RunRyder - Please evaluate performance data (what's killing the batteries?)

rrTV-PHOTO

New HD TV

HOME rrTV-PHOTO GALLERIES MY GALLERY HELP-FAQ

myHOME PM pmRR MEMBERS 689 ONLINE 20 EVENTS SEARCH REGISTER START HERE

1 page

286 views

POST REPLY

HeliProz	.	ZoomsHobbies	.	HeliHobby
	.		.

e-Mikado Logo 400 500 600 > Please evaluate performance data (what's killing the batteries?)

Dan A.
Senior Heliman
Location: Rancho Santa Margarita, CA

I would appreciate it if an experienced Logo 10 hard 3D pilot would evaluate my battery performance and tell me what is the biggest killer? I'm sure I need to adjust something (pinion, pak size, radio curves, flight timer, or other) in order to get more reasonable battery life. I hear others getting 100 to 200 cycles of 3D flights on their lipos, while I'm consistently only getting 39 flights before battery death. That equates to $6.50 per flight. MY GOAL: significantly lower the $/flight ratio without sacrificing much 3D performance.

Logo 10C
Neu 1910 1Y fanned 1020 kv
21 tooth pinion (9.524 gear ratio)
TP6S1P 3800mAH Extreme series 195mm
CC HV85 ESC
+-11 degrees collective
+-7 degrees cyclic
5 minute flight timer

Comparative FDR information:

When the pak is new, average headspeed=2350, high amps=60, 1200W, low pak V=19.8, 2300 mAH, high temp=138, flight time=5.5 minutes

39 flights later, average headspeed=2200, high amps=45, 858W, low pak V=17.2, 1200 mAH, high temp=121, flight time=3 minutes

The most significant factor in my mind is how much the pak volts are dropped during flight. From 25V at no load, to 19V in the middle of a flight. I believe the belt has just the right amount of slack, with occasional momentary slap. I believe the gear backlash is perfect also (judged by slight movement with fingers).

What would you change?

08-19-2008 05:15 AM

helicraze
Key Veteran
Location: Victoria - Australia

what packs have you got?

08-19-2008 06:10 AM

lloyd
Key Veteran
Location: Port Elizabeth,South Africa

Try the Outrage 6s 3700mah lipos,very powerful,holds voltage well even at the end and cool to the touch after flight.They are cheaper than F/Powers and 50% crash replacement within 6 months of purchase.

lloyd

future of nitro is ELECTRIC

08-19-2008 06:23 AM

TomC
Veteran
Location: Gold Coast, Queensland, Australia

Dan A.,

If you want more battery life, in general, the best thing you can do is to drop down from your current 21t pinion to a lower toothed one and reduce your headspeed. A 20t pinion should give you ~2200 hs and your batteries may last ~100 cycles. Drop this down to a 19t pinion (~2100 hs) and you may get ~200 cycles out of them.

Also, while you say you time 5 min flights, you really need to time and measure the mahr's put back into the pack. Ideally you should aim for ~75-80% pack capacity at most. If you really need/want the high hs then you probably need to reduce your flightimes down to ~4 min.

I'm not a hard 3D flyer, so this is only my $0.02 worth.

Cheers,
Tom C

CX2 2s
Logo10- 3D 5s
Trex600 10s
2x Ion-x, 1x15s DS, 1x15s SS

08-19-2008 08:30 AM

Yug
rrProfessor
Location: UK. Herts

How about moving from 6S to 8 or 10S and reduce your pinion size. In this way, the current demands on the battery will be reduced which is the biggest killer.

Vegetable rights and Peace

08-20-2008 12:33 AM

Dan A.
Senior Heliman
Location: Rancho Santa Margarita, CA

Thanks for the advice so far guys. I'll probably try Outrage after these packs are depleted. Tom, when full charging, I put back only 60 to 70% of the capacity after each flight. I'm wondering how you estimated headspeed and battery life for 20 tooth and 19 tooth?

I'm wondering if the motor speed is so far below the power band that it may be mostly an efficiency issue? With the 21 tooth pinion and headspead maxed at 2300 RPM, the motor is running at 21905 RPM. I believe the max design speed for the motor is 30000 and I'm wondering if that's where the motor will be much happier. If I install an 18 tooth pinion, do you think the efficiency improvement would enable head speed above 2200 RPM? Or would I need 8S voltage to run at that speed? I don't know how to accurately calculate this.

08-20-2008 02:14 AM

TomC
Veteran
Location: Gold Coast, Queensland, Australia

Dan A.,

Dropping a tooth or 2 off your motor pinion will reduce your amp draw (and your hs too of course). If you want to improve your battery life, this is the easiest way to do it imop. I'd guestimate that your peak amps will go down at least ~5 amps with a 20t pinion and at least ~10 amps with a 19t pinion. The increased battery life is purely a gut-feel guestimate on my part based on a few years of lipo experience.

If you really want high headspeeds, together with long battery life it would be a good idea, as you suggest, to go to 8s ~37-3800 packs and use, say a ~15t pinion. This higher voltage should improve your motor eff. a bit (maybe 1-2%) but most imp it will reduce your amp draw by +10 amps over your current set-up, or about the same as dropping down to a 19t on 6s would do.

Hope this helps.

Cheers,
TomC

CX2 2s
Logo10- 3D 5s
Trex600 10s
2x Ion-x, 1x15s DS, 1x15s SS

08-20-2008 03:31 AM

Dan A.
Senior Heliman
Location: Rancho Santa Margarita, CA

Thanks a lot Tom.

I'll try 19 tooth first and see what headspeed I can get.

After these packs reach EOL, I'll change to 8S configuration. 8S is a little higher voltage than the 1910 1Y stator was designed for, but Steve says it should be OK if I keep the speed under 30000. I used to run 8 emolis which is almost that high (like 7S lipo).

Cheers

p.s. corrected my language in original post (changed "runout" to "backlash"

08-21-2008 12:59 AM

MrMel
Elite Veteran
Location: Lidingo, Sweden

First of all, I would contact ThunderPower customer service, I had exteme packs going bad after 40ish flights and they replaced them for me.

Second, try Outrage or DesirePower batteries.

Your setup shouldnt kill the batteries, actually, your current setup is quite low amp-draw-wise.
My rule is that Peak current shouldnt exceed "cont" rating of the battery, that way it tends to stay good for a long while.
that said, I havent really been lucky with FP/TP lately...

Team Autopartner - Team pilot

08-21-2008 09:52 AM

TomC
Veteran
Location: Gold Coast, Queensland, Australia

MrMel,

I agree that it seems that you need to try to limit peak amps to ~max continuous rating, or maybe a bit less, on FP/TP 20-25C packs if you want them to last. My gut-feel is that pushing a Logo 10 above 2300 rpm hs (depending on the main blades used), on 6s, will push this limit somewhat. I suspect that this guy's real peak amps are a bit higher than he has recorded. Not his fault, just the limit of inexpensive monitors imop.

I have found that even limiting these packs to ~max C peaks pushes these packs a bit too much after ~50 cycles. Like you, I have had numerous packs replaced (like ~12x 5s1pEvo20-25C 3700 packs over the last 18 months) and this starts to get a bit embarassing, to say the least!

I've tried a few Outrage XP 25C 5s 3700 packs lately and I agree they seem great. Lots more power (like +150 rpm hs) and cooler battery temps. I've only got ~20 cycles on these packs so far so I don't know how they will perform in the long run. My guess is that if you push them too hard they will increase their internal resistance and either puff or refuse to put out max amps. Time will tell.

Right now I think that the best way to go with these Outrage packs is to gear-down and/or govern-down to ~ what head speed you would expect from your FP/TP 20-25C packs. This should give you a bit more runtime and hopefully a good, +150 cycle, battery life.

Cheers,
TomC

CX2 2s
Logo10- 3D 5s
Trex600 10s
2x Ion-x, 1x15s DS, 1x15s SS

08-21-2008 03:18 PM

1 page

286 views

POST REPLY

Ron’s HeliProz South	.	Century Helicopter	.	MTA Hobbies
	.		.

e-Mikado Logo 400 500 600 > Please evaluate performance data (what's killing the batteries?)

PRINT TOPIC

Advertisers

Subscribe to This Topic