Looking for CR2 unprotected batteries..

Hello!

I recently bought a dilda from DealExtreme and some CR2 batteries and it seems they are just to big to fit, I bought those Lifepoh 3.2V thing but it needs 3V it says and I guess my batteries are protected and thats why they don't fit (like a green outer layer)..

So I'm wondering, does anyone have normal CR2 3V batteries (2 pieces) and maybe a charger?

I live in Sweden.

I just don't wanna wait for a new DealExtreme package and the batteries here in Sweden costs $22 a piece..

Thanks.

I don't think this is possible:

- Rechargeable
- 3.0V
- No internal battery circuitry adding bulk

As far as I'm aware, lithium ion rechargeable cell chemistry implies a nominal cell voltage of ~3.7V, except for LifePo4 which is a bit lower. But to get the 3V that we see from "3V" rechargeable lithium ions, there's some sort of little (buck? linear?) regulator on a chip inside the cell.

At least, that's what I remember reading on CPF many years ago before the rechargeable 3V cells were really out there.

I used eBay Australia: Buy new & used fashion, electronics & home d and eBay Australia: Buy new & used fashion, electronics & home d for my dilda. Are you sure your not using cr123's? The batteries I linked are 3.7v @ full charge, NOT 4.2v, so they are defined as 3v

Nocturnal said:

I used eBay Australia: Buy new & used fashion, electronics & home d and eBay Australia: Buy new & used fashion, electronics & home d for my dilda. Are you sure your not using cr123's? The batteries I linked are 3.7v @ full charge, NOT 4.2v, so they are defined as 3v

Click to expand...

Well, I made a mistake it turns out.

I had purchased dual CR123A's and thats the problem. I kept asking why did I do it and it turns out that the DragonLasers Spartan that is on its way needs CR123A's so I had purchased them for that.. Now I ruined one of the batteries by removing the green thing around them.

Oh well, bought a new pair + new pair for the dilda.

"The mistake that netted me a CR123A battery" haha. :cryyy:

I'm sorry to harp on about this, but can someone help me understand where we get 3V (nominal) lithium ion cells from, if they're not just regular 3.6/3.7V (nominal) cells with a voltage dropping diode on a PCB integrated into the cell?

I was under the impression that we have:
- 3.6/3.7V (nominal) Typical Lithium Ions
- 3.0V (nominal) Typical Lithium Ions (with a diode onboard dropping voltage)
- 3.2V (nominal) LifePo4s

So, what are the little 3V green CR2s we all use in our GLP pointers? I had assumed they were lithium ions with a diode inside to drop the voltage. Are they something else?

Is there actually a 3V lithium ion rechargeable?

i think the 3.7v ones are lithium-ion and the 3v ones are just lithium.??

Nocturnal said:

i think the 3.7v ones are lithium-ion and the 3v ones are just lithium.??

Click to expand...

Lithium cells are primary cells - not rechargeable.

rhd said:

I'm sorry to harp on about this, but can someone help me understand where we get 3V (nominal) lithium ion cells from, if they're not just regular 3.6/3.7V (nominal) cells with a voltage dropping diode on a PCB integrated into the cell?

I was under the impression that we have:
- 3.6/3.7V (nominal) Typical Lithium Ions
- 3.0V (nominal) Typical Lithium Ions (with a diode onboard dropping voltage)
- 3.2V (nominal) LifePo4s

So, what are the little 3V green CR2s we all use in our GLP pointers? I had assumed they were lithium ions with a diode inside to drop the voltage. Are they something else?

Is there actually a 3V lithium ion rechargeable?

Click to expand...

I don't think it could be a diode dropping the voltage because that would cause problems charging right?

I'm not sure what they really are, but I think they have some type of circuitry responsible for it because 3v ones are usually longer. (so Ive heard)

benmwv said:

I don't think it could be a diode dropping the voltage because that would cause problems charging right?

I'm not sure what they really are, but I think they have some type of circuitry responsible for it because 3v ones are usually longer. (so Ive heard)

Click to expand...

You might be right. There's something inside though. If you look up li ion chemistries on wikipedia, none are 3.0 V.

Some secondary CR123 Li-ion battery (or 16340) and CR2 have a circuit to bring the 3.7v down to 3.0v, to make compatible with devices
that use primary Lithium Manganese Dioxide cells, so you can use a rechargable cell in a device which is expecting run only with a primary 3.0v battery.

However, this tends to sacrifice a substantial portion of its capacity, also note that normally they need to use a different charger from normal li-ion cells.

Here's what a lot of us are familiar with:
Rechargeable 3V CR2 800mAh Green (Pair) - Free Shipping - DealExtreme

Looks to me like a cell with a PCB on it.

I suppose my remaining question is - should they be charged with:

1) A regular li-ion charger (meant for 3.6/3.7V nominal cells)
2) A LifePo4 charger (meant for 3.2V nominal cells)
3) Some other charger ?

^^ This was already answered before, you need a specific charger,
and yes, as mentioned above, also contain a Circuit Board to regulate the voltaje.

Also this type of batteries "normally" uses a protection circuit against overcharge/overdischarge/overcurrent,
(maybe not all the cited before) and many chargers do not like this.

For charge a secondary 3V CR123 battery this as an example (Is not very good, but it is for instance).

UltraFire 3.0V/3.6V CR123A Charger - Free Shipping - DealExtreme

I've never tried to recharge these batteries with a LiFePo4 charger, but the LifePo4 charger
uses also a constant-current, and constant-voltage like the li-ion battery chargers,
what is most different between the 2 types of batteries is the charge current, which for LiFePo4
batteries is higher, and the voltage which also differs somewhat, 3.2 ~ 3.3v.

If the charge current can be adjusted to the needs of the your secondary 3v li-ion battery,
"maybe you can use it", but for security I would rather have a dedicated charger to recharge each battery type.