R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 04-14-2013, 02:02 PM   #196
Tech Elite
 
bvoltz's Avatar
 
Join Date: Jun 2005
Location: Bedtime with Teddi
Posts: 3,635
Trader Rating: 44 (100%+)
Default

Quote:
Originally Posted by DarthRacer View Post
That is pretty neat. Wonder what the retail is on those.
60.00 on ebay...
__________________
Wheeling an Xray T4 and T4 14 using a Ko Propo, powered by EA motors and Speed Passion Speedo, paid for by my wife.

Digi3Dworks - 3D printing for the medical Field.
bvoltz is offline   Reply With Quote
Old 04-14-2013, 08:49 PM   #197
Tech Addict
 
Team Grid RC's Avatar
 
Join Date: Sep 2010
Posts: 622
Trader Rating: 3 (100%+)
Thumbs up

Quote:
Originally Posted by bvoltz View Post
I just looked up the melting point... I guess I just wasted 8.00, rather this then the other option... Man I was so looking forward showing up to the track with my Marilyn Monroe lunch box....

Well, bvoltz....looks like your Marilyn Monroe lunch box maybe more than good enough as a lipo charging box.

Metal boxes from what I have seen are reusable and appears to be safer than lipo bags. Once the fabric ignites within the bag, it continues to burn, whereas a metal box has nothing to burn.

Boxes
http://www.youtube.com/watch?v=rusHrUSMmcw
http://www.youtube.com/watch?v=6M5ftkN9PtY
http://www.youtube.com/watch?v=Rx--a...layer_embedded

Bags
http://www.youtube.com/watch?v=IAgzf44Fgeo
http://www.youtube.com/watch?NR=1&v=...ture=endscreen

Mike says the Venom box is made of aluminum and it also has a plastic window. Apparently the Lipo may have a peak temp of 1000 deg F, but that is very brief and in a closed box, it does not have enough oxygen to maintain that high temp very long. Looks like your $8 lunch box will work
__________________
www.GridRC.com

Last edited by Team Grid RC; 04-14-2013 at 09:53 PM.
Team Grid RC is offline   Reply With Quote
Old 04-15-2013, 08:15 PM   #198
Tech Master
 
Join Date: Jan 2004
Location: Outside of Crook County Illinois
Posts: 1,947
Trader Rating: 2 (100%+)
Send a message via AIM to A-Ko
Default

Have had good luck with the Army Surplus Ammo Boxes.
__________________
Jeffrey
teamgravityrc.com - motivrc.com
USVTA National Points Member #101
A-Ko is offline   Reply With Quote
Old 04-15-2013, 08:25 PM   #199
Tech Champion
 
Join Date: Feb 2011
Posts: 5,717
Trader Rating: 1 (100%+)
Default

Lunch box & snack box are the best ! $8 beats $60 anytime , and no plastic !
bertrandsv87 is offline   Reply With Quote
Old 04-15-2013, 09:49 PM   #200
Tech Elite
 
bvoltz's Avatar
 
Join Date: Jun 2005
Location: Bedtime with Teddi
Posts: 3,635
Trader Rating: 44 (100%+)
Default

Quote:
Originally Posted by Team Grid RC View Post
Well, bvoltz....looks like your Marilyn Monroe lunch box maybe more than good enough as a lipo charging box.

Metal boxes from what I have seen are reusable and appears to be safer than lipo bags. Once the fabric ignites within the bag, it continues to burn, whereas a metal box has nothing to burn.

Boxes
http://www.youtube.com/watch?v=rusHrUSMmcw
http://www.youtube.com/watch?v=6M5ftkN9PtY
http://www.youtube.com/watch?v=Rx--a...layer_embedded

Bags
http://www.youtube.com/watch?v=IAgzf44Fgeo
http://www.youtube.com/watch?NR=1&v=...ture=endscreen

Mike says the Venom box is made of aluminum and it also has a plastic window. Apparently the Lipo may have a peak temp of 1000 deg F, but that is very brief and in a closed box, it does not have enough oxygen to maintain that high temp very long. Looks like your $8 lunch box will work
Got a Army Surplus Ammo Box.... I think these "lunch" boxes are made out of tin, which has a melting point of 449.5 so this would not work...

I really like the Venom box, but for 60... I think I will stick with the Ammo box...
__________________
Wheeling an Xray T4 and T4 14 using a Ko Propo, powered by EA motors and Speed Passion Speedo, paid for by my wife.

Digi3Dworks - 3D printing for the medical Field.
bvoltz is offline   Reply With Quote
Old 04-17-2013, 11:28 AM   #201
Tech Regular
 
Conrad's Avatar
 
Join Date: Jun 2005
Location: Scotland
Posts: 456
Trader Rating: 2 (100%+)
Default

Just to add some real world numbers to the discussion I broke out my old Turbo35 The test was done with half (1S) of a Trackpower 3200mah saddle pack, not the greatest lipo ever, it's sat unused for maybe two years now.

1st charge at 1C (3.2A) and 30A discharge.
Average Voltage - 3.24, IR - 11.0

A couple of low voltage drops during the discharge tripped the cutoff so this result was null n void but I thought I'd include the results anyway.

2nd charge at 1C (3.2A) and 30A discharge.
Average Voltage - 3.30, IR - 10.5

3rd charge at 2C (6.4A) and 30A discharge
Average Voltage - 3.38, IR - 8.8

Tests were done back to back, no rest between charging and discharging, their was definitely more heat in the pack after the 2C charge. The pack was only rated to a 2C charge so I didn't take it any further but can already see big benefits to the higher charge rates.
__________________
Swith Racing [www.swithracing.co.uk]
Conrad is offline   Reply With Quote
Old 04-17-2013, 11:46 AM   #202
Tech Champion
 
Join Date: Feb 2011
Posts: 5,717
Trader Rating: 1 (100%+)
Default

It would also seem like the pack was coming alive on the second charge up...... So 1C cycle to wake it up, and then close to the max C possible to get the best Performance... That's worth a try , but you can quickly realize how much more Work needs to be done to get better chargers out there to meet the potential of these competion(7200mah) lipo packs ... Like I said before, we'll need 100+ amps chargers and power supplies to meet that demand ! Right now those 40amp chargers can only meet the potential of a TP 3300mah 65C pack(12C charge rate)......
bertrandsv87 is offline   Reply With Quote
Old 04-17-2013, 12:17 PM   #203
Tech Champion
 
Join Date: Feb 2011
Posts: 5,717
Trader Rating: 1 (100%+)
Default

There are many 12v 100amp power supplies out there, but they cost over $500.... The 100amp battery chargers out there are mainly for the automotive and RV industry, and cost over $2000(for the computer controlled versions).... Their weight can also be a deterrent: 25+lbs !!!! I'll stick to 22amps max for now......lol......
bertrandsv87 is offline   Reply With Quote
Old 04-17-2013, 01:20 PM   #204
Tech Elite
 
bvoltz's Avatar
 
Join Date: Jun 2005
Location: Bedtime with Teddi
Posts: 3,635
Trader Rating: 44 (100%+)
Default

Does anyone have suggestions for the heat wrap? Having a hard time find someone locally or on line for a reasonable price.
__________________
Wheeling an Xray T4 and T4 14 using a Ko Propo, powered by EA motors and Speed Passion Speedo, paid for by my wife.

Digi3Dworks - 3D printing for the medical Field.
bvoltz is offline   Reply With Quote
Old 04-17-2013, 04:09 PM   #205
Tech Master
 
Mr RCTech's Avatar
 
Join Date: Dec 2005
Posts: 1,291
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by bvoltz View Post
Does anyone have suggestions for the heat wrap? Having a hard time find someone locally or on line for a reasonable price.
Heat wrapping your lipo is dangerous.
You will not get the results as if charging at a higher rate.
Charge heating lipos from inside and not from the outside in!

Also, big races check exterior temperature.
Mr RCTech is offline   Reply With Quote
Old 04-17-2013, 05:33 PM   #206
Tech Elite
 
bvoltz's Avatar
 
Join Date: Jun 2005
Location: Bedtime with Teddi
Posts: 3,635
Trader Rating: 44 (100%+)
Default

Quote:
Originally Posted by Mr RCTech View Post
Heat wrapping your lipo is dangerous.
You will not get the results as if charging at a higher rate.
Charge heating lipos from inside and not from the outside in!

Also, big races check exterior temperature.
Sorry... not for the lipo... for the Power Supply... the HP power supply... I found a reasonable price, the question is will it fit... If it all works out, I will post the place here..
__________________
Wheeling an Xray T4 and T4 14 using a Ko Propo, powered by EA motors and Speed Passion Speedo, paid for by my wife.

Digi3Dworks - 3D printing for the medical Field.
bvoltz is offline   Reply With Quote
Old 04-17-2013, 07:39 PM   #207
Tech Addict
 
Join Date: Aug 2001
Location: Singapore
Posts: 698
Trader Rating: 5 (100%+)
Default real data

hi,

does anyone has any data point on high amp charging will be better or worse for the lipo pack ?

Recently, I tested on two brand new 1S pack from Yokomo (YB-P169BE) and see no diff in performance when I charged via 10A or 20A.
The IR reading from icharger 206B seems to show the same, which is around 20mOhm I think.

I don't have experience on Yokomo cells if it is good or not. But so far, it is new and it is holding up well.

The only time that helps is charging at 20A reduce the charging time to ~30mins. This allow to run 2 packs back to back during a practice session.

I usually practice until the pack reaches the Lipo Voltage cut which I set to around 3.2V.
__________________
My blog: http://ongbenghui.blogspot.com
ongbenghui is offline   Reply With Quote
Old 04-17-2013, 07:45 PM   #208
Tech Champion
 
teeforb's Avatar
 
Join Date: Sep 2005
Location: San Diego & Compton CA
Posts: 7,142
Trader Rating: 92 (100%+)
Send a message via Yahoo to teeforb
Default

I charge my nano tech lipo at 40A. I have the same packs since Nov of 2011. No problem, no puffing. Key thing, I only charge up to 4.18v per cell instead is the full 4.20v.

My 5600, completely dead, 8 min charge time. Most of that 8mins are balancing.
__________________
$$ Team High Budget $$
17.5 stock buggy fb page
https://www.facebook.com/groups/17.5stockbuggy/
teeforb is offline   Reply With Quote
Old 04-17-2013, 08:12 PM   #209
Tech Elite
 
Join Date: Nov 2009
Location: Woodinville, WA
Posts: 2,512
Trader Rating: 8 (100%+)
Default

Quote:
Originally Posted by ongbenghui View Post
I usually practice until the pack reaches the Lipo Voltage cut which I set to around 3.2V.
IMO, that's not a great idea. Battery health aside (I honestly don't know), when the voltage gets lower than perhaps 3.6-3.7v per cell, the car will be so much slower that it's dramatically easier to drive. For me in a touring car, that's about 8 minutes. Not to mention that the motor might be fading a bit due to heat buildup, too. And by that point, my tires are fading fast, too, and I've probably tapped the boards or other drivers enough that the setup has gone out, too. Usually better to pull the car, re-sort it, let things cool down, put in a fresh pack, re-sauce, and go back out for a more representative run.

-Mike
grippgoat is offline   Reply With Quote
Old 04-17-2013, 08:14 PM   #210
Tech Addict
 
Join Date: Aug 2001
Location: Singapore
Posts: 698
Trader Rating: 5 (100%+)
Default

Quote:
Originally Posted by teeforb View Post
I charge my nano tech lipo at 40A. I have the same packs since Nov of 2011. No problem, no puffing. Key thing, I only charge up to 4.18v per cell instead is the full 4.20v.

My 5600, completely dead, 8 min charge time. Most of that 8mins are balancing.
I tried charging the HobbyKing Nano tech Aspec 1S at 20A.
No diff in IR before and after. I will usually charge at 10A.
The cell seems to have a lower IR reading than yokomo, at 19mOhm.

But I only have a chance to test once.
__________________
My blog: http://ongbenghui.blogspot.com
ongbenghui is offline   Reply With Quote
Reply



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 03:22 AM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net

SEO by vBSEO 3.5.0