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View Full Version : Battery Performance 7.4v LiPo v. 9.6v GP



mpetrich
04-12-2005, 05:13 PM
Hi you guys,
Looking for some insight here.
I am currently running the Half8 with a Mamba 6800 and an 8 cell Team Helotes GP1100 pack (a GREAT pack by the way!). I really want to run with LiPo's but I would be dropping from 9.6v to 7.4v. I will gain an increase in mah from 1100 to roughly 1600 but with the drop in voltage, am I going to see a reduction in speed? The Half8 is really flying now (after the slipper fix) and I don't really want to reduce the top end.
Thanks for the help.
Matt

UNITED_RC
04-12-2005, 06:51 PM
Hi you guys,
Looking for some insight here.
I am currently running the Half8 with a Mamba 6800 and an 8 cell Team Helotes GP1100 pack (a GREAT pack by the way!). I really want to run with LiPo's but I would be dropping from 9.6v to 7.4v. I will gain an increase in mah from 1100 to roughly 1600 but with the drop in voltage, am I going to see a reduction in speed? The Half8 is really flying now (after the slipper fix) and I don't really want to reduce the top end.
Thanks for the help.
Matt

Matt,

Naturally, by dropping from 9.6v to 7.4v you will see a reduction in speed. But...the advantages are this: The lipo solution weighs a fraction of the weight compared to the GP cells, so your H8 will weigh less. Lipo's technology actually will increase your runtimes as well....not only due to the extra 560mah, but lipo cells give a longer runtime when comparing mah to mah.

URC

mpetrich
04-12-2005, 06:57 PM
HI Jon,
Thanks for the reply. That makes sense and I like the fact of the greater mah and the lighter batteries.
Thanks,
Matt

Shawn Palmer
04-12-2005, 07:54 PM
Fully charged, a 2 cell lipo pack is actually 8.4v, and with adequate Mah inside - they hold voltage under load generally a bit better than even GP's.

In our running, an Apogee brand 2 cell lipo is a bit better, or at the very least every bit as good as an 8 cell GP pack.

You won't be dissapointed!

Shawn

mpetrich
04-12-2005, 07:59 PM
Hey Shawn!
Nice to see you drop by!!!
Thanks for the info.
By the way, the Mamba 6800 is holding up very well with the Half8 (after you fix the slipper). The addition of a heat sink on the motor really helped and if you gear it right, no cogging and the temps are manageable.
The Half8 really handles the power of the Mamba wonderfully.
It is a great combo!!!
Thanks,
Matt

Shawn Palmer
04-12-2005, 08:03 PM
That's good news!

We've got 2 incoming for testing and evaluation.

We see these as "the next best thing" in micro, and are gonna do all we can to accomodate everyone who wants to Mambanize them as painlessly as possible.

There's a nationals race coming up in the Fall in NJ and they'll be running them as a class - I can't wait!

Shawn

BitHed
04-12-2005, 08:36 PM
...AWWW MAAAN...It is getting harder and harder to stay NON-brushless and NON-lipo in this industry...This is BitHed trying NOT to get sucked in, NOT to get sucked in!!! AAAHH!!!

...Lighter and longer is just SO inviting :D

mpetrich
04-12-2005, 08:43 PM
Hey Bit!!
Get the Mamba......get the Mamba....get the Mamba................. :D :D :D
You WILL NOT regret it...........
hehehehehhe!!!!
Matt

BitHed
04-12-2005, 08:48 PM
..aw man...ok brushless i can cope with but lipo? cant we keep it easier than that? :p

acsubie
04-12-2005, 08:48 PM
That's good news!

We've got 2 incoming for testing and evaluation.

We see these as "the next best thing" in micro, and are gonna do all we can to accomodate everyone who wants to Mambanize them as painlessly as possible.

There's a nationals race coming up in the Fall in NJ and they'll be running them as a class - I can't wait!

Shawn


cant wait for those nats in my home state

BitHed
04-12-2005, 08:50 PM
...acsubie..need a pit-man cause i think i am free that weekend :)

...Matt BTW do i HAVE to get Mamba? How about the other offerings that are coming...Here we go...Back to NoobVille agaiin...

TNB
04-12-2005, 08:54 PM
..aw man...ok brushless i can cope with but lipo? cant we keep it easier than that? :p
The problem that I see is that once "you" go lipo, you'll want more and more speed. For example, one of my friends dropped the Comp X package in a 1/24th scale ABC DTMx4--it lives up to the name of Pocket Rocket. I also have an ABC DTMx4 rolling chassis.... waiting. :)

mpetrich
04-12-2005, 08:56 PM
..aw man...ok brushless i can cope with but lipo? cant we keep it easier than that? :p

Brushless without LiPo's is like kissing your sister :mad: ......................Mamba with LiPo's, that a BETTER story....... :D

BitHed
04-12-2005, 09:02 PM
:p you guys suck..stop trying to make me spend more money..just 10 minutes ago i purchased a UNITED K4 that I KNOW ia m going to be very happy with...Nope...I will stay brushed a while longer...Then you guys can sell me your 'used' gear at cheaper rates ;) You have JUST been Vulcan mind-melded :D

TNB
04-12-2005, 09:05 PM
Do you have a LiPo charger yet? Well, you better start shopping.

BitHed
04-12-2005, 09:09 PM
...Senor i know NOTHING!!

TNB
04-12-2005, 09:12 PM
Here is a link to a local company to help get you started. :D

http://www.thunderpower-batteries.com

BitHed
04-12-2005, 09:17 PM
..Thanks TNB..i will look into it...

hkopium
04-13-2005, 12:47 AM
This website is filled with devils! They keep tempting you to spend money. :p

Rcdriver
04-13-2005, 01:05 AM
Also a good site to get lipo stuff is Bishop Power Products (http://www.b-p-p.com/) and to get really good lipo packs is Cheap Battery Packs (http://www.cheapbatterypacks.com/cbpsite/mainasp.asp?session_id=288725&cmd=&promoid=) .

Little more temptation...:D

halfEIGHT
04-13-2005, 06:13 PM
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04-14-2005, 11:12 AM
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UNITED_RC
04-14-2005, 05:35 PM
Hey Shawn!
Nice to see you drop by!!!
Thanks for the info.
By the way, the Mamba 6800 is holding up very well with the Half8 (after you fix the slipper). The addition of a heat sink on the motor really helped and if you gear it right, no cogging and the temps are manageable.
The Half8 really handles the power of the Mamba wonderfully.
It is a great combo!!!
Thanks,
Matt

Matt,

your pack is shipping today....so you should have it in Saturday's mail. What pinion are you running with your 68k mamba?

URC

mpetrich
04-14-2005, 07:10 PM
Matt,

your pack is shipping today....so you should have it in Saturday's mail. What pinion are you running with your 68k mamba?

URC

Excellent! Thanks for the prompt service!
I will check tonight for the pinion size and let you know.
I ran last night on a carpet track for the first time and the Mamba ran MUCH warner than when outside on the street.
The heat may be an issue but we still have to work on the gearing.
Thanks,
Matt

ThievingScouser
04-19-2005, 10:23 PM
Hi Guys,
My first post here, just wanted to say hi, and I have a question about LiPo batteries.

I've been very tempted to go over to the lithium side but there's one factor holding me back, even more so with the Half8.

I run GP1100's in my brushless MiniT and have been toying with just getting an order of 100 or so more to make up packs for my other 3 recent micro purchases. The thing that puts me off LiPo is the quoted max current they can deliver. Am I reading things wrong, or can they only deliver 15Amps?

This is of particular concern with the Half8 as I have a Mega 16/15/2 sat in it at the moment with a Phoenix 35 ESC. Now that ESC can draw upto 50Amps surge, and 35Amps continuous according to BPP. GP1100's have been tested at 40Amps apparently, but what I've seen of the LiPo's supplying 15 just isn't going to cut it.

Can someone help me out here and (hopefully) point out where I'm going wrong? :)

Cheers,
Ed

ThievingScouser
04-20-2005, 09:35 PM
I think I must have been looking at poorer/older cells than is currently available.

The MaxAmps 3s2p 1800mah pack (using the 900mah cells) looks good for my RC18T (although the 26Amp burst, when the Phoenix 25 ESC can take 25 continuous and 40 burst, might be cutting it a bit fine?)

For the Half8 though, what to do. I measured the battery space either side tonight and there's 48mm x 50mm x 21mm each side (maybe a fraction more, I was being a little conservative but there'd still be a little of the cell overhanging in the back corner)
This is a good size for a 4s2p saddle pack using the same cells above, but then the 26Amp limit becomes more of a problem with a 35A continuous, 50A peak ESC).

The 1650 cells would be ideal, but just too long.

Has anyone done any more research into this? I see Kokam have some 20C+ cells out. I'll have a look into their availability/size/price.