Qulbix Q76R Frame Kits & Complete Bikes PRE-ORDER

madin88 said:
i believe he means the placement of the cells is so complex that it would be hard to keep the resistance of the connection form one p-group to the next similar (so that every single cells sees the same current).

offroader, i can imagine that it takes a lot of time to build that pack.
now, do you still have the space for insulation between the s-groups for better protection against a short?
i normally use some tape with about 0.2mm thickness for having a larger gap here. with the shrinktube only there is almost no distance here.
Click to expand...

Exactly, it is recommended to make sure that all cells have equal resistance. This adds a bit more complexity into the pack build as you just can't connect the cells, you have to make sure the wire and strip are the same for all cells.

madin88, I didn't have the room to add this, I did put a thin layer of capton tape between the series groups but that is all. I believe insulation isn't necessary at all as the pack will be hot glued together.

The pack will also be compressed from the sides rather tightly, because I will put foam on the battery sides and when I screw on the side panels it will compress the battery very tight. I will also be milling a battery holder inside the battery compartment to make sure the battery doesn't move front to back. My goal is to make sure there is no movement to begin and there won't be a chance for any rubbing.

I will also do periodic checks of the pack to make sure it is still solid. I should be able to feel any loose cells especially since I won't have nickel holding the series groups together and just wires.

I was also thinking, I have this 1000 volt insulation tester, I wonder if testing with this device periodically will help determine if the insulation is failing between the series groups.

I really think this whole series groups shorts are over rated. The people who had issues with this probably didn't have the pack secure to begin with. They also did not hot glue the pack together, which is huge. With a hot glued pack that is also secured well, the risk of this is happening is probably close zero. The Q76R frame is so narrow that it is easy to squeeze the pack tightly from the sides.
 
Some pictures of my pack.

You can see from the pictures that 280 cells just fit inside the frame opening. This is why it must be build compressed. The pack in the pictures is hot glued only on one side.

Good thing the frame must have been built with very good tolerances because the pack just fits through both sides equally. I didn't expect this would be the case.

When hot gluing the pack compressed, it is difficult to get the glue between the cells so it has to be plunged down, more hot glue added, plunged again and again. It is a pain in the ass to do. I can't fill the whole space perfectly with hot glue but it isn't needed. The glue is so strong that just one cell on the outside of the pack, hot glued on one side, can easily hold the whole weight of the pack. Each cell has 4 sides hot glued also in the center. This is ridiculously strong. A cell can't be removed without ripping off the insulation, unless you use isopropyl alcohol. This is why series group insulation is probably not needed with this kind of strength.

When hot gluing with the cells compressed it makes a mess of hot glue on the tops of the battery. This was so difficult to remove after it dried that I had to take an clothes iron and melt it flat against the pack. I was happy to have found this to have worked as the hot glue would have prevented me from using the nickel strips.

This pack is a pain to build because partly because I have to figure out everything as I go along and it is my first pack build. If I had to do it again, it wouldn't be so bad, but still much more difficult then if I just built it normally, if I had more room, without having to compress it.

Pack just fits in frame opening, getting this side prepared for hot gluing. Other side was already hot glued.


Pack is compressed before hot gluing, to make sure all cells are tight. cardboard and paper are used to push the cells tightly.


Cell gaskets are used. I forgot to put these on one side and the hot glue now prevents me from doing this. The Sanyo 3500 cells already have blue gaskets on them, which are not as thick as the green ones but still very strong.




I use a copper wire to help plunge the hot glue down, or else the hot glue would only stay on the very top.
 
Wow...offroader. This seems so complex and so much work, but hats off to you for pulling this off. It seems like a very tight fit. Hopefully once the pack is built and wrapped, you shouldn't have any issues fitting the side covers. I wonder if battery holders would actually fit in such a tight space?
 
madin88 said:
jmz said:
Planning my battery layout thanks to Offroaders useful pictures. 22s9p should be a cinch.
Click to expand...

wouldn't it be possible to place 22 of 9p groups side by side into that frame (from left to right)?
doing so, THAN would make welding and gluing the pack a cinch, because you could use one single 25mm nickel strip for making p and s connection at once :wink:
Click to expand...

You know, it looks like that will actually fit, according to my spectacularly crappy image editing skills:

https://imgur.com/ITz0Lz0

That's probably the way I will go.

Offroader, was there any reason you didn't hot glue the cells on their sides as you added them? I may not need to glue at all, but if I did, I would have thought first to do it that way.
 
jmz said:
Offroader, was there any reason you didn't hot glue the cells on their sides as you added them? I may not need to glue at all, but if I did, I would have thought first to do it that way.
Click to expand...

When you add them like that, even if you press them together tightly, you never get them perfectly tight. This will add a small amount of space between the cells and eventually add up enough where the pack won't fit.

Another reason is to fit 280 cells without filing the frame opening, the cell in the right corner needs to be pushed up slightly. You can see it in the picture and how all the cells above it don't line up perfectly. Only way to get this right is to build it together.


 
i see the next problem comin. Heatshrink and wires. What about the bms? no way to put a bms also in.
i think 260 cell is the deal with 20s.

this 76R is on the wishlist from my gf. thats why i also look on the 18650 side.(still happy with lipos :p)
 
Trying to figure out how to secure this huge battery in the battery compartment.

Does anyone see any trouble with this idea?

I am going to make a custom plastic battery tray that fits at the bottom of the frame and will be bolted down to the frame. The battery will sit on top of this tray. I believe we all have to make something like this because the screws for the side panel do not allow the battery to sit at the very bottom of the frame.

I will then use Velcro and tightly secure the battery to this battery tray. I like Velcro because I have minimal room for any other kind of clasp. This will secure it from moving up and down. Front to back, I haven't figured out what I will do yet.

I assume I will need the strap to be elastic to make sure it is held down firmly? I can also try and get some padding under the battery to squish the battery down into that when I secure the straps.

Looking for some ideas here.


In the picture here this is how I would secure the battery to the bottom of the frame.

 
I would run the strap the other way (longitudinally) to prevent stressing/cutting through the pack.

If you pack the pack in with foam/rubber, the covers will support it laterally.
 
I wouldn't use velcro as I had a case of the "hard side" of the velcro grinding through a heatshrink due to vibrations. I would stick to foam and use compression to hold everything in place
 
I would pack it in with foam as well. I know you intend to ride that thing hard and I would expect the velcro to tear at some point. I used velcro straps to secure my batteries to the bottom of my long board and one of the straps broke after about 100 miles. Your battery is 6 times the mass with similar straps. I do recognize that a skateboard has zero suspension and transmits a lot more shock, but still...
 
Thanks for the responses. I would have to pack in the foam before inserting the battery.

I think it is possible by removing both side covers when inserting it, I'll hold up the foam on one side and insert the battery in the other.

It could work.

Do you think foam alone is enough to hold this 30 lbs pack stable?
 
Offroader said:
Do you think foam alone is enough to hold this 30 lbs pack stable?
Click to expand...
This is hard to say...

one thing though : my batt (that I didn't build myself) is much smaller and I had to use the strap provided with the frame. You can kind of view it here :
1458667564sselection_768.png

but yours is so big that I would just put as much foam as I can in the frame in order to fill the clearance
 
So.. after cleaning out the threads with a razor blade, the bb cup still wouldn't screw in. I assumed there was still some form of paint in the threads.

I took the frame to a bike shop in Melbourne who specialises in ebikes, who checked the threads and determined that it has nothing to do with the paint as there really isn't any holding it up. Rather, it appears part or all of the thread on one cup has been threaded at an angle, preventing the cup from screwing in all the way and certainly would prevent it being straight.

The bloke at the shop advised that he cannot use the die tool because it will definitely attempt to cut the threads again, but straight, which will destroy what's there. Basically, I'm now stuck with a frame which I cannot fit a BB cup to. :?

Any ideas?
 
Well, you should at least reach out to qulbix... But then I'm out of ideas...
Quick question: is the problem located on the right side? On my frame the left side went smoothly but I used lots of lube and went in and out (ahem...) a good number of times before screwing the cup all the way in for the right side
 
I didn't use force, ultimately it went in... it was just something like "2/4 of a turn in, then 1/4 of a turn out, etc..." not forcing anything at all.

as for Ziva, if this helps, I noticed that if I send a mail to her on a weekday at 3PM (GMT+1) she usually answers on the same day. but if it's during the weekend or too late in the evening i get no answer at all.
 
schlumpf is not worth the money.

pretty sure (but no one do it right now) take a half price hammerschmidt.

all BBs available, way better quality as it is for hard downhill use.
unfortunately only 1:1,6 Ratio and not 1:2,5 like the schlumpf.

But you have only to make a 30€ Adapter to use every sprocket u want. If i had the knowing before, i would go 100% with a hammerschmidt drive.
 
Building this pack is very time consuming, especially because I have to figure everything out as I go along. I would say building it the way I'm building it, is taking me probably 5-10x longer than if I built it without compressing it first, and just used nickel instead of wires.

I got my first two parallel groups connected in series with 16 gauge wire. All wire is equal length.

Now that I know what i am doing, I am hoping I can pick up some speed. I really want to get this bike completed to see how it rides.



 
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