Gary Jefferson

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I am looking at replacing both the Jetcat 1250ma ECU pack and my receiver packs. I will probably run the 4 cell redundant pack for the receiver with the Duralite fail safe switch. Open to suggestions also!!

Question 1; What size Duralites is everyone using?

Question 2; I typically run two receiver packs and two switches but I am wondering if you really need the second switch if you use one of their fail safe switches.

Question 3; How long does it take to charge the Li-ion batteries using the Duralite charger for your size pack?

Question 4; Is the charger from Duralite a field charger. I am asking mostly to know if it is possible to charge the batteries quickly, if you decide to go fly at the last minute, or does is field charging not possible?

Thanks in advance for any help, Gary

lov2flyrc

My Feedback: (24)

Gary,

#1) 4000mah for all my jets

#2) No, Not necessary. Redundancy in pack already and switch/regulator will fail closed

#3) Roughly 8 hours using duralite charger from depleted pack

#4) Yes, you can field charge with their charger and leads are incuded. You can also charge a a rate of 2C with a Li capable field charger

I have PM'ed you my # if you wish to discuss further
BRG,
Todd

Gary Jefferson

My Feedback: (167)

Todd, I was looking at one of the Duralite chargers, do you know if it will charge at 2C and does that mean 4 hours charge time with a completely depleted battery. In other words at 2C is it half of the charge time?

I am guessing that after the 6-8 flights everyone is claiming that the battery is not completely depleted so you may be looking at 1-2 hour charge time with a 2C charger. Does that sound about right?

I just don't want to put these batteries in my plane and then not be able to fly because I forgot to charge my batteries overnight. I can live with a couple of hours charge time I guess but 8 hours is an entire day wasted at an event. Let me know what you think, I guess you can see what I am trying to ask? If not let me know...Thanks for the help, Gary

lov2flyrc

My Feedback: (24)

Gary,
Actually, I was off a tad on the charge rate. The Duralite charger is a fixed charge rate of 800mah. A depleted 4000mah pack would take roughly 5 hours to charge to capacity on the Duralite charger. If you used a Li capable field charger like the camealeon and set the charge rate at 4amp which = 2C (2000mah cells x2) you would charge the pack in one hour from a complete depletion.

Todd

Gary Jefferson

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Todd, who makes the Chameleon charger?

lov2flyrc

My Feedback: (24)

Gary,

Made by Schulze, available from jetcat or BVM.... http://jetcatusa.sitewavesonline.net/chargers.html

Todd

lov2flyrc

My Feedback: (24)

Found it cheaper here:

http://www.greatmodeldeals.com/chargers.htm

and

http://www.helihobby.com/html/chargers.html

Tom Antlfinger

My Feedback: (24)

Hi Todd and Gary:

I think you want the reciprocal of 2C, i.e. C/2......as the maximum charge rate for lithium ions.....in fact, the Ultra Duo 30 defaults to this setting......so when you select a 4000maH pack, it charges at up to 2000 ma maximum.....

According to posts I have seen on the Battery Forum, liths do not like chronic high charge rates.....it will shorten their # of cycles in the long run......that is why Duralite and Powerflite chargers stay at 800-1000 ma rates, even for their big 4000-4800 packs......

Also not a good idea for cell longevity to drain them down to minimimal safe voltage.....charge after every flight while you are re-fueling or chatting......

I have used Liths in my Bandit and HotSpot for most of last season.....I charge overnite in a safe place, just in case somethings goofs in the charger and/or protective circuitry.....and then at the field, while I am refueling or flying another plane, I throw on the charger.....that way, I find I can fly all day, never having to wait for a charger....I stay about 6 flights ahead all the time....

If you do arrive at the field with depleted packs, you still can catch up by throwing on the Ultra 30 or Schultze, etc. and charge at the 2000 rate for about 30 minutes and you will be ready to fly.....then you're sort of back to the NiCad scenario......fly-charge, fly-charge....

Tom

seanreit

My Feedback: (60)

The triton charger works as well and costs around 130 at towerhobbies.

BCoston

My Feedback: (7)

I am thinking of switching to Duralite in my Roo, do you guys leave the RX battery in the jet when charging or do you remove it to be safe?

lov2flyrc

My Feedback: (24)

Absolutely correct Tom, my comments on charging at 2C was only if you arrive at the field forgetting to charge the night before. By no means do you want to charge at this rate on a regular basis or pack degradation will occur. As I understand it, occasional occurrences of 2C charge will have a very minimal impact on the packs life. I have not had to field charge since I switched to duralite, charge the night before and I can fly 8 to 10 flights per plane per charge, more than I can conceivably fly since I bring multiple planes on my outings.

I always charge with duralites in the plane..... No concerns with the Duralite Charge safe circuitry built into the pack. As safe as plugging your cell phone into its charger....

Todd

Gary Jefferson

My Feedback: (167)

Thanks, for all of the help guys. After all my battery research, I just got off the phone with Duralite and placed my order for the ECU and receiver packs, chargers, regulators/switches, adapters, etc. Over $500.00 to get started using Lith-ion batteries but I think it will be well worth it when I am at the jet meets and do not have to deal with the charging of all the nicads.

I always run two receiver packs in my jets so I had three packs total inluding my ECU pack. Because of the redundancy built into the Lith-ion batteries I now only have two packs on board, one receiver pack and one ECU pack, plus I saved a 1/2 lb. of on-board weight and and can fly all day w/o charging. It was well worth it to me!!

I ended up ordering the standard charger from Duralite and will not fast charge the Duralites because of the negative effects on them from fast charging. I will just need to be a little more conscious of plugging them in the night before I guess.

Thanks again for all the help guys.

lov2flyrc

My Feedback: (24)

Happy to help Gary and..... Welcome to the world of Duralite

BRG,
Todd

jetguy34695

My Feedback: (11)

do you need to unplug the battery from the ecu on a jetcat system when you charge the ecu (duralite) battery?

Thanks for the help
Tom

Gary Jefferson

My Feedback: (167)

I can't answer your question directly but I do know that the Duralites all come with a separate yellow lead on the battery that is just for charging the Duralites thru their safe charge circuit. My guess would be no but I am sure Todd can better answer your question. I would like to know the answer myself, including if it applies to the receiver pack.

lov2flyrc

My Feedback: (24)

Good question tom.....

I am not sure what the charge pulse is as to whether or not it is safe to do so, I have a deans plug installed inline on my ECU batts and always unplug at the end of my flying sessions anyway. I never charge with the battery plugged into the ECU just to be safe..... I will check into this though.... Perhaps Matt or Bob have the answer? I forget which pulse is harmful to the Jetcat ECU [sm=confused.gif]
Todd

lov2flyrc

My Feedback: (24)

Spoke to Bob Wilcox, the reverse reflex pulse is what you do not what to feed into the Jecat ECU. This is used in NiCd technology and the Duralite systems can be charged with the ECU plugged in without issue.

Todd

jetguy34695

My Feedback: (11)

Thanks for the info.

Todd did you get your bobcat painted yet. Mine is just about ready to fly I am trying to get it ready for fl jets.

Thanks again
Tom

seanreit

My Feedback: (60)

Todd, can you tell me a little about this duralite powerbox that tells you how much you consumed per flight etc. I thought I heard this was not available yet, but my building partner is telling me he read about it in an advertisement?

Also, can someone direct me where I can get that flight metal stuff? I need some pretty quick to put on the bottom of our F-15.

Thanks,

Sean

seanreit

My Feedback: (60)

PS, I'm ordering duralites in about 10 days, they are very very good!

lov2flyrc

My Feedback: (24)

Tom,

Bobcat is in the booth, final coat of primer went on last night. Colors begin tonight (if the wife lets me [X(]). Lots of work still to do [].

Sean,
The powerbox does not tell you how much has been consumed per flight, what it does do is tell you the batteries status (IE: like putting a load tester on the pack/packs to check current voltage status of the battery). They are however going to produce a "Gas Guage" that will give you current battery status plus the mah consumed per flight so you can monitor the system like we do with the nicads, this unit is not available yet.....
Todd

sideshow

My Feedback: (11)

I'll be pulling the trigger too. I really like the idea of a fail-safe switch with one redundant pack.

So...is charging at 1C gonna be 4 amps or is it 2 amps because of the configuration of the pack? Is 1C a safe rate to use regularly? I'll be using an Orbit V6.....

lov2flyrc

My Feedback: (24)

Bob,
1C would be 2 amps for a 4000mah pack. Ideal charge rate would be around half C or slightly less. IE: Normal Charge rate at 800 to 1000 mah

Todd

Tom Antlfinger

My Feedback: (24)

Bob:

According to Red and the rest of the techno gang on the Batteries forum, C/2 is calculated using the rated pack maH, so a 4000 pack would be charged max at 2000 ma since you are using (2) 2000 mah packs in parallel, thereby splitting the load......most of the techno articles I have read on Liths state unequivocally not to charge over C/2 even for short periods....generates heat which is an absolute no-no for Liths....it degrades long term performance, and in the worst case, the Li salt is partially converted back to metallic Li, which reacts with the aqueous media and leads to explosion and fire.....

When Powerflite and Duralite came out with their chargers, the largest Li packs were between 2000-2800, hence the lower (800-1000 ma) charge rate so as not to exceed the C/2 of those older packs......especially the Li Polys which chemically are near-identical to 18650 Can Liths except for the the more malleable polymer case and a more viscous aequeous medium that allows forming them into tighter packages of odd shapes.....still useable chargers, since this C/4 rate on the big 4000-4800 cells is very kind to the batteries in the long run.....

Like I noted before, after a nights charge, both my ECU 4400 Powerflite and RX 4400, I can have 8 flights on my Bandit if I don't recharge at all, but it is better not to drain the packs to depletion, but rather keep them topped up, so I charge all day long whenever I am not flying the Bandit........always remain about 6-8 flights ahead that way, no matter how long I am at the field.....

I have been using "Super Swithches for many years, since Jim Oddino first popularized them......I can't disagree with the redundancy in the Liths and SuperSwitch, but I still run 2 batts, and 2 regular switches and voltmeters, plugging into 2 separate channels on the RX bus......no doubt overkill, but when a regulator burned up on me 2 years ago(cracked circuit board), with a single Nicad and superswitch, the Bandit bit the big one.......I was gonna do my KingCat with dual Nicads for help in C.G., but have decided on Liths....now I have to talk to Emory about whether it is O.K to run 2 regulator outputs into the common receiver bus.....I seem to remember that Tony Tehan commented that he doesn't recommend that with his regulators......

Anyone interested in the PowerBox offered by Duralite and others can learn all about them on the Battery Forum on RCU..the designer from Modellbau-Deutsch has been posting recently under the "Power Box" thread.....

Tom

lov2flyrc

My Feedback: (24)

Hmm.... Interesting, I believe was told differently as I was originally assumed what Tom states to be correct. I have to double check with emory as I am sure he explaind to me that C/2 is calculated from each cell [sm=confused.gif].... Could be the paint fumes rotting the brain [sm=spinnyeyes.gif]