New CNC blade grips, New Packs, Newly refurbished EP550....

[Cralis]

... So I'm excited for the first flight. Grab all my stuff, load the boot, and drive to the field. Take out the TX, go over the settings - all good. Check. Quick run over the heli - all looks OK and tight. Check. Go to connect battery - NOT check... :arggg:

I LEFT THE DAMN SPLITTER CABLE AT HOME!

Will try not to do that again. So dissapointed. Got home - and was told to start the BBQ. Agh!!!

[mjdee14]

Bummer...:arggg::arggg::arggg::arggg::arggg:

Theres alway tomorrow....:OK:OK:OK

[mysticmead]

I did that the day I went to maiden mine... I got lucky, another pilot had a spare Y cable and I was able to maiden my hurri... now mine is attached with a zip tie.. so I can't forget it (damn short term memory)

[Cralis]

Yeah... I screwed up... But, tomorrow, I will NOT make the same mistake. (Probably a different one).

Anyways, a question: Is it safe/ok/frowned apon to charge your packs attached to the heli?

[mysticmead]

well... there are 2 schools of thought about that... one says yes because LiPo charging technology is MUCH better than it once was. the other says never do that unless you're willing to lose a heli in case a pack explodes... personally, I do both.. I charge my main packs out of the heli.. be cause it's easier.. but I charge my rx pack in the heli... again, because it's easier

[Mikej]

Bugger - that's one of the reasons that I leave the Y-piece on the heli and simply plug the batteries into it on the heli

[kgfly]

" Is it safe/ok to charge your packs attached to the heli?"

Sure is if they are A123 :)

One of the downsides of the H550 is all the fiddling required to mount the two separated packs. It really bugs me compared to every other heli I have had. So it's very nice with the A123 packs to just belly the heli up to the charger and let her rip. 18 minutes later she's ready to go again. Every couple of weeks or so I will take them off for a balance charge (although they don't seem to need it now that they are run in).

[mjdee14]

" 18 minutes later she's ready to go again. ).


Boy that is one good reason to fly A123's....18mins....:banana

I have 7 sets of lipos......can fly within minutes...BUT....takes me hours to recharge all packs with 3 different chargers....

I would still have to hav two sets of 123's....18minutes is TOO long to wait !!!;)

[xodarap1]

I've got ten 2200 hurri packs (soon will be adding six 3000mAh's), charge them all in series, on five chargers. 20 minutes of flight and then 55 minutes to recharge. My goal is to only use the 3000's on the z30 heli and the older 2200's in the z20 heli.

[tibbs]

Hey KGFLY where do you get your A123 batteries from and how many do you use.A123s are almost non existant in the uk.

cheers


tibbs

[kahn10]

to all you boys running 2 times 3sp1 exclusively..........why a separate y lead?why don't you just solder a deans to each one of the power feeds off your esc and link it there? you've then ditched 2 deans connectors losing a place of potential power drop shortened a wire run at the highest power feed in your chopper lost four points of potential failure(the soldered joints on each side of your extra deans) and a fifth point of potential failure (deans connector separating due to low quality(hawk:lol:) sacrifices to heli gods) AND 10 to 15 grams of wieght from the nose of your hurri......????:dontknow:dontknow:dontknow:dontkno w

[mysticmead]

or just start using 5.5mm or 6mm bullet plugs.. then there's no need for a Y cable.. just plug and go

[kahn10]

and best of all with both solutions.......YA CAN'T LEAVE THE BLOODY THING AT HOME:YeaBaby:

[mysticmead]

or just run a single 6s pack... no cable needed that way either

[kahn10]

yeah thats what i run.come to think of it if you had both you could use your hard wired twin dean connector to hook up a 6sp1 as well.with a couple of caps to insulate the two exposed deans posts that wouldn't be in use.......thats it!!!! ban the Y......BRING BACK THE THONG......whoops wrong subject

[ICCA]

This is how I did it. Works great! :thumbup:

[kahn10]

1st prize bro.see...... like genius stroking.....wait stroke a genius.damn it if it feels good do it

[xodarap1]

to all you boys running 2 times 3sp1 exclusively..........why a separate y lead?why don't you just solder a deans to each one of the power feeds off your esc and link it there?

I've been running that since i got the z30 heli.. using a very short version of that so there is no y cable to lose or forget.. it's wired right into the ESC.

[kgfly]

I would still have to hav two sets of 123's....18minutes is TOO long to wait !!!With the right charging setup you can bring it down to about 6 to 7 minutes if you like ;) Charles (everydayflier) over at RCG has a 3S pack he has charged at 26A over 300 times so far (total 500+ cycles on that pack) and it is just now showing a slight reduction in capacity but no increase in Ri so same power output as when new.

Hey KGFLY where do you get your A123 batteries from and how many do you use.A123s are almost non existant in the uk.I bought some DeWalt 9360 packs on eBay and had them shipped out to me in Australia. Then I make up my own packs. You can buy individual cells or premade packs from various sources.Where to buy A123 pre-made packs ?
==================================
kgfly, 18 Apr 2008

http://www.battlepack.com/packs.asp

http://www.modelelectronicscorp.com/view_products.php?tid=1&stid=2

http://www.tanicpacks.com/


Single Cells also here:
======================
http://www.aircraft-world.com
http://www.eheli.com.au


The prices have gone up somewhat over the past six months but when you take cycle life into account, they are still very cheap. Due to the size/weight penalty, A123 is great for learning and sport flying/acrobatics (flips/loops/rolls etc) but if you are into aggressive 3D lipo is a better choice. There is quite a lot of info available about A123 (where, what, how) in the Batteries and How-To Reference sections on this page: http://www.helifreak.com/showthread.php?t=41692

For an H550 you might find this interesting:Comparison of LiPo and A123 packs for a Hurricane550 eHeli
================================================== ========
kgfly, 27 Jun 2008

Assumes:
a) Top quality lipo holds 3.5V/cell under load

b) A123 holds 2.8V/cell under load

c) Runtime is related to available energy: Wh = no_cells x V_per_cell x mAh_capacity/1000 x usable %
LiPo = no_cells x 3.5 x capacity/1000 x 0.80 = 0.00280 x no_cells x mAh
A123 = no_cells x 2.8 x capacity/1000 x 0.90 = 0.00252 x no_cells x mAh

d) For maximum lifetime in excess of 100 cycles for lipos usable power is about 75% of nominal for high quality packs. For A123 FMADirect measurements showed that 16c/33c were good operating points for 500+ cycles. The estimates below take these guidelines into account and the real maximum power that can be delivered is considerably higher for both technologies.

---- ----- -------- ------ ------ ------- ------------ --------
Pack Cells Capacity Weight Energy Rating Power Price
(mAh) (g) (Wh) (W) USD
---- ----- -------- ------ ------ ------- ------------ --------
Lipo 6s 2200 360 37 20c/30c 700 - 1000 ~80-150
Lipo 6s 2500 400 42 20c/30c 800 - 1200 ~80-200
Lipo 6s 3300 560 55 20c/30c 1000 - 1600 ~80-240
---- ----- -------- ------ ------ ------- ------------ --------
A123 7s 2300 560 41 16c/33c 700 - 1500 ~105-140
A123 8s 2300 640 46 16c/33c 780 - 1700 ~120-160
---- ----- -------- ------ ------ ------- ------------ --------