Ian Southerton 1 Posted October 3, 2013 Share Posted October 3, 2013 Hi, has anybody ever fitted a power switch to lipos? I want to leave my lipo in my plane, then i can pop it in the car without removing the wings, fly it, then remove the wings to charge the lipo at home. I usually fly when i get home about 2:30 for 10 mins before i pick my son up from school and it would save me some hassle! I wondered whether a receiver power switch on the esc to receiver cable would be a possible method? Quote Link to comment Share on other sites More sharing options...
Matthew Clive Posted October 3, 2013 Share Posted October 3, 2013 I think you'll have a hard time finding a power cable switch big enough to handle the current a lipo will be supply during flight. The other option of a switch on the receiver cable is not hopeful either because unless you unplugged the lipo, current will still flow through the esc and motor and within a few days completely flatten the cells...not good for lipos. Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted October 3, 2013 Share Posted October 3, 2013 You could make up an external plug using the same plug as on the Lipo which when you pull out breaks the circuit. I think there was an article in a recent RCME which showed this (I'm sure David will be along soon to advise) Quote Link to comment Share on other sites More sharing options...
Ian Southerton 1 Posted October 3, 2013 Author Share Posted October 3, 2013 Thanks for the fast replies. I found a receiver switch and just tried that idea out, as you said, the motor draws current-it keeos beeping too! I like the idea of a link cable, I could charge the batts in situ. Ian. Quote Link to comment Share on other sites More sharing options...
Greybeard Posted October 3, 2013 Share Posted October 3, 2013 Charging Lipo's whilst they are in a model is not to be recommended as it presents a serious fire risk. Quote Link to comment Share on other sites More sharing options...
Glyn R Posted October 3, 2013 Share Posted October 3, 2013 Charging in situ is not advised for Lipo. There is a fire risk when charging, you would lose the model in addition to the battery, I always charge Lipo's in a safe bag. The switch you used could allow the motor to start spontaneously. Quote Link to comment Share on other sites More sharing options...
crispin church Posted October 3, 2013 Share Posted October 3, 2013 mount a female deans plug out side the fuse and have a male plug with wire soldered across inside cut wire from battery connector to esc any one and solder the 2 ends to the deans one switch just plug in to use plane un plug not Quote Link to comment Share on other sites More sharing options...
kc Posted October 3, 2013 Share Posted October 3, 2013 Wouldn't it be better to put a different type of shorting plug to your Lipo plug. To avoid absent mindedly putting a shorting plug straight on a Lipo causing a dead short? Quote Link to comment Share on other sites More sharing options...
Malcolm Fisher Posted October 3, 2013 Share Posted October 3, 2013 There is a commercial safety plug of this type. Not sure who markets it but it was mentioned in RCME some months ago. I think Nigel Hawes said somethoing about it in his column. Don't have the magazine to hand but 4-Max comes to mind as the source. I use one of these and find it does the job very well. Malcolm Quote Link to comment Share on other sites More sharing options...
Pete B Posted October 3, 2013 Share Posted October 3, 2013 Posted by kc on 03/10/2013 19:58:41: Wouldn't it be better to put a different type of shorting plug to your Lipo plug. To avoid absent mindedly putting a shorting plug straight on a Lipo causing a dead short? Fair point, kc, but I think if I reach the stage where that is a distinct possibility I shall hang up my Tx on public safety grounds....... Plenty of ideas to follow-up with the links from these images I've used Deans arming plugs for several years without issues - easy enough to make up Pete Quote Link to comment Share on other sites More sharing options...
Andy48 Posted October 3, 2013 Share Posted October 3, 2013 For an arming plug/ shorting plug/ safety plug see here. Quote Link to comment Share on other sites More sharing options...
IanR Posted October 4, 2013 Share Posted October 4, 2013 There is a commercially available system with a special deans "arming" plug :- **LINK** Available in the USA but don't know about over here. Ian PS There's a how to/review of it here :- http://www.youtube.com/watch?v=VjupETdN6V4 Edited By IanR on 04/10/2013 00:19:20 Quote Link to comment Share on other sites More sharing options...
Ian Southerton 1 Posted October 4, 2013 Author Share Posted October 4, 2013 Thanks for your replies, i am guilty of leaving lipos in my model-i wonder how many occurences of fires there have been? I've looked at the deans kit and may go for pne of these. Wonder if they make a quick realease wing fastener like a dzus?. Ian. Quote Link to comment Share on other sites More sharing options...
kc Posted October 4, 2013 Share Posted October 4, 2013 Pete B,My point about putting a different type of plug was because I thought it possible other people ( helpers or wives etc ) might think " that's a handy little plug to cover the end" ...... Quote Link to comment Share on other sites More sharing options...
Ian Southerton 1 Posted October 4, 2013 Author Share Posted October 4, 2013 Posted by kc on 04/10/2013 19:25:25: Pete B, My point about putting a different type of plug was because I thought it possible other people ( helpers or wives etc ) might think " that's a handy little plug to cover the end" ...... My wife wouldn't dare Quote Link to comment Share on other sites More sharing options...
Dane Crosby Posted October 9, 2013 Share Posted October 9, 2013 Hi, I made this connector using a deans plug! **LINK** Edited By Dane Crosby on 09/10/2013 20:55:13 Quote Link to comment Share on other sites More sharing options...
Mike Smith Posted January 10, 2014 Share Posted January 10, 2014 Just wondering if anyone has come up with a design for electronic switching of the LIPO (eg a MOSFET or solid state relay, etc). I'm no expert, but I've seen inexpensive MOSFETs rated at 100A 30V and fairly simple switching circuits which would presumably mean that you could use a low voltage/current switch to activate the high current MOSFET or relay???? After all, ESCs presumably employ similar technology? Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted January 10, 2014 Share Posted January 10, 2014 Such devices are commercially available and have been for years. German manufacturer Emcotec offer a range to suit different voltage/current ratings. here is one type: **LINK** Not cheap, but proves the concept... Quote Link to comment Share on other sites More sharing options...
Mike Smith Posted January 10, 2014 Share Posted January 10, 2014 Thanks Alan, it would be interesting to see just what's inside one of these... I suspect the necessary components would amount to only a few pounds. But then I guess it would be quite a critical application to risk as a DIY project. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted January 10, 2014 Share Posted January 10, 2014 Whilst a Mosfet switch might be ok for use at the field I would have thought it most unwise to travel in a car with a Lipo still connected. Surely the only safe method (particularly when in a confined space like a car) is to physically break the battery connection. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted January 10, 2014 Share Posted January 10, 2014 Posted by Simon Chaddock on 10/01/2014 14:09:05: Whilst a Mosfet switch might be ok for use at the field I would have thought it most unwise to travel in a car with a Lipo still connected. Surely the only safe method (particularly when in a confined space like a car) is to physically break the battery connection. Amen Quote Link to comment Share on other sites More sharing options...
Dave Miller Posted January 10, 2014 Share Posted January 10, 2014 Posted by Alan Gorham 2 on 10/01/2014 13:19:33: Such devices are commercially available and have been for years. German manufacturer Emcotec offer a range to suit different voltage/current ratings. here is one type: **LINK** Not cheap, but proves the concept... Does it? The use of these has been discussed before but no one (so far) has been able to say that they are 100% safe insomuch that it is impossible for one to make a circuit unless activated with the correct signal. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted January 10, 2014 Share Posted January 10, 2014 and the reciver needs it's own power supply! There are various electronic switches available for use with receiver/servo battery supplies, but they are failover - ie if there is a fault with the mechanical switch they fail to the 'on' state so you could have a live model without realising it. Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted January 10, 2014 Share Posted January 10, 2014 I think that any so-called safety isolation device will have it's limitations. I simply posted the link to the Emcotec unit in response to Michael Smiths' query regarding using high power MOSFETs in this application. I do not think that the products specifications imply or suggest that it is suitable for long-term isolation (F.E. as some have suggested while the model is transported from home to field in car. Having considered fitting the Emcotec unit to my high powered scale models where the primary motivation was to cut down on the amount of handling the model received while fitting and removing the LiPos before and after every flight, I came to the conclusion that the benefits did not outweigh the purchase costs and there was also the matter of the unsightly safety switch to conceal. Personally, I never viewed a unit such as this as offering 100% percent foolproof isolation. Just as I wouldn't view a Dean's connector or other such device as being suitable. I concur that the only guarantee of complete safe isolation is to only install the battery into the model and then connect up electrically immediately prior to flight. And obviously to immediately disconnect and then remove the battery after landing. In my case, I always use a separate supply for the Rx in any case so I did not view that factor as a limitation or disadvantage of the product. In conclusion, I would suggest that if the battery is fitted to the model then there is always the potential for it to become live inadvertently (however small that risk may be). So the old adage about viewing such models as 'live' would be a good idea. Edited By Alan Gorham 2 on 10/01/2014 17:21:37 Edited By Alan Gorham 2 on 10/01/2014 17:25:35 Quote Link to comment Share on other sites More sharing options...
AJ Posted January 10, 2014 Share Posted January 10, 2014 Any electronic switch will always have a small leakage current present which is going to destroy the lipo if left connected for too long. It needs full physical isolation. Unfortunatly any mechanical switch or relay rated for a high enougth current is going to be just too big/heavy to be practical, the use of a deans or xt60 in the main battery feed is cheap, light and reliable so difficult to see any benefit for the alternatives. As for charging in situ, yes there is always some risk, but if you treat your batteries properly then the risk is no greater than many others. Your phone/laptop/etc probably all use lipos, how much do you worry about these when charging? I can just imagine the reaction if I told the wife that she has to charge her phone in the shed and she has to sit and watch it charging as well! Andrew Quote Link to comment Share on other sites More sharing options...
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