Re: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior
On Mon, Nov 14, 2005 at 09:06:52PM -0600, Lee Estingoy wrote: | This could go on forever. Perhaps, but there's still value in the discussion. | Proper cycling and observation of cells will indicate whether they are to | be trusted. True, but even so, even batteries that `are to be trusted' fail occasionally. And then there's human error, where you forget to charge your pack, or charge the wrong plane, etc. Is there any reason why you couldn't have both a BEC and a seperate RX pack, both hooked up in parallel? If the BEC provides 5.0 volts and the four cell RX pack starts at 5.6 volts, then the RX pack will provide most of the current to the servos, but as the RX pack voltage drops, the BEC will provide more and more of the current, and if the RX pack fails completely, the BEC will provide all the current and vice versa. With the BEC providing only 5.0 volts, it won't charge the RX pack signifigantly, even if the RX pack was completely dead at first, so that wouldn't be a problem. (If the BEC provides 6.0 volts, then things will be complicated, as 6.0 volts *is* enough to charge the RX pack, so it may overcharge the RX pack and overload the BEC. A diodes would be required -- either that, or a five cell RX pack.) The normal failure mode for a battery pack is either 1) to go dead, which usually means that the output voltage becomes too low for use, or 2) for a cell to fail open, which basically means that the internal resistance of the cell increases greatly. Neither one of these failure modes would cause any problems with a BEC in parallel. I only see two possible problems here -- 1) how will a voltage regulator respond if the voltage at the output is slightly higher than it's normal output voltage? (Hopefully nothing happens.) and 2) is the normal failure mode of a BEC to fail with the output shorted or the output open? (Open would be better, and it sounds more likely thinking about how it works.) All of these possible problems could be corrected with appropriately placed diodes, but they'd reduce the voltages, and so you might want a five cell RX pack. That, and I'm wondering about keeping it simple, and diodes would provide another thing to fail. Just an idea. For my larger planes, I'm now using two smaller RX packs rather than one large one, along with a low battery alarm so I'll know if something is really wrong. But none of these planes are electrics, so I haven't really tried replacing one of the packs with the BEC. | However, using motor cells for RX has more mechanisms of failure due | to the higher amp draw/heat/Motor/Controller failure/more joints to | fail/etc. Could be something as stupid as the firewall coming | unglued and jamming the motor/prop/ Of course, if the firewall comes unglued, the motor may fall off the plane completely by pulling the wires loose, and then the CoG of the plane will be so screwed up that it's unflyable. Not pretty -- ask me how I know! :) (Actually, it's not that unpretty. The plane fell, but with the fuse level so it was a relatively gentle crash. Never did find the engine, however.) But you're right -- there's lots of things that could go wrong. | I'd go with simplicity, the weight savings are minimal, perhaps de | minimis, in perspective of the size of ship that we are talking | about. For a Pike, yes. For a 1.5 meter electric glider, maybe not so much. -- Doug McLaren, [EMAIL PROTECTED] Wrinkled was not one of the things I wanted to be when i grew up RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior
The one thing that would concern me with a BEC on a higher cell count set up is the remaining charge in your cells when the cutoff occurs. The BEC cuts off at a certain voltage; divide that by the number of cells to get what each cell is still holding - as you add cells, that gets smaller. I'm doing Sesame Street math here, but the gist is you're cutting the margin closer as you add cells. A ship of any size shouldn't complain about a small Nimh receiver pack; I've seen too many hour long flights end in a terminal dive because someone didn't have enough charge in a 2000mah pack to drive an elevator servo... Lift, Brent RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior
At 5:20 PM -0800 11/14/05, Dan Neelands wrote: If no one has mentioned it don't forget to look at Neu motors. I am running a 1506 2D 6.71 gearbox on 10 GP 3300s with terrific results. 80 amps with an 18x10 prop in an electric Escape. It's smoother than a Hacker and I can talk to the people who built it on the phone. I had some range issues with a UBEC too. Now that I have a little 4 cell AAA pack in there the worry of motive pack failure is gone as are the range issues. If a cell goes bad in the motive pack or something else it's still a glider! Dan Neelands Dan That is a very small battery for a full house glider. I have been up with my Graphite-E, Topaz-E for many over 1 hr flights. I use 4x1650 nimh AA for my flight pack. I don't like BEC either. Both my plane pull well into the low 3-digits current. Any cell failure on the motor pack or the failure on the ESC will send your plane into free-flight. Brian -- Brian Chan An Electric Airplane [EMAIL PROTECTED] Mateo.Ca.USA RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
[RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior
On Monday 14 November 2005 16.37, lee wrote: I personally think that the BEC idea for a ship this size is a bad, bad, idea. Rethinking, yes, of course! But one of those gizmos that replaces a rx battery saves a lot of weight. And yes, form factors when it comes to Li-Ion packs can make them impossible to use - but check around, there are many brands! Sensorless Hacker controllers are a blessing, after having used AVeox's sensored, 'nuff said :-)! Tord RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior
Have a look at http://www.rcgroups.com/forums/showthread.php?t=440307. It's about the crash of a Stratos SL/e, tentatively blamed on an SBEC, which is a stand-alone battery eliminator. Frank -Original Message- From: Tord Eriksson [mailto:[EMAIL PROTECTED] Sent: Monday, November 14, 2005 12:16 PM To: Soaring@airage.com Subject: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior On Monday 14 November 2005 16.37, lee wrote: I personally think that the BEC idea for a ship this size is a bad, bad, idea. Rethinking, yes, of course! But one of those gizmos that replaces a rx battery saves a lot of weight. And yes, form factors when it comes to Li-Ion packs can make them impossible to use - but check around, there are many brands! Sensorless Hacker controllers are a blessing, after having used AVeox's sensored, 'nuff said :-)! Tord RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior
If no one has mentioned it don't forget to look at Neu motors. I am running a 1506 2D 6.71 gearbox on 10 GP 3300s with terrific results. 80 amps with an 18x10 prop in an electric Escape. It's smoother than a Hacker and I can talk to the people who built it on the phone. I had some range issues with a UBEC too. Now that I have a little 4 cell AAA pack in there the worry of motive pack failure is gone as are the range issues. If a cell goes bad in the motive pack or something else it's still a glider! Dan Neelands -- Date: Mon, 14 Nov 2005 15:38:23 -0500 From: Frank Slaughter [EMAIL PROTECTED] To: Tord Eriksson [EMAIL PROTECTED], Soaring@airage.com Subject: RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior Message-ID: [EMAIL PROTECTED] Have a look at http://www.rcgroups.com/forums/showthread.php?t=3D440307. It's about the crash of a Stratos SL/e, tentatively blamed on an SBEC, which is a stand-alone battery eliminator. Frank=20 -Original Message- From: Tord Eriksson [mailto:[EMAIL PROTECTED] Sent: Monday, November 14, 2005 12:16 PM To: Soaring@airage.com Subject: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior On Monday 14 November 2005 16.37, lee wrote: I personally think that the BEC idea for a ship this size is a bad,=20 bad, idea. Rethinking, yes, of course! But one of those gizmos that replaces a rx battery saves a lot of weight. And yes, form factors when it comes to Li-Ion packs can make them impossible to use - but check around, there are many brands! Sensorless Hacker controllers are a blessing, after having used AVeox's sensored, 'nuff said :-)! Tord -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.362 / Virus Database: 267.13.0/167 - Release Date: 11/11/2005 RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior
But what if the rx pack goes south? Then what is left is garbage. If a cell goes bad on the motive pack with a UBEC installed, you still have power to control the servos. Aloha to all on RCSE, Al Battad - WH6VE AMA #506981 -Original Message- From: Dan Neelands [mailto:[EMAIL PROTECTED] Sent: Monday, November 14, 2005 3:21 PM To: Soaring@airage.com Subject: RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior If no one has mentioned it don't forget to look at Neu motors. I am running a 1506 2D 6.71 gearbox on 10 GP 3300s with terrific results. 80 amps with an 18x10 prop in an electric Escape. It's smoother than a Hacker and I can talk to the people who built it on the phone. I had some range issues with a UBEC too. Now that I have a little 4 cell AAA pack in there the worry of motive pack failure is gone as are the range issues. If a cell goes bad in the motive pack or something else it's still a glider! Dan Neelands -- Date: Mon, 14 Nov 2005 15:38:23 -0500 From: Frank Slaughter [EMAIL PROTECTED] To: Tord Eriksson [EMAIL PROTECTED], Soaring@airage.com Subject: RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior Message-ID: [EMAIL PROTECTED] Have a look at http://www.rcgroups.com/forums/showthread.php?t=3D440307. It's about the crash of a Stratos SL/e, tentatively blamed on an SBEC, which is a stand-alone battery eliminator. Frank=20 -Original Message- From: Tord Eriksson [mailto:[EMAIL PROTECTED] Sent: Monday, November 14, 2005 12:16 PM To: Soaring@airage.com Subject: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior On Monday 14 November 2005 16.37, lee wrote: I personally think that the BEC idea for a ship this size is a bad,=20 bad, idea. Rethinking, yes, of course! But one of those gizmos that replaces a rx battery saves a lot of weight. And yes, form factors when it comes to Li-Ion packs can make them impossible to use - but check around, there are many brands! Sensorless Hacker controllers are a blessing, after having used AVeox's sensored, 'nuff said :-)! Tord -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.362 / Virus Database: 267.13.0/167 - Release Date: 11/11/2005 RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
Re: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior
This could go on forever. Proper cycling and observation of cells will indicate whether they are to be trusted. However, using motor cells for RX has more mechanisms of failure due to the higher amp draw/heat/Motor/Controller failure/more joints to fail/etc. Could be something as stupid as the firewall coming unglued and jamming the motor/prop/ Similarly, more in the UBEC to fail too. It's up to the user. I'd go with simplicity, the weight savings are minimal, perhaps de minimis, in perspective of the size of ship that we are talking about. Over and out. Lee - Original Message - From: glide [EMAIL PROTECTED] To: Soaring@airage.com Sent: Monday, November 14, 2005 8:48 PM Subject: RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior But what if the rx pack goes south? Then what is left is garbage. If a cell goes bad on the motive pack with a UBEC installed, you still have power to control the servos. Aloha to all on RCSE, Al Battad - WH6VE AMA #506981 -Original Message- From: Dan Neelands [mailto:[EMAIL PROTECTED] Sent: Monday, November 14, 2005 3:21 PM To: Soaring@airage.com Subject: RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior If no one has mentioned it don't forget to look at Neu motors. I am running a 1506 2D 6.71 gearbox on 10 GP 3300s with terrific results. 80 amps with an 18x10 prop in an electric Escape. It's smoother than a Hacker and I can talk to the people who built it on the phone. I had some range issues with a UBEC too. Now that I have a little 4 cell AAA pack in there the worry of motive pack failure is gone as are the range issues. If a cell goes bad in the motive pack or something else it's still a glider! Dan Neelands -- Date: Mon, 14 Nov 2005 15:38:23 -0500 From: Frank Slaughter [EMAIL PROTECTED] To: Tord Eriksson [EMAIL PROTECTED], Soaring@airage.com Subject: RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior Message-ID: [EMAIL PROTECTED] Have a look at http://www.rcgroups.com/forums/showthread.php?t=3D440307. It's about the crash of a Stratos SL/e, tentatively blamed on an SBEC, which is a stand-alone battery eliminator. Frank=20 -Original Message- From: Tord Eriksson [mailto:[EMAIL PROTECTED] Sent: Monday, November 14, 2005 12:16 PM To: Soaring@airage.com Subject: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior On Monday 14 November 2005 16.37, lee wrote: I personally think that the BEC idea for a ship this size is a bad,=20 bad, idea. Rethinking, yes, of course! But one of those gizmos that replaces a rx battery saves a lot of weight. And yes, form factors when it comes to Li-Ion packs can make them impossible to use - but check around, there are many brands! Sensorless Hacker controllers are a blessing, after having used AVeox's sensored, 'nuff said :-)! Tord -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.362 / Virus Database: 267.13.0/167 - Release Date: 11/11/2005 RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior
While I don't think anyone has a definitive answer to the question to BEC or not to BEC, the argument against a BEC is that the system drawing 100+ amps is much more likely to fail than the one drawing 1+ amps. Remember, we trust our unpowered gliders to those Rx packs all the time. Frank -Original Message- From: glide [mailto:[EMAIL PROTECTED] Sent: Monday, November 14, 2005 7:48 PM To: Soaring@airage.com Subject: RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior But what if the rx pack goes south? Then what is left is garbage. If a cell goes bad on the motive pack with a UBEC installed, you still have power to control the servos. Aloha to all on RCSE, Al Battad - WH6VE AMA #506981 -Original Message- From: Dan Neelands [mailto:[EMAIL PROTECTED] Sent: Monday, November 14, 2005 3:21 PM To: Soaring@airage.com Subject: RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior If no one has mentioned it don't forget to look at Neu motors. I am running a 1506 2D 6.71 gearbox on 10 GP 3300s with terrific results. 80 amps with an 18x10 prop in an electric Escape. It's smoother than a Hacker and I can talk to the people who built it on the phone. I had some range issues with a UBEC too. Now that I have a little 4 cell AAA pack in there the worry of motive pack failure is gone as are the range issues. If a cell goes bad in the motive pack or something else it's still a glider! Dan Neelands -- Date: Mon, 14 Nov 2005 15:38:23 -0500 From: Frank Slaughter [EMAIL PROTECTED] To: Tord Eriksson [EMAIL PROTECTED], Soaring@airage.com Subject: RE: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior Message-ID: [EMAIL PROTECTED] Have a look at http://www.rcgroups.com/forums/showthread.php?t=3D440307. It's about the crash of a Stratos SL/e, tentatively blamed on an SBEC, which is a stand-alone battery eliminator. Frank=20 -Original Message- From: Tord Eriksson [mailto:[EMAIL PROTECTED] Sent: Monday, November 14, 2005 12:16 PM To: Soaring@airage.com Subject: [RCSE] Re: Soaring V1 #6696: LMR motor for Pike Superior On Monday 14 November 2005 16.37, lee wrote: I personally think that the BEC idea for a ship this size is a bad,=20 bad, idea. Rethinking, yes, of course! But one of those gizmos that replaces a rx battery saves a lot of weight. And yes, form factors when it comes to Li-Ion packs can make them impossible to use - but check around, there are many brands! Sensorless Hacker controllers are a blessing, after having used AVeox's sensored, 'nuff said :-)! Tord -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.362 / Virus Database: 267.13.0/167 - Release Date: 11/11/2005 RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
