon.
 
the problem is not external forces. its simply that you can pull the whole thing off, so it WILL simply shake loose.
 
Some pics...the bus strips are definitely copper core, with a thin zinc plating for corrosion protection. The softness of the copper core allows the bus to conform to the cell end under the pressure from the coil-spring.


Nishi6.jpg

Nishi5.jpg

In the pic below, the materials on the left side are 1/4-inch plywood and 1/4-inch HDPE kitchen cutting board.

Nishi4.jpg

Nishi7.jpg
 
I just made a 4S/1P pack from these (12V+), and it was very easy. The pressed hole in the tips of the plated copper series-strip easily threads a common hardware-store 6-32 screw.
 
The thing I would be worried about is corrosion on the bare copper spring. I would probably spray the coils down with ACF50 or similar corrosion preventative, provided it doesn't react with the platics or anything like that.

In addition to that if I had a nice wooden or plastic box that was designed to provide additional compression then I don't see a problem with it. As simple as two pieces of plywood with enough long thin bolts that connected both sides together to provide a constant pressure. A person who was a experienced wood-worker would be able to make something that looked very nice.

With 54 pieces it probably would be good for a nice little 15-25 amp 13s4p battery. A nice match for a geared hub motor.
 
Regardless of he spring type (leaf vs coil), I have long been an advocate of the spring and the electrically-conductive contact being two separate elements.

That being said, Beryllium-Copper (2% Be - 98% Cu) is an excellent coil-spring material, with a fatigue-strength measured in millions of cycles...
 
I agree about not relying on friction fit.

I also agree that two plates or U-channel profiles compressing both ends would be ideal.

However I believe there would be enough variation in length between brands or even output from different factories, that the compression pressure could not be set accurately enough with fixed-length "spacer" rods or blocks.

My approach would be pretty closely spaced through-bolts, and a right-sized precise torque tester / wrench. Perhaps Poron providing a bit of spring-style cushioning against shock & vibration.

The goal of solderless / no-weld connections is too important to allow negativity to discourage innovative experimentation.

Is it the consensus here, based on experience, that the Vruzend approach really is "crap"?
 
john61ct said:
The goal of solderless / no-weld connections is too important to allow negativity to discourage innovative experimentation.

I agree. :thumb: these things should be explored. Making 18650/21700 packs easier to build is a holy grail for us builders these days.

I don't have any confidence in this approach but i understand it *could* work if was properly designed.
 
That being said, Beryllium-Copper (2% Be - 98% Cu) is an excellent coil-spring material,

I wasn't worried about the springiness. I was just concerned about green oxide coating in humid environments causing increased resistance. But I think that is something easy to take care of with some anti-corrosion something or other.

I'm always worried about corrosion and copper after I seen how it can eat it's way up and under the insulation on copper car battery cables.

Sorry if that wasn't a reply to me.
 
With the Vruzend kit, the spring-element and a electrically-conductive element are the same part. With Nishi, the spring and the electrical-contact are two separate elements.

The V2 Vruzend sold by Micah Toll in the USA seems to have many satisfied customers at 10A peak per cell...I would humbly suggest that the contacts in the Nishi kit can handle more amps, such as the 15A 30Q cell, and the 20A 25R and HB2 cells...
 
I wonder about adding into the design , a small clamp similar to the seatpost clamp on a bike with a torx screw at the opening of those types of caps, wouldn't take much compression on them to hold them securely. Maybe add $ .25 to the cost of each pair ,but to me it would seem worth it.
 
I live where it is hot and worry about different materials expanding and contracting at different rates. With that said, am a fan of this topic and would like to try something like this with a lot of thought. Keep us updated please! :)
 
neptronix said:
Making 18650/21700 packs easier to build is a holy grail for us builders these days.
Not to mention easily disassembling packs as they weaken to individually load test the cells for capacity, or ESR/IR test, for "go/no-go" replacement, rebalancing groups, etc



 
sleepy_tired said:
The thing I would be worried about is corrosion on the bare copper spring. I would probably spray the coils down with ACF50 or similar corrosion preventative, provided it doesn't react with the platics or anything like that.

In addition to that if I had a nice wooden or plastic box that was designed to provide additional compression then I don't see a problem with it. As simple as two pieces of plywood with enough long thin bolts that connected both sides together to provide a constant pressure. A person who was a experienced wood-worker would be able to make something that looked very nice.

With 54 pieces it probably would be good for a nice little 15-25 amp 13s4p battery. A nice match for a geared hub motor.

Uncoated/untreated copper sucks in most environments. (ACF 50 is a great solution. I’m always surprised when someone suggests those Vaseline consistency products.)

Do we have testing at higher amps?
 
It am sure it's dielectric, but it's not a hard paint-like thing like conformal coating. It's just a sort of thin oil. So it won't interfere with direct metal on metal conduction.

I learned about it on this forum, people use it to protect their battery terminal blades on hailong-style battery packs from corrosion. Works great for that.

It's been popularized as a popular coating on motorcycle bits to prevent corrosion on bare metal parts to make it easier to clean.
 
One of the advantages to this design, maybe, is that it would be very easy to modify to have fusible links.

Take one of those metal screw bits, cut it in half, and then bridge the two parts together with a short bit of fuse wire and solder it. Or just grind it down in the middle so it is it's own fuse.
 
sleepy_tired said:
It am sure it's dielectric, but it's not a hard paint-like thing like conformal coating. It's just a sort of thin oil. So it won't interfere with direct metal on metal conduction.

I learned about it on this forum, people use it to protect their battery terminal blades on hailong-style battery packs from corrosion. Works great for that.

It's been popularized as a popular coating on motorcycle bits to prevent corrosion on bare metal parts to make it easier to clean.
Think I'll stick with NO-OX-ID for this use case.

Craig Labs T5 is also magic stuff.
 
I decided to re-orient the cell configuration, which required me to disassemble and relocate one of the cells. Turned out to be fairly easy to pull apart. I'm happy with it so far and I wish there was a US dealer.
 
john61ct said:
tomjasz said:
ACF 50 is a great solution
Can't find whether it's dielectric or conductive, do you know?
It is NOT conductive and commonly used in avionics.

https://www.youtube.com/watch?v=30paBTt8Oko

It will protect electrical joints, plugs and components and prevent corrosion causing high resistance joints. This goes for PCB’s and electronics as well, such as computerised ignition and fuel control units and their multi pin plugs, while switches, controls and levers will all be lubricated as well as protected from corrosion. Multi pin plugs and connectors benefit from having ACF‐50 applied directly to the contacts.
 
Back
Top