Reciever batts regulators

[ethinger]

Hi guys,
any idea where i can find step down regulators for LiPo batts?
2 cells should give me 7.4v. and 3 cells should give me 11.1v.
is there a step down Reg from 11.1v to a 4.8v?
or just a standard 7.4v to a 4.8?
i dont want to convert it into a 6v, i would hurt my gyro?

[HZM]

Check out post number #5 and above

http://www.daddyhobby.com/forum/showthread.php?t=7537

See also this thread to use the Digital BEC safely

http://www.daddyhobby.com/forum/showthread.php?t=7336

Mike

[helirulz]

Try 2 BEC's connected in parallel for 3S1P lipo
If not use 2S2P with a linear regulator (eg. Fromeco's Arizona regulator)

[ethinger]

Hi Mike,
Since the BEC u posted can take 7 to 40V
that means i can use a 3s1p? thats only 11.1V.
do i need to do anything else?

[HZM]

In fact, u can choose to use 2S but risk the Digital BEC go in low voltage cutoff. If u use 3S, the lowest u can go also around 10-11V.... by then u will feel yr servo sluggish


Mike

[ethinger]

so what is probably the best set up for lipo Rx packs,
am running full digital with 502, i think its dranage is too high.

[helirulz]

so what is probably the best set up for lipo Rx packs,
am running full digital with 502, i think its dranage is too high.

if ur current draw is high then do as i said...go 2 BEC's in parallel for 3s1p lipo.
Or 2s2p with Fromeco Arizona regulator.
Cheapest option would be get two 2400mah Sub-C NiCd pack.
Fly 3 or 4 flights and switch packs. Charge while u fly at 2C so charging time shd be half an hour.

[ethinger]

Hi Helirulz,
where can i get the Fromeco Arizona regulator?
i think 2s2p sounds good.

[helirulz]

https://www.fromeco.org

The good thing abt the Arizona is tt there is 2 outputs, one which is variable from 5 - 6.25V for flight controls and another which is 5V only for the gyro/ tail servo

[HZM]

Go with 3S1P Etec from Mack..... he got various capacity. Most using 1700mah. I think the someone in the forum might have did some testing on 2S, 3S, 4S and 5S for the digital BEC Seems like higher the "S" the lower the current draw to the digital BEC. I think I can merely pump in 500+ mah after about 6 flights on the 1700mah.

All this is base on my limited flight experience on Hitec non digital servo, GY401 + 9254 .....



Mike

[helirulz]

For the BEC method:
try to find lower 'C' discharge bateries and get those tt are 1500mah+
It shd be the cheaper option.
Or else if u have any 3s batteries...just use them

[Super-Hornet]

Some words of advise...

Higher Serial battery connection meanning higher voltage. That means the BEC have to work hard converting the voltage. That means more stress in BEC. (U will see your BEC are much hotter at high i/p voltage than low i/p voltage)

Remember, BEC is like transformer... I/p Wattage = O/p Wattage (In theory). So, Higher i/p voltage meaning it uses lesser current i/p to produce constant o/p.

I think I can say that all Li-Poly or Li-Ion, when it reaches 2.2V or lower, it will go to cut off or open circuit state. Meaning that for 3Cells, when voltage drop to 6.6V, the voltage will suddenly become 0V! So, lets say if u use voltage regulator like LM780x (linear type), even it working voltage differences is 2V, if i/p is 6V, it still produce some voltage at the o/p for your RX and servos to work... but once your 3Cell suddenly goes o/p circuit (due to less than 2.2v), your RX and Servos and Gyro suddenly no power. Therefore, heli/Nitro = NO CONTROL in Mid Air!

Some Switching Mode type of BEC CANNOT connect in 2 or more BEC in parallel due to its internal circuitry. So, if u want to use 2 or more BEC in parallel, make sure it support it.

Super-Hornet