Brian Dicks Posted April 22, 2017 Share Posted April 22, 2017 I have a 1/4 scale Cub with an OSGT22 engine. I would like to add a back up battery for the Rx. Can I add a second 6v Eneloop pack via a spare Rx channel or do I need a switching system? Brian Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 23, 2017 Share Posted April 23, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted April 23, 2017 Share Posted April 23, 2017 As Percy states Brian, it is worth spending on this one. Finding 2 matched packs would be pure luck, and for a time, one would dominate and either would then be pulled down by its partner. Your flight time would be extended, but so would fitting just one larger pack It would be nice if one pack reached the cut off point and another fresh pack was introduced, and an electronic battery back up switch will do this Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted April 23, 2017 Share Posted April 23, 2017 I'd second what Percy has said, go for Sub C cells or a 2s LiFe battery packs. You can plug 2 receivers direct into the Rx but if one goes the other would start to charge it, hence use a dual battery safety switch or put diodes in each line. Mine own choice would be to go with single decent sub C sized pack in preference to 2 AA packs Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 23, 2017 Share Posted April 23, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
MattyB Posted April 23, 2017 Share Posted April 23, 2017 Another option is the Optipower Ultraguard - the advantages with that are that you know your backup battery will always be charged, and telemetry or visual (via high intensity lighting) alerts can be added so you know if you have an issue with your main power supply. From my Sebart Miss Wind thread... Edited By MattyB on 23/04/2017 08:41:55 Quote Link to comment Share on other sites More sharing options...
MattyB Posted April 23, 2017 Share Posted April 23, 2017 Posted by MattyB on 10/06/2016 17:48:14: Even separate UBECs fail occasionally, so I wanted to mitigate that possibility. I am not a fan of separate RX battery packs in electric models though - I always feel like they are the item you are most likely to forget to charge! Instead I did some digging and came up with a little jewel of a device I'd never heard of previously - the Optipower Ultra Guard 430: "OPTIFUEL is building a highly respected reputation for developing products and accessories for the model enthusiast which now covers brands such as OPTIPOWER Ultra Guard 430, a new intelligent concept in model flight safety. ULTRA GUARD 430 is a small lightweight easy to install smart landing system designed to restore total backup control allowing you to land your model safely following a main power failure... The device is plugged into a free port on your RX or FBL system and when you power up the device waits, monitors the system set voltage, then arms at that voltage less 0.5V. The device is then armed and monitoring the system voltage and the state of the buffer pack. If the buffer pack needs topping up it will do that and balance it from the main packs or RX pack and stop when it gets to a nominal 8.1V. The device samples the system voltage every 2mS and if the system voltage drops below the armed set voltage then the buffer pack steps in if the system voltage recovers it drops out, this is seamless. The device when working can and does indicate locally that its operational and if it is charging or not but this is not able to be seen at distance. A separate external high intensity LED can be fitted that shows you are on the buffer pack, this is an option and these can be cascaded if required. The device works across 4.6V to 8V. The combo version (the board and buffer pack) are bound together by clear shrink wrap as is the super combo version (inc LED system). The total weight is <39g inc LED <35g ex the LED. All parts can be purchased separately. The device can go to storage charge if its not going to be used for some time." At £30 and 35g it was a no brainer; I didn't go for the LED though, as I will be able to setup a telemetry alarm on my Taranis if it is ever called into action. Testing this fully will be the next stage of my install. Edited By MattyB on 23/04/2017 08:30:39 Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted April 23, 2017 Share Posted April 23, 2017 Brian, I agree with Percy & MattyB, think of what you are doing and hoping to achieve? Greater resilience at a cost of added complexity? You appear to be adding more complexity with possibly no increase in reliability (unless you go to more cost/complex option!). Its like links in a chain the more you add the more likely there will be a failure (unless they are true backup/standby systems) PS TX's are normally close enough to you to warn of low battery for you to do something, without telemetry the RX is based on "safety factor" Or MattyB other suggestion... nice one Edited By Chris Walby on 23/04/2017 08:38:52 Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 23, 2017 Share Posted April 23, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
MattyB Posted April 23, 2017 Share Posted April 23, 2017 Some videos of my resilient power (using the Ultraguard) and RF (using an XPS X10+) setup... Posted by MattyB on 15/06/2016 00:20:31: A couple of videos of the X10+ and Ultra Guard on the bench - after 4hrs burn in testing tonight nothing has failed, so it's time to install all this in the model... Overview of setup: Testing the X10+ and Ultra Guard: Edited By MattyB on 23/04/2017 09:06:58 Quote Link to comment Share on other sites More sharing options...
MattyB Posted April 23, 2017 Share Posted April 23, 2017 Posted by Percy Verance on 23/04/2017 08:42:31: Not seen or heard of that before Matty. It isn't a carry on flying solution, but it does at least get you safely back on the ground, and that of course means the model flies again another day. Nice one. Yes, that's correct. The reason I like it is because a) I know the backup battery will always be charged and ready to go, and b) in the event of a main power failure the Ultra Guard will supply 0.5V less than the main pack at switch on, meaning a telemetry alarm can be set to alert me to a main power failure. I don't see the fact that it doesn't enable you to fly on through the rest of the day as a real disadvantage either - if you believe your model needed resilient power before the failure then it needs it afterwards too, so you will have to troubleshoot the issue/recharge the exhausted pack before flying again anyway. Ps - If you are uncomfortable running such a small pack as backup any sized 2S Lipo with a matching balance plug can be used instead of the standard one; the only disadvantage is weight, but that's not an issue on an 1/4 scale Cub I would imagine! Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted April 23, 2017 Share Posted April 23, 2017 I have a sebart model sbach...I enquired at BRC about a backup for the RX? I was told as I was only going to be using 4 servo's that I would be wasting my money...the lad(Tony) said even if the bec cut in I would still have enough in the batt to power the rx...and it was very rare if ever for a lipo batt to run out of power totally......... and come to think i'm flying half a dozen models using the one lipo for everything. he did say to consider the backup for models with 6+ servo's ...... larger more expensive models a different kettle of fish of course. ken Anderson...ne...1...... kettle of fish dept. Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 23, 2017 Share Posted April 23, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
cymaz Posted April 23, 2017 Share Posted April 23, 2017 Good quality switches, ( one for ignition and another for Rx) .Good quality batteries well maintained and clean fuel would be my best bet for a club model. And a well maintained and correctly set up engine. Edited By cymaz on 23/04/2017 09:48:19 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted April 23, 2017 Share Posted April 23, 2017 No need for complicated expensive systems. Use two packs of your choice,I'm currently favouring LiFe two cell packs as no voltage reduction is required unlike Look packs. These are plugged into their own switch harnesses then into a "y" lead fitted with diodes .  The diodes are cheap to buy and can be  found on the net  This stop any current from one battery running through the other if it fails. This system will work with other battery types but if using NiMh use 5 cell packs as diodes reduce the voltage by up to 0.5v Also make sure your servos are ok with 6volt as some were known to "let the smoke out" if use with more than 4.8 volt. Quote Link to comment Share on other sites More sharing options...
MattyB Posted April 23, 2017 Share Posted April 23, 2017 Posted by ken anderson. on 23/04/2017 09:25:51: I have a sebart model sbach...I enquired at BRC about a backup for the RX? I was told as I was only going to be using 4 servo's that I would be wasting my money...the lad(Tony) said even if the bec cut in I would still have enough in the batt to power the rx...and it was very rare if ever for a lipo batt to run out of power totally......... and come to think i'm flying half a dozen models using the one lipo for everything. he did say to consider the backup for models with 6+ servo's ...... larger more expensive models a different kettle of fish of course. ken Anderson...ne...1...... kettle of fish dept. Sorry, but he was talking twaddle. If you are using a BEC (whether it is built into the ESC or a separate UBEC) and that BEC fails, power to the RX and servos will go with it. The amount of power left in the battery is entirely irrelevant. Ultimately the decision as to how you fit out your model - servos, radio install, power supply etc - is yours and yours alone. If you deem the model to need resilient power, go ahead and fit it - it's you who bought, built and fly the thing, so the opinion of the Saturday boy in the local model shop is not relevant. Edited By MattyB on 23/04/2017 10:15:51 Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted April 23, 2017 Share Posted April 23, 2017 hello matty...my post may have come over wrong/ish...he wasn't talking about total failure of the BEC...... .. ken Anderson...ne....1..... BEC dept. Quote Link to comment Share on other sites More sharing options...
MattyB Posted April 23, 2017 Share Posted April 23, 2017 What do you mean then by "...if the BEC cut in..."? Your post is a little confusing. Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted April 23, 2017 Share Posted April 23, 2017 matty ......low battery...not bec failure.... sorry if I confused you... ken Anderson...ne...1 confused dept. Quote Link to comment Share on other sites More sharing options...
Paul Marsh Posted April 23, 2017 Share Posted April 23, 2017 I get these, from Rapid RC. around £20 and work well. I have the more expensive Powerbox version, but someone I know has had 2 of them burn out, where the HK.Rapid RC ones have worke 100% **LINK** Edited By Paul Marsh on 23/04/2017 10:51:06 Quote Link to comment Share on other sites More sharing options...
Rich too Posted April 23, 2017 Share Posted April 23, 2017 Two Life batteries, two decent switches plugged directly into the receiver. Tech Aero ibec for ign. Quote Link to comment Share on other sites More sharing options...
John Lee Posted April 23, 2017 Share Posted April 23, 2017 +1 for the Optiguard. I've been using one since starting to fly 6cell a couple of years ago. It's never been triggered but I test at least once each flying session by unplugging the main Lipo & verifying that I still have Rx control & the warning LED flashes. Mine's fixed with velcro so is easily switched from model to model, I've just swapped it from my Carbon Cub to the big T28 & am about to load it in the car for this afternoon's session. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted April 23, 2017 Share Posted April 23, 2017 Posted by Paul Marsh on 23/04/2017 10:47:32: I get these, from Rapid RC. around £20 and work well. I have the more expensive Powerbox version, but someone I know has had 2 of them burn out, where the HK.Rapid RC ones have worke 100% Precisely why I prefer the 2 battery/2 switch method with optional diodes. There is a maximum of one electronic component per supply and that is a very rugged silicon diode. Any single failure other than a dead short in the wiring (including losing a Nixx cell on a non diode protected system) will still provide a sufficient voltage to land (telemetry is invaluable in this case). If 2 of the expensive and well regarded Powerbox versions have failed without an identified external cause, I wouldn't even contemplate using them - and be very wary of cheaper copies, however reliable they've been so far. Quote Link to comment Share on other sites More sharing options...
MattyB Posted April 23, 2017 Share Posted April 23, 2017 Posted by ken anderson. on 23/04/2017 10:37:31: matty ......low battery...not bec failure.... sorry if I confused you... ken Anderson...ne...1 confused dept. A bit of a tangent given the OP is looking for a solution for an IC model, but still worth stating... You do not really fit redundant power to electrics that utilise a BEC in order to prevent a crash caused by total exhaustion of the Lipo. That is a human error, not an equipment failure; using timers and/or telemetry plus solid prep routines should mean that never happens. After all, any battery they is on it's way out will tell you via incremental lost performance over a period of time long before it goes completely dead early in a flight. No, redundancy is primarily there in those models in case your BEC dies; they can and do fail, so it's a sensible precaution on larger, more expensive models of >4S. An alternative is to fit dedicated RX pack(s), but if you want to avoid the weight associated with that a separate high quality UBEC scaled for the load is still a good option. Edited By MattyB on 23/04/2017 20:33:11 Quote Link to comment Share on other sites More sharing options...
ChrisB Posted April 23, 2017 Share Posted April 23, 2017 Two 3300 subC 5cell packs via two HD switches, directly into the RX and job done! No other fancy bits! Quote Link to comment Share on other sites More sharing options...
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