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Lipo voltage is rated by cell, 3.7 volts per cell. 1s = 3.7, 2s = 7.4, 3s = 11.1, etc., etc. No 8.4 volt lipos. They are wired in series. They use (s) to designate cell count instead of (c) so that cell count will not get confused with the C rating of the cells. The C rating is the cells discharge capacity. The higher the C rating the more amps the cell will put out. 1 C is 10 times the ah of the cell.

Using one of my flight packs for example...

A 3s-11.1v-1800mah-20c rated pack= 3 cells, 11.1 volts, 1800mah (1.8ah) capacity (run time), 36 amp max continuous discharge rating (1.8ahx20).

Hope that helps more than it confuses.

justinspeed79 wrote:They use (s) to designate cell count instead of (c) so that cell count will not get confused with the C rating of the cells.

actually they use S to designate that the cells are connected in Series.
some air packs will have names like 2p3s meaning they have 6 cells, 3 sets of parallel cells in series with each other.

aconsola wrote:

justinspeed79 wrote:They use (s) to designate cell count instead of (c) so that cell count will not get confused with the C rating of the cells.

actually they use S to designate that the cells are connected in Series.
some air packs will have names like 2p3s meaning they have 6 cells, 3 sets of parallel cells in series with each other.

My bad. You learn something new every day.

justinspeed79 wrote:Hope that helps more than it confuses.

I think I should've just stopped while I was ahead . I get the jist I guess for now...yep, just throwing numbers out there from the NIMH packs and stuff but like you said...you learn something every day.
Todd

Look, Im only new to LiPo myself.. Ive got 2x Reedy 5000 Pro's, 2x Intellect (trinity) IP3800's and 2x cheapie 3200 Yeah Racing packs (for practice and bashing)..

Yery impressed with the Yeah racing packs because they are only $40 each, and will fit in cars that need a stick pack (eg Tamiya Mini), buy they are not ROAR approved..

The Intellect IP3800, very impressed, especially considering that they are only $60 - $65 each.. Hopefully they wont have the same "explosive" power that the Intellect NiMh cells have had...Time will tell..

Reedy 5000.. I expected more from these batteries, especially for the money they cost.... They are also heavier than what is advertised on the packaging and AE website..

Things to consider when selecting LiPo batteries..
Voltage - Is directly proportional to speed, but can your ESC/Motor handle anything greater than 7.2/7.4 Volts.
Capacity - How long do you want your model to run for.. The greater the mAh rating, the longer it will run for per charge..
"C" rating - Stated the maximun continuous discharge current the battery can deliver.. eg For a 5000mAh (5Ah) @ 20 C maximun continuous discharge current 100A..
Other considerations - Hard case / soft case - Do you need the pack to be ROAR approved (eg for racing)... - Will your charger charge LiPo batteries...

Goodluck.

Eau Rouge wrote: In the last couple of years, he's also taken out ads in every R/C magazine printed telling everyone how LiPos would burn your house down, rape your women and steal your children. Today, Ernie can't get the LiPo packs to the market fast enough to make his pocket happy.

Haha, that's funny

The Orions are always a good choice. As mentioned previously the 3200 & 3600 fit in some chassis better than the 4800. They are in the process of updating to a new series, 3400, 3800, & 5000. The 3400 is supposed to fit even better in sub c designed rides.

But if it's a modern ride or you have the room for a squared off pack consider the TrakPower batteries. In my experience they perform better than the Orions, higher C rating and thus better voltage under load. And they also maintain balance. Of course the new Orions probably have closed the gap. Don't know how well they fit in a RC10, but I mention them partly because of their gold color. If they fit they would really bling out a gold tub.

These are all hard cased batteries. Strongly recommended, lipos are sensitive to puncture damage, one of the ways they can end up burning your house down, raping the wife, stealing the kids thing that Uncle Ernie warned us about.

Another thing I didn't see mentioned here, is that your esc MUST be able to handle a voltage cut-off...LIpo DO NOT LIKE being completely discharged while running...I think the one that was originally mentioned will do lipo cut-offs, but I figured it was a point to be made...

for a 2cell lipo pack (7.4v), the esc needs to be able to do a 6v cut-off - its basically 3v per cell, so a 11.1 lipo would have a 9v cut-off..Most of the newer esc are all lipo "friendly" and will have a setting to do a voltage cut-off - not like in the "old" nimh days where you would run a pack until it was completely dead

Also when storing lipo packs they need to be at least 1/2 charged for weekly use, and full charge if they are going to sit for a while Lipo's don't like sitting with low voltage...

and i would whole-heartedly go with a hardcase lipo pack - if you run in any kind of sanctioned event (ROAR or other-wise), they are now requiring LIPOs being in a hard-case and some places even go as far as requiring them to be charged in a lipo-sack...

and as far as the new Tekin Lipos - they are now available and at stormerhobbies and towerhobbies and axiom motors. Yes, Tekin takes a while to get some things to market, but all good things are worth the wait

justinspeed79 wrote:The higher the C rating the more amps the cell will put out. 1 C is 10 times the ah of the cell.

Just to clarify as I'm not sure this wasn't a typo. I was under the impression that 1C is 1 times the amp hour rating of the cell, this is important as I believe most Lipos charge at 1C (certainly all of my flight packs do) so unless Lipo technology has moved on whilst I wasn't looking (and it may well have done) if you charge them at 10 times amp hour rating you might just burn you house down

More great info. Thanx again guys. I learned my lesson and scared myself to death when I found it a couple years ago. I use nicd in my radios and had just bought the revolutionary state of the art futaba am 2pl(yes, I'm laughing too/still using it) and had plugged it in overnight to my trickle charger so it would be ready for the next day. Well the power strip had been shut off so I put it on my field charger in my rc room to get it charged for that night and forgot about it after lunch. No biggie I thought since it went to a trickle charge after it peaked. I went to grab it and the bottom of the radio was melted to the carpet . Seems I had a bad Nicd amongst the 8 and it shorted but the fuse didn't blow on the field charger. This was with nicd and I no longer use it in the house. Now it goes to a steel table in the garage for ANY battery charging. Yep, so when the lipos came out and some bad publicity came with it I just stuck to nitro. Now I feel like Billy Madison starting all over with these things . Thanx and hope the info keeps coming. I'd like to hear from anyone with an opinion or advice!
Todd

Synergy wrote:

justinspeed79 wrote:The higher the C rating the more amps the cell will put out. 1 C is 10 times the ah of the cell.

Just to clarify as I'm not sure this wasn't a typo. I was under the impression that 1C is 1 times the amp hour rating of the cell, this is important as I believe most Lipos charge at 1C (certainly all of my flight packs do) so unless Lipo technology has moved on whilst I wasn't looking (and it may well have done) if you charge them at 10 times amp hour rating you might just burn you house down

Yes, you are right. Wow, I even proof read that before I posted it. Guess I should have checked it twice!