NiCD sub-c capacity data ?

[InHisName]

I just found sub-c Ansmann 3000MAH listed on a site for 11.5 eruros, Uggh!

I guess I'll have to stay with NiCDs then. I have 4 old drills with 2 batt packs each. 44 cells in all. I think I'll re-build one drills batteries first. Of the two best prices I can afford/ justify, has anyone tested all 24 cells with C9000 or similar ? Is there much spread among the cells sent ?

Tenergy brand --- UnNamed brand

Both of these are about $1.60 / cell including shipping. If you know of any better pricing and whether the spread of MAH is tight or spread out ?

 

[Curious_character]

One word of caution -- cells almost never have the claimed capacity. And in general, the more obscure the brand, the greater the exaggeration. It's unwise to choose a cell based only on the manufacturer's claimed capacity -- if you do, you'll usually end up getting poor quality cells with a lot less capacity than claimed, and less than you would have gotten from more reputable and honestly specified cells.

c_c

 

[InHisName]

I am MORE interested in keeping the spread from min to max MAH nearly the same in a battery pack that actually having all cells meet the number printed on the wrapper.

 

[lctorana]

Sub-C NiCads are between 1200 and 2000mAH typically.

Reliable, high-quality and high-current ones are usually in the 1700 to 1800mAH range.

 

[clintb]

Sub-C NiCads are between 1200 and 2000mAH typically.

Reliable, high-quality and high-current ones are usually in the 1700 to 1800mAH range.

Actually a bit higher. You can still find Sanyo CP2400's, but they're around $5.75 each. Ouch!

 

[45/70]

I am MORE interested in keeping the spread from min to max MAH nearly the same in a battery pack that actually having all cells meet the number printed on the wrapper.

The same guidelines as Curious_character mentioned, apply to variance of capacity between cells. The cheaper, less known brands have more variance between cells.

If I were building a pack for a drill (which I have done), or any other high load tool, I'd use some good NiCds like Sanyos. They'll last longer, and have more oomph than NiMHs, though you will have to charge them more often.

Dave

 

[lctorana]

Actually a bit higher. You can still find Sanyo CP2400's, but they're around $5.75 each. Ouch!

That's bordering on unbelievable for NiCads in that size, and a price per cell that low would only be seen here in a clearance sale.

 

[InHisName]

That's bordering on unbelievable for NiCads in that size, and a price per cell that low would only be seen here in a clearance sale.

You are saying that $5.75 is a LOW? price ! Hah! The drill was bought years ago when NiMH was unavailable and NiCDs were much more costly. It was $49 and incl 2 batteries. I checked then and replacements were $39. Even @ $4 per cell, the parts at $44 is way more that the builder was doing back in early 90's. The adv claims was that the cells were 'matched', which implied knowledge of MAH of each cell and picking 11 closely matched ones for building a pack.

Anyway that is what I'd like to do with an eBay buy. However, I'd prefer if somewone has already tested a batch on their C9000, then I'd know how spread out one bactch really was. I could calc two groups of 11 and decide if that was good enough for me to make a buy and try.

 

[Curious_character]

I have an 11 cell pack of Sanyo sub-C NiCd cells that I've measured several times by discharging in series groups of 3 or 4 to prevent any possibility of cell reversal. These cells are specified at 2.4 Ah, and were discharged at a constant 400 mA rate. The first discharge showed:

1st 4 cells: 2320 mAh
2nd 4 cells: 2307 mAh
3rd 3 cells: 2287 mAh

After some abuse, long periods of cold storage, and a number of cycles:

1st 4 cells: 2200 mAh
2nd 4 cells: 2193 mAh
3rd 3 cells: 2173 mAh

These cells are all from the same batch, and weren't otherwise selected or sorted. I think this is about what you could expect from high quality cells from the same batch. I'd expect a lot more variation, less capacity, and shorter lifetime from off-brand cells.

c_c

 

[clintb]

That's bordering on unbelievable for NiCads in that size, and a price per cell that low would only be seen here in a clearance sale.

Unbelievable, for it to be 2400mAH? Nah, Sanyo 2400's were THE thing before NiMh came along in the RC world. Now, I'm not sure of the CP2400's durability since it was the RC2400 that was so widely used, but some Google searching could give answers.

 

[InHisName]

I have an 11 cell pack of Sanyo sub-C NiCd cells that I've measured several times by discharging in series groups of 3 or 4 to prevent any possibility of cell reversal. These cells are specified at 2.4 Ah, and were discharged at a constant 400 mA rate.

Thanks! Finally someone who has measured something with sub-c's. So for no-one has admitted ordering a big batch from and eBay seller and measuring what was sent.

Interesting when new you got 33 diff range and after being abused only 27 diff. Just a bit north of 1% of total. Sure seems MOST excellent. I'd be tickled with even 2-3% variation, if I spent less than $2/cell.