Rx battery
04-17-2011 | 03:18 AM
#26
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From: Ossining,
NY
RE: Rx battery
John,
I agree, and this is also why I am a big fan of the Tech-Aero "fail-on" switches.
If one uses these switch/regs and regularly checks battery voltage under load, the chances of loss are greatly reduced. This has saved at least 2 planes for me. Both 50cc gassers and not pattern thus far, but an extremely good habit nonetheless.
I agree, and this is also why I am a big fan of the Tech-Aero "fail-on" switches.
If one uses these switch/regs and regularly checks battery voltage under load, the chances of loss are greatly reduced. This has saved at least 2 planes for me. Both 50cc gassers and not pattern thus far, but an extremely good habit nonetheless.
04-17-2011 | 03:29 AM
#27
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RE: Rx battery
ORIGINAL: cmoulder
Matt,
The electric flights are about 6 minutes, plenty for the intermediate sequence and then a couple more minutes to repeat some parts. It isn't very demanding, of course, but I am flying it pretty big.
My typical flights with the gasser are about 9 to 10 minutes, so the difference in battery usage is larger because of that. I typically used about 150-200mAh per flight with the Focus II. That's for Rx and Ignition, as you mentioned.
When I went out and flew last Thursday I purposely did not recharge the Rx LiPo's for the Sickle, which means that they now have 9 flights on them without recharging. I did, however, keep a very close eye on them to make sure there was no chance of over-discharging, and the catastrophic results that could follow!
I have not had a chance yet to recharge them on the Cellpro 10s to see how much charge they take. But I was VERY surprised last time to see a recharge value of only 152 mAh for 6 flights. And very interested to see what I get this time, whether the previous number was a fluke.
However, I did just check the present voltages of the two 350 mAh packs, and after 9 flights one of them is reading 7.67 volts (7.35 with a 500mAh load, 7.00 with a 1amp load) and the other is 7.96 volts (7.68 with a 500mAh load, 7.28 with a 1amp load), so these Rx batteries could have handled several more flights.
Matt,
The electric flights are about 6 minutes, plenty for the intermediate sequence and then a couple more minutes to repeat some parts. It isn't very demanding, of course, but I am flying it pretty big.
My typical flights with the gasser are about 9 to 10 minutes, so the difference in battery usage is larger because of that. I typically used about 150-200mAh per flight with the Focus II. That's for Rx and Ignition, as you mentioned.
When I went out and flew last Thursday I purposely did not recharge the Rx LiPo's for the Sickle, which means that they now have 9 flights on them without recharging. I did, however, keep a very close eye on them to make sure there was no chance of over-discharging, and the catastrophic results that could follow!
I have not had a chance yet to recharge them on the Cellpro 10s to see how much charge they take. But I was VERY surprised last time to see a recharge value of only 152 mAh for 6 flights. And very interested to see what I get this time, whether the previous number was a fluke.
However, I did just check the present voltages of the two 350 mAh packs, and after 9 flights one of them is reading 7.67 volts (7.35 with a 500mAh load, 7.00 with a 1amp load) and the other is 7.96 volts (7.68 with a 500mAh load, 7.28 with a 1amp load), so these Rx batteries could have handled several more flights.
I drove mine hard one time when I flew a fifth full flight once last year(95 min + of flying that day), with a starting voltage at 7.55 or so. After the flight, voltage had dropped to 6.2. Revived the battery okay but that told me to never do that again. So now, 75 minutes of flying session is all I do. Ending voltage is consistently around 7.5V
04-17-2011 | 05:36 AM
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From: Ossining,
NY
RE: Rx battery
Matt,
I'm still feeling out the capacity which is why I very carefully streched the Rx battery experiment a little. I don't think I did anything monumentally moronic with the experiment, and I don't plan to make a regular habit of not recharging before each flying session. I wouldn't want to fly with batteries showing less than 6.6v under load.
Total flight time for the 9 flights is only 54 minutes, so we really are comparing watermelons and strawberries with the gasser vs electric contrast. The e-bird Rx really sips the mAh's; it is a totally different beast.
When warmer weather finally arrives I will be flying the Focus/Syssa a lot more.
I'm still feeling out the capacity which is why I very carefully streched the Rx battery experiment a little. I don't think I did anything monumentally moronic with the experiment, and I don't plan to make a regular habit of not recharging before each flying session. I wouldn't want to fly with batteries showing less than 6.6v under load.
Total flight time for the 9 flights is only 54 minutes, so we really are comparing watermelons and strawberries with the gasser vs electric contrast. The e-bird Rx really sips the mAh's; it is a totally different beast.
When warmer weather finally arrives I will be flying the Focus/Syssa a lot more.
04-17-2011 | 07:07 AM
#29
RE: Rx battery
ORIGINAL: cmoulder
When warmer weather finally arrives I will be flying the Focus/Syssa a lot more.
When warmer weather finally arrives I will be flying the Focus/Syssa a lot more.
04-17-2011 | 07:31 AM
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From: Ossining,
NY
RE: Rx battery
But Bob... When warmer weather arrives you will likely have a 2M Vanquish...with one of these....
Don't you have the Pletty in the Sickle??
Actually, I may hold out for the much-rumored 2M Osiris. I like the Spark-like lines.
04-17-2011 | 09:48 AM
#31
Senior Member
RE: Rx battery
ORIGINAL: cmoulder
Matt,
I'm still feeling out the capacity which is why I very carefully streched the Rx battery experiment a little. I don't think I did anything monumentally moronic with the experiment, and I don't plan to make a regular habit of not recharging before each flying session. I wouldn't want to fly with batteries showing less than 6.6v under load.
Total flight time for the 9 flights is only 54 minutes, so we really are comparing watermelons and strawberries with the gasser vs electric contrast. The e-bird Rx really sips the mAh's; it is a totally different beast.
When warmer weather finally arrives I will be flying the Focus/Syssa a lot more.
Matt,
I'm still feeling out the capacity which is why I very carefully streched the Rx battery experiment a little. I don't think I did anything monumentally moronic with the experiment, and I don't plan to make a regular habit of not recharging before each flying session. I wouldn't want to fly with batteries showing less than 6.6v under load.
Total flight time for the 9 flights is only 54 minutes, so we really are comparing watermelons and strawberries with the gasser vs electric contrast. The e-bird Rx really sips the mAh's; it is a totally different beast.
When warmer weather finally arrives I will be flying the Focus/Syssa a lot more.
54 minutes of flying time for a total capacity that is about 800mah, right? I get around 75 minutes at little more than double that capacity. So my set-up draws about twice what your electric draws. That's what I was trying to determine....interesting
It will be very kool to get an electric of my own in the air; but that won't happen until after the Nats. I love the sound of IC in the morning but electric has my curiosity piqued.
04-17-2011 | 12:38 PM
#33
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From: Tampa,
FL
RE: Rx battery
ORIGINAL: blacknchap
I have a 2x2 slingshot i am gearing up, it is running jr digital servos and spektrum radio gear. What rx battery would you guys suggest??
I have a 2x2 slingshot i am gearing up, it is running jr digital servos and spektrum radio gear. What rx battery would you guys suggest??
thats a Car or truck right ?
04-17-2011 | 02:30 PM
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From: Ossining,
NY
RE: Rx battery
54 minutes of flying time for a total capacity that is about 800mah, right?
I'm using 2 FP 350's for a total of 700mAh. But I think I could have easily gotten a few more flights, and 12 total would have been conservative. So say 72 minutes total with a reasonable margin of safety.
Not yet recharged the Rx batts to check total mAh because between work and weather I don't know when I'll be able to fly again and don't want to store fully charged.
04-17-2011 | 03:31 PM
#36
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From: Albuquerque,
NM
RE: Rx battery
That is a Lotus not a Slingshot. Peter Goldsmith designed a 2 meter version of the Lotus back in 1990. He put an Enya 1204S in his and I used a YS 120 in mine. They were both underpowered. Pete later designed a slightly smaller Lotus which was more suited to the engines of the time. I still have mine with a YS 120AC in it. Flew it last year and was amazed at how far designs have come since those days.
John
John
04-17-2011 | 08:06 PM
#37
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From: Garland,
TX
RE: Rx battery
ORIGINAL: nonstoprc
Anybody has done a redundancy setup with dual regulators, dual switches and dual lipo batteries?
Anybody has done a redundancy setup with dual regulators, dual switches and dual lipo batteries?
With regulators you also have the choice to have both regulators at the same voltage to share the load between batteries, or have one regulated at a lower voltage (say one at 5.7 volts and one at6 volts). What this will do is pull only from the one at a higher voltage thus only using the backup battery if there is a failure. This is useful if you wish to cut weight by having a really small backup battery with lower capacity. My procedure is to always turn on one battery at a time prior to each flight to make sure both are working.
I've had two occasions where the backup saved me. One when the primary battery was dead when Ilanded, the other when one of the batteries came lose during flight.
Keith B
04-18-2011 | 05:48 AM
#39
Senior Member
RE: Rx battery
ORIGINAL: MTK
I drove mine hard one time when I flew a fifth full flight once last year(95 min + of flying that day), with a starting voltage at 7.55 or so. After the flight, voltage had dropped to 6.2. Revived the battery okay but that told me to never do that again. So now, 75 minutes of flying session is all I do. Ending voltage is consistently around 7.5V
I drove mine hard one time when I flew a fifth full flight once last year(95 min + of flying that day), with a starting voltage at 7.55 or so. After the flight, voltage had dropped to 6.2. Revived the battery okay but that told me to never do that again. So now, 75 minutes of flying session is all I do. Ending voltage is consistently around 7.5V
What I didn't mention is that an average 20min flight drops my 2S airborne lipo voltage about 0.2 V, starting with a full charge. After about 75 minutes of flying pattern style (not 3D which would draw more), my airborne has dropped to about 7.5-7.6V.
Point is that one should exercize caution when the lipo voltage drops to around its rated voltage of 7.4.....there is point where the voltage drops like a stone.
04-20-2011 | 03:44 PM
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From: Ossining,
NY
RE: Rx battery
Matt,
I just finished recharging the 2 350mAh Lipo's and they took a total of 383mAh (250+133) after 9 6-minute flights and also about an hour of being on continuosly today as I set up the new Airtronics SD-10G radio system. I was moving and holding the control surfaces in position while using the throw gauge, so I reckon that is very conservatively worth at least 1 more flight, so make that about 38mAh per flight.
That's it. It reaches the point sometimes where it isn't going to help to test any more. I will continue to carefully monitor the batteries as I normally do.
I just finished recharging the 2 350mAh Lipo's and they took a total of 383mAh (250+133) after 9 6-minute flights and also about an hour of being on continuosly today as I set up the new Airtronics SD-10G radio system. I was moving and holding the control surfaces in position while using the throw gauge, so I reckon that is very conservatively worth at least 1 more flight, so make that about 38mAh per flight.
That's it. It reaches the point sometimes where it isn't going to help to test any more. I will continue to carefully monitor the batteries as I normally do.
04-20-2011 | 05:02 PM
#42
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From: Ossining,
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RE: Rx battery
ORIGINAL: rcpattern
Bob,
I can easily get 8 flights on dual 350's. I never fly more than that in one day, and usually never more than 5 or 6, and the I just charge every night.
Arch
Bob,
I can easily get 8 flights on dual 350's. I never fly more than that in one day, and usually never more than 5 or 6, and the I just charge every night.
Arch
However, I am going to keep a very close eye on it for a while just in case the ATX receiver pulls a bit more current than Futaba. I have no idea why or if it should, but as usual when any component is changed it's a good habit not to assume things.
04-20-2011 | 07:52 PM
#43
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RE: Rx battery
I usually carry an extra charged lipo receiver pack when heading to the field. I can easily swap in the charged pack if I really want to make more flights. It is a good idea to know the # of flights that I can safely get with a good margin out of a charged pack so that I can make the swap at the right time.
On my e-powered Sequel, I can safely have five flights with the Intermediate sequence in each, with a fully charged 480mah TP Pro pack.
On my e-powered Sequel, I can safely have five flights with the Intermediate sequence in each, with a fully charged 480mah TP Pro pack.
