Lone Star Charles

I'm finally going to make the change to LiFe batteries. I really like the systems that allow charging and balancing through the switch charge port. I plan on re-using the existing MPI one-piece charge switch with LED display for both the receiver and the ignition (after I modify it to remove the white wire from the switch to the receiver/ignition). Most of the installation seems pretty straightforward, but I have a few questions.

• Although www.hangtimes.com seems to have everything that I need, are there any other vendors that I should look at?
• For those of you who have already gone through this conversion, what would you advise me to do differently?
• I don't currently own any balancing chargers and will have to buy one (or two). Since one of my sons borrows my equipment often, I would like to keep the purchase of a charger simple, failsafe and perhaps dedicated to LiFe. I don't need to have a charger that will charge everything. Any suggestions?

Thanks for sharing your experience.

Charles

flyinwalenda

My Feedback: (5)

I have and still am converting Nixx packs over to Lixx and now A123. I have been using two leads to charge the packs. One going to/through the switch jack as the main charge lead and the second being an extension of the balance lead to the charger I would install an extension to the balance lead of the pack and either install it to a port on the fuse or have it accessible to a hatch where I could connect it to the charger.
That set-up looks interesting in that they have their own "box" to charge and balance through the main power lead. On less cable to worry about BUT you have to deal with them for future packs.
Lixx and A123 receiver packs have worked well for me compared to the Nixx packs. Flights per charge are increased and the life span is longer too compared to Nixx packs. The only thing to watch is that the discharge curve is rather flat compared to Nixx . It settles to a certain voltage and stays there throughout the discharge and when it reaches discharge it will fall flat off. Nixx would give you an indication of reaching discharge with lower voltage readings. You just have to do a few timed flights on a charged pack and then see how much charge you put back in to determine your baseline for flights per charge.
As far as chargers you can spend as little as $50.00 or a few hundred dollars. There are what they call "4-Button" chargers that work with LiPo, LiFe/A123, NiCd, NiMh packs and do a good job. They range from 50 watts to several hundred watts of power. Many folks have cloned the original design and make their own . Imax, GtPower, Venom, Thunderpower, Dynamite, Cellpro are a few makes but there are more. You will find they work almost the same and charge 4 or 5 different types/chemistry batteries....hard to find one that just charges A123 batteries..
I have a few lower priced 50 and 80 watt 4-buttons and they work fine at the field and I also have a very good 200watt charger for home.
If you are only going to be charging receiver packs and not getting into electric flight with large LiPo packs then you don't really need a high wattage/high priced charger.

Lone Star Charles

[QUOTE=flyinwalenda;11704452 BUT you have to deal with them for future packs. ....hard to find one that just charges A123 batteries... If you are only going to be charging receiver packs and not getting into electric flight with large LiPo packs then you don't really need a high wattage/high priced charger.[/QUOTE]

Thanks for the info and encouragement. I take it that you don't know of anyone who produces a LiFe pack with only the one combo charge/balance lead? I have not been able to find another either. I really don't see a down side for this application other than the wire size limiting charge current, or someone who is uninformed about the battery/switch wiring diagram plugging something in wrong and letting out all the smoke. If this works like it seems, I suspect I will change everything over as the old batteries wear out and my budget allows.


I did find this charger for about $35 - http://www.lifesourcebatteries.com/chargers.html . Seems like it will 'fill the bill'. Anyone with any experience on this charger?

I do not plan on getting into electric flight. Although I did not plan on getting into anything over .60 nitro, or gas or.......... This hobby is too addicting........ You start out small and the next thing you know you are on a 12 step program with the other addicts.

flyinwalenda

My Feedback: (5)

I don't know of any other place that sells a similar set-up for the packs. All the other places that sell packs have the typical power leads and the balance plug separate.
I would buy a lower priced 4-button charger that has a display to show you how the pack cells are charged and balanced plus it can be used for other battery types as well.
Here is one that is close in price.http://www.valuehobby.com/power-syst...d-charger.html

flyinwalenda

My Feedback: (5)

Found this place that makes it's packs and switches to work together .
http://electrodynam.com/store/RxBatt.html

Lone Star Charles

Thanks for the link, Brian. They have a lot of good stuff.
Appreciate the comment about the four button charger. The display seems more useful than just a 'green' light to let you know the batteries are full as well.

kwblake

I have a lifesource charger, but haven't used it since I got batt's and the "combo power/balance lead" from Hangtime. I use a Thunder AC6 charger, but there are others out there that use the same internals, and a different case. Basically the same charger. One thing with the AC6,(and I am sure others like it) is the manual. It's in "chinglish" , and I found it difficult to understand. I have got help here on the forums though, and now it's OK. It is good to have a display, to see what you are putting back into the battery. One other thing with the lifesource charger is that it uses a 3 pin balance plug, and the cable from Hangtime has a 7 pin balance plug. I guess you could change it, but again, you don't have the display. For a couple extra bucks, it's worth having the display.

flyinwalenda

My Feedback: (5)

The "4-button" charger software is not difficult to grasp but some of the manuals are difficult to understand while others offer usable flow charts. It's really comes down to pressing the left button until you see the battery type you want to charge come up on the display and then select it with the right button. Then scroll through the charging selections(normal, fast, balance, store, etc) and select that . Then change the amperage and cell count to the correct numbers . Press the right button twice and away it goes.
The part that does confuse some is how to select LiFe(A123). You have to enter "user set program" settings from the initial pushing of the left button and select LiPo screen. Then you select and change the Voltage Type to 3.3 volts per cell and LiPo will change to LiFe on the display. Now you can charge LiFe packs. When charging LiPo pack you need to go back and change the voltage type again.

kwblake

I have a bit of a grasp on it now, but as I said it took a while, and some help from people on these forums. It's all good now.

Truckracer

My Feedback: (19)

flyinwalenda, you are so right about the 4 button chargers. When I first got one, you would not imagine the flurry of words that came out of my mouth trying to figure out how to use it. The manuals were horrible. But I stayed with it and now own several of them, mostly the Turnigy 8150. I find these charges very versatile and extremely easy to use.

Lone Star Charles

Thanks for all the info. Although I am still gathering information, I seem to be narrowing down a selection of equipment. I wrote the following note to Maxx Products today:
All of my planes have the 5170 LED Switch installed with either 6.0 or 4.8 volt batteries. Over the next year or so, I will be changing over to LiFe batteries. I plan to charge as well as balance them through the charge port on the switch. Currently, I am not planning on replacing the existing switches; however, I will be removing the white wire from the switch to the receiver in order to facilitate the balance/charge arrangement. With the new setup, I do not expect the LED to serve any purpose other than as an on/off indicator.

I have a few questions:

1. Does my plan as described above seem OK?
2. What are the voltages that turn on the existing 5170 LEDs?
3. Will you be producing a heavy duty LED switch that is compatible with LiFe batteries?

Thanks for your help

I'll post their response here as well.

Lone Star Charles

Here is the response from Tom at MPI (He also send a .pdf of the 6272 switch):

Charles,


Your plan sounds reasonable as long as you understand that the lights on the 5170 will never show anything other than green with a lithium battery connected.


I'm not positive what the actual voltages are that trigger the change in color, the switch is designed as a general warning of battery state, not a lab-quality measuring device.


We have switch 6272 ( http://www.maxxprod.com/mpi/mpi-4.html ) that is designed for Lipo/Life voltages. I am attaching the instruction sheet for this switch for your perusal.

tom/MPI

Truckracer

My Feedback: (19)

Lone Star, I know you are set on charging your new batteries through the switch and some people do that but you may want to reconsider. While you can charge through the switch, many of the switches on the market are less than great and if you charge at even a 1C rate, you might find the switch failing sooner than normal. My prediction is that some months down the road you'll be back on here wondering why you are having early switch failures. Like servo connectors, the small RC switches do not like high continuous current through them.

There is a reason most people charge directly through the power leads and use a separate balance connection. It is a well proven and reliable method for charging the batteries that does not pass the charge current through the switch. Along with this as Flyinwalenda has sugggested, I would strongly recommend one of the common 4 button chargers. Even the cheapest of these has a display and offers quite a bit of versatility that allows you to control and monitor battery charging. They will charge any of the battery chemistrys and they also offer several test modes.

Lone Star Charles

Truckracer - I am not 'set' on charging through the switch. That is why I posted on here asking for advice. I do find charging through the switch to be a very convenient and simple way to charge.

You bring up a good point about the continuous current rating of switches and perhaps I should look into that a little further. What do you know of that issue? Do you have any personal experience that might shed a little more light?

I have heard that most servo connectors can handle about 3 amps continuously and have been assuming that most HD switches would handle a similar amount or greater without significant voltage drop. That seems as if a 1C charge on a 2500 mah rx pack would be OK. What else am I missing on this?


Thanks so much for your help and your willingness to share your expertise.

flyinwalenda

My Feedback: (5)

I have two planes set-up to charge through the switch but I keep the amps low around 1C that would equal 1.5 or 2 amps for the packs. Just keep the amps set low on the charger to 1C or 1/2C and use real good switches.
Otherwise on my other set-ups I have extensions for the charge and balance leads coming to the hatch and connect them directly to the charger. With the amount of flights you get on Lixx packs you only have to charge once in a while anyway.

Truckracer

My Feedback: (19)

Switch quality varies so much ..... most parallel two sets of contacts for both the receiver / servo load and the charge load with the battery contacts being common to both. There are some switches on the market that only charge through one side of the switch or one set of contacts.

Switch ratings (the actual switch itself, not the assembly) vary all over the place and some have no known ratings at all ..... at least none that are published outside of China. Few if any RC companies rate their switches. Switches are known sources of problems in RC equipment and never work better than the day they were new ..... only degrading from that point forward. Switch resistance increases with age and resistance leads to heating and failure.

The point of all this is why tax an already weak component with charging current if you don't have to! Certainly, charging at low current can prevent a problem but what about the one time you decide to increase the current for a quick charge or if you just forget and have the charger incorrectly set .... the switch can be damaged. Charging through a charge jack is certainly convenient but as airplanes get larger, this practice all but completely goes away. Why? First, they don't have charge jacks and second, the charge jacks couldn't take the higher current. Many don't even use switches and this practice is quite common.

I'll leave it at that ....

Lone Star Charles

Thanks for everyone's input. Brian, it's good to hear that you have already successfully tried this approach.

Although I have used switches with chargeports for the last 20 years or so and never had a failure, I have also never charged over about 0.2C. Truckracer makes a good point regarding switch quality; however, there do appear to be several manufacturers out there who make switches with chargeports and claim that they will withstand recommended charging currents. I did several searches for switch/chargeport failures and cannot find any threads warning against this approach.

Truckracer, do you have any data or information that you have accumulated on various switches from any manufacturers? Are there any that you would recommend I use? Or stay away from? If you fly nitro or gas and use LiFe batteries, I would be interested in knowing a little more detail about your aircrafts' electrical system. How do you hook your systems up?

Truckracer

My Feedback: (19)

Lone Star, yes, I have lots of collected data regarding switches (many are junk) but will not post it here on a public forum. Just ruffles the feathers of the various fan boys when you knock their favorite product, even when supported with real tests and facts. I'm very surprised you could not find any information regarding switch failures as the various forums have been full of this info over the years.

My system is simple and very common. I use the large Deans connectors on all my batteries though I'm considering changing to something better. Deans are still quite good though and I'm not knocking them .... there are just better connectors available these days. I unplug the battery when not in use and charge directly through the Deans plug. I balance every third or so charge and use a balance extender cable connected directly from the battery to the charger. Very simple, reliable and it doesn't stress the switch in any way. Further, many switch systems such as the Wolverine or Badger don't give you the option of a charge jack.

Lone Star Charles

Truckracer - Thanks for sharing your suspicions about switches. I went out to the shop, removed and disassembled one of the existing MPI 5170 switches. After all, I have used these switches for nearly 20 years and never had one that did not outlast the airplane. Wow! Was I surprised. I would have guessed that the components inside would have been considerably heavier duty than what I found. The switch is basically a double pole, double throw switch. The white lead as well as the black lead from the battery are connected continuously through the switch to both the receiver and the chargeport. Only the red wire is switched, connecting the battery to either the receiver, or the chargeport. I did mention that the switch is a DPDT, but the red lead is connected to both poles in the switch. I guess that does give a little additional current carrying ability as well as some redundancy in the connection, but holy smokes, wow. Although I suppose that it does work as advertised (and the ones that I owned have), I really expected something a little more substantial. At the very least, I will be replacing the switches when I change these batteries.


I looked at the Wolverine and Badger switches from Fromeco. There is a company that seems to carry pretty good quality stuff. I have one of their tachometers - quality unit. Their soft switches seem very good as well with the 15A capacity, although that seems more than I will ever use. I also like the blue light indicator.

Truckracer

My Feedback: (19)

Lone Star, my compliments to you! By you opening up that switch, you probably learned far more than the average person does about what goes on inside that switch housing. What you described is pretty much the normal design for our mechanical switches but from there, the execution of the design varies considerably between brands. If you were to open several different brands, you would find considerable variation in overall quality, the size and current capacity of the switch itself, the quality of the soldering and the small circuit board used ... if any, etc. Even the wires and connectors varies quite a bit. Some switches don't even connect the two sides of the switch in parallel for redundancy and I have seen this from a major radio brand. Such a simple thing as a switch is really not simple at all, especially considering if it doesn't work properly, nothing works. Anybody that has been around the hobby any time at all has seen switch failures either on their own planes or on someone else's. This is a major part of the reason why I am critical of putting charge current through the switch. Why stress such a critical part any more than necessary?

flyinwalenda

My Feedback: (5)

That's why it doesn't "pay" to buy those $4.00 bargain switches or re-use old ones ! Risk a few/several hundred/thousand dollars on a cheap switch.? No thanks!

Truckracer

My Feedback: (19)

Price alone doesn't always guarantee a good switch! Usually though .....

Lone Star Charles

I looked through my box of RC "miscellaneous stuff" today and found two old switches. One of them was the stock switch that came with an old Spektrum radio. I could not identify the other switch, but it was fairly large and came with mini-Deans connectors on each of the leads. The Spektrum switch actually had reasonably substantial components and used a heavy 'slider' over the contacts - I suspect that it would have held up as well as any on the market. The other switch had similar construction to the MPI switch - again, it probably would have held up as well as any, but did not give me a whole lot of confidence as a long term component. Both units were DPDT and switched both the + as well as the - lead.

What I have learned:

1. Always replace switches when you replace your batteries.
2. Price does not always determine quality. (I preferred the construction of the Spektrum switch to the others and I suspect that it was the cheapest)
3. If you do charge through the switch, do not charge at more than 1 or 2 amps. I would be a little concerned about heat generation.
4. Disassemble any switch that you remove for replacement and analyze its guts. It'll help you make better decisions.

Lone Star Charles

Thought I would follow up with final purchases and decisions. First off, thanks for all the advice from here - it really does help when selecting a system.

OK. I went with http://www.hangtimes.com. I picked the 6.6v 2500 mah battery for the receiver and the 6.6v 1100 mah battery for the ignition. Both packs have only the 20g 3-wire Combined Univ Balance and Power Feed connected to them. I changed both switches to the NoBS Ultra Switch II with the 20g Combo Input Connector. Although I was originally concerned about the size of the switches, I was surprised to find that with only a little increase in the width of the cutout, the new switches fit almost exactly. While I was ordering, I went ahead and ordered the FMA Multi-4 12v Field Charger.

Everything arrived last Friday, and I installed it today. I've got to say that I am really impressed with how everything fit into the aircraft with minimal modification. After installation, I charged the batteries. Again, I was a little skeptical of the FMA charger, but I don't know that I have ever used a charger that was easier to use.

Again, thanks for all the help from this forum.

flyinwalenda

My Feedback: (5)

I love it when a plan comes together !
Hannibal Smith