What size receiver battery
12-09-2012 | 12:35 PM
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From: Sterling,
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What size receiver battery
I will have 5 DS821 and 1 std. servo in my Spacewalker.
What size receiver battery should I be using? MAH and voltage.
I will not be flying this plane aggressively....if that makes a difference.
Laurence
What size receiver battery should I be using? MAH and voltage.
I will not be flying this plane aggressively....if that makes a difference.
Laurence
12-09-2012 | 01:07 PM
#2
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RE: What size receiver battery
Laurence I have no idea what DS821's are but my guess is you are using a 2.4 system and for that reason and the size airplane I remember from your previous postings I would indeed use a six volt pack (five cell) and not a 4.8. I refuse to use 4.8 in any of my airplanes except just a couple of controlline airplanes that I use 2.4 for throttle.
I have never had a brownoout or low voltage problem ever and perhaps because of this and the fact I do not scrimp on the Mah's of my battery packs either. That include my early use of XPS 2.4 and now Hitec with some fifty receivers installed in an eclectic variety.
My recomendation is a five cell pack starting out at around 2000 mah
John
I have never had a brownoout or low voltage problem ever and perhaps because of this and the fact I do not scrimp on the Mah's of my battery packs either. That include my early use of XPS 2.4 and now Hitec with some fifty receivers installed in an eclectic variety.
My recomendation is a five cell pack starting out at around 2000 mah
John
12-09-2012 | 03:19 PM
#3
RE: What size receiver battery
As always, John gives good advice. If the Seagull Spacewalker is the 120 size, then it will handle a little extra weight by using a second switch harness and two flight batteries. The advantages are a little redundancy for switch failures and slightly in a failed battery. I use two 1100 mah packs in such configurations.
As John points out, 5 cell packs would be better and is recommended for 2.4 systems. As well, the DS-821 servos will provide a little more torque overhead with 5 cells and if the Spacewalker is the 120 size, the 821s at 4.8v are on the lower edge of torque requirements. Another issue is cold weather and NiMH. They don't output near as well when cold, so if using NiMH the use of two flight packs halves the cold restrictions or constrictions.
As John points out, 5 cell packs would be better and is recommended for 2.4 systems. As well, the DS-821 servos will provide a little more torque overhead with 5 cells and if the Spacewalker is the 120 size, the 821s at 4.8v are on the lower edge of torque requirements. Another issue is cold weather and NiMH. They don't output near as well when cold, so if using NiMH the use of two flight packs halves the cold restrictions or constrictions.
12-10-2012 | 07:54 AM
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From: Sterling,
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RE: What size receiver battery
Gentlemen,
Many thanks for your replies.
The DS821 is a JR servo with torque of 88 @ 6v. or 72 @ 4.8v.
I do use the 2.4 system (Spektrum DX7)and will go with 6 volts and 2000+ MAH in the Spacewalker.
I have the BUSA 1/3 scale Stearman and in it I use SR batteries @ 6v,2400MAH with dual leads. (a SR suggestion)
Laurence
Many thanks for your replies.
The DS821 is a JR servo with torque of 88 @ 6v. or 72 @ 4.8v.
I do use the 2.4 system (Spektrum DX7)and will go with 6 volts and 2000+ MAH in the Spacewalker.
I have the BUSA 1/3 scale Stearman and in it I use SR batteries @ 6v,2400MAH with dual leads. (a SR suggestion)
Laurence
12-10-2012 | 10:09 AM
#7
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RE: What size receiver battery
Sure. JR/Spektrum says this...
The DS821 servo is a powerful, accurate sport digital servo recommended for RC airplane applications up to 1.20-size. For helicopters, the DS821 operates best with 30-size glow models, and up to 50-size electric. Loads and vibration in larger models may cause premature failure of the servo resulting in damage or injury to property and persons.
12-12-2012 | 11:13 AM
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From: Poolesville, MD
RE: What size receiver battery
The Spacewalker is a pretty gentle flyer, with thinner strip ailerons. On a 3D or a larger more agressive plane, I would consider them "on the edge".
Those JR's would be perfect for the Spacewalker IMHO.
I'd be more concerned about the receiver pack sizing.
On a 1.20 size Spacewalker I'd be looking at a large pack ( something OVER 2000mAh though John's suggestion IS a good starting point ) if not a pair of 2200 LiFE packs for redundancy. Two of the latter still weigh less than one 2000mAh 6v NiCD or NiMH pack.
Those JR's would be perfect for the Spacewalker IMHO.
I'd be more concerned about the receiver pack sizing.
On a 1.20 size Spacewalker I'd be looking at a large pack ( something OVER 2000mAh though John's suggestion IS a good starting point ) if not a pair of 2200 LiFE packs for redundancy. Two of the latter still weigh less than one 2000mAh 6v NiCD or NiMH pack.
