Lupomen

Hi we are building a hangar 9 extra and would like some battery advice from you experienced guys. We will be using Hi Tec 5625mg on surfaces and 5735 on rudder, we will be using a powerbox 40/24 and twin 6v batteries. My question is: as I am paranoid about weight could we use 2100 nimh twin packs 6v which will discharge at 10amps each, or should we double the weight and go for 2400 nicads ? advice will be appreciated. Merry xmas

Paul Bromley & son

H. Wayne S

My Feedback: (18)

I think the twin 2100 will work fine, When I had mine, (crashed it 2 weeks ago,) I ran twin 1650 nimh and could fly all day with them,(8 to 12 flights),and still have around 6.6 volts at the end of the day.

Geistware

My Feedback: (16)

I would recommend that you go with the NiCad's The extra 1/2 lb will not make a difference in your plane and how it flies.
I am not an proponent for NiMH except for ignition systems.

Stick Jammer

H. Wayne S,
Man, sorry to hear that. What happened?, if you don't mind me asking.

Stick Jammer

Lupomen,
The 2100's are more than enough.

OSilfa

My Feedback: (2)

You can flight all that you want with 2150MAH i have the same set up in my plane and in 5 flights the batts are like new.

capthis

My Feedback: (67)

Geistware
What is wrong with nimh batteries in an airplane? I have been using them for a while now, in all my planes, and haven't had any problems. Enlighten me?

rmh

We are building a dual batteryand switch setup for our new 330-
the batteries are not finalized yet as some bench testing is still ongoing.
It looks like--we will use a dual setup of 950 ma Kan cells in 6 v packs.
The reason?
in doing checks of voltage droop with servos in excess of 200 in ozs torque--some of the batteries tried, show pretty large changes in reading under a heavy load-
The Kan are batteries we picked up for our electric power models and seen to show a notably higher discharge capability.

pcm

My Feedback: (13)

I use dual 2200ma SR Nicads for receiver and 1 for the ignition. I get 4 to 5, thirteen minute flights. I stop and toss them on the charger at 4.9 volts tested under a 250ma load. So I suppose I could still get another flight out of them before I charge them. But to be safe I do it this way.

I am running 9 JR8411's and I am using them pretty hard through out the flight.

Good luck, Marty

H. Wayne S

My Feedback: (18)

Slick Hammer, don't mind you asking. It was caused by a severe case of FOYHS. or, flying over your head syndrome. and Dumb thumbs. I went into a death sprial, then an inverted flat spin then tried to forward flip into a hover. was about 5 feet too low when I started the forward flip. S&%# happens. You never know till you try.

m.gramling

My Feedback: (8)

I also would really like to know why you shouldn't use, NimH batteries in a rundant battery system. I have been running NimH in my .40 profiles all year and haven't had a problem,

also have duel 1650mah 6volt NimH in my 30% carden cap. That I bought late this year. Only have flown it 1 day. but, I am only running 5-JR 4721's and a standard on throttle. but I do plan on swapping over to digitals this winter.

Stick Jammer

H. Wayne S,
Slick Hammer That's funny, I like it! That sucks about your 330S, but you're right, S$#t does happen.

Geistware

My Feedback: (16)

NiMH packs have high energy density and lighter weight than NiCads.
Due to the internal resistance of NiMH packs, large loads cause a large voltage drop.
With that said, I have tested a 5 cell 2700maH NiMH pack at 1 amp discharge and cutoff at 1.1 volt per cell and only removed 1000maH from the pack. I tested a 1800maH NiCad pack under the same conditions and removed 1500maH from the pack.

ROGER RUSSELL

My Feedback: (12)

No expert here, but should you look at Mah used and not really look at voltage??????
Not sure, but you could show a high voltage but be close to being drained due to Mah used out of the battery.??????????

JUST a thought.

I am getting a new 330 and will be going to a single 2700 Nickel using 5 8611a's and two 537's.
My older 330 has two 2700's, with two servos on each surface.
The newer has single servos on all surfaces and single battery, HOPE it is enuf??????????

PaulBK

i know a lot of guys flying big airplanes that use redundant nimh...never heard or read anywhere - except here - that they weren't supposed to.

a little common sense has to weave its way into these threads..JR sells NIMH packs, JR sells big packs for big airplanes. JR knows that guys who buy big packs to put in big airplanes like to use redundant systems. Is there a warning anywhere that it isin't a good idea? No.

ROGER RUSSELL

My Feedback: (12)

I have heard a TEAM JR pilot say one time that a 33% airplane does not need the two battery system.

With the higher Mah it is not needed.

He did say that he flies the two batt systme in is 40%er and bigger.

I will soon find out later next month.

Panzlflyer

My Feedback: (15)

What Geistware says is partially true. The older Nimh packs had high resitance and under a load the voltage dropped quite rapidly. I tested this out on a onboard monitor system.
The NEWER packs coming out can handle a much larger load in the region of 20amps is claimed on some. Check out Nobs and Radica and SRl for specks.
These should be hands down better although they are also quite large/heavy packs. the load issue was always SR selling point but now I see they are offering the newer style packs in Nimhs with low resistance.