18650 battery holder

[leamcorp]

I'm having a bit of confusion with the pack building. Hope someone can help,

Here's my scenerio - 16S and 7P A123 pack and thinking of using GGoodrum's 16 cell LVC board (this will also help me with 18650 pack building too). I'm so confused...

1) In order to build this A123 pack, do I need 7 LVC board? If not, how many do I need? Where do I solder the wire (If I need 7, then I understand. If less, then where?)
2) I'm thinking of buying this 10 cell charger/balancer - 10 cell Charger I'll be using this on every 5th charge to keep the cells balanced.

Since these only charge 10 cells at a time - do I need to plan the charge wiring for 10 at a time? For Example, charge 10 cell from one series, then charge remaining 6 cell from same series + 4 more cell from next series. This seems like it will be lots of extra wiring.

Hope this make sense. Thanks

 

[MitchJi]

Hi,

I'm having a bit of confusion with the pack building. Hope someone can help,

Here's my scenario - 16S and 7P A123 pack and thinking of using GGoodrum's 16 cell LVC board (this will also help me with 18650 pack building too). I'm so confused...

1) In order to build this A123 pack, do I need 7 LVC board? If not, how many do I need? Where do I solder the wire (If I need 7, then I understand. If less, then where?)

You need the 16 channel LVC board. Think of each 7p group as a single cell.

2) I'm thinking of buying this 10 cell charger/balancer -
Since these only charge 10 cells at a time - do I need to plan the charge wiring for 10 at a time?

You need to provide for charging 16 channels (as above).

 

[GGoodrum]

All you need is one LVC board. What you do is wire the cells in parallel first so what you end up with is 16 groups of 7 cells in parallel and then you wire the groups in series. Putting the cells in parallel will automatically balance all of the cells to the same level. You can then treat them as one big cell, hence the reason you only need one 16-channel LVC board.

If you use that charger, I'd just wire the pack so that you first do the 1st 10 cells, and then the last 6. You will need a 12V supply to power the charger.

-- Gary

 

[paultrafalgar]

I didn't read the whole of this thread, but you might like to thing about this:
viewto ... 91#p131191

Paul what you suggest in that thread is pretty similar to what I'm attempting with my triangle build. I'll have 14 subpacks of 10 konions that will essentially slide in and out of custom "boxes" in a triangle mount that will be side-closed with some sort of bolts that tighten down on the springs/cells. I'll have a little "ram air" slot in the very top left/tip that provides a little air flow, but I don't expect to ever pull more than 3-4C and konions don't get very warm under light loads like that so it should be fine. Each side of the triangle board will have the copper bus bars and springs mounted directly to the wood and wired up to the controller internally in 14s (if I can get it all to fit). It's going to take forever and be a complicated build, but in the end I should have a large 52v/15ah triangle mount pack that will be easy to replace individual cells as needed and last for a really long time. I'll have a ton of extra konions and will carry a spare dozen or so in my backpack (1.2lbs no big deal) on the trail in case one or more dud mid-ride.

This is not to scale or anything, but gives an idea of what I'm talking about.

View attachment 1

Excellent, pbwset! Great to see that someone has realised this idea. I see no reason why someone shouldn't mass-produce that board, maybe in different sizes to fit different cell sizes. That would take the arduous out of it!

 

[leamcorp]

I think I'm now getting the idea. Maybe.

So to build this pack, my battery holder will looks like,

A) 1 holder housing 7 cells (two copper strips on each end with 14 clips for contact). This will make up the parallel and all I would need to do is solder a wire to copper strips for charging (consider 1 channel or 1 cell?)

Question 1 - Should I also wire each cell so that it can be balanced individually or same idea apply for balancing (treating this as 1 cell)
Question 2 - can I use the single cell charger to charge these 7 cells in parallel (so I need 16 total single cell charger) - or will this take too long to charge.
Question 3 - Ggoodrum, do you recommend a particular charger that has power supply built in? I guess I would like to have 8 cell capability so that I could use two at the same time. I also assume that you use SLA charger also - Brand?

B) Make 16 - 7 cell holder, then connect each 7 cell holder to each other.

Thanks again!!!

 

[leamcorp]

Paul and PW,

Its not difficult to make a custom case - but setting up the jigs' and creating a box to make the shape take some time and exact measurement. But once those are in place, it could made very quickly.

The holder I'm making is very generic - better as straight line box to be mounted in rear rack. I'm trying to make it modular so that pack could be disassembled quickly to troubleshoot and not have to worry about soldering coming loose or breaking apart a large pack (like all those duct taped battery gone wrong threads).

I know there are some bad cells in one of my pack but I am afraid of opening them up and breaking some of the solder - or can't fix it since its in middle of the pack. Can't wait till I re-use those cells in this holder.

By the way, I'll be using semi-rigid plastic (typically used for impact tooling). Its much more expensive but probably could handle 4 ft drop.

 

[GGoodrum]

I think I'm now getting the idea. Maybe.

So to build this pack, my battery holder will looks like,

A) 1 holder housing 7 cells (two copper strips on each end with 14 clips for contact). This will make up the parallel and all I would need to do is solder a wire to copper strips for charging (consider 1 channel or 1 cell?)

Question 1 - Should I also wire each cell so that it can be balanced individually or same idea apply for balancing (treating this as 1 cell)
Question 2 - can I use the single cell charger to charge these 7 cells in parallel (so I need 16 total single cell charger) - or will this take too long to charge.
Question 3 - Ggoodrum, do you recommend a particular charger that has power supply built in? I guess I would like to have 8 cell capability so that I could use two at the same time. I also assume that you use SLA charger also - Brand?

B) Make 16 - 7 cell holder, then connect each 7 cell holder to each other.

Thanks again!!!

Yes, you can treat the 7-cell block as one big cell, both for charging or for discharging. One block of paralleled cells = one channel, or one big cell. Going the individual charger route, you would need 16, yes. If you go with the VoltPhreaks chargers, which basically are standalone 3.7V 2A chargers that each have a 110VAC plug. You can plug them into powerstrips. You can then wire the outputs up in series, with a 17-pin AMP 4.2mm PE plug that can connect into the matching connector on the front of the LVC board. Here's a shot of my original setup:

The only problem with these is they only charge at a 2A rate, so if this were the only mans of charging it would take awhile. There's no reason you can't also use a bulk charger/supply to charge the whole pack, and then use the 2A chargers to "top off"/balance the cells. That's what I've done with several packs, for quite some time. Typically, I would charge the pack with a my Zivan NG1, which originally was supposed to be used with a 48V SLA setup, and then every 5th charge, or so, I'd use the individual chargers after charging with the NG1, just to make sure each cell got a 100% charge at least once in awhile. You can also simply use any regulated supply that can put out 58-59V, as a bulk charger. I got an HP 0-60V 0-15A supply off of ebay for about $100.

Another option, one I'm exploring right now, is using 16 of the 48V/3.7V DC-DC convertors that Bill Zleman is selling in the "For Sale" section. These are small (1.5" x 2.25") modules that can be used just like the VP chargers to individually charge each cell, but each module can supply up to 20A. They are driven by a 48VDC power source, which can be pretty much any 48V supply you can easily find on ebay. What you can also do is use the same supply/charger that you use to bulk charge the 16s pack, as the source. That would allow you to just use the bulk charger, or use the bulk charger "in series" with these modules. I'm mounting all 16 modules to a 2-1/4 x 12" piece of aluminum, eight to a side. It is acutally very compact.

-- Gary

 

[pwbset]

Its not difficult to make a custom case - but setting up the jigs' and creating a box to make the shape take some time and exact measurement. But once those are in place, it could made very quickly.

I'm really looking forward to seeing your final designs!! Please do post as many photos as you can. I'm taking the triangle route as I have a very heavy rear motor.. plus the triangle Milwaukee mount I used last summer worked incredibly well and was very balanced. I'm reading about custom fabrication of stuff a bit and it's way over my head... think I'm just going to stick with a thin, dense wood for now despite that it will add a few pounds. :?

 

[leamcorp]

Its not difficult to make a custom case - but setting up the jigs' and creating a box to make the shape take some time and exact measurement. But once those are in place, it could made very quickly.

I'm really looking forward to seeing your final designs!! Please do post as many photos as you can. I'm taking the triangle route as I have a very heavy rear motor.. plus the triangle Milwaukee mount I used last summer worked incredibly well and was very balanced. I'm reading about custom fabrication of stuff a bit and it's way over my head... think I'm just going to stick with a thin, dense wood for now despite that it will add a few pounds. :?

I will.

You don't think having the battery will not interfere with pedaling? The 18650 cells are 2.6" and holder I'm making is 3.571" at narrow end (3.847 at the widest). With wood, it might even be thicker? That would seem like it would stick out and rub against the leg?


GGoodrum - thanks for the info. I think I got it now. I think I'm going with all three solution (single cell, 10 cell charger and SLA charger) - I'll just rotate them pending time pressure. Just let me know when you'll have that LVC board.

 

[pwbset]

You don't think having the battery will not interfere with pedaling?

Nah... check out this pack from last summer.. that didn't interfere at all and it's a lot wider than an 18650.. you just get used to it and can still pedal full power.

 

[MitchJi]

Hi,

You don't think having the battery will not interfere with pedaling?

Nah... check out this pack from last summer.. that didn't interfere at all and it's a lot wider than an 18650.. you just get used to it and can still pedal full power.

People have posted that anywhere from 100mm (3.9") to 130mm (5.12") is OK. How wide is your board with the packs?

Thanks!

Mitch

 

[Icewrench]

How wide is your board with the packs?

When mounted in the holders the milwuakee packs sit 3.6 inch high.

3.6 x 2 plus wood = almost 8 inches

 

[leamcorp]

I'm nearly done with the 18650 - doing one last rough casting before casting lead master for vulcanizer.

This is the last time I'm doing it by hand - it was a bitch to get it squared and come out fairly straight. For A123, I'm going to use a mill for higher tolerance.

As for the dimension - its 3.7 (W) x 3.5 (H) x 1" (all rough as its still not finished). This is for 4 cell version that can be interconnected. I'm going to make the 8 cell version also, may save some space.

As for the space on the frame - its out of question for me. I'm a roadie and I ride in specific style + I have a tree trunk for a leg. I can squat few hundred pounds at the gym but can't ride with anything in frame (sigh).

 

[pwbset]

How wide is your board with the packs?

:lol: You're the one that bought them from me Icewrench. You tell me how wide it is! Heh, heh! :wink:

Keep in mind they sat pretty high up in the triangle so that helped too.

 

[Icewrench]

Well for me those old milwaukees are riding high wide and horizontally handsome on some fine rear rack mounted plywood.
They get used on my test sled for melting stuff...........

 

[theyerb]

Does anyone have any extra 209 battery clips they want to sell?

 

[leamcorp]

Here's the latest version before sanding and making it neater for 2 part master mold - hopefully you'll get the idea.

4 Cell 18650 holder. The battery clips were bought from Mouser.com and copper strip from Mcmaster.com These markers - for matching top/bottom pieces will change. I've just used what I had in the shop. For final version, I'll be using accurate dowels/threaded rod.


Here's a top view. I will be drilling a hole on the copper strip to add a screw. This screw will be used to interconnect each holder using another copper strip. The back end of the clips could be used for individual cell monitoring/LVC/charging.



Top view with battery.


This shows how each holder will fit into each other. I wanted maximum flexibility, so this works well. One thing that isn't shown is foam cushion on the back of the holder. This will keep the cells in place and also give little bit of soft cushioning so that it won't hurt the battery.


3 holders - again, its not finished... it won't win beauty contest but I'm hoping to make it much tighter tolerance.


Here's another way this could be modular - I just dremel where the copper strip would rest and you could make 4/8/12 cell holder. The back is flat, so you could brace it with aluminum strip.


I don't think I'm going to spend too much more time on this as I want to get my A123 pack built. So, I'll be spending more time on that and hopefully I could make modular/expandable holder for A123.

cheers.

 

[Takemehome]

Does it really need a clip on both ends of the cell ?
Would not just one clip on negative end of the cell do the job ?
Just curious.

 

[leamcorp]

Does it really need a clip on both ends of the cell ?
Would not just one clip on negative end of the cell do the job ?
Just curious.

Not all cells have nub on the positive side, thus contact is hit or miss (Tenergy is one example). The other reason is that clip on both side will hold the cell better.

 

[MitchJi]

Hi,

Looks very good!

Are the "waves" high enough to provide sufficient support for the straps?

Should there be "waves" on the other side (back side of holder) so that both the top and bottom of the straps are supported?

 

[leamcorp]

Mitch - yes, its high enough. Actually its not even needed but I've left it there as I didn't want to sand it down further.

Changes in plan...

I was playing further last night and I've decided to change the design a little bit. The one you see above will still be there but not for Ebike - rather I'll use it for external power source for my bike light. I'll change the design so that its a self containing piece with cover for all weather application.

For the ebike setup - I've went back to the original idea and will have even simpler design. The critical point is expandability for a parallel setup without taking up lot of space. I want to make this so that its easy to go from 4, 5, 6, 7, 8 or even 12 cells in a row for parallel block, then connect them in series. The design is really simple, I should have it in couple of days.

 

[sharkmobil]

Any news on the project?

 

[MitchJi]

Hi,

Mitch - yes, its high enough. Actually its not even needed but I've left it there as I didn't want to sand it down further.

Changes in plan...

I was playing further last night and I've decided to change the design a little bit. The one you see above will still be there but not for Ebike - rather I'll use it for external power source for my bike light. I'll change the design so that its a self containing piece with cover for all weather application.

For the ebike setup - I've went back to the original idea and will have even simpler design. The critical point is expandability for a parallel setup without taking up lot of space. I want to make this so that its easy to go from 4, 5, 6, 7, 8 or even 12 cells in a row for parallel block, then connect them in series. The design is really simple, I should have it in couple of days.

I think it might be better to just put the holders in a weatherproof container than to make the holders weatherproof.

Using your current design for large groups of parallel cells is fine except that there is no easy way I can see to connect the blocks either in parallel or in series. I might like 8p/12s. So with your 4 packs above I would need to connect 2 packs x 12 (connect 12 packs) for parallel and 12 groups of 2 in series (connect 12 sets of packs). So I think its equally important to have an easy way to connect the holders both in parallel and in series (see 1 below).

I think your existing design, if you made 3x, 4x and 5x sizes is pretty good and would cover most pack sizes. I prefer (if there is an easy way to combine and connect them back to back in groups of 4 or 5 because I think that's more flexible in terms of squeezing them into limited space. The two things I would change/add are:
1. Provide a method to connect the straps with straps similar to these:

2. Either make thing covers that will fit on the open side of the last group or allow the groups to face in opposite directions.

 

[leamcorp]

Mitch, actually its easy to do serial using that holder - I just haven't connected them yet.

But as mentioned, I am doing even simpler version - I think you'll like that one. I'll work on it this weekend as I really want to build up pack next week.

 

[MitchJi]

Hi,

The only problem I see with the Dewalt pack holders is I think they will be difficult to use if you want a p configuration that isn't a multiple of 5.

So I think something similar to these that can be cut to the desired length would be excellent (more pictures on the thread):
http://endless-sphere.com/forums/viewtopic.php?f=14&t=8976#p138660
(the holders with the A123 cells):

another picture: