Today's Fllight pack options.
 

I took a few years away from RC. I want to take it up again. I fly giant scale, 1/4 scale, gas. I was running dual A123 2S packs. Dual RX switches with charging jacks. The ignition uses a BEC that i can switch from the TX.

My old A123s are at about 1/2 the rated capacity. A123s are now more expensive. At $13 a cell, that is $52 a plane, and with four planes, that is a lot.

For somewhat less money, and less messing around building packs I could just use these:

https://hobbyking.com/en_us/zippy-fl...epo4-pack.html

I do want to stay with LiFe batteries. I am not interested in LiPO or NIMH.

Any opinions on the zippys or something similar?

These are the best. Dan.
http://www.hangtimes.com/a123_packs.html

I guess it has not changed.

IMHO A123's is the way to go. I get my A123's from Richard at Wrong Way R/C who is a great guy to do business with.

I have been using the HK Life packs for many years now with zero failures. I'm not advocating them, just reporting the facts. I use them in 60cc warbirds all the way down to .15 glow powered sport planes. Zero failures.

I have switched all my planes to the A123 batteries, using the same set up you use. I buy my batteries from Value Hobby http://www.valuehobby.com. I have not had any failure and the price is right.

Rich

They only list 5C and 10C LiFE batteries. My understanding is that current is a big deal with the big servos. That I why I switched to the A123 2300mah batteries. They spec at 20C, 50 amps. That is far more than the wires or switches can handle. IF a 10C battery is enough I can cut the cost of packs in half.

I run four Hitech HS-755MG and HS-311 for the throttle. IF I don't need all those amps that changes things. Can I get by with less? What is the current draw on a set up like mine flown with moderate (pattern type) aerobatics?

Scota, Charge your batteries. Fly for ten minutes. Charge your batteries. Write down the mah returned to the battery. Do this six times. Add up the six numbers. The total is the number of mah you have consumed in one hour of flying. If you fly for one hour each time you go flying double this number for a safety factor for your battery capacity. That "C" number is the charge rate. It has nothing to do with the discharge capacity. It sounds like you are have one battery pack for you RC and ignition. This adds a significant load to the battery. Most guys use a separate battery pack for the ignition. It's a more reliable configuration.If the BEC fries you'll be out of luck. Dan.

I understand that the "C" rating IS the max discharge rate for high energy situations.

The BEC allows me to switch the ignition from the TX. IMHO it is a very important safety factor.

"I understand that the "C" rating IS the max discharge rate for high energy situations."

That is my understanding too.

I have been checking my old AA NIMH 5-cell packs. They are nothing fancy, just tenergy cells. They are in better shape than my newer brand name A123 26650 cells. They are right at original capacity, 2000 mah. At 5 amp discharge they get warm but deliver the current. The pigtails get warm too.

IF the wires in the power system are the limiting factor on how much current can be delivered, why am I using batteries that can pump out 50 amps?

Could be Lifer but it has no value for RC use. We have to be very careful with the discharge rate because those Life batteries collapse dramatically. Dan.


http://www.rcuniverse.com/forum/atta...mentid=2197676

I think we're dealing with convoluted terms. There is no way any current battery system would survive being charged at 50 times it rated capacity. A high discharge-rate battery simply means it is capable of releasing its energy at a fast rate, for a short period of time, and not getting damaged or overheating in the process. There is absolutely no risk in using a high "C" rated battery in the flight pack. You will never draw current anywhere near those capabilities. Higher "C" rated batteries are more expensive to produce, and that is why less exotic 5 or 10 "C" rated packs are typically recommended for radio system operation.

To the original poster: Research is always a good idea, but asking open-ended questions on these forums tend to bring out a lot of arm-chair quarterbacks that really need to separate opinion from knowledge.

Thanks

I've been checking my packs. I have eight packs. They are all junk. I bought the cells from the most prominent Chinese hobby dealer as cells. They look just like real A123 systems #26650, and were advertised as such, at about $14 a cell. I have very few cycles on the packs. I left them at full charge 3-years ago.

I suspect they are not the real deal. That is probably my answer to the "what happened to my batteries" Question. The genuine A123 Systems 26650 cells still seem to be still state of the art.

Thanks everybody. It was not my intention to start an argument.

Scot

One last opinion based on hard-earned experience: Never be loyal to a battery pack. If it is old, questionable, etc., toss it out. Batteries are the least expensive component in your airplane. Replace whenever there is any doubt.

Enjoy your giant-scale planes! There are a lot of fun.

I've never had a problem with Hobby King batteries either from foamys to turbines.

[QUOTE=Lifer;12298587]One last opinion based on hard-earned experience: Never be loyal to a battery pack. If it is old, questionable, etc., toss it out. Batteries are the least expensive component in your airplane. Replace whenever there is any doubt.

How old is too old for A123 batteries ?? So far I have some that are approaching 8 years old that still perform just as well as they did when I bought them.

Oops, I got my "C"s mixed up. Thanks for everyone who caught that. The moral of this story is that only flight testing can determine the capacity of the pack needed for the individual's model and flying habits. Dan.

I checked my packs by cycling them and noting MAH for a discharge and for a charge. All of the packs were way below specs. They did not hold what they were supposed to. Trying drain them at any substancial rate pulled them below 2V/cell. They were marked 2011 manufacture date. They were the Olevin Hobby King version. Since mine were gently used an stored in favorable condtions, it might be worth analyzing any packs or cells you all have out here before you fly them.

I ordered a bunch of brand new A123 cells. There is only one authorized dealer in the USA for GENUINE cells. They also drop the price in half if you order several cells. I'll make up news packs.

I use the 3rd wire on a Futaba type plug for a tap between the cells. That makes it possible to balance the packs in the airplane using the charge port. So, I need to make my own packs. Pretty good deal for $20 a pack.

Scota, Try doing the same tests with the fresh set of batteries. Use a cutoff voltage of 3.2 volts per cell. I tried it and was very surprised, unpleasantly, with what I got. Dan.

Please share Dan.

If the A123 cells don't live up to promises I want to know. I switched from Sub-C Nimh to them because of the promises. They cost more after all. I did nottice that my voltage monitor on the airplane showed less lights when I operated the control surfaces with the A123s than the Sub-Cs. That indicated the voltage sags and the cells are not giving as much current. IF that is so the 50+ amp promises are BS. I attributed it to something I was not understanding.

Interesting, I've been flying real A123 cells from Wrongway RC and Tail Dragger RC for years. Hundreds of flights, many times what any average modeler would get per year.

I also run my ignition from the flight pack on anything up to and including 60cc with no ill effects using a single 2500mah A123 and a Tech Aero IBEC.

Anything larger gets a power safe rx and a tech aero IBEC