voltage on a futaba rx.?

[mid-air]

i want to use a 2cell pack of lion 7.4 v to power a futaba rx. and futaba servos but dont want to use a v reg. will the rx. and servos stand the voltage? AL

[Julez]

While the rx might barely stand it, the servos will not make it long.

[AndyOne]

Mid-air,

A fully charged 6V Ni-MH battery will be close to 7.4V which I routinely subject my Futaba receivers to without problems but a fully charged 2 cell Li-ion pack will be 8.4V, that's probably going a little too far. The 7.4V rating of the Li-ion pack is the average voltage not the peak when fully charged.

Andy.

[alexcmag]

Most receivers will accept 7.4V (6V-8.4V actually) without trouble, since they have an internal 3.3V regulator.

The trouble are the servos, most are designed to 4-cell NiCd (up to 6V) and some to 5-cell NiCd (up to 7.5V).

A lot of people fried servos this way.

[mid-air]

HI GUYS: my lion cells are rated ad 3.3v which is 6.6 per pack, when according to my charger are done i checked the volts, it reads 7.4v , must be some older cells. maybe i should get some new ones? AL

[Rodney]

You may severly overheat and destroy the regulator in the receiver if you input to high a voltage as even a 5 cell battery pushes them to the limit suggested by the manufacturer. You will also overstress the electrolytic capacitor voltage ratings.

[mid-air]

HI GUYS: my lion cells are rated ad 3.3v which is 6.6 per pack, when according to my charger are done i checked the volts, it reads 7.4v , must be some older cells. maybe i should get some new ones? AL
my mistake my volt ohlm meter is wrong, i checked the voltage on a pro peak charger it read 8.130 v so my batteries are ok.

[ZAGNUT]

You may severly overheat and destroy the regulator in the receiver if you input to high a voltage as even a 5 cell battery pushes them to the limit suggested by the manufacturer. You will also overstress the electrolytic capacitor voltage ratings.

no modern receiver uses more than 20mA and everyone that i have is rated for at least 9.6 volts if not higher.

have flown for a while using 2 lipo cells and no regulator. servos where quicker but never had a problem until i puffed a Tx pack and decided that lipos and their charging characteristics are not for me. if ever i decide to try electric power i may look at them again.



dave