RunRyder RC
 8  Topic Subscribe
WATCH
 4 pages [ <<    <    ( 1 )     2      3     NEXT    >> ] 2531 views POST REPLY
11-27-2017 03:43 PM  84 days agoPost 1
mcfast

rrKey Veteran

Quebec Quebec Canada

My Posts: All  Forum  Topic

I am building an LHS 700e heli, HK got a good deal on a 6s 8000ma but it is only 25c, do you guys think that 25c has enough power, just for sport flying.

P.S. sorry for the spelling or the grammar I am dyslexic!

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 04:11 PM  84 days agoPost 2
RM3

rrElite Veteran

Killeen, Texas - USA

My Posts: All  Forum  Topic

yeah they should be OK in a 12S setup as it will not draw high current with mild sport flying.... though they are on the "minimal" C rating for most. Care in the charging and storage is going to be key... and not taking them below 3.7v per cell should ensure minimal puffing in the long term.

The issue I have is the fact that they are HK lipos... And I am very aware that all lipos are pretty much manufactured by 4 or 5 places, then sorted and sold based on testing to whomever... so not sure about the quality there...

showing a preference will only get you into trouble, 90% of everything is crap...

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 04:32 PM  84 days agoPost 3
mcfast

rrKey Veteran

Quebec Quebec Canada

My Posts: All  Forum  Topic

I was looking to run s a 6s setup.

P.S. sorry for the spelling or the grammar I am dyslexic!

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 05:14 PM  84 days agoPost 4
ticedoff8

rrKey Veteran

Morgan Hill, CA. USA

My Posts: All  Forum  Topic

mcfast
I am building an LHS 700e heli, HK got a good deal on a 6s 8000ma but it is only 25c, do you guys think that 25c has enough power, just for sport flying.
If they are cheap, then buy them.

Keep in mind that there is no standardization for defining a battery's "C-rating".
Assuming there is some ethics within the distributor, they will make a best-guess estimate at what they think is optimistically accurate.
Of course, that estimate will be on the "high side" to make their product look better than the competition.
Or, they may just lie their ass off.

Believe 1/2 of what you see and none of what you hear.
Fake News will be the downfall of our Republic!

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 05:21 PM  84 days agoPost 5
RM3

rrElite Veteran

Killeen, Texas - USA

My Posts: All  Forum  Topic

I was looking to run s a 6s setup.
on a 6S... for me... I would not recommend. especially on a 700 that will draw more amps.

Ive run 6S setups on 600e... anything less than 30C just didnt last more than a single season even when flying sport.

IMHO I wouldnt go less than 35C if you expect them to last with good care.

showing a preference will only get you into trouble, 90% of everything is crap...

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 07:10 PM  84 days agoPost 6
mcfast

rrKey Veteran

Quebec Quebec Canada

My Posts: All  Forum  Topic

That is what I thought, I was thinking, going to a 7s setup, but I only have 6s chargers, I do not what to go out and buy new charges, just because of that.

P.S. sorry for the spelling or the grammar I am dyslexic!

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 07:56 PM  84 days agoPost 7
ssmith512

rrKey Veteran

Indianapolis, IN USA

My Posts: All  Forum  Topic

What is YOUR definition of "sport flying"? I sport fly as well and rarely see anything over 100A - most of the time I average around 60-75A for a flight. My flying style is very easy on the collective/cyclic, no rapid changes in pitch. Those 25C batteries are "capable" of 200A discharge.

If you are not doing high pitch, high load flying, then those batteries would perform just fine.

Steve

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 08:03 PM  84 days agoPost 8
RM3

rrElite Veteran

Killeen, Texas - USA

My Posts: All  Forum  Topic

well nothing wrong with using them in a 12S setup... provided you have an ESC to handle it and a simple series connector... Thats what I did for a my heli a while back as I also only have 6S chargers and had some cheap 4500mha 3S packs... its a PITA but it got the job done till the packs died.

then stepped up to 30C packs, then the last set is now 35C Opti-power... and they've lasted for two years now.

sometimes though going cheap isn't all its cracked up to be.

showing a preference will only get you into trouble, 90% of everything is crap...

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 08:33 PM  84 days agoPost 9
ICUR1-2

rrElite Veteran

Ottawa, Ontario

My Posts: All  Forum  Topic

What I aim for is a high enough amp rating at end of battery cycle.
Let's say you land at 20%.
A 25C 8000mah battery in your case at 20% (1600 mah) left can deliver only 40 amps output constant.
If you land at 30% then you have 60 amps.

If your model averages 80 amps constant you can see how your puffing lipos.

Or am I off base and Lipos are able to supply 200 amps in this case until the end?

spending time, paying attention

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 08:34 PM  84 days agoPost 10
cmezip

rrNovice

San Francisco, Ca

My Posts: All  Forum  Topic

25c 5000ma pack = 125 amps of continuous current
25c 8000ma pack = 200 amps of continuous current

Normal LHS flight for me is 25 amps @ hover with some 60-70 amp peaks doing sport 3d flying.

An 8000mah 25c pack has more current available due to it's larger capacity. If you are sport flying LHS you will be fine (1400-1700 head speed). If you are trying to run 2150 head speed and smack it I would avoid running 6s.

If you are running only LHS I would consider gearing, try to gear for the intended head speed. This is much easier on everything.

Steve

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 08:42 PM  84 days agoPost 11
RM3

rrElite Veteran

Killeen, Texas - USA

My Posts: All  Forum  Topic

25c 5000ma pack = 125 amps of continuous current
25c 8000ma pack = 200 amps of continuous current
yeah at least once... but in the real world not so much.

go ahead and try this if you want... make sure you have three 5 gallon buckets of sand ready...

showing a preference will only get you into trouble, 90% of everything is crap...

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 09:00 PM  84 days agoPost 12
EEngineer

rrProfessor

TX

My Posts: All  Forum  Topic

The way I look at it, 25C packs, are not that good.

Given the higher C ratings of other packs....which are of higher quality.

You always get what you pay for....

Price vs C rating....

Logo 600SXs, 800XX, TDR IIs

PM  EMAIL  Attn:RR  Quote
11-27-2017 09:02 PM  84 days agoPost 13
cmezip

rrNovice

San Francisco, Ca

My Posts: All  Forum  Topic

I agree with what "ICUR1-2" said as well.

As far as 7s I ran it for a while but ended up going 8s and I charge the packs 4s in parallel. I actually have several extra 4s 5000mah Nano-techs I will sell cheap if you are interested in trying them.

Steve

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 09:11 PM  84 days agoPost 14
cmezip

rrNovice

San Francisco, Ca

My Posts: All  Forum  Topic

..

Steve

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 09:46 PM  84 days agoPost 15
AirWolfRC

rrProfessor

42½ N, 83½ W

My Posts: All  Forum  Topic

Nobody finds it necessary to specify the cell count when talking batteries. Like talking about engines and not bothering to specify the number of cylinders.

Anyway, an observation,

If you're running 5000 mah 6S and pulling 25C . . .
You are pulling 125 amps at about 22 volts
That's 2750 watts or 3.7 HP
That's about the equal of a 120cc on nitro.

You really are trying to beat the air into submission

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
11-27-2017 09:53 PM  84 days agoPost 16
EEngineer

rrProfessor

TX

My Posts: All  Forum  Topic

Thanks for pointing out I am stupid
Nobody said any such thing.....but if that's the way you want to spin it, go right ahead.

If that's the way you feel.....and you know best....why even ask?

Just go right ahead and do it....

Logo 600SXs, 800XX, TDR IIs

PM  EMAIL  Attn:RR  Quote
11-27-2017 10:12 PM  84 days agoPost 17
ICUR1-2

rrElite Veteran

Ottawa, Ontario

My Posts: All  Forum  Topic

Another thing to consider is pack weight .
A 45C weighs more than a 25C of the same size.
At some point the extra weight has diminishing returns.
A light machine draws less amps as well.

The diameter of the rotor disc plays a part on amp draw as well .

In the OP's case they will do ok ,until you dumb thumb it and try to recover.
If near the end of flight ....

spending time, paying attention

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 10:49 PM  84 days agoPost 18
RM3

rrElite Veteran

Killeen, Texas - USA

My Posts: All  Forum  Topic

In the OP's case they will do ok ,until you dumb thumb it and try to recover
good point. Ive run lower C packs (like 30C) and have maxed the collective in an attempt to prevent a smouch with the soil on a 6s with a 100A ESC... I have a volt monitor that beeps when the pack goes low and in many instances Ive heard the monitor beep and flash red when pushing max collective... thats a clear indication that the pack may be marked as able to provide the amps... but the reality is it cant. So the volts drop below safe levels (lower than 3.2 per cell) and that in itself is the leading cause of premature pack failure. In these cases Im surprised I haven't had a FBL reset...

When I had a 450 that used 3S packs anything under 35C often puffed on me over time as well... So it goes.

take it for what its worth, but my rule has been to never trust C ratings from bargain brands and always try to stick with C ratings that will deliver 50% + over what your ESC can handle from reputable brands if you expect them to last more than one season...

showing a preference will only get you into trouble, 90% of everything is crap...

PM  EMAIL  GALLERY  Attn:RR  Quote
11-27-2017 11:08 PM  84 days agoPost 19
EEngineer

rrProfessor

TX

My Posts: All  Forum  Topic

+1

Logo 600SXs, 800XX, TDR IIs

PM  EMAIL  Attn:RR  Quote
11-28-2017 12:55 AM  84 days agoPost 20
Flyin for Jesus

rrVeteran

Dana Point, Ca. 92629

My Posts: All  Forum  Topic

ICUR1-2
What I aim for is a high enough amp rating at end of battery cycle.
Let's say you land at 20%.
A 25C 8000mah battery in your case at 20% (1600 mah) left can deliver only 40 amps output constant.
If you land at 30% then you have 60 amps.
This is the second time I have heard this logic in the last 7-8 years.
Where the C rating is not a factor of a pack's max capacity, but rather its current capacity.
I fly a 14s 5000 65c in my 800 down to about 70%. So my remaining 1500mAh or, 1.5Ah x 65 gives me just under 100A. Then my packs must be higher than 65c as I pull well over 100A still without setting off my LVA set to 3.4v per cell.
I don't agree with your interpretation of the C rating.
I understand I might be wrong, but as of now, I don't agree.

PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 4 pages [ <<    <    ( 1 )     2      3     NEXT    >> ] 2531 views POST REPLY
 Print TOPIC  Make Suggestion 

 8  Topic Subscribe

Tuesday, February 20 - 11:59 am - Copyright © 2000-2018 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online