Li-ion batteries

[gman]

Anyone seen these new batteries from batteryspace? http://www.batteryspace.com/panasonic-l ... assed.aspx

They are 3.6v but have a huge capacity! Are these like safe to use? Also I dont see a 7.2v protection circuit or charger so would you just use the normal 7.4 setup?

 

[watsug]

That battery has built in protection pcb. The charging voltage is 4.2v so it should be chargeable with 8.4v smart chargers. The battery has a cutoff at 2.5v while most I've seen before is 3v. Is the "extra" capacity from the extra voltage it can discharge (to 2.5v)?

This battery for example is 3500mAh but says not to discharge below 3v. http://eu.nkon.nl/rechargeable/18650-si ... 0-mj1.html

 

[gman]

That battery has built in protection pcb. The charging voltage is 4.2v so it should be chargeable with 8.4v smart chargers. The battery has a cutoff at 2.5v while most I've seen before is 3v. Is the "extra" capacity from the extra voltage it can discharge (to 2.5v)?

This battery for example is 3500mAh but says not to discharge below 3v. http://eu.nkon.nl/rechargeable/18650-si ... 0-mj1.html

Hmm well in my experiences the last volt left in the battery usually drops pretty quickly and the batteries stay at there rated voltage longest, so maybe your partially right but I'd like to be hopeful.

Well seeing as the minimum voltage input for regulators is 4.5v and the minimum voltage for an lcd screen is around 6v, is there anything stopping me from using these in a gamecube portable? It doesnt look like it but I'd like to check before I blow something up

 

[watsug]

The specification pdf show the dropoff, how quick it is when it gets ~3v and below, as you said.
http://www.batteryspace.com/prod-specs/NCR18650B.pdf

The internal protection pcb, maybe they behave differently when two cells wired together? This seem to be the same cell, but without the built in protection. http://www.batteryspace.com/hi-power-pa ... assed.aspx
Wire that with a 2S protection circuit is probably better. But I don't know, I'm mostly speculating here, but I feel I've heard something like this before

 

[gman]

Great! I guess I'll do some more research and maybe i'll give this a try in the future. It would be interesting if you could use only 2 of these cells for 7.2v at 3400mah in a gamecube portable. Still a small battery life but probably better than 7.4v at 2800mah.

 

[Mooper]

I used the unprotected version of these batteries in my gcp.

 

[frostedfires]

Looks like the panasonic batteries that I use. Same capacity too. You can find them cheaper on amazon:

http://www.amazon.com/gp/offer-listing/ ... dition=new

Comes with 4 and free shipping

 

[muelkorb]

As far as i know, the 3.6V Lithium Batteries are just an older Version of the now more common ones
whereat Lithium Polymer is an upgraded version of Lithium Ion.
Just bear in mind, that those (3.6V) are a bit less save to use (again, thats something i read some time ago) and some charger pcb's might have
issues with the different voltage and inner resistance of the batteries.

Note: the more Batteries you use in parallel the less each cell is burdend and the less it should bother you which technology to use.
So if you need a current of 2 A and have 2 cells in parallel (gives also more capacity) each of them just needs to deliver 2A/2 (parallel cell) = 1 A/(parallel cell)

Usually you want to get 3.7V Lithium polymer for particularly stable batteries, but again it might be a little bit over the top for portables.
Just be sure your charger or charger pcb is capable of loading it properly and you should be fine.

just my 2 cents