RunRyder - Li-whatever Versus Ni-mh

rrTV-PHOTO

New HD TV

HOME rrTV-PHOTO GALLERIES MY GALLERY HELP-FAQ

myHOME PM pmRR MEMBERS 743 ONLINE 28 EVENTS SEARCH REGISTER START HERE

1 page

587 views

POST REPLY

CarbonXtreme	.	Midland Helicopters	.	HeliProz
	.		.

Got Jet Fuel? Turbine Helicopters > Li-whatever Versus Ni-mh

lperagallo
Senior Heliman
Location: Westfield, Indiana, USA

OK, so the verdict is in. The batteries for my turbine need to be replaced. As I sit here and think, I wonder why we use Li-whatever in anything. Most times they need a regulator, they are sensitive, expensive, require special chargers and quite frankly not worth the pain. Why can't I just use some good 4500MAH Ni-MH?s While weight may be an issue for smaller helis, it really isn't that much of a problem in the turbine.

Were there more problems with batteries going bad in turbines before the Li-pos, Li-on, Li-mn?

What makes the Li-anything make it better? What benefits do we get?

Bergen Intrepid EB, G-26, 720mm; Bergen Turbine, Wren MW54; Raptor 50V2, OS50-Hyper

03-30-2008 04:17 PM

bcook01
Senior Heliman
Location: central ontario

lperagallo

Ni-MH are a good power source for powering servos, radios and gyros. you might want a seperate power source for the turbine if you are using kero start.

A NiMH battery can have two to three times the capacity of an equivalent size NiCd. However, compared to the lithium-ion battery, the volumetric energy density is lower and self-discharge is higher

There have been improvements with regard to self discharge which has been a problem in the past. They are well suited for high discharge applications and are far more stable than Lipos.

Be sure to obtain 5000 ma battery capacity (pack) which is in fact a true "C" cell. Some "AA" are packaged for C applications but only have a capacity of <2500 mah.

You must use a Delta V charger or constant current charger. Never use a NICAD charger. There are a number of newer chargers that do a good job.

Periodically use a charger that has a combined discharge function to determine the actual capacity as well as doing a conditioning recycle.

LiPO's are dangerous and now are being labeled as "hazardous material" with the airlines. TSA will confiscate larger lipos.

Personally, I wouldn't use anything else. You can make up a good pack using Panasonic industrial Ni-mh. They appear to have the best chemistry.

hope this helps.

Bob

You cannot afford to learn by your own mistakes.

03-30-2008 11:30 PM

WIRLYBIRD
Senior Heliman
Location: CAPE TOWN / SOUTH AFRICA.

Hi Iperagallo , I'm old school ,and in my NH90 am using good old NI-Cads , they last three years , 38 hours of flying , just threw them in the bin and replaced the lot. In fact I'm getting very adventurous , and am putting my first NI-MH 3600mah to power the ECU , like you said the turbines don't feel the little extra grams. That means I still use NI-Cads to power the RX , and nine top of the range digital JR servo's lights and warning fuel level strobes and low battery warning lights , very cost effective I'd say.
Dave.

WHAT GOES UP MUST SURELY COME DOWN.

03-30-2008 11:32 PM

lperagallo
Senior Heliman
Location: Westfield, Indiana, USA

Thanks for the replies. I do use two sets of batteries, one for the FADEC and one for the RX and servos. Both need replacing. I like to fly all day and I really don't want to have to charge during the day. I usually put 6 or 7 flights on it a day, so I will probably look into the 5000MAH Ni-MHs.

Lou

Bergen Intrepid EB, G-26, 720mm; Bergen Turbine, Wren MW54; Raptor 50V2, OS50-Hyper

03-31-2008 02:49 AM

human213
Senior Heliman
Location: malibu

The 5000mah Longo Lipo

has been my pack of choice for some time now.

As for danger, your cell phone is much more hazardous, and it

has built in balancing connections.

I got mine from desert aircraft, along with the emcotech dpsi, etc.

michael

Not everything that can be counted counts, and not everything that counts can be counted.

03-31-2008 03:19 AM

mcfast
Veteran
Location: Canada

Get one of these "Dual output RC Generator"

http://air starintl.com/webshop/index.php?main_page=product_info&cPath=15&products_id=473

03-31-2008 03:44 AM

andyman_sf
Senior Heliman
Location:

I can tell to why you should go Li-ion vesus NiMH. Discharge rate is lower on Li-ion. I also like the fact that i can tell exactly how much charge I have left on the Li-ion by measuring voltage. NiMH will leak over time and is higher maitanence if you don't fly often.

Why I would use NiMH? The only time I will use it is in a heli with an onboard generator. I don't have to worry about building a complex charging circuit for NiMH like you would with Li-ion.

andy

04-05-2008 09:23 AM

Peter Wales
Key Veteran
Location: Orlando Fl

I have switched all of my flight and ECU batteries over to Sanyo Eneloop NiMH batteries. They have an ultra low self discharge rate and will still have 85% of their charge after 1 year storage. The AA size are 2.1 AH and where I think there is a need I have made up parallel packs to give me 4.2 AH capacity.

No fancy chargers or regulators needed, just charge up on a trickle charger AFTER you fly. Mine cost around $2 per cell in 4 packs and I got 1850 mAH out of a pack dated 7/2006. Thats before charging as they come pre charged!

Peter Wales

04-05-2008 01:16 PM

HOMEPAGE

lperagallo
Senior Heliman
Location: Westfield, Indiana, USA

Thanks for all the information. I ended up with a combination of a LI-ion for my RX and servos and a LI-MN for the ECU. I was almost ready to buy NI-MH until I saw the weight for a 4200MAH and the price. They ended up being almost as much as teh LI-ion so I decided to stay with the dualities.

I think I'll watch this set of batteries better and since I keep a log on the turbine, I'll include batteries.

Lou.

Bergen Intrepid EB, G-26, 720mm; Bergen Turbine, Wren MW54; Raptor 50V2, OS50-Hyper

04-05-2008 02:59 PM

seattle_helo
Key Veteran
Location: Washington State, USA

My preference is LiPo for everything.

Love LiPo's! But when running a kerostart plug I do think that NiMH offers the best overall performance. I guess it's because those cells can best withstand a deep, temporary voltage drop with the high amps associated with the kerostart. If weight is not an issue, i.e. for balance purposes, Sanyo makes some 9500mAh D-size NiMh cells that are awesome for a kerostart ECU setup. That pack will last all day on one charge and still have significant capacity left over.

nick

04-05-2008 05:43 PM

HOMEPAGE

MattJen
Elite Veteran
Location: UK,Gravesend, Kent

Sanyo makes some 9500mAh D-size NiMh cells that are awesome for a kerostart ECU setup. That pack will last all day on one charge and still have significant capacity left over.

WOW Nick,
that must be like a brick in the fuse, does the helli tilt with that thing in it?

9500, that must give one hell of a kick to the kero start system

Matt

I bought mymother in law a chair for xmas, but she would not plug it in.

04-05-2008 08:13 PM

seattle_helo
Key Veteran
Location: Washington State, USA

Matt, it is a brick! But I needed the weight to bring the CG in line anyway. As luck would have it I did not need to add any "dead" weight to the heli after installing that 9500mAh monster.

04-05-2008 08:30 PM

HOMEPAGE

G-SWSM
Heliman
Location: Midlands, UK

Holy moly.

A 9500mAh bat pack, you really could go all day on that one.

Whats the sizes of it come in at ?

Thanks.

PS I wonder if Overlander will be doing something like this, and all we need then is to get our hands on a better Radio bat pack.

Steve.W Remember, under no circumstances take a laxative and a sleeping pill on the same night

04-06-2008 11:53 PM

seattle_helo
Key Veteran
Location: Washington State, USA

Steve, the approximate dimensions are:

195mm x 60mm x 32mm

And I think it weighs approx. 1kg

04-07-2008 04:55 AM

HOMEPAGE

1 page

587 views

POST REPLY

ZoomsHobbies	.	HeliHobby	.	Ron’s HeliProz South
	.		.

Got Jet Fuel? Turbine Helicopters > Li-whatever Versus Ni-mh

UPDATE SCREEN PRINT TOPIC

Advertisers

Subscribe to This Topic