|
Rx battery
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??
|
RE: Rx battery
I'm building a Genesis and it will have all digital servos. I've decided on a 2200 mah LiFe reveiver battery. Lighter than nickel and no need for a voltage regulator.
Rob |
RE: Rx battery
Hokie flyer, have you considered the weight of that battery? A 2200 mah rx battery is overkill (weight and capacity) no matter if you run glow or electric. Unless you just don't want to be bothered with charging, I would suggest you consider a lipo rx battery of approx 750 mah/2 cell with a small switch/voltage regulator combo. Just my thoughts. Regards, Everette
|
RE: Rx battery
I am also using the 2200 mah Life, it is very lightweight and I can do 6 flights with my Passport with all digital servos. At the end of the day it will take only around 1000 milliamps of charge . There is also a smaller capacity 1100 mAh pack and it only weights 85 grams versus 143 grams of the 2100 mAh. The Lipo and voltage regulator is also a good combination but personally I think that it is one more possible point of failure (the regulator).
|
RE: Rx battery
Everette, I'm moving away from LiPo's and voltage regulators. I agree with Neil, it's one more potential failure point. A few months ago, I watched Houston Schweitzer's Pinnacle take a core sample on either itrs second or third flight (for him) because of battery failure. There was extensive damage to the on-board electromics, so we couldn't determine if it was a lipo failure or a regulator failure. I think I'm going to go with Neil's suggestion and drop down to an 1100. My Genesis is going to be electric. I estimate it'll draw 40 to 50 mils per flight. I wish there was a 700 to 900 mah LiFe on the market. Rob</p> |
RE: Rx battery
Rob, I've been using the same system for the last 5 years without a hint of a failure or a problem. But like everything else, we all have to be comfortable with what we use. Wish you the best!
Everette |
RE: Rx battery
Rob,
Another option is the Tech Aero dual regulator setup. Very light and easy to use and gives you redundancy. One problem I have seen with the simple setups is that you have the possibility of a switch failure and that has always scared me. With the Tech Aero setup you can run two small Lipos, I run dual 350's, with the perfect switch option. So, for very little weight penalty and still much less than a stock 1100mah NiCd, or LiFE, you get added redundancy. I don't believe there are many RF link problems anymore. Not to say there are none, but they are few and far between, much less than power system problems with batteries and switches. After almost losing my Black Magic a couple of years ago to a bad cell, I have run the redundant setup exclusively since then. Arch |
RE: Rx battery
After losing two planes due to unexplained power failures(all components still functional at the crash site) I switched to using a dual Tech-Aero dual lipo system, similar to Arch. The weight of the dual power system using 350mah 2s lipos is only 100 grams and that includes two switchs. for an electric power system you can drop the second battery and connect to two cells of the main battery through the balance connector as the primary source.
If you choose the regulator voltages appropriately, you will not have to charge the backup receiver battery, just check it every few flights. The dual switches allow you to confirm that each power path is functional prior to each flight. This power setup is only 72 grams with full redundancy. I also had Ed put in JST connectors for the regulator battery connection. This eliminates any wire splicing(failure point) and will prevent you from ever plugging in a lipo directly to the receiver(Murphy issue). John |
RE: Rx battery
I also run the Tech Aero as Arch does and it saved my plane last year, when I landed I had a dead battery . Had that been the only battery I would have lost the plane. The Tech Aero setup is great, I use two Thunder Power 900 as I fly YS and need a little larger battery due to vibration . I get 8-9 flights before recharge.
Kirk |
RE: Rx battery
I forgot to mention that I have had two battery failures since switching to a dual regulator system, one on the ground prior to flight and one in the air. Clearly the battery system is the weak link in our aircraft today and when you can put in a dual system with very little or no weight penalty at a very reasonable cost, it is cheap insurance.
|
RE: Rx battery
I agree. For glow, you want larger batteries as the packs use significantly more. I am running my dual reg setup with both regulators equal so that I'm using both batteries concurrently rather than a primary and a backup. Both ways work, I just have to charge two batteres instead of one. Since both run through the same "perfect" switch, it makes it very easy. The second regulator to plugs into the system.
Arch |
RE: Rx battery
ORIGINAL: jgg215 After losing two planes due to unexplained power failures(all components still functional at the crash site) I switched to using a dual Tech-Aero dual lipo system, similar to Arch. The weight of the dual power system using 350mah 2s lipos is only 100 grams and that includes two switchs. for an electric power system you can drop the second battery and connect to two cells of the main battery through the balance connector as the primary source. If you choose the regulator voltages appropriately, you will not have to charge the backup receiver battery, just check it every few flights. The dual switches allow you to confirm that each power path is functional prior to each flight. This power setup is only 72 grams with full redundancy. I also had Ed put in JST connectors for the regulator battery connection. This eliminates any wire splicing(failure point) and will prevent you from ever plugging in a lipo directly to the receiver(Murphy issue). John Actually, now that I think about it, your method does have one less failure point... always the risk of the esc getting zapped and losing bec capability... What brand 2S 350 lipo's you guys happy with? |
RE: Rx battery
Mark,
If you have an ESC that can handle the radio power required and will support a 10s input, you could do this but I wouldn't recommend it. Usually you can't use the ESC BEC(if there is one) to do this when we are talking 8-10s batteries. When you read the instructions for the BEC it usually places limits on the number of cells you can use and also the available current will drop with the number of cells. Since the BEC is embedded in the ESC you cannot use the balance connector to supply the BEC with a lower input voltage. If you are using a motor battery that is 3-4s total it would work but this is probably a cheaper smaller model and I usually use only the BEC as a single source power input for the receiver and batteries in those planes. There just isn't the same amount of money and effort in the model. One advantage of this dual system is the use of cheap batteries. Go someplace where you can find 350 2s batteries for less than $10. Right now HobbyLobby has 350 2s 30C packs on sale for $5.99. Hobbypartz and hobbyking are other sources. Cheers John |
RE: Rx battery
I'm currently using an 1100 LiFe battery pack in my wind S 110.
It's electric so the values per flight are lower than could be expected for a glow engine, but even so. After 6 flights I put 450mah in. that's 75mah a flight and it weighs less than a 4 cell nicad! +1 on the LiFe! |
RE: Rx battery
ORIGINAL: Hokie Flyer Everette, I'm moving away from LiPo's and voltage regulators. I agree with Neil, it's one more potential failure point. A few months ago, I watched Houston Schweitzer's Pinnacle take a core sample on either itrs second or third flight (for him) because of battery failure. There was extensive damage to the on-board electromics, so we couldn't determine if it was a lipo failure or a regulator failure. I think I'm going to go with Neil's suggestion and drop down to an 1100. My Genesis is going to be electric. I estimate it'll draw 40 to 50 mils per flight. I wish there was a 700 to 900 mah LiFe on the market. Rob</p> http://www.aircraft-world.com/shopexd.asp?id=3155 |
RE: Rx battery
1 Attachment(s)
ORIGINAL: rcpattern I agree. For glow, you want larger batteries as the packs use significantly more. I am running my dual reg setup with both regulators equal so that I'm using both batteries concurrently rather than a primary and a backup. Both ways work, I just have to charge two batteres instead of one. Since both run through the same ''perfect'' switch, it makes it very easy. The second regulator to plugs into the system. Arch I took your advice and switched to the two 350mAh batteries. The reason I did this was that I recharged the two 800mAh batteries this morning and they took 285mAh total, this after my last day of flying them (a couple of weeks ago, with the crappy weather we've had lately) and eight 6-minute flights doing the intermediate sequence and then repeating a maneuver or 2 or 3 and then landing. So these 8 'moderate' flights (I'm still taking it easy on the batteries) consumed an average of 35.6 mAh per flight for the Rx batteries. Seems a little funny looking into the cavernous fuse and seeing the teensy weensy battery packs. But at least now I'm convinced that their capacity is adequate.... just had to see for myself. |
RE: Rx battery
I got in 6 more flights this morning.
I arrived at the field early enough that, while windy, it was still fun to fly. The last couple of flights were done with gusts kicking up 25-30 mph (estimated, but it was damn windy!) By then, it was not fun any more. First flights with the dual FP 350mAh Rx batteries were interesting, in a good way. I topped off the Rx batteries with a Polycharge 4 (non-balancing charger) and voltages read 8.32 and 8.29. I checked voltages after each flight and one battery was drawing more than the other, but only by a small amount. At the end of the 6 flights the voltage of Batt 1 was 7.96V and Batt 2 was 8.14V. So I could have - as Arch assured me earlier - easily gotten 12 flights from these 2 tiny batteries. Upon recharging (with the balance taps on the Cellpro 10S), Batt 1 took 105 mAh and Batt 2 took 47 mAh, for a total of 152 mAh, which when divided by 6 flights is about 25 mah per flight. Granted, I am flying the humble Intermediate sequence and am learning to be judicious with my control inputs, but this was quite a surprise. Regarding the difference in battery draw, the regs were factory set identically for 6.2 volts, so I am guessing the small discrepancy is caused by slightly different resistance in the connecting wires, wire length or connector contact/conductivity. Just to be sure, I re-checked the Tech-Aero regs with Ed's EZ Set Programmer and they were indeed reading 6.19v and 6.20v. With such minimal amp draw, the slight discrepancy is not an issue. EDIT: While putting the batteries back in the model I remembered that the receiver is a 7-channel and that I had to use a Y connector for Elevator 2 and the second battery, which probably affects the resistance and accounts for the difference in current draw. |
RE: Rx battery
All,
I went ahead and ordered a Hyperion 850 LiFe from All E RC. They have them available here in the states. The $17 dollar price was too much to pass on, especially since I was laid off recently, so money is a consideration. Once I get back to work, I plan on buying a 2 meter Vanquish. Once I get a new job, may move the Hyperion over to the Vanquish and refit the Genesis with a Tech Aero dual regulator and dual 350's. Given my expected amp draw, 850 mah is overkill. Thanks for all the great ideas. Rob |
RE: Rx battery
If using the Tech Aero dual regulator for my Nitro 2x2 what would be good batteries to use. I need to watch my weight too :)
Can Life be used? All Digital servos EDIT Thanks to Arch, got all the answers I needed. Thanks a million guys |
RE: Rx battery
ORIGINAL: jgg215 I forgot to mention that I have had two battery failures since switching to a dual regulator system, one on the ground prior to flight and one in the air. Clearly the battery system is the weak link in our aircraft today and when you can put in a dual system with very little or no weight penalty at a very reasonable cost, it is cheap insurance. |
RE: Rx battery
Just wonder what kind of batteries were involved in the two failures. Thanks. IMHO, mechanical switches are in some cases an even weaker link than batteries. And if the batteries were LiPo, what cell count? I could imagine that a small 3s LiPo might cause problems with some regulators. If you try to cram 12.4 volts through a small 5.2 volt regulator, that can't be a good thing. |
RE: Rx battery
ORIGINAL: cmoulder I got in 6 more flights this morning. I arrived at the field early enough that, while windy, it was still fun to fly. The last couple of flights were done with gusts kicking up 25-30 mph (estimated, but it was damn windy!) By then, it was not fun any more. First flights with the dual FP 350mAh Rx batteries were interesting, in a good way. I topped off the Rx batteries with a Polycharge 4 (non-balancing charger) and voltages read 8.32 and 8.29. I checked voltages after each flight and one battery was drawing more than the other, but only by a small amount. At the end of the 6 flights the voltage of Batt 1 was 7.96V and Batt 2 was 8.14V. So I could have - as Arch assured me earlier - easily gotten 12 flights from these 2 tiny batteries. Upon recharging (with the balance taps on the Cellpro 10S), Batt 1 took 105 mAh and Batt 2 took 47 mAh, for a total of 152 mAh, which when divided by 6 flights is about 25 mah per flight. Granted, I am flying the humble Intermediate sequence and am learning to be judicious with my control inputs, but this was quite a surprise. Regarding the difference in battery draw, the regs were factory set identically for 6.2 volts, so I am guessing the small discrepancy is caused by slightly different resistance in the connecting wires, wire length or connector contact/conductivity. Just to be sure, I re-checked the Tech-Aero regs with Ed's EZ Set Programmer and they were indeed reading 6.19v and 6.20v. With such minimal amp draw, the slight discrepancy is not an issue. EDIT: While putting the batteries back in the model I remembered that the receiver is a 7-channel and that I had to use a Y connector for Elevator 2 and the second battery, which probably affects the resistance and accounts for the difference in current draw. How long are your electric flights? Compare to the SAP gasoline powered set-up which draws about 250+ mah per 20 minute flight (includes radio plus ignition). After 75 minutes of flying on the 1780 mah lipo, it measures about 7.5V |
RE: Rx battery
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. |
RE: Rx battery
2s lipos. See post #7 for full description of the system I am using. One failed with a bad cell and the other was a broken wire
John |
RE: Rx battery
The regulators are tech-aero with the incorporated light weight switch. These switches do not carry the current from the battery and if they fail open will keep the regulator powered. I agree that the power switch can be a weak link but using them this way plus the redundancy of a dual system makes a switch failure a non event.
John |
| All times are GMT -8. The time now is 05:53 PM. |
Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.