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6 volt battery with AA rechargeables?

MegaVovaN

Diamond Member
There is a youtube video where some dude takes apart a 6 volt battery (lantern type thing) and there's a bunch of AA batteries.

I want a 6 volt battery "case" where I can PUT AA rechargeables!
 
It's shens, HOWEVER, it wouldn't be too hard to make one for yourself.

Incidentally, the 12V garage door opener batteries actually DO contain a bunch of 1.5V button cells.
 
I see...now I am going to wonder how to do it myself. Five of AA rechargeables (rechargeables run at 1.2 volts constantly) will equal exactly 6 volts...mmm want to put that 1 million candlepower light to good use!
 
buy a 6 volt battery, use it, when dead, tear it apart and rebuild with rechargeable batteries.

I've done this with laptop LiIon batteries and loose LiIon cells
 

Many device that have >1.5V may employ multiple AA cells, however they are not all created equally because some cell are design to tollerate high drain, other are design to last @ low drain for certain electronic/motor.
 
Originally posted by: RU482
buy a 6 volt battery, use it, when dead, tear it apart and rebuild with rechargeable batteries.

I've done this with laptop LiIon batteries and loose LiIon cells
I once try putting high discharge AA cells into battery operated drill and the power was dismal compare to Sub-C.
 
Cool, I already have a 6v battery in that $4 walmart light. When dead I'll tear it down and make 5 AA rechargeables in serial for 6 volt, or if I can fit it there, two banks of 5AAs in serial connected in parallel for more capacity. (5 within bank in serial, banks themselves in parallel). If I can find a way to make it modular - so I don't have to tape/solder batteries between each recharge, I'm golden!
 
Originally posted by: NoShangriLa
Originally posted by: RU482
buy a 6 volt battery, use it, when dead, tear it apart and rebuild with rechargeable batteries.

I've done this with laptop LiIon batteries and loose LiIon cells
I once try putting high discharge AA cells into battery operated drill and the power was dismal compare to Sub-C.
Were the Sub-C cells NiCad, and the AA's NiMH? NiMH generally has a lower maximum discharge rate than NiCads, because the former's internal resistance is a bit higher.

But a drill is a high-drain device; putting such a large drain on a AA would likely drop the voltage very low, causing that poor performance you saw.


Originally posted by: frostedflakes
You need something like this OP.
Nifty. 🙂
Now just get a few AA->D adapters, and it's good to go. :laugh:

 
Originally posted by: feralkid
Originally posted by: frostedflakes
You need something like this OP.

That is darned clever!

It's clever, but I want 5 AA's. Even with AA>D adapters voltage would only be 1.2*4=4.8 volts out of 6. With five AA's it will be exactly 6 volts, and unlike regular batteries it will STAY 6 volts until AA's run out of charge completely.
 
What exactly is this application? Why must they be AAs, and why in a 6V lantern battery case? They won't give an amperage rating anywhere near that of a regular lantern battery.

Batteries also don't have a linear discharge curve anyway.
Sample curves from some testing I did.

They'll start out around 1.2-1.5V, but then drop down closer to 1V, and hold steady there for a majority of the discharge cycle, with an abrupt dropoff at the end.

Note that those curves aren't really very good, as I was looking at a bunch of potential lemon batteries. However the general shape is still reasonably accurate.

 
Jeff, the application is typical light/lantern thing:
http://www.walmart.com/catalog....do?product_id=8111410

They must be AA's because I have lots of rechargeable AA's.

You bring up interesting point about amperage...so even if I wire the 5 rechargeable AAs together, it won't work?

You are correct about batteries not having linear discharge curve. I was saying the rechargeables have pretty straight rate: they start at 1.2 volts and stay there until they turn off completely. Or so I heard.
 
I wondered about the application because AAs simply might not be able to provide enough current.
But if it's a simple lantern, that shouldn't be bad. You just won't get such long life out of it. I don't know what the typical current draw of a lantern lamp like that would be though.
And you might be able to get lower voltage lamps for it.


That, or else venture into some flashlight forum (Candlepower forums perhaps?) and look at getting an LED retrofit kit of some sort. 😀
Those things should have regulation circuitry, capable of taking in a wide range of voltage inputs.

4.8V 500mA lamp at Radio Shack
They've got a wide range of voltages there; you'd just need to find something that fit that lantern.

Then get that adapter thing on eBay, and get some D-cell adapters....by that point, you could probably just buy another flashlight though. 😉


 
AA's will have less capacity, typically 2 - 2.5 Ah vs 4 - 5.5 Ah for D cells. Second, you can discharge NiMH cells in parallel, but it is not recommended to charge them this way as the strong cells can discharge in the weak ones causing them to explode.
 
Buy them bulk. 40.40lbs. 😉

SLA batteries are nice in that they can retain a charge for awhile, but lead acid always loses in the weight department.
Be careful that you don't accidentally contact those springy terminals though. Those things could easily spot-weld themselves together from the initial spark, and then start to glow red-hot. I don't know exactly what a lead acid battery does when it's shorted out for several seconds, but I know it's not good news. At worst, it may burst. At best, you might just have to buy a new battery.

Triton 2 - if you really want to go nuts with a battery charger. It can charge almost anything.


 
Originally posted by: Cheesehead
You can get a 5 amp-hour battery in roughly the right shape for $15 online. Just solder a Molex connector to the leads and the original battery terminals.
It's not much good without a charger though. 🙂
I prefer to have reasonably intelligent chargers too, with some kind of voltage detection. You could probably get a fairly cheap trickle charger, but I don't know how hard those are on batteries if they're just left plugged in.
My experience with cheap chargers is that they kill batteries. I once had a Dustbuster, and its entire charging circuit consisted of a resistor and a diode, connected to a standard wall-wart power supply. Those batteries died after just a few months. In my opinion, a good charger should sense the voltage of the batteries it's charging, and drop down to a very low maintenance charge once the battery has reached a full charge. An even better charger would taper the voltage off gradually as the battery reaches full capacity.


Another option, but it involves some "customization":
This and this, with this. Do some splicing, covering the soldered splices with heat shrink tubing.
Short out one of the connections in the battery holder, allowing you to use just 5 AAs.
Then get this, and retrofit it into the lantern somehow. (Bad idea. 20W @ 6V would give a current draw of 3.3A. It'll be bright as hell, but you'll probably melt some insulation somewhere.)
Surround the adaptor in some custom-cut styrofoam so it fits snugly in the lantern.

Don't sue me if you burn your house down.😉

 
Originally posted by: Jeff7
Originally posted by: Cheesehead
You can get a 5 amp-hour battery in roughly the right shape for $15 online. Just solder a Molex connector to the leads and the original battery terminals.
It's not much good without a charger though. 🙂
I prefer to have reasonably intelligent chargers too, with some kind of voltage detection. You could probably get a fairly cheap trickle charger, but I don't know how hard those are on batteries if they're just left plugged in.
My experience with cheap chargers is that they kill batteries. I once had a Dustbuster, and its entire charging circuit consisted of a resistor and a diode, connected to a standard wall-wart power supply. Those batteries died after just a few months. In my opinion, a good charger should sense the voltage of the batteries it's charging, and drop down to a very low maintenance charge once the battery has reached a full charge. An even better charger would taper the voltage off gradually as the battery reaches full capacity.


Another option, but it involves some "customization":
This and this, with this. Do some splicing, covering the soldered splices with heat shrink tubing.
Short out one of the connections in the battery holder, allowing you to use just 5 AAs.
Then get this, and retrofit it into the lantern somehow. (Bad idea. 20W @ 6V would give a current draw of 3.3A. It'll be bright as hell, but you'll probably melt some insulation somewhere.)
Surround the adaptor in some custom-cut styrofoam so it fits snugly in the lantern.

Don't sue me if you burn your house down.😉

Sweet!
Maybe I can use this as my second light on the bicycle (get a on/off switch and custom case, since lantern case is too big for a bike). "Bright as hell" is what I need! No worries about house fire, I got extinguisher ready.. 😉
 
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