bvoltz

iTrader: (44)

60.00 on ebay...

Team Grid RC

iTrader: (3)

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

A-Ko

iTrader: (2)

Have had good luck with the Army Surplus Ammo Boxes.

bertrandsv87

iTrader: (2)

Lunch box & snack box are the best ! $8 beats $60 anytime , and no plastic !

bvoltz

iTrader: (44)

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...

Conrad

iTrader: (3)

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.

bertrandsv87

iTrader: (2)

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

iTrader: (2)

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......

bvoltz

iTrader: (44)

Does anyone have suggestions for the heat wrap? Having a hard time find someone locally or on line for a reasonable price.

Mr RCTech

iTrader: (2)

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.

bvoltz

iTrader: (44)

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..

ongbenghui

iTrader: (5)

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.

teeforb

iTrader: (94)

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.

grippgoat

iTrader: (8)

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

ongbenghui

iTrader: (5)

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.