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Jedibowls
04-29-2008, 11:19 AM
Are Li-Ion batterys safe for our application? I have seen plenty of warnings and wnted input from people who use them... Thank you

xwingband
04-29-2008, 11:27 AM
Yes, provided you use them properly. Treat them respectfully and they're no harder than NiMH.

I'd say any danger is in people making packs and don't know what they're doing... like soldering that could have been done with a blowtorch it was so bad. (Seen it!)

Dark Navel
04-29-2008, 06:26 PM
Jedibowls,

Make sure you read through the forums about these batteries not only from the custom made packs but also using too many batteries and frying the valuable boards inside the hilts.

It would be a bad day if you fry a Corbin board and a REALLY bad day if you end up frying a Crystal Focus, (CF from Plecterlabs.)

Dark Helmet
04-29-2008, 10:44 PM
I love mine, but the down fall is the high output when it isn't needed. like DN said, you can easily burn out a board or led, but the really great thing is if you make sure they have a pcb (TCSS one's DO) it will shut down the battery if you get a short in the system (that will not prevent you from burning out anything though). you can reset the battery by disconnecting the ground. with a properly installed chargeport you can reset the pack by just inserting a killswitch, that easy! So many times have I overlooked a "minor" detail that would have blown an led or slowly burned out a board... so in the long run it saved me a bit of money. They also take up very little room for the power they have.....with that said, the nimh packs are getting longer run times, as long as you want to fit it in mhs parts. Li-Ion also has very little weight, so there is a lot to consider when choosing a battery, just don't worry about the hype of li-ion being unsafe, as they are often mistaken for li-poly, which could be a nightmare if you swing it around and hit something...just get a pre built pack and make sure you pad it a bit in the hilt ( protect that pcb!), it should do fine otherwise^^

Novastar
05-01-2008, 12:09 AM
To echo what Dark H. said... YES they are perfectly safe--if not safer in most cases, thanks to the PCB.

You *CANNOT* run Li-Ions effectively WITHOUT the PCB. If you do... you're asking for some big trouble:

1. If w/o a PCB... and you charge it--there is NOTHING to prevent it from over-charging and it WILL explode at one point. Theoretically. I've never been so foolish and stupid to do this.

2. If w/o a PCB... and you drain the cell to a certain low point of voltage... something like 2.5v... that's the end of it. It will NOT recharge again, and become useless.

3. If w/o a PCB... and you cause a short circuit... you might blow the cell up and damage circuitry attached to said batteries.

Those are just three examples.

The PCB is... well... exactly what it is-- a printed circuit board that "drives" the cell, protects it, and pretty much PREVENTS *ALL* of the above problems and more.

I have momentarily shorted my cells at points... and all sorts of weird things have gone on... but the PCB has *ALWAYS* saved my dumb arse... :)

Anyhow. They're cool. 3.6v packs a punch for a single cell too. Lithium is also the lightest metal on the periodic table, so... where weight is concerned--that's it right now. It doesn't get any lighter, lol!

X
05-01-2008, 09:52 PM
What kind of MAH and voltage are you guys running from Li-ion I've seen some that are from 2400-4800mah and 7.4v

Novastar
05-01-2008, 11:40 PM
As with any battery cells, you can wire them "for the voltage" or "for the current output".

So... if you set up the following: 2 x 18650 Li-Ion 3.7v cells rated at 2400mah... they can be expressed in the following ways...

3.7v with 4800mah
7.4v with 2400mah

A single Li-Ion 18650 cells will usually have anywhere from 2000 to 2600mah, depending on the vendor, company, and what they list as their "spec".

I say most cells will get 2200mah, and sometimes manufacturer's "push" their specs to sell more easily. Or... sometimes they really DO have more layers of anode/cathode or whatever.

Again, the "mah" is nothing but saying: "if you ran me and drew 1A of current consistently... I will last [its mah rating] divided by that 1A (1000ma).

In other words about 2 hours sucking down a consistent 1000ma like an elephant on crack in a peanut farm.

BlackDOG
05-05-2008, 10:56 PM
Working on my pack tonight......

Xwing- I read you tutorial on soldering packs(btw..I can't find it...I am really punchy tonight), but I am curious....how much insulation would you use to prevent shorting the pack out along its length.....

you cautioned against using naked (or as we say in the South- nekkid) wire and relying on the insulation around the case, but is ordinary insulated wire OK....

bd

Novastar
05-06-2008, 06:38 AM
You can pad the battery cells in anything from a thin layer of electrical tape... to padding it with... you know--squishy foam so that they can touch nothing from any end.

The Lithium Ion cells are pretty hardy though... I mean, you handle them as you would most any other cell. The beauty is the PCB... it really does act as a great failsafe for many many many possible concerns/issues! A short being one.

If you short the cell(s)... the PCB will cut the power, and the cell(s) will read 0v (or something bizarre like 1.03v, lol) in a charger for a bit. Plugging them into a charger will usually reset the PCB... or you simply wait some time until it does so on its own. This "low" voltage is *NOT* "real"... it is just the PCB doing its job.

If the PCB is working, you cannot really short the cells, nor can you under/over-charge them. TMI, huh? :)

Hasid Lafre
05-06-2008, 07:10 AM
Iam wondering when tim will stock thoes kinda of battery packs.

3.7v with 4800mah
7.4v with 2400mah

I would love to see some longer runtimes on the li-ion packs.

Mad Hatter
05-06-2008, 09:27 AM
If you are making your own, BatterySpace sells 2600mAh 18650's.
I used those for my pack. It's only 200mAh difference, but every little bit helps. :)

Novastar
05-07-2008, 06:35 PM
Additionally, some packs are sold touting "7.4v", whereas others are "7.2v".

Well... if you're using a driver, it will all essentially translate into the same thing: longer run time. Whether 7.4v @ 2200 or 7.2v @ 2400... it's all the same ball o' wax for the mostpart.

Besides... *I* think some of the manufacturers "tweak" their ratings so that it seems "better". When, in ESSENCE... you only get so much out of a certain size with Li-Ion (as with any cell). You can only play with the physics so much, ya know? I mean... how thin can each anode/cathode layer BE?! hahhaha

Mad Hatter
05-07-2008, 08:50 PM
Besides... *I* think some of the manufacturers "tweak" their ratings so that it seems "better".

Yes. UltraFire is one that way overstates their ratings. Check out the cells on DealExtreme. Look at the info from the site and also in the reviews. You can find "real world" specs for several li-ion batteries.