Thread Tools
Jun 11, 2003, 02:29 AM
ZippoGeek
zippogeek's Avatar
Thread OP

HR-4/5FAUP: too good to be true?


Could someone please double-check my numbers in MotoCalc and put my doubts to rest -- it just seems like my projected performance is OFF THE CHARTS for my prospective Unicorn setup, both in terms of WOT flight time and thrust:

Mega 16/15/5
10 x HR-4/5FAUP 1950; .005 ohm; 1.38 oz.
7x4 direct APC
Astro 805 Brushless ESC, 30 AMP
Classic Clark Y Airfoil, 42" span, 493 sq. in. area, 13 oz. empty. (Just plug a Zagi in if it's easier)

I end up with 6:08 WOT at a peak of 25 oz. thrust! 19.1 amps is safe for the 5-turn Mega.

One other fella has already assured me that the heat "warning" I'm getting (228 deg.) is a conservative MotoCalc feature and I should be okay in the air if well ventilated...other opinions on that?

Why do these cells seem too good to be true? What's the catch? What am I forgetting? (other than the fact that they are *#!$ expensive!)

Thanks in advance guys,

Jason

BTW -- thanks a million to all those who've been helping me straighten this e-flight stuff out. I think I'm finally starting to get it!
Sign up now
to remove ads between posts
Jun 11, 2003, 04:25 AM
THINK SMALL
Blue Sky's Avatar
Let's do a rough rule-of-thumb check.
1.95 A/H at 10C equals 19.5A.
1H (60min) devided by 10C equals 6min.
So, sounds about right!
-Dave
Jun 11, 2003, 06:50 AM
Registered User
They're just really good cells.

Somehow, they managed to produce a cell with lower internal resistance than a CP1700 NiCd that weighs only slightly more than a CP1300 NiCd. According to several reports, they're good to 40 Amps. I'm putting 16 of them in a .40 size ARF conversion I'm working on.
Jun 11, 2003, 07:39 AM
Registered User
Bill Glover's Avatar
Quote:
Originally posted by mkirsch1
They're just really good cells.

Somehow, they managed to produce a cell with lower internal resistance than a CP1700 NiCd that weighs only slightly more than a CP1300 NiCd. According to several reports, they're good to 40 Amps. I'm putting 16 of them in a .40 size ARF conversion I'm working on.
The attraction of CP1700s is being able to charge them hard for minimal delay between flights. 5A if I'm not in a hurry (i.e. when sharing the frequency at a club field), up to 10A (in auto mode) if I have the freq. to myself. With 2 packs I can fly almost non-stop (14 cells in a .40 IC conversion).

I'd love to drop the AUW and have a little more power & duration, but I assume you have to charge the 1950s a lot slower? I tend to stick to 2A with my 1700AUPs, though I know others push them harder.
Latest blog entry: Eachine QX65 FPV quad review
Jun 11, 2003, 07:48 AM
jrb
jrb
Member
jrb's Avatar
Just got my 1st pack of Zapped 1950s from Diversity (http://flydma.com/batteries/index.html ), and have to say they’re impressive; see the following Whattmeter readings:

Zapped 1950s: 42amps & 12.3volts, stabilized 41 & 12.1
CP1300s: 38amps & 11.2volts, stabilized 36 & 10.8
Zapped 1250s: 37amps & 11.5volts, stabilized 36 & 11.1

The 1250s are getting tired and is the pack the 1950s will be replacing for Brushless T-33; beyond the upgraded power the new pack is about ¼” shorter, 1/8” narrower, 1/16” taller, and about ¾ oz lighter!
Jun 11, 2003, 03:11 PM
AMA 697691 / FAA 13675
My 8-cell, 1950FAUP NiMH powered ProJeti pulled away from an identical ProJeti using 8 CP1300 cells.

I knew it would...that's why I used them.
Latest blog entry: Greg's Web Hangar
Jun 11, 2003, 03:46 PM
FLYER spelled I-squared-R
fliir's Avatar
I run a 36 amp (static) twin -480 application on the 1950s (see avatar).
Jun 11, 2003, 10:19 PM
Tragic case
davidleitch's Avatar
Quote:
Originally posted by Bill Glover
The attraction of CP1700s is being able to charge them hard for minimal delay between flights. 5A if I'm not in a hurry (i.e. when sharing the frequency at a club field), up to 10A (in auto mode) if I have the freq. to myself. With 2 packs I can fly almost non-stop (14 cells in a .40 IC conversion).

I'd love to drop the AUW and have a little more power & duration, but I assume you have to charge the 1950s a lot slower? I tend to stick to 2A with my 1700AUPs, though I know others push them harder.
Bill

The 1950s are a bit slower to charge than the cp1700s, both have to be cooled down first of course, and the 1950s don't seem to take the charge properly unless cooled first.

Originally I charged the 1950s at 1X on the Supernova and it would take around 40 minutes from memory. Now I am doing them on auto mode using the Schulze with the v 8 software and they are getting done just about as quickly as the 1700s. The schulze ramps up to around 6 amps on them (from memory) and they come off the charger just mildly warm.

I do not think they are noticeably more powerful than cp1700s although I wouldn't swear to that. They are good for 80 amps (measured) although there is probably a big voltage drop at that current draw, and they are lighter, longer and thinner.

I am extremely happy with my 1950s (I have 2x10 and 2x8), but if I had 1700s in a particular application I doubt that the improvements would be that significant to the overall performance. The 8x cell packs are used in a glider where the form factor was a big help and the 10 cell packs are used in a hotliner where they performed brilliantly at 50-60 amps.

Certainly Lipos are a much bigger performance improvement.

dave
Jun 12, 2003, 04:14 AM
Registered User
Bill Glover's Avatar
Good info., thanks Dave. It's never clear with 'new generation' nimh cells quite how hard you can charge them without reducing lifespan, I like to fly a lot so turnaround time is important (that's why I saved up for a 10A capable charger )!

MY 14xCP1700 model only pulls about 38A at full throttle, and aerobats nicely on quite low power. So I can normally put the pack on charge, straight from the model. I got the Schulze carry case with the cooling tunnel/fan built in (good value for money, IMO) ... so if it's a bit warm I charge it in the cooler.

I will definitely consider the 1950s in future, and my next sub C packs will be HR-SC 2600s (as you can supposedly treat these pretty much like the 2400 nicds I've stuck to up to now). I never bothered with 3000 or 3300 nimhs because of the long recharge time (compared to 2400s at 10A).
Latest blog entry: Eachine QX65 FPV quad review
Jun 12, 2003, 07:26 AM
Quote:
Originally posted by Bill Glover
I will definitely consider the 1950s in future, and my next sub C packs will be HR-SC 2600s (as you can supposedly treat these pretty much like the 2400 nicds I've stuck to up to now). I never bothered with 3000 or 3300 nimhs because of the long recharge time (compared to 2400s at 10A).
We charge GP3300 NIMH cells at 6.0 amps so I am not sure I undertand your long recharge time comment. If your below 40 amps, the 3300 cells are the way to go in my opinion.

thanks
Steve
Jun 12, 2003, 08:24 AM
Registered User
Bill Glover's Avatar
Quote:
Originally posted by sjslhill
We charge GP3300 NIMH cells at 6.0 amps so I am not sure I undertand your long recharge time comment.

OK, a rough calculation (allowing for putting 10% extra in, and assuming rated capacities):

3300 at 6A - charge time 36 mins
2400 at 10A - charge time 16 mins

Let's say I've got a typical average in-flight current draw of 18A. That means duration with the 2400s is 8 mins, duration with 3300s is 11 mins.

So 3 mins of extra flight time would cost me 20 mins of extra charging time.

Put it another way. With two packs of 2400s if I charge one while flying the other, when I land I only have 8 mins till the next pack is ready (8 + 8 = 16) and I can fly again. With 3300s I have a little longer in the air, but after landing there's a 25 minute wait before the next pack is ready (11 + 25 = 36)!

So unless you're running several chargers and lots of packs you get more airtime with the 2400s.
Latest blog entry: Eachine QX65 FPV quad review


Quick Reply
Message:

Thread Tools