A 3S pack is three LiPo cells in series - 11.1V nominal, 12.6V fully charged. It is the most widely used size in the hobby, and the default for 1/10 electric cars, mid-size helicopters, sport planes and a lot of FPV gear. If you are not sure what your model takes, 3S is the most likely answer.
What we stock
Gens Ace - the mainstream choice, in hard case and soft case, with XT60, T-plug (Deans) and EC3 connectors. Radient - good value packs from 1300mAh upwards, mostly EC3 and XT60. Maniax - receiver and transmitter packs as well as main flight packs. We also carry Spektrum Smart and Traxxas iD batteries for models that use those systems.
Choosing capacity and C rating
Capacity in mAh sets run time; C rating sets how hard the pack can be discharged. A 5000mAh 50C pack will deliver more current than a 5000mAh 25C pack of the same size, which matters on a brushless car or a 3D heli and matters very little on a sport plane. Bigger is not automatically better - check the battery bay dimensions and the weight before buying, because a pack that does not fit or upsets the balance is no use.
Connectors
Check what your model and charger use before ordering. XT60 is the most common on modern cars, T-plug (Deans) is still widespread, EC3 and EC5 turn up on Horizon products, and Traxxas iD packs only work properly with Traxxas iD chargers. We stock adapters if you have a mix.
Safety
Charge on a LiPo-capable balance charger, never leave a pack charging unattended, and store at around 3.8V per cell rather than fully charged. A swollen or punctured pack should be retired, not used. We sell LiPo safety bags and balance chargers.
Other sizes
See 2S, 4S and 6S LiPo batteries, or the full LiPo battery range.
