RMG failsafe - why turn it off?

[s vernon]

If I forget to check my boat battery voltage before the racing starts and it turns out my boat battery pack is not fully charged and only lasts for a few heats, is the answer to that part of my problems that I should turn off the RMG failsafe?

Scott

[Doug Wotring]

answer is to confirm you have charged batteries.

turing off the failsafe will only result in more heats till it fails fully

[Rick West]

If you turn it off there it is less likely it will shutdown when you do not want it to. If you turn it off it means you know it is off and managing the system. It has been proven before 2.4 that it is prefered. I frankly, find no profit in this feature and do not understand its need.

...94

[Albert Stall]

If you want to eliminate the "voltage regulator" in the winch, I have a drawing that will show you how to remove the red wire and a wiring diagram to wire it properly. The diagram in the RMG instructions is a little misleading as to the placement of a switch. It's a crude drawing but if you keep your wits about you, you should be able to hack it.

Follow this link:

http://picasaweb.google.com/Mywebpictur ... 677t2lgQE#

Al Stall

[Rick West]

The Alternative wiring in the RMG manual is required for the EC12. That was the result of the Phantom in the Bilge article. The diagram and the process has been on the Building site for several years.

It is good to bring up now, Al. It is part and parcel to the radio board assembly.

...94

[Rob Guyatt]

Sorry about the poor drawing in the booklet. I agree with Al. It's on the todo list.

Rick, to answer about why battery monitoring is there, the short answer is; I thought it was a good idea at the time [:)]

It is quite a popular feature. I was considering dropping this feature from the E series and so called friends threatened bodily harm to my person should I do so. Being a chicken and allergic to pain I decided to leave it in[B)]

It can be a problem in C and earlier winches because it was a permanent shutdown. From D models and currently in E's, the winch comes back to life if the battery recovers. A false shutdown can occur if battery goes low due to the load of rudder or other device operation. Corroded connections/wiring and/or low(ish) battery can result in voltage drop. One thing that has always been the case is that it can not be due to the winch pulling current because monitoring is only done while the winch motor is idle.


Rob

Rob

[Rick West]

Yes, this is understood, Rob. The consideration here by those that will not tolerate a power problem or failure is that with it off you know it will not go to broad reach on its own. It is up to the competitor to discipline the battery checking and rotation to ensure no interruption in the progress of a regatta. Battery failure is sailing slow big time and avoidable.

...94

[michaele69]

Never mind. Found the answer in another post. What a forum, answering questions before they are even asked [:)]

ME.

Speaking of which... If one is running a 2000mah NIMH 6.0 volt battery in the boat, at what voltage should I change the pack?

I have tested the transmitter and can get over 8 hours of continuious use out of it.

Thanks again,

Michael Edwards - EC-12 1969

[Rick West]

6.4 for RX. 6.5 in moderate wind.
9.4 on the TX.

...94

[MichaelJ2K]

Rob,
Since we are discussing winch voltages, what is your opinion of the A123 packs that are available? I see airplane guys flying 2.4Ghz having great success with two cell, 6.6V 2300ma packs.

Mike Denest
EC12 #899

[Rick West]

Know nothing about them. What is the data?

...94

[Rob Guyatt]

I haven't heard of "A123" as such. Is it Li-Fe? Anyway, whatever battery is used voltage just needs to be under 9V fully charged. For example a 2 cell LiPo is specified as 7.4V but will be 8.4V fully charged. Likewise a 5 Cell NiCad or NimH is said to be 6V pack but charges to over 7V.

But a bigger consideration for EC12 would be the voltage to the Rx if using one pack and alternative SmartWinch connections. So find out what the fully charged voltage is and then ask yourself if you can put that voltage directly into the Rx. As I understand it, the Spektrum Rx's will take up to 9V (e.g.) but I aint so sure about most servos.

SmartWinch low battery shutdown is a personal choice. I understand Scott's point. Yes it is the skippers responsibility like Rick says but we can all make mistakes and sneeze as we are going around a corner and nearly end up in a ditch like I nearly did last night. That's why I have insurance. Boy that was scarey[:I]

Rob

[Rick West]

Were you sniffing or drinking? ...[:D]

...94

[Albert Stall]

You know, we are sailing boats here. Not flying RC planes. I've been flying RC for over 40 years and I can't remember one time when I lost a plane due to battery failure. Now remember that 40 years ago battery technology was not what it is today. But still I lost planes due to inattention or midairs or poor landings. But I truly cannot remember a loss due to low batteries.

What is the worst that can happen with our ships? Your stuck in the middle of the pond and can't bring your ship back. Well, look at it from a positive point of view......a nice swim won't harm anybody (don't do that in Florida) or you can beg that fisherman to get your boat back or you might be lucky enough to have a retriever boat at your beckoned call.

The point is, this whole issue is a non issue. A skipper knows his boat. As was said by Rick, shouldn't it be the skippers reponsibility to know his ship? All these safety circuits that cause the servos or winch to move in a given direction when your power goes low is all well and good but it ends up that it is a more expensive product for us to purchase and I don't think the advantages are worth the cost. And that doesn't include the vast amount of discussion that this subject has and probably will continue to generate.

But you guys know your ships. If the behavior is erratic or slow, you know you better get back to shore and check it out. Learn how to properly take care of your batteries-proper charging techniques, cycling, good quality cycle/chargers that create a "no worry" atmosphere..

<center><font color="blue"><font size="4">And most important, use the right batteries and wire size to do the job.</font id="size4"></font id="blue"></center>
Use a minimum of 20awg wire, keep the wiring short, seal the hatch with tape to prevent water entry.

I use 2700MA AA 6volt RX packs and 2700MA AA 4.8volt cells in my Spektrum Dx6i TX. That amazes me that the technology has changed so a 4.8volt TX supply will last a day of sailing. It is rare that I have to change batteries during a day of sailing.

When I first started sailing EC12's, my RMG 250DL winch was wired using the standard connections. I quickly learned that for me it was not a good thing. After losing power due to the internal regulator, I quickly rewired to the alternate connections. There is no reason, as far as I can see, to regulate the voltage. All the components we use can tolerate low as well as high voltage (up to 9volts) so why inhibit the low voltage side.

Sorry about the rant, let the skippers be reponsible for their ships.

Al Stall

[MichaelJ2K]

http://www.a123systems.com/a123/products

Take note of the 26650 2300ma batteries. A 6.6 volt two cell pack is all you would need for an entire day, maybe the weekend. These are designed for power tool applications where a high current draw is common. They are currently being used in electric power rc models with excellent results and are very safe to use vs. lipo packs and are "indestructible". The average recharge rate for an aircraft power pack is 15 minutes. Although lipo cells have better performance over all, these cells come in at a close second. Many of the guys using them buy the power tool packs, disassemble them and make up their own packs for their needs. People are using a two cell pack for 2.4Ghz onboard power supply in the airplane to prevent the receiver from losing power when you need it the most.

There are a couple of A123 threads you can read in the RC Groups forum. http://www.rcgroups.com/batteries-and-chargers-129/. Search for A123.

Mike Denest
EC12 #899