Soldering battery holders?

[kuksul08]

I have been constantly thinking about this since it's the only thing left to consider. I think this will be a good solution. The idea is to not have to spend a lot of money on a new battery pack+charger, while still having good performance (Since I already have about 12 1600mAh nimh AA's)

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=BH14AAL-ND

There are only two springs in that holder, and solder leads. The plan is to solder some 20Ga gauge wire to those leads, and use two of them in parallel. Hopefully not too much extra resistance, 4.8V nominal, and 3200mAh capacity. That means 1.4-2.0 Amps coming from both packs combined. I don't really trust the 26AWG wire that some of them come with.

Can anyone confirm this is viable before I buy them? Hopefully this is better than the previous packs, because of the fewer springs.

 

[kuksul08]

bump, then I will let this thread die :sick2:

 

[Fallingwater]

My opinion is that none of those holders work for high current draws. The series-connected terminals at the far end are probably just the spring wire pressed under the positive terminal.

When facing your problem, I took a holder and rewired it completely, soldering thick wire to all four terminals. I may or may not have replaced the springs with bendy tabs - can't remember right now.
The plastic softening is only a problem if you push the terminal while soldering; if you don't push against it, or keep something on the other side, the plastic hardens after you're done and the holder works.

 

[kuksul08]

Wow, forget trying to solder those plastic holders, I found these!!

Absolutely perfect for my project. Nice tinned brass contacts

 

[purduephotog]

Wow, forget trying to solder those plastic holders, I found these!!


Absolutely perfect for my project. Nice tinned brass contacts

Where did you find that? Did you actually order it- and if so, do you have higher res photos of the spring contacts? What sort of insulation do they use on the inside of the bulkhead?

 

[hit4six]

I'm a latecomer. Most of the pics have been removed. Were they all similar to
http://search.digikey.com/scripts/Dk...ame=BH14AAL-ND ?

Without the pics I can't be sure but I think I was doing something similar, using battery holders with springs. 18650 cells, current 0.5a -1.5A. It has only had about 20 minutes use total (seemed fine) so I can't say if it will work. I could keep it to below 1a.

Fallingwater, a source for tabs?

'4 series aa in parallel with 4 more' - isn't 4 pairs better than 2 ?

1.2 1.2 1.2 1.2
I + I + I + I
1.2 1.2 1.2 1.2

better than

1.2 +1.2+1.2+1.2
I
1.2+1.2+1.2+1.2 ?

 

[Fallingwater]

Can't remember where I got the tabs. Possibly from old holders inside toys and other assorted appliances.

 

[-LightOn-]

I modified one of these holders so that I cut 2/3 of spring away and soldered a piece of soldering wick (braided copper wire) to the positive terminal (without the spring). The negative side with the spring I left unsoldered since I was not able to solder it. The wire rests on top of the spring so that when a cell is placed there, the terminal first contacts the copper wire. The spring gives just little mechanical tension. This set up seems to working fine with currents up to 1.5A, haven't tested further.

I measured the resistance of the spring pieces that I cut away. It was something like 0.5Ohms so 0.5W is dissipated at 1Amp, 1.125W at 1.5Amps. No wonder they get so freaking hot.

 

[kuksul08]

Where did you find that? Did you actually order it- and if so, do you have higher res photos of the spring contacts? What sort of insulation do they use on the inside of the bulkhead?

I have not ordered it. It is Keystone electronics Catalog #148 and they are available on Mouser... about $3 each. They have a similar steel variant as well. The insulation I believe they call it fibre impregnated resin or something.

I'm a latecomer. Most of the pics have been removed. Were they all similar to
http://search.digikey.com/scripts/Dk...ame=BH14AAL-ND ?

Without the pics I can't be sure but I think I was doing something similar, using battery holders with springs. 18650 cells, current 0.5a -1.5A. It has only had about 20 minutes use total (seemed fine) so I can't say if it will work. I could keep it to below 1a.

Fallingwater, a source for tabs?

'4 series aa in parallel with 4 more' - isn't 4 pairs better than 2 ?

1.2 1.2 1.2 1.2
I + I + I + I
1.2 1.2 1.2 1.2

better than

1.2 +1.2+1.2+1.2
I
1.2+1.2+1.2+1.2 ?

Yes that is the holder I was looking at. It is the only one I could find that held 4 cells with the least number of those coil spring contacts. I have since found a springless variant with a plastic strap across the top, and a PC pin for each terminal of the batteries (8 total).

Why would 4 packs of 2 be better than 2 packs of 4?

 

[hit4six]

I understood that was how 18650 packs were wired. I don't know why or if it matters, it is not my field. Someone out there knows, a google search will probably yield the information. I guess it is somehow more even.

Clever solutions, wire + spring. My spring did not get hot and cells had even voltage. I could post a pic of my 18650 3s3sp pack, give you all a laugh. The body of 3 cheapo dual 18650 chargers (tabs) and 3 18650 battery holders (springs). Pvc tube is a better idea. The appeal of my pack was it was all ready made, all i did was solder. If I go for tube I will be search existing designs on cpf for ideas, maybe and ask for tips.

 

[kuksul08]

I understood that was how 18650 packs were wired. I don't know why or if it matters, it is not my field. Someone out there knows, a google search will probably yield the information. I guess it is somehow more even.

Clever solutions, wire + spring. My spring did not get hot and cells had even voltage. I could post a pic of my 18650 3s3sp pack, give you all a laugh. The body of 3 cheapo dual 18650 chargers (tabs) and 3 18650 battery holders (springs). Pvc tube is a better idea. The appeal of my pack was it was all ready made, all i did was solder. If I go for tube I will be search existing designs on cpf for ideas, maybe and ask for tips.

Do it! I can't quite visualize what you're talking about