RunRyder RC
 5  Topic Subscribe
WATCH
 1 page 728 views POST REPLY
HomeAircraftHelicopter
e-
Century Radikal E640 - Swift 16 NX
› Swift 620 SE flight time and LiPo ...
03-12-2010 08:41 AM  8 years agoPost 1
HarveyR

rrVeteran

France - North

My Posts: All  Forum  Topic

I have the 620SE 6S Combo with 610 CF bladed. I fly "mild 3D" at around 1650 HS I'd say (have to measure this one day).

I have two FlightPower 5000mAH 25C and one ThunderPower 5000mAH 30C + since yesterday one Zippy 5000mAH 30C (not tested yet).

I fly for around 7 minutes. When I plug the LiPos in the balancer after the flight I read between 3.65 and 3.80 per cell.

I know I shouldn't go below 3.3. So in theory I could fly longer (maybe 8 or 9 minutes).

So first question : What do you read on your balancer after flying, do you read around 3.3 or around 3.7 like me?

Because in fact, I stop after 7 mins, because if I fly longer the FlightPower (25C) LiPos get hot, that's the main reason why I've set 7 mins. But the ThunderPower (30C) is cool after 7 mins, so I could probably fly longer with it.

Would you say that 25C is too low, that's why they get hot too soon?

PM  EMAIL  GALLERY  Attn:RR  Quote
03-12-2010 11:35 AM  8 years agoPost 2
Greybird

rrVeteran

Davie, Florida

My Posts: All  Forum  Topic

The packs should read 22.2 volts after cooling for a few minutes. Keep going lower, and you risk ruining the packs. At least, that is how I understand it.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-12-2010 01:16 PM  8 years agoPost 3
MAXHSHV

rrKey Veteran

,mn usa

My Posts: All  Forum  Topic

you can't go off the voltage, you need to check what you are putting back in.if a 5000 mah battery to stay within the 80% rule so as not destroy the pack would be 4000 mah, if you are putting less then that back in you could go longer, that is if the packs are still new and at full capacity still.also how warm is the pack?after flight.you need to keep them below 160 f to get good life out of them, a pack that cosistantley comes out hot may have lost some of it's capacity and therefor with 4000 mah you would be going past the 80% witch is what is probably causeing the batterey to get so hot.

Century heli rep. To much power is never enough.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-12-2010 03:52 PM  8 years agoPost 4
HarveyR

rrVeteran

France - North

My Posts: All  Forum  Topic

I have a quite good charger (Hyperion Duo 615i or something). How can I know how many mAH I'm putting back.

When I charge, it starts around 5A (ie 1C), then near the end it wobbles aroung 0.5A. The whole process (charge + balance) takes aroung 70minutes with my Hyperion.

Is there a function on the charger to know how much mAH were put back in?

PM  EMAIL  GALLERY  Attn:RR  Quote
03-12-2010 03:58 PM  8 years agoPost 5
Frank Bostwick

rrElite Veteran

Cincinnati Ohio

My Posts: All  Forum  Topic

The charger will display how many mah it has put into the pack, I know my Hyperion 1210i does and that is a generation older than yours. Its (mah) is critical info so Im sure yours must show it.

RIP ROMAN

PM  EMAIL  GALLERY  Attn:RR  Quote
03-12-2010 03:59 PM  8 years agoPost 6
Frank Bostwick

rrElite Veteran

Cincinnati Ohio

My Posts: All  Forum  Topic

How are you "guessing" your head speed?

RIP ROMAN

PM  EMAIL  GALLERY  Attn:RR  Quote
03-12-2010 04:48 PM  8 years agoPost 7
oldfart

rrProfessor

Vancouver, Canada

My Posts: All  Forum  Topic

The flight times you are quoting are about right for a 1650 head speed on those packs.

The biggest consumer by far of power is rotor speed, because the drag increases exponentially on a rotor blade, as the speed it rotates is increased.

So a good rule of thumb is that you will get a 30% to 35% increase in power draw for every 10% increase in rotor speed.

As for voltage after flight, a good pack (with all cells of equal internal resistance), you will find each cell to be about 3.7 after a flight in which you have not drained more then 80$ to 85% of their nominal capacity. As Greybird stated that will mean you should measure a total of 22.2V from your 6S packs after they have cooled down after a flight.
I fly for around 7 minutes. When I plug the LiPos in the balancer after the flight I read between 3.65 and 3.80 per cell.
This shows that some of your cells (e.g. the one indicating 3.65) are starting to develop a lot more internal resistance (the aging process of any battery cell) then others. Most chargers that have built in balancer circuits will not even kick in if they detect a bigger then 0.2V difference in cells. NOTE: That one already has a 0.15 difference between two.

The fear with that pack is that if you ran it any longer, so that your 3.8 cell is down to 3.7, then that weak cell may get damaged too much, and not recover.

Phil

PM  EMAIL  GALLERY  Attn:RR  Quote
03-15-2010 10:04 AM  8 years agoPost 8
HarveyR

rrVeteran

France - North

My Posts: All  Forum  Topic

FBoss, my charger does too, I've found the info (just press "down" arrow at the end of the charge, there's also the resistance in mOHM)).

For the HS, I approximate it mathematically:

Engine speed : 1110Kv * 22.2V = 24 642 RPM
Gear Ratio : 9 Teeth Pinion / 96 Teeth Gear = 0.0938
HS = 24 642 * 0.0938 = 2310 RMP with 100% throttle and 100 % Efficiency ratio.

I fly 80% throttle (gov mode) and "guess" a 90% efficiency ratio, so

HS = 2310 * 80% * 90% = 1663 RPM

oldfart, thanks for these details, I'll reduce my timer to 6"30' to be on the safe side. I'll check closer next time the exact range between lowest and highest cells.

After the flight, my LiPos are "warm", I'd say way below 160F, more like around 100F-130F. You can easily hold them, you just feel they are warm. They don't feel warmer than the water for a baby's bath (which is around 100 F). 160F must feel really hot (like a cup of tea a few minutes after boiling).

Yesterday I tested measuring the mAH put in :

On my old FlightPower 25C 5000mAH : I put in 3850mAH with a resistance of 67mOhm. So as this is old, it's likely I'm pushing it too far, because that's nearly 80%.

On my new Zippy (first charge ever) 30C 5000mAH : I put in 2020mAH with a resistance of 12mOhm. I'll check next time how much I put back into the zippy to see how much I took out fr a 7.15 minutes flight).

Whatever, it's interisting to see the resistance difference between old and new (67 vs 12).

Anyone have an idea of what is the kind of maximum resistance it will reach before "failing"?

PM  EMAIL  GALLERY  Attn:RR  Quote
03-15-2010 07:41 PM  8 years agoPost 9
oldfart

rrProfessor

Vancouver, Canada

My Posts: All  Forum  Topic

I do not know, as they do not just "fail", they just deteriorate in performance until they are no longer worth using.

Phil

PM  EMAIL  GALLERY  Attn:RR  Quote
03-15-2010 10:05 PM  8 years agoPost 10
HarveyR

rrVeteran

France - North

My Posts: All  Forum  Topic

Oh, well, that's quite reassuring, so they don't just suddenly go in flames in the middle of the flight! at least I'll see it coming. Thanks.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-15-2010 11:43 PM  8 years agoPost 11
oldfart

rrProfessor

Vancouver, Canada

My Posts: All  Forum  Topic

Mais les lipos en France sont un peut different. Peut être ils peuvent se mise en feu.

en jeste

Phil

PM  EMAIL  GALLERY  Attn:RR  Quote
03-16-2010 03:06 AM  8 years agoPost 12
MAXHSHV

rrKey Veteran

,mn usa

My Posts: All  Forum  Topic

as oldfart said for the most part they deteriate slowly , however some cheap packs will sometimes just have a cell go bad for no apperent reason, and most chargers won't even try to charge the pack if there is a bad cell and for good reason.but I've never had one catch on fire in the heli.

Century heli rep. To much power is never enough.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-17-2010 11:47 AM  8 years agoPost 13
HarveyR

rrVeteran

France - North

My Posts: All  Forum  Topic

Phil NOEL, sounds quite French (NOEL=Christmas)... I'd be interested to know what you wrote to get "en geste" as a translation ?

PM  EMAIL  GALLERY  Attn:RR  Quote
03-17-2010 04:53 PM  8 years agoPost 14
oldfart

rrProfessor

Vancouver, Canada

My Posts: All  Forum  Topic

"in jest"

Phil

PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 1 page 728 views POST REPLY
HomeAircraftHelicopter
e-
Century Radikal E640 - Swift 16 NX
› Swift 620 SE flight time and LiPo ...
 Print TOPIC  Make Suggestion 

 5  Topic Subscribe

Wednesday, June 20 - 10:15 pm - Copyright © 2000-2018 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online