Building dual 18650 mod help

[batteredwombat]

I am trying to build a dual 18650 dna 40 mod with a power bank enclosure and had a few questions. There is no way battery sleds will fit.

1. Is going springs for both positive and negative the best route. If so is battery size C correct for the batteries i am using? (keystone springs steel coated in nickel)
2. I only have to insulate the positive springs right? What plastic insulator should i use or can i DIY one with random plastic?
3. So far the only place i have found these is at mouser, any ideas locally or can i DIY with some wire?

I already have a dna 40 mod i built in hammond G box but its so big to carry around and might gut it but desoldering everything might not be a good idea.

Thats all the questions for now as im sure i will have more later. Thank you for your help.

 

[SupplyDaddy]

Doesn't the power bank already have battery areas?
The C sized springs and plates will work, although you will need to trim them down a bit. There are clips that you could use as an alternate. Of course, making your own connections with wire is always an option if you don't want to wait for a mouser shipment.
I think ABS would be your best bet for a plastic insulator.

 

[batteredwombat]

The bank doesnt, its an open flask looking thing with plates to screw into the top and bottom. THe ABS do i buy a sheet or make some out of ABS pipe cap and i only have to insulate positive? I was thinking of ripping the coils from a battery housing from radio shack but not sure of the quality. The keystone are steel with nickel coating, does the quality matter if it is controlled by dna chip not mechanical?

Thanks for your reply!

 

[mauricem00]

I am trying to build a dual 18650 dna 40 mod with a power bank enclosure and had a few questions. There is no way battery sleds will fit.

1. Is going springs for both positive and negative the best route. If so is battery size C correct for the batteries i am using? (keystone springs steel coated in nickel)
2. I only have to insulate the positive springs right? What plastic insulator should i use or can i DIY one with random plastic?
3. So far the only place i have found these is at mouser, any ideas locally or can i DIY with some wire?

I already have a dna 40 mod i built in hammond G box but its so big to carry around and might gut it but desoldering everything might not be a good idea.

Thats all the questions for now as im sure i will have more later. Thank you for your help.

for an insulator you can solder the springs to a piece of single sided PC board.if you tin the copper it should handle much more current that you will ever use. you can find cheap 510 connectors at fastech.$1.84 510 Connector for Wooden Mod - brass + stainless steel at FastTech - Worldwide Free Shipping and mosfets on e-bay 2pcs IRLB3034PBF IRLB3034 HEXFET Power MOSFET to 220 New | eBay everything else you need should be available from any electronics store if you are building a mechanical mod

 

[dc99]

I have made quite a few out of pieces of derlin. You can get it pretty reasonable on ebay. It will hold up to the heat a lot better. You don't really have to do springs on both ends. You can do a solid piece for the pos and use springs on the neg side. I think Im working on the same power bank as you right now but with an sx350

 

[edyle]

I am trying to build a dual 18650 dna 40 mod with a power bank enclosure and had a few questions. There is no way battery sleds will fit.

1. Is going springs for both positive and negative the best route. If so is battery size C correct for the batteries i am using? (keystone springs steel coated in nickel)
2. I only have to insulate the positive springs right? What plastic insulator should i use or can i DIY one with random plastic?
3. So far the only place i have found these is at mouser, any ideas locally or can i DIY with some wire?

I already have a dna 40 mod i built in hammond G box but its so big to carry around and might gut it but desoldering everything might not be a good idea.

Thats all the questions for now as im sure i will have more later. Thank you for your help.

1: The reason for springs is so that you have wiggle room to fit; it's a self-adjusting-to-length mechanism.
To answer the question: No. Not both positive and negative; you only want 1 spring;
The downside to the spring is you end up compromising on electrical contact.
2: Usually you connect the negative to the body of the device if it is metal, and so the body becomes negative, then you only make sure to keep the positive insulated/isolated.

As for insulator materials, besides making out of plastic, a versatile item to use is the rubber washers you can get from plumbing supplies; they already come in a variety to sizes as well as shapes, and even material

 

[batteredwombat]

I am going to use these for the positive battery connection http://www.mouser.com/Search/ProductDetail.aspx?R=5240virtualkey53400000virtualkey534-5240 cut out and glued into 1/2 delrin plug which i can lengthen to fit, and these for the neg 5241 Keystone Electronics | Mouser. I plan to glue the neg springs to the bottom plate but am wondering if it will ground through the epoxy. I have seen this type done by mamu (props for idea) but I was wondering if i will have to parallel the neg and pos wires with the dna40, as i have wired a dna40 before and it has 1 ground for 510 solder tab and 1 for battery same with positive wires. Mabey im over-thinking this but want to be sure before i fry something. I am still tempted to try out the sx350j ). Thanks again for all the advice.

 

[batteredwombat]

I forgot to mention I have never needed to use the full 40 watts on the dna 40 so not sure if i should sx350j it . )

 

[dc99]

Then I would stick with the DNA. If running duel batteries you need to parallel the neg but I would fuse the pos before hooking them together.

 

[batteredwombat]

Thanks. I hope your build goes well, i am sure we are using the same enclosure.

 

[batteredwombat]

I forgot to ask about the fuses i will need 9A resettables for each pos wire but there are many variations of trip current, hold current ect. Which should i get?

 

[dc99]

http://www.digikey.com/product-detail/en/2920L700SLPR/F6137CT-ND/4147147
You will need two of these for each battery. I actually got this from Mamu. There not that bad to solder.

 

[batteredwombat]

Thanks. Mamu is awesome builder and gave me inspiration for this build. I guess the fuses are for reverse battery protection? The dna doesnt need them but i see people put them on the posi wires anyhow. Currently i am looking at mamus arlo wiring schematics to use for this device. 18 gauge wire should be enough for the wires i take it as i used them for my hammond dna 40? I could sandwich the fuses between the wire or fuse the fuses together and then solder wire? i am just worried about too much degradation to the fuses from the heat. thanks again dc.

I just read about fuses messing with the pre-heat from one of your replies on another thread. So have 14a fuses on each battery is overkill but it keeps it from messing with preheat? If it messes with it id rather not use fuses.

 

[dc99]

I followed her advice on these and it worked great.Yes its for reverse protection. I always like to fuse batteries anyway. Just because a board will protect itself it wont protect the batteries. Yes the preheat is the reason for the dual fuses. I made a tiny board from a copper clad board for the fuses. Just dremel it. Its a lot smaller than you would think.

 

[batteredwombat]

Thanks, i ordered those fuses. How would i use magnets as switches as I have heard of? I noted mamu said to put the liquid electrical tape around the switch itself but would the magnet be strong enough to stick onto switch through the liquid tape? Good idea with the copper link! Now ill have to salvage some from something.

 

[dc99]

I have never heard of it. Magnets on a mechanical switch yes but not as a switch. Single sided copper clad is cheap on ebay or at mouser. 506 MG Chemicals | Mouser
10 Pcs Fr 062 2 oz 4 x 6 Single Sided Copper Clad Circuit Board PCB | eBay

 

[batteredwombat]

so i solder both fuses side by side on the pcb then connect wires to each ends of pcb?

 

[dc99]

You could stack them and the foot print would be smaller.

 

[batteredwombat]

How would you use the pcb, in between the stacked fuses? I noticed i ordered single sided pcb, not sure if thats the right kind.

 

[dc99]

Cut the copper between the ends and lay the fuses over the cut out. Solder them to the board. Leave enough on each end to solder wires to.