Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Jul 23, 2012, 09:33 AM
I've got gas
BrightCap232's Avatar
United States, PA, Quakertown
Joined Aug 2011
365 Posts
Question
Redundant rx battery setup

Do you guys use one? Thinking I should get a second rx battery for my cap 232 as a backup but having a hard time choosing what to get. Would it defeat the purpose of "redundant" if I just plug the second battery into an unused port in my rx? Or do I need a unit like a "Batshare". Would i need a regulator if i have 6 servos (they're not high voltage) Just looking for some more security. Any advice is appreciated.
BrightCap232 is online now Find More Posts by BrightCap232
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 23, 2012, 03:02 PM
OK,so what's the speed of dark
mred3's Avatar
Glenwood,GA
Joined Aug 2006
1,071 Posts
You didn't say how big your plane is. Putting a battery into another port is just putting them in parallel and can help if you need more capacity, but that is not a real battery back up. A real battery back up is one where you have one battery that is being used while the other is pretty much doing nothing. If the battery drops below a certain level then the second battery kicks in and the first one is taken out. Then there is the ones that have a battery for the receiver only and a second battery for the servos only. JR has a receiver that will take a second battery also. It sort of depends on how much that plane cost and what kind of insurance you want. I never use them, but my planes don't need them even when I am using 6 servos.

Ed
mred3 is offline Find More Posts by mred3
Reply With Quote
Old Jul 23, 2012, 03:11 PM
I've got gas
BrightCap232's Avatar
United States, PA, Quakertown
Joined Aug 2011
365 Posts
Quote:
Originally Posted by mred3 View Post
You didn't say how big your plane is. Putting a battery into another port is just putting them in parallel and can help if you need more capacity, but that is not a real battery back up. A real battery back up is one where you have one battery that is being used while the other is pretty much doing nothing. If the battery drops below a certain level then the second battery kicks in and the first one is taken out. Then there is the ones that have a battery for the receiver only and a second battery for the servos only. JR has a receiver that will take a second battery also. It sort of depends on how much that plane cost and what kind of insurance you want. I never use them, but my planes don't need them even when I am using 6 servos.

Ed
Its a 73" Cap 232 with a Saito 150
BrightCap232 is online now Find More Posts by BrightCap232
Reply With Quote
Old Jul 23, 2012, 04:52 PM
Registered User
Jacksonville Fla.
Joined Mar 2007
2,170 Posts
A battery in parallel is doing something.....In a parallel circuit voltage remains the same but available current capacity is additive. So 2 6.0V 2000mAh batteries will give you 6.0V with 4000mAh capacity...in other words longer between charges. Now both batteries should be the same voltage and capacity. A batt share will allow both batteries to still be in parallel but if one battery were to go bad shut it off and the remaining battery to power the airplane. of course you'd have half the capacity available that you had with 2 batteries.
But don't worry I've never had a battery failure. A battery can go open in other words a cut wire or a break somewhere it could even be the switch.
But if a battery were to short out the results would be heat. The other battery in a parallel circuit could add its capacity to the heat if you didn't have a batt share.
Yes I run 2 batteries 2 voltage regs and a batt share on my gassers. I ran only 1 batt and 1 switch on an Edge the same size as yours
Always wire things in this order batt, switch, voltage reg if used, batt share, then receiver.
The choice is of course yours, everything is a trade off, the weight of an extra switch and battery worth it to you? Frankly you have a better chance of the switch going bad than a battery that is taken care of.
Good Flying
jetmech05 is offline Find More Posts by jetmech05
Last edited by jetmech05; Jul 23, 2012 at 04:58 PM.
Reply With Quote
Old Jul 23, 2012, 08:23 PM
Registered User
United States, OR, The Dalles
Joined Apr 2011
1,273 Posts
If you are running Specktrum, I like their power safe reciever. It has 2 14ga power leads which are isolated (if one battery has a cell short it doesn't draw down the other).

It also incorporates a fail-on switch. Disadvantage is that you need to disconnect batteries for storage as the fail on system draws a tiny amount of power when off.

I use Li-Fe on these, which I prefer to pull to charge anyway.
JeffinTD is offline Find More Posts by JeffinTD
Reply With Quote
Old Jul 24, 2012, 02:04 PM
Registered User
Mikecam's Avatar
Canada, MB, Winnipeg
Joined Apr 2008
920 Posts
Yes you can just add the second battery to an empty port on your Rx. Use 2 switches to get redundancy. If one battery goes bad it will not pull down the other.

http://www.hangtimes.com/parallel_packs.html
Mikecam is offline Find More Posts by Mikecam
Reply With Quote
Old Jul 24, 2012, 07:52 PM
Registered User
Jacksonville Fla.
Joined Mar 2007
2,170 Posts
Batteries in parallel...hooking up to 2 ports in a receiver.....is the same, electrically, as hooking up to a Y harness. The ports are bussed together for power and return...only the signal is seperate. If one battery were to go bad it could indeed cause a load on the remainning battery.
jetmech05 is offline Find More Posts by jetmech05
Reply With Quote
Old Jul 24, 2012, 08:40 PM
Registered User
United States, OR, The Dalles
Joined Apr 2011
1,273 Posts
It would protect against an open circuit in one of the batteries that way, but would not work if one of the batteries had a shorted cell.
JeffinTD is offline Find More Posts by JeffinTD
Reply With Quote
Old Jul 25, 2012, 04:40 AM
Registered User
Kansas City
Joined Apr 2010
628 Posts
On my larger planes I use a device called a "Batshare." It is sold by a company called Smartfly. About $35 shipped to your door. A worthwhile investment.
Lifer is offline Find More Posts by Lifer
Reply With Quote
Old Jul 25, 2012, 05:21 AM
Registered User
epoxyearl's Avatar
United States, MD, Elkton
Joined Oct 2011
8,428 Posts
I've never used two batteries,but I'm highly interested now for a couple of reasons.
I have a 12' Fairchild F24K model I'll be flying in full scale Airshows.

I want all the safety built in that I can supply....for reliability,and a hedge against liability,if anything goes wrong.

I'd like to "fly" the right side with it's own,separate radio system,the left side the same.-Would I be wise to have a Batshare system on each receiver ?Weight is not a consideration.
Is there any problem with two receivers within 12" of each other?

Batteries will be 4.8 v 2000 ma NiMh.
epoxyearl is online now Find More Posts by epoxyearl
RCG Plus Member
Latest blog entry: Water Sports
Reply With Quote
Old Jul 25, 2012, 09:11 AM
Registered User
Mikecam's Avatar
Canada, MB, Winnipeg
Joined Apr 2008
920 Posts
I had one battery go bad in a dual battery plane and it did nothing to the other battery. Been running them like that for years now with zero problems. Sometimes manufacturers like to sell their products, I like simple.
Mikecam is offline Find More Posts by Mikecam
Reply With Quote
Old Jul 25, 2012, 10:40 AM
Registered User
Jacksonville Fla.
Joined Mar 2007
2,170 Posts
Mike I understand what you're saying....depending on how a battery goes bad it may not effect the good battery...
But like I said battery failure on a well maintained battery is rare....usually a battery going bad is going to give you warning signs...not holding a charge is the biggest warning sign.
jetmech05 is offline Find More Posts by jetmech05
Reply With Quote
Old Jul 25, 2012, 10:41 AM
Registered User
earlwb's Avatar
USA, TX, Grapevine
Joined Dec 2008
12,679 Posts
There are a few businesses that make and sell special circuits to run two battery packs in parallel. So if one pack goes bad, it doesn't draw down the other pack too.

A simpler method involves using Schottkey diodes to isolate the battery packs. Just choose diodes that can handle your power needs and current draw from the servos.
ref http://www.rcgroups.com/forums/showthread.php?t=936395
There is a slight voltage drop across the diode but it shouldn't be a problem. You can use a 5 cell pack instead of a 4 cell pack for example.
earlwb is offline Find More Posts by earlwb
RCG Plus Member
Old Jul 25, 2012, 12:45 PM
Registered User
Mikecam's Avatar
Canada, MB, Winnipeg
Joined Apr 2008
920 Posts
I agree with you 100% Jet. The one and only time I lost a battery was with a dual set up and the other battery was dead. Lots of fliers have gone years and years and not had a battery fail.

I use dual battery's more so for the switches, wiring and connections that could go wrong. I have seen my fair share of switches that have gone bad and caused crashes, especially with the vibration in the gassers.

The added expense of power sharing devices and the added failure point are not required by most of us and like I said I had an experience with a pack going bad and not causing a crash so even if a pack goes bad in a dual pack setup it does not always equal a crash.

My answer was to the OP, yes you can add a second pack and just plug it into your Rx and have a redundant setup that will survive 99% of the issues you might have.
Mikecam is offline Find More Posts by Mikecam
Reply With Quote
Old Jul 27, 2012, 04:39 PM
Registered User
Joined May 2012
432 Posts
Just two packs of the same capacity using two separate switches going to the RX ports. I use two in my bigger planes but not in my smaller 60 size.
Today we have all kinds of new electronics to buy but it is all pretty much doing the same thing.
Gray Beard is offline Find More Posts by Gray Beard
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Idea Backup RX or OSD battery for Redundancy iskess DIY Electronics 25 Jun 11, 2012 02:30 PM
Discussion Redundant Battery Power? BirdsEyeProd Multirotor Talk 9 May 03, 2012 10:48 AM
Discussion Redundant RX battery packs mentor34 Batteries and Chargers 12 Jan 01, 2010 03:27 AM
Discussion Redundant Receiver setup joe manor Giant Electric Planes 8 Apr 15, 2009 11:11 AM
Discussion Battery redundancy for RX Evandro And Batteries and Chargers 5 May 03, 2007 01:12 PM