PDA

View Full Version : Homebrew 11.1V 1700mAh lipoly pack



ph2t
03-08-2006, 12:56 PM
I've got my own URC 11.1V 1660mAh pack but I wanted another one, realised the buggers were out of stock so I put my own together..

The main thing with lipo at this size is that of length. They all are too long usually so it took some searching to find a good pack. In the end I bought two Blue Arrow 12-15C 11.1V 850mAh packs.

Here's some pics.......

http://halfeight.com/gallery/data/500/DSC07564.JPG

Here's a comparison shot to my URC 11.1V 1660mAh pack. My packs are taller than the URC ones.

http://halfeight.com/gallery/data/500/DSC07571.JPG

And here they are sitting pretty, well tight, but pretty! You need to make new pin holes in the battery hinge posts due to the lack of space from the tall packs....

http://halfeight.com/gallery/data/500/DSC07573.JPG

The specs (on paper) are pretty good too. Calculating it out.

my pack, nominal discharge (12C) = 20.4A
URC pack, nominal discharge (10.5C) = 17.4A

my pack, peak/burst discharge (15C) = 25.5A
URC pack, peak/burst discharge (14C) = 23.2A

Of course this is just theory. I'm yet to try the pack out, will hope to tomorrow, but we'll see.......I'll let you fellas know how it goes....

ph2t.

leapingbug
03-09-2006, 10:06 PM
Im not a fan of the stock sattle pack form but thats looking pertty good ;)

ph2t
03-10-2006, 01:09 PM
thanks! after running my RC18T into the ground I found I wasn't a fan of the side mounted pack, I really like this arrangement and enjoy running a chassis that is quite well balanced. ALthough a puritan might make the front a bit heavier since the lipo's are lighter.....but I don't drive well enough to make that an excuse!

ph2t.

dirtdynamics
03-15-2006, 02:08 AM
love the layout but isn't it more costly to have the packs made since they are split up?
curious...

OvaYaHead
03-27-2006, 04:35 PM
ph2t - are you charging the packs individually still? Or are you just charging them together through the deans plug?

ph2t
03-27-2006, 08:49 PM
I charge through the deans plugs at the total mAh rating of the pack.

ie: I charge at 1.7A (2 x 850mA) which is the 1C of this pack.

As a note, when charging mutli celled lithium polymer packs you ALWAYS charge them through the main power wires. NEVER should you charge them through the seperate cell tap plugs that is also connect.

here's an example of what I mean:

http://www.tedani.com/images/stmodel-111-2040lipo-12c.jpg

Note in the picture above the small plug off to the side? this is the cell balancer port. It is where you connect a lipoly balancer before/during/after you charge your li-polys. You DO NOT charge though this port.

I use the "blinky" cell balancer from astroflight.com, it works a treat. I can test before a charge to ensure all the cells in a pack are above the 3V level and after charging I use it to balance the voltage levels. this way I get more consistant mAh's into the pack.

To ensure ongoing performance out of your lipoly's a good balancer is a must when your batts are subjected to high current draining applications like 1:16 scale carnage! lol....

ph2t.

OvaYaHead
03-29-2006, 07:07 AM
thanks ph2t, that was the info I was looking for. I was wondering why you left the cell tap.

:D now about using a whoa nelly in the MI ST. just kidding, i'll message you the question. its for the new z I picked up.

Stickyfingers
03-29-2006, 03:10 PM
Note in the picture above the small plug off to the side? this is the cell balancer port. It is where you connect a lipoly balancer before/during/after you charge your li-polys. You DO NOT charge though this port.

Weird. I've run various Align and E-Pro lipolys for about 3 years in my Trex heli and they have always been charged through the multiplug. In fact, it's the only way that the Align chargers can work.

Think thats a bit of duff info personally but hey I'm new here so dont want to rock the boat!

ph2t
03-29-2006, 08:55 PM
Think thats a bit of duff info personally but hey I'm new here so dont want to rock the boat!

lol, that's cool, no offence taken. I've always been told to charge through the main connector. Obviously your setup is different.

I've always been keen to do my own charging through the blancer port, I bought a few connectors to allow me to hook them up. I just never did it. As long as you're only connected to one lipo at each time the other lipos won't have any effect since they're not in circuit with the charger.

That charger looks pretty good:

http://www.deeteeenterprises.com/NS.T.Rex.Align.Charger.1a.php

The only bugger is the charge rate is fixed at 1A. So whilst it works fine in your case it's not suited to the general micro hobby class.

cheers,

ph2t.