3s or 4s?

[Royston]

Hi
Lookng to get some new lipos.
Best for 450/525 3s or 4s brand and capacity.
As a newbie only gentle use ie. Hovering an poss cicuits.
Regards
Roy

[guest325]

If you want to get long flight times go for the higher mah packs i.e. 4000 - 5000 mah. I use Turnigy Blue packs and think they';re OK.
As regards 3S or 4S if your motors are OK with 4S then that';s the way to go, you get a better power density by going 4S and they are going to run the motors at lower amps for the same power so should run cooler; if you do go 4S you might need to look at getting smaller props, when prop sizes for motors are quoted the larger size is for the lower cell count and the smaller size for the higher cell count - sound ar5e about face but that';s the way it is.

[Royston]

Cheers Darrell
Am I right in saying you need to power with a ubec to use 4s?

[robshaw]

You will need ubec for 4s and 3s. Ubec is to reduce the voltage from your lipo to 5-6v for the fc and rx.

[Balders]

The thing that';s gonna emit the magic smoke is going to be your esc';s if they are not rated for 4S.  Check your esc';s first.
Also make sure you check the weight of the packs.  A 3S 2200mah pack is gonna weigh half a 4S 4000mah pack, and your airframe may struggle.

My 400mm quad on 3 year old 2200 3S packs still gets a good 8 minutes generally pottering about.  If I add a gopro, that time comes down pretty quickly so definitely consider weight the enemy.

[guest325]

Assuming your esc';s and motors are up to 4S the thing to do is decide how much flight time you want then work out from the wattage of your motors (this would be at full throttle so hover times would be a lot more) how many Watthours you want then you can work out the battery size you need for 3S or 4S
Volts x amps x hours = Watt hours
You can then go into the weights of the packs and see which gives best advantage.
That';s a bit simplistic because it doesn';t take efficiencies into account but accurate enough for your needs.