R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 09-01-2008, 07:38 PM   #136
Tech Elite
 
tallyrc's Avatar
 
Join Date: Mar 2003
Location: palm city, fl
Posts: 2,594
Trader Rating: 12 (100%+)
Default

found this project when looking for dc3v to dc5v.. maybe some of you smart guys can adapt it.. http://ladyada.net/make/mintyboost/index.html
__________________
WWW.STORMERHOBBIES.COM helping keep pan cars alive!

Turns out not where, but who your with that really matters... DMB
tallyrc is offline   Reply With Quote
Old 09-01-2008, 08:08 PM   #137
Tech Master
 
Join Date: Nov 2003
Posts: 1,850
Trader Rating: 5 (100%+)
Default

The only problem, possibly, with the step up IC is how much current they can deliver. Is 600 mA enough to run a Spektrum receiver and a high speed servo? Guess I'll have to break out the O-Scope and do some measuring.
Even if it has plenty of amperage capacity, you are still taking power and runtime out of your main battery. A receiver battery will always give you more runtime.
__________________
Serpent SRX8 electric
Serpent Cobra 811TE-E
Serpent S120LTR 17.5 1/12th and S100LTR Pro-10
Serpent S411 Eryx 4.0 USGT
Team Serpent America and Desoto Racing
Stealth_RT is offline   Reply With Quote
Old 09-01-2008, 08:26 PM   #138
Tech Regular
 
S.Heath's Avatar
 
Join Date: Sep 2003
Location: Ft.Wayne, IN
Posts: 463
Trader Rating: 21 (100%+)
Send a message via AIM to S.Heath
Default

I appreciate the research and the possibility of someone being able to create a voltage step-up circuit. If it can be done, I'm sure someone in the R/C community will have the know-how and ability to make it happen. At that point we will need to weigh the benefits against the drawbacks. Until that time, there is a proven alternative that is already available... the receiver pack. Only a few years ago, before the appearance of the higher capacity NiMh cells, many modified drivers routinely ran receiver packs to squeeze the runtime of their 4-cell packs to the 8 minute level.
Don't get caught up in overthinking the problem... use the KISS method... (KISS; Keep It Simple, Stupid).
S.Heath is offline   Reply With Quote
Old 09-01-2008, 08:49 PM   #139
Tech Fanatic
 
trailranger's Avatar
 
Join Date: Feb 2007
Location: Springfield, MO
Posts: 946
Default

Rightnow keeping it simple will be a RX pack. In the future a 5V IC will be the better choice for space, weight and less fuss.

Will taking 250mah out of 5700 battery to run the RX and servo hurt run time? Highly doubtful, since runs are only 8Min and the motors really can not pull a strong enough average load without overheating. The load would have to average 40Amps or greater to dump in 8min and only single digit windings will do that in 1:12.

Plus by time a 5V 3A IC comes out, the same lipo pack could be 7000mah.
trailranger is offline   Reply With Quote
Old 09-01-2008, 09:46 PM   #140
Tech Elite
 
reenmachine's Avatar
 
Join Date: May 2008
Location: Studio City, CA
Posts: 2,539
Trader Rating: 26 (100%+)
Default

I've seen receiver packs as light as 20g so I don't see what the fuss is about running one. The flexibility in placing it for ballast would probably be welcome.

I'm running a Tekin RS ESC in my touring car and have the Hotwire programming interface. It looks like this would be a great ESC for 12th scale BL/lipo as it has lipo cutoffs for 1S, 2S, and 3S packs. You can also choose from 5 throttle profiles (and create custom ones soon) and change drag brake, current limit, etc., all of which may be key in such a lightweight platform.
__________________
Pete Waydo
2010 Big Fat Turkey Race Mini Cooper AAA Main Champion
*** currently in stasis ***
reenmachine is offline   Reply With Quote
Old 09-02-2008, 07:18 PM   #141
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

Finally back from Vegas. Jacks post pretty much sums it up for now. We will be sending some packs out to various people to play with in the coming weeks but we did order 300 packs as I think this will be the way to go and if the 12th scale guys don't adopt it right away we have had allot of interest from the oval guys.

One of the problems is the speed controls have built cutoff in the 3.2v range and maybe different from manufacturer to manufacturer. This seems to create a problem with the low turn motors. We will test 13.5 and up to see if the same issue will occur.

I spoke to the Novak guys at the race and making a converter is possible and they could possibly include it in future speed controls.

As this is something new it may require a bit different electronic setup but with a bit of time I'm sure it will be figured out. The interest so far is very positive and I think this will be the way to go.

As we have more test results we will let you guys know.
Danny/SMC is offline   Reply With Quote
Old 09-02-2008, 07:52 PM   #142
Tech Elite
 
KHoff7's Avatar
 
Join Date: Jan 2007
Posts: 3,166
Trader Rating: 4 (100%+)
Default

__________________
Awesomatix USA / Middle River Hobbies / Sweep / Psycho Cells Racing
Karl Hoffmeister
KHoff7 is offline   Reply With Quote
Old 09-02-2008, 08:50 PM   #143
Tech Elite
 
reenmachine's Avatar
 
Join Date: May 2008
Location: Studio City, CA
Posts: 2,539
Trader Rating: 26 (100%+)
Default

Quote:
Originally Posted by Danny/SMC View Post
I spoke to the Novak guys at the race and making a converter is possible and they could possibly include it in future speed controls.
See, that's what I'm talkin' about. An ESC that internally steps up the rx voltage -- reverse BEC if you will. If the 1S lipo technology shows promise, the industry will respond and accommodate, jst like they did with lipo technology in the first place.

FWIW, my Tekin RS ESC lipo cutoff can be set as low as 3.0V.
__________________
Pete Waydo
2010 Big Fat Turkey Race Mini Cooper AAA Main Champion
*** currently in stasis ***
reenmachine is offline   Reply With Quote
Old 09-03-2008, 07:39 AM   #144
Tech Addict
 
Join Date: Mar 2008
Posts: 649
Trader Rating: 1 (100%+)
Default

I can't wait to be able to order a pack to try. Even if it's only in practice.

For some reason, the 12th guys seem to be a little slow to change so it might take a little bit to get people to make the switch. The same thing happened with brushless at first.
Fred_B is offline   Reply With Quote
Old 09-05-2008, 07:16 AM   #145
Tech Master
 
slakr's Avatar
 
Join Date: Jan 2007
Location: NC
Posts: 1,743
Trader Rating: 33 (100%+)
Default

BUMP
__________________
TLR 22 4.0, 22-4 2.0, 8IGHT & 8IGHT-E 4.0~XRAY XB2C~AE TC7.1
Tim aka "slakr" ROAR No. 3-119960
slakr is offline   Reply With Quote
Old 09-05-2008, 05:18 PM   #146
Tech Addict
 
Bigshades's Avatar
 
Join Date: Nov 2007
Location: Texas
Posts: 582
Trader Rating: 22 (96%+)
Default

I did a little update on my project...

I re-wired everything, and it is a little neater than i originally had it. It still looks like a mess, but it works. If you look closely at the attached picture, you can see 2 AAA cells connected in series with the Lipo, powering the BEC.

Enjoy!
Attached Thumbnails
SMC 5700mAh 25C Single Cell Lipo-dscf3853.jpg  
Bigshades is offline   Reply With Quote
Old 09-05-2008, 06:16 PM   #147
Tech Elite
 
RCSteve93's Avatar
 
Join Date: Dec 2005
Location: Long Island, New York
Posts: 4,601
Trader Rating: 11 (100%+)
Default

I'll test... the durability of the case. I can't wait for it to come out.
__________________
rm -rf /windows
RCSteve93 is offline   Reply With Quote
Old 09-06-2008, 06:57 PM   #148
Tech Rookie
 
Join Date: May 2007
Posts: 13
Default

I'm ready to test this booger out. Keep the updates coming.
69mkitmine is offline   Reply With Quote
Old 09-10-2008, 12:40 PM   #149
Ty
Tech Addict
 
Ty's Avatar
 
Join Date: Aug 2001
Location: Long Island NY
Posts: 518
Trader Rating: 29 (100%+)
Default

Danny,
What will the single cell pack weigh (in grams) compared to a 4 cell pack of the current EnerG cells?

Thanks,
Ty
Ty is offline   Reply With Quote
Old 09-10-2008, 04:48 PM   #150
Company Representative
 
Danny/SMC's Avatar
 
Join Date: Oct 2001
Location: Elkton, VA
Posts: 3,097
Trader Rating: 2 (100%+)
Default

I'm not sure of the exact weight but it's close to 2 sub-c cells.

After fitting the pack in different cars and talking to some of the racers and manufacurers we will most likely go with a 2 cell pack which will make the pack thinner. The capacity will be in the 3800-4000 range which is more than enough for the stock classes and may require some milder motors for the mod classes which will be a good thing as the cars are to fast.
Danny/SMC is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
CE SINGLE CELL HOLDER rogtsaamokin R/C Items: For Sale/Trade 3 09-11-2006 10:03 PM
Single Cell evaluation andrewdoherty Electric On-Road 2 09-09-2006 07:58 PM
CE Single cell holder II Fast R/C Items: For Sale/Trade 10 03-31-2006 04:31 PM
NiMah batteries//single cell as well dasgruvn Rookie Zone 6 09-13-2003 09:17 PM
Single cell label..??? Speed Demon Electric On-Road 4 02-28-2003 08:11 AM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 11:30 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net