I have used NiCad batteries since day one of entering RC flying. I now have my first jet, a Reaction 54 with a JetCat P-70 turbine. The turbine came with a JetCat 1250 mah Nicad, 6 cell, 7.4 volt battery and I am using a 5 cell, 1700mah Nicad, 6 volt battery with a MiniHobby 5.1 voltage regulator for the 8 servos in the jet. My JetCat manual states that 1250mah is good for 3 flights, but suggest that I recharge the batteries for the turbine after every flight. I would like to use batteries that will give me several flights between charging. I am considering Lithium batteries, but I am not sure which lithium to use...Poly, ion...and which brand.....Fromeco, Durilite..... What do you suggest. Thanks.

I use the JetCat 1250 mah Nicad, 6 cell, 7.4 volt battery and swap it out with another for three additional flights. I've got as many as 4 on one with a P-120. I have another spare, which is a 3800 mah NiMH 7.4V that weighs 15oz that I got from Tower. Works well so long as you charge it slow the first few times.

I also use 2X, 5 cell 2700 mah NiMH batteries for the receiver. Each go direct to a charge switch, then y-harnessed together direct to the receiver. I can get minimum 6-7 flights without charge.

I used two 5 cell 1500mah NiCads (no regulator) and a six cell 3000 NiMH for the ECU all in the nose. No other nose weight is needed.
I think the most flights I got without recharging was four. This is on a P60 with kero start which uses a lot of juice.

4 cell 3600 NiMH for the rx, and 6 cell 3600NiMH ECU.

Latest setup I am using is a powerbox sensor switch with two 2100Mah 7.4V lipo's. Good for at least 12 flights in my flash. Works fantastic.

In case you are interested this is the URL for the switch

http://www.modellbau-deutsch.com/e/p...nsor/start.php

Geoff.

P.S. Lipos are Thunderpower if my memory is correct.

Airforce7 - Have you considered not Y-harnessing your receiver batteries together and plugging them separately into your receiver? You can plug into any open channel. This gives you battery redundancy - you don't have to worry about a Y-harness failing on you. Just a thought.

Bob

FROMECO'S Lithiums 4800's on ECU no regulator and RX with their regulator.

Link for them http://www.fromeco.org/shop/apeerless.htm

Two homemade packs of 5 elements 1600 mah ni-mh´s each with two standard futaba switches connected on the receiver channel 1 and 8. No voltage regulators or diodes. A typical flight consumes about 150 mah of each battery on a Roo with 9 servos.

I also use a onboard led voltage meter and test both circuits separately before each flying session, (pretty much like a full size magneto check before takeoff) , to test both packs under load or if any servo is stalled or burned inside the plane..


Enrique

2 x 3s 1200mah Lipo at 12 volts...

Runs ECU and with 2 x BEC at 6.0 runs the whole plane...

Saved over a pound with I switched.

Eddie Weeks
http://www.variablepitchhobbies.com/

Fromeco on both RX and ECU 4800 perless will get the job done.

Bob,

Pretty tough to do when I'm running 11 servos, 2 matchboxes and a smoke system/bomb drop with a 9-channel radio (JR 9303). All my ports are taken and them some.

Should I be worried about my y-harness failing with two Rx batteries and two switches connected to my Rx battery port? It's a heavy duty gold JR y-harness with 128 proven flights on it. At this point I fear more of a flame out than anything else.

Now, I do have a question and I've always wondered about this. My two matchboxes have a battery port, which is used mainly for connecting a battery to them if the matchboxes are connected far (36" +) from the Rx. Would the matchboxes allow battery power (e.g. 2X 5 cell @ 6V) to power the Rx instead of using the battery port on the Rx? So if my batteries going to the Rx port were to fail, would the matchbox batteries continue powering my Rx?

Ken

Doesn't have to be an open channel - power and ground on the servo and battery port(s) on the RX are on a common bus. So, you can use a Y-harness on any channel, run the servo off one side and the battery pack on the other side. The other battery can be plugged into the Rx battery port or on any other channel using another Y-harness.

This also halves the current flowing through any single port, generally a good thing. I'd put the Y-harness on whatever channel is likely to see the highest current, as the current flow path for that servo will be through the Y-harness only. Just a thought.

Barry

If My memory serves me correctly, the matchbox power will go to the servos only, the Rx will need its own power. There is a jumper in the matchbox to tell it if it has seperate power to the servos.

Hi Barry - you are right - I forgot that you can Y-harness any channel with a servo on one side and the battery on the other.

Ken - you are also right, a flame out is probably much more likely than a Y-harness failure. I guess I just feel more secure with two, entirely separate, power sources to the receiver. I don't know anything about matchboxes Ken, but Ehab commented about your question.


Bob

On my Reaction I am using two 5 cell 1800mah Ni-Mh NoBs batteries with two switches into the Rx with Y's and no regulator. I've flown five flights and still was in the 6.20 - 6.30V range with a load. I had the kero start on my P-60 but have since changed it out after it failed on the twentieth start(Jetcat sent me a new one under warranty) not to mention the current it sucks out, the 60 + seconds it takes to start the engine and the flames that come out during start up. I put a 3300 Ni- Mh pack up front for the ECU. Could probably get seven starts with it but I charge it after four. You need nose weight up front with the R54 anyway so it's no problem stuffing all these batteries up there.

Marty

I have used FROMECO 4800 Lithium Ion Batteries on ECU and receiver in 9 of my jets with NO problems and I can get nearly 6-7 flights per charge. If you want a PREMIUM Lithium Ion Battery use the FROMECO "Pierless" batteries as I have noticed a considerable difference with these. If you like to fly alot and dont want to mess with "down time" this is the BEST way to go. Before FROMECO I used POWERFLITE batteries years ago but they have since gone out of business and lithium ion batteries have come a long way in the last 8 years.

Thanks guys, The Lithium Ion batteries sound great to me. Small package, high mah's, fast charging and multiple flights. The only problem is see is that JetCat USA does not recommend the use of Lithium batteries. Are any of you using Lithium batteries with JetCat turbines? Does anyone know why JetCat does not recommend Lithium batteries?

I would save my money and just use NiCads or NiMH as you will need the nose weight anyway. Lithiums are great if you're trying to save weight. In the Jet Cat Turbine Clinic there are a few threads on Lithiums.

I have ALL JetCat turbines and have owned 14 JetCats so far with NO problems whatsoever on Lithium Ion. Once you educate yourself on the Lithium Ion batteries you will never look back.

I believe the reason was because the older Li-Ion batteries couldn't supply the current that was needed for startup. The newer ones can. But like I said and mark said, you need the nose weight anyway for the Reaction and Ni-Cd's or Ni-mh's are probably about a 1/4 of the cost of the Li-Ion or Li-Manganese. My Ni-Mh 3300mah car pack was about 25.00. I think the Duralites start at 100.00 and as far as fast charging goes, I think you better check that. I can charge my 3300 pack at 5 amps if I want. I'm not so sure I'd try that with a Li-Ion.

Marty

I scrolled through this thread and did not find a post from anyone using Duralites. I thought Duralites were considered reliable and were widely used in the jet community. Any thoughts or comments on Duralites?

On most of my jets and turbine helis I have been using Duralite LiIon 4000 packs for both RX and ECU .. up until last week i have been using NiMh batteries for everything else ( including lights and smoke systems in the jets ) ...I think im going back to NiCds over the NiMh, as i have been having mixed results with the NiMh batteries .. last week i set a 1200 mah 7.2V 6 cell nimh pack on charge at .5 amp which was set up on my smoke pump. The charge finished with the battery taking on around 700 miliamps .. I disconnected everything from the plane, and 20 min later left the garage. ... Couple of hours later going back in the garage, i noticed it smelled badly like an electrical fire !!!! I found that the 6 cell NiMh pack burned up INSIDE my BobCat ... charred soot all over the place ... the cells were in pieces under the radio tray, and the innards were spewed all over the place. I have no idea why the whole plane had not gone up in flames !! followed by my garage ( several gallons of flammables there !! ) and the rest of my house ..

I used to only think that this could happen while charging or discharging at too high of a rate, and mostly such problems were prone to Lithium type of batteries. I have now heard of NiMh batteries choosing to blow up several hours after being charged from other people as well .... Needles to say, i had the crap scared out of me with what could have happened ! I think i will be going back to NiCds for some applications [] ... just more solid and reliable, and safe ..


Voy

JetCatUSA sales a 3300 mah NiCad battery pack for $70 and it is good for 6 flights. I think that for my current jet that I will stick with the NiCads. I guess I thought that I was missing something by not using Lithium batteries. I may try lithium batteries on a future project.

My 3000 "car" pack was about $25.

i use the car packs as well on my bigger engines ... ( where a LiIon won't do .. )


Voy