Home made battery-pack

[dellagd]

Hello All-

I am wanting to build a 6 volt rechargeable battery pack out of 5 , 1.2 volt standard rechargeable NiMH AA batteries.
I plan on attaching them all in a voltage tandem (voltage would be 1.2 x 5 battries and mAh is averaged between the 5 batteries. May main question in if I could simply solder a bare copper wire between the - and + ends of the batteries, ending up with one - and one + pole for all 5 batteries. It seems common sense that If I leave the soldering iron on the battery too long it would rupture (bad  )

Any thoughts on how to do this?


On a side note, 4 of these batteries are Energizer and the other one is Duracell. They are all NiMH and the only differences are the brand and the Duracell is 300 mAh lower then the Energizer. Would the only side effects of this be dropping the average mAh from 2300 mAh (would be if all Energizer) to 2240 mAh (The 4 energizers and the duracell)

[SmAsH]

Hmm, about the soldering. You are right in thinking that you could screw the batteries up by soldering them, its best to solder it in a quick go and not hold the iron on there for too long. As for the batteries, i would not suggest mixing batteries of different specs, somehow it does not seem too good... Is there anyway you can get another of the energizer?

[dellagd]

I guess I could, but I would have to buy another 4 (I dont see any 2 packs) and then chi ching goes the register... You get it. It is really not desirable. They are both NiMH? what could be bad?

[SmAsH]

Well, if one battery is lower mah than the others, it will run out before the others then drain off them for the rest of their time. You COULD do it and it would work, its just that it would not work the best it could.

[dellagd]

it would not just do this?

Would the only side effects of this be dropping the average mAh from 2300 mAh (would be if all Energizer) to 2240 mAh (The 4 energizers and the duracell)

[Razor Concepts]

Rechargable AAs are not designed to be soldered to, and soldering may damage the cells. I would reccomend just modifying a 6-aa battery holder.

[dellagd]

well, I guess I should, besides doing the 6-AA holder pack idea, I could just electrical tape some metal onto it to connect the - and + terminals together.


New question:

would a 9v 350mA power adapter work fine to charge them? I would mod it to connect to the 6v battery pack.

[waltr]

I agree with all the comments posted above. The cells must be matched to build a pack.

When I build packs I buy cells that have a tab welded on each end of the cells. The tabs are then easily and safely soldered together.

[Soeren]

Hi,

They are both NiMH? what could be bad?

When the lower capacity battery runs out before the other cells and the circuit is still consuming, the weak battery will go toward 0V and continue to pole reversal, as the rest of the batteries in series with the load will be a charger of wrong polarity - draw it on paper if you cannot imagine it.

Some things just don't mix well, like drinking and driving, shoes and battery cells.


Cells should be spot welded if anything.


Your adapter can be made into a slow charger, but it will be... Slow.

[dellagd]

point taken

thank you!

[Gertlex]

I use a 6V supply with 5 NIMH rechargeables and copper wire + spring from a pen to join the terminals in the empty battery slot.  I remove the batteries for charging, though.  Don't have said pack with me, so I can't provide a pic.