3000Mah Ni-cd pack for 25% Yak-54 (Full Version)

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Pilot013 -> 3000Mah Ni-cd pack for 25% Yak-54 (12/10/2007 7:39:49 PM)

Hi to everybody!

I want to buy for my Great Planes Yak-54 25% a 3000mah Ni-Cd 6V pack available from batteryspace. The price there is about 25$. I noticed that the weight is very accepetable and the cells are Sc. I'd like to hear your opinion about this pack! Now I am flying with a 6V pack 2000 mah.

Here is the link to the batterie's page:

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3761

Waiting for your commentary!



k8svrick -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/10/2007 8:22:04 PM)

I don't see a problem using that pack. NiMh would require less space and would probably be a bit lighter as well. Do you have a particular reason for using NiCd cells? Price maybe?



Pilot013 -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/10/2007 8:40:56 PM)

Hi!

Well, as far as, this site is a more special one for batteries the choice is limited. In the Ni-Mh section there aren't many nice packs for the RC purposes. Also the price is good. Currently I am flying the Yak-54 with a Ni-MH batteries bought from Tower Hobbies. Well the reason is that I just want to have more power without recharging. Now the batteries won't last for more than 1 hour and half. You think Ni-CD are bad? Well if somebody could propose to me a 3000mah 6V Ni-Mh and light weight of course, I'll be more than happy!

Best regards!



OldRookie -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/10/2007 11:12:13 PM)

If you are using a single 5 cell RX battery pack, I would go for the NiCd. If one cell goes out an a NiMh pack you will loose all power to your system, if you loose 1 cell on the NiCd battery, you are flying at 4.8v approximately, depending on the charge.
The NiMh are good for a redundant set-up.
This is the way I understand it. Please correct me if I am wrong.

Greg



Pilot013 -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/11/2007 6:29:21 AM)

Hi Greg!

I think you are correct. I plan to put this pack for the RX of the plane. I am using 6 Futaba S3305 at 6V and 1 JR for the throttle.
I noticed that on all the servos is written, that's better to use them with a Ni-Cd batteries. I don't know why, maybe there is a reason!

Best regards!



SitNFly -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/11/2007 2:20:16 PM)

If you would like to read a good comparison of the various battery chemistries available, go to http://www.hangtimes.com/ and click on the links on the left side of the page. Good NiMh are just as capable of delivering current as NiCds. They are lighter as well. The downside is that they are not as rugged and they self-discharge quicker. I run 4 cell NiMh from NoBS in my 87" QQ Yak and they are great packs.



Pilot013 -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/11/2007 5:08:48 PM)

Hi!

Thanks for the info - nice site!

Well let's do it like that, could you suggest me from where I could buy a 3000mah Ni-Mh 6V Sc dimension if possible, and I'll buy them. I just went towards the Ni-CD because I saw a nice pack. If somebody could help me I'll be very happy of buying this kind of pack!

Best regards!



Flyfast1 -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/13/2007 7:00:42 PM)

From what I've read on these forums and from information provided by Futaba, the 3305s draw a lot of current. So, the NiCds might better, depending upon the internal resistance of the NiMH packs.

What is the rationale on a NiMH pack that if a cell dies the entire pack dies?

-Ed B.



OldRookie -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/15/2007 9:57:27 PM)

Flyfast1,

I have been looking at a lot of sites for battery packs, and other electronic equipment for a 30% gas plane set-up. One of these sites stated that when a NiMh pack looses a cell that the whole pack is in a short out condition. I have never heard this before either, and figured I would bring it up here. That is why I asked to be corrected if wrong. I tried to find the site again but couldn't. I was at the site twice and read it both times. This statement was in the context that a 5 cell NiCd pack is more reliable than a 5 cell NiMh pack for the reason that if the pack had a bad cell the NiCd pack would still be at 4.8v and the NiMh would be in a short out condition.
If this information is true it would be good to know. Maybe someone that knows for sure could chime in and clear this up.

Greg



Flyfast1 -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/16/2007 10:45:41 PM)

Greg,

I have never seen anything that indicates that if a cell goes bad in a NiMH pack, that the entire pack goes bad. I didn't think there was anything different about the construction or wiring configuration of a NiMH pack versus a NiCd pack, so it would seem to me that if a cell goes bad and shorts, that the pack becomes just a wire. So, the pack still provides current, just with one less cell. I don't see why having a NiMH cell go bad would make any difference. But, as you said, perhaps someone with more experience can confirm this. I am far from being a battery expert! In fact, since I fly warbirds, I still use NiCd packs. Any weight savings with NiMH is negligible for me and I am very careful about how I care for my batteries, so the memory issue isn't a problem for me. Also, the extra capacity provided by NiMH isn't that important to me. I use multiple receiver packs with separate switches and never fly any one plane more than four times in a day.

I will keep an eye on this thread and see what we learn.

Thanks,

-Ed



Red Scholefield -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/19/2007 12:35:10 AM)


quote:

ORIGINAL: OldRookie

If you are using a single 5 cell RX battery pack, I would go for the NiCd. If one cell goes out an a NiMh pack you will loose all power to your system, if you loose 1 cell on the NiCd battery, you are flying at 4.8v approximately, depending on the charge.
The NiMh are good for a redundant set-up.
This is the way I understand it. Please correct me if I am wrong.

Greg


You are wrong, sorry. One cell failure (99.9% of the time it is a short) in either Ni-Cd or Ni-Mh, the 5 cell pack will operate like a 4 cell pack, that is one of the few advantages of using 5 cells



Panzlflyer -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/19/2007 1:04:00 AM)

One Sanyo 1950 Faup 5 cell pack is capable of flying a 33% for 3-4 flights with 8411s or 5945s all round (9 servos) insane flying style.

The problem you have is the pack youre using. If it is a Hobbico Hydrimax Ultra or not it is utterly useless at handling any current draw and is some serious misinformation marketing.
Try discharging their so called high current pack (2000)as featured in many magazines and see how fast it drops voltage, I have even quit using them on ignition systems.



Flyfast1 -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/19/2007 1:50:37 AM)

Thanks for the confirmation.

-Ed B.


quote:

ORIGINAL: Red Scholefield


quote:

ORIGINAL: OldRookie

If you are using a single 5 cell RX battery pack, I would go for the NiCd. If one cell goes out an a NiMh pack you will loose all power to your system, if you loose 1 cell on the NiCd battery, you are flying at 4.8v approximately, depending on the charge.
The NiMh are good for a redundant set-up.
This is the way I understand it. Please correct me if I am wrong.

Greg


You are wrong, sorry. One cell failure (99.9% of the time it is a short) in either Ni-Cd or Ni-Mh, the 5 cell pack will operate like a 4 cell pack, that is one of the few advantages of using 5 cells





OldRookie -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/19/2007 2:00:53 AM)

Thanks for clearing that up Red.
It didn't sound right, but needed to know.
Now if I could only find where I saw that.

Greg



feihu -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/20/2007 10:15:38 PM)


quote:

ORIGINAL: OldRookie

Thanks for clearing that up Red.
It didn't sound right, but needed to know.
Now if I could only find where I saw that.

Greg


I could be that a shorted NiMh cell burned its connection causing an open circuit - but that could also happen with a NiCad.

feihu



hilleyja -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/26/2007 6:00:55 PM)

My 3 cents.

3000mah 6V NICADS definitely mean sub-C and the weight 5 of them will bring.

I can't figure out why you NEED this configuration. You can easily find inexpensive 2200mah 6V NIMH packs that should handle your configuration quite well. If you really need extended use then simply field charge after two or three flights. I have been doing this for years and haven't had a single battery failure.

NOTE: Another way to combat possible battery failures is to dual-switch, dual-battery your application. The chance that both battery packs will fail at the same time is extremely remote.



shall36 -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/27/2007 1:55:17 AM)

Another 2 cents you probably don't need...I use two Li-IO 2700mah packs with 6v regulators in a redundant setup on my 30% Extra. Lots of power for lots of flights. Cost isn't all that bad, either, about $32 per pack. Each pack weighs in at 3.5 oz. You can get a matched pair of MPI miracle switches for $90' you're up to $152. Sounds like a lot of money, but if you have a $1500+ airplane, $150 isn't all that much. Of course, you need another pack and switch/regulator for the ignition if you're running gas. You get lots of fly time, light weight, and super performance. My only complaint is that it takes my Triton charger quite a while to charge up the packs.

Gee, $25 for a Ni-MH packs sounds dirt cheap in comparison...don't go too cheap, though, or it could end up costing you a plane.



SinCityJets -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/27/2007 6:34:56 AM)

I'm surprised no one has mentioned A123 packs. They are perfect for this type of set-up and can be made in 2300 or 4600 Mah configurations.



Pilot013 -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/27/2007 5:02:45 PM)

Hi!

Thanks for the advices! Well after checking some more resources I found out that Ni-MH is pretty good at all. Well if possible I am trying to find a 2500-2600maH pack 6V with a SubC or C cells. I hope this is possible. for reasonable price...

Hope some of you will be able to link me to these type of batteries!

Best regards!



hilleyja -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/27/2007 5:59:55 PM)


quote:

ORIGINAL: Pilot013

Hi!

Thanks for the advices! Well after checking some more resources I found out that Ni-MH is pretty good at all. Well if possible I am trying to find a 2500-2600maH pack 6V with a SubC or C cells. I hope this is possible. for reasonable price...

Hope some of you will be able to link me to these type of batteries!

Best regards!

You should be able to find that range in NIMH with AA cells instead of Sub-C.

Example:

http://cgi.ebay.com/2-RC-6V-2500mAh-BATTERY-FOR-FUTABA-HITEC-JR-AIRPLANE_W0QQitemZ190184067196QQihZ009QQcategoryZ34056QQssPageNameZWDVWQQrdZ1QQcmdZViewItem



Pilot013 -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/27/2007 6:40:37 PM)

thanks!

I have heard that when the batteries diameter is bigger, then the cell gives more voltage, and when it's thinner - less momentum voltage.

I don' know if this is right..?!

Best regards!



pilotpete2 -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/27/2007 7:45:03 PM)

High capacity Nimh AA cells are not suited to high current situations, they are OK for low current use, such as in a transmitter, not for powering high current giant scale servos.
Pete



Pilot013 -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/27/2007 8:19:36 PM)

Yes!

This is what I meant. So I am trying to find 6V 2400MAH SubC NiMh battereis somewhere about 6.5-7 ounces if possible, not greater than 250 gr.

best regards!



hilleyja -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/27/2007 9:34:03 PM)

quote:

ORIGINAL: pilotpete2

High capacity Nimh AA cells are not suited to high current situations, they are OK for low current use, such as in a transmitter, not for powering high current giant scale servos.
Pete


This is certainly true and is actually true of all NIMHs -- they cannot handle discharge rates as high as NICADs can. But, are we really talking about giant scale servos? After-all, we are talking about a 1/4-scale Yak. I have routinely flown with HS-5600s series servos in this size airplane and they are more than capable of being handled by a 2200mah AA-size 6v NIMH. I believe we are also talking about (2) servos for airlons (I used HS-5625s), (1) servo for rudder (I used HS-5645), and maybe upwards of (2) servos for a split elevator (I used HS-5625s) and finally (1) standard size servo for throttle. If he is running a gasser with a choke he might have a micro servo for the choke. I have even used a similar configuration for my 1/3-scale GP Christen Eagle II. The difference there was I had (4) servos (HS-5645s) for the airlons and my battery pack was a 3500mah NIMH, cells larger than AA but smaller than Sub-C.

If he really wants to go all out with maximum battery capability then go with a power distribution system running off a (regulated) 4800mah Lipo -- way overkill for a 1/4 scale anything. BTW, keep in mind NIMHs tend to have a higher-than-normal shelf discharge -- about 10% a day; you still need to charge them even if you only flew it one time a few days ago.



Pilot013 -> RE: 3000Mah Ni-cd pack for 25% Yak-54 (12/27/2007 9:52:02 PM)

Hi!

Thanks for the answer! Well the charging is no problem for me. Since I am from Bulgaria and a LiPo pack is a bit expansive for me at this point. However could you explain me in details what do I need to have to run properly a Lipo battery. I have a microprocessor Robbe charger and there is written that it can handle up to 8 cell LiPo batteries. As far as I know sometimes a balancer is used, but I do not know its function. Also I know that I'll need to buy a regulator lets say from 7.4V to 6V, right? I think an EVO Flight pack will suite very well my configuration. I'll be happy if you explain more about the charging of Lipo's and what will I need.

About the NimH's the charging is not a problem - I am always charging when going flying, so no rush. I wasn't able to to find a pack like we talked....

Best regards!



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