why no lipo?

[jetboat]

Why is Lipo not allowed in sanctioned pulling?


Ive been running lipo only for 5 yrs now and never had a real problem. (I dont count puffed cells). Price wise it has become cheaper to go lipo than NiMh, its hard to get a charger that doesnt do lipo's. Almost every esc made anymore is lipo ready... I could go on. We use them in crawling and beat the living heck out of them so Im trying to figure out why pulling doesnt allow them.

[TNT_Pulling]

The main reason that lipos are not being used in pulling . . . . at this time, is safety. They may be alright to be used in dirt pulling, as there is a little "give" and the tires break loose. BUT in carpet pulling, once the tires are hooked, the amp draw goes up and that is when the problems happen.

They are not out of the question, they are just not used at this time. More testing is required, so that it is safe for all involved.

[racerrandy]

Its going to take a large milliamp battery to handle carpet pulling. You are probably talking about a $200 battery. Ouch!



Randy

[nrctpaXpres]

one more item....normally we are based on multiples of 7 cells 7, 14 & 28 the lipo is a (6)cell pack....sort of...

[MR TRUCKPULL]

I have tried Liops in dirt pulling.

A 2S lipo pack will not out preform a 7 cell sub "C" pack in a 10 Second
run on dirt.

2 cell lipo is a MAX of 8.4 volts
7 cells charge up to about 10 Volts

4 cell lipo is a MAX of 16.8 volts
14 cells charge up to about 20 Volts

Lipos will not be effective in pulling until the rules are changed
FROM 7, 14, and 28 cell classes
TO 6, 12, and 24 cell classes

Don't worry about safety when it comes to Amperage in Lipos
They will give you more Amperage then any Sub "C" cell out there.

I race boats, and have setups that draw over 140 Amps. average
draw. for over a 1:45 Minute run.

Larry

[Ball Racing]

Originally Posted by MR TRUCKPULL

2 cell lipo is a MAX of 8.4 volts
7 cells charge up to about 10 Volts

4 cell lipo is a MAX of 16.8 volts
14 cells charge up to about 20 Volts



Larry

Charging up to a crazy high voltage, then holding it under AMP load is 2 different things.

A good C rate high Mah Li-po holds voltage higher in constant amp load better than any nicad or nimh of the same voltage class..

[MR TRUCKPULL]

Daniel

Lipos can NOT be charged above there set voltage.
High C rating or high capacity will not be better then
the sub C's we use now.

On dirt we are only looking at a 8 second run.

A 7 cell pack charged to about 10 volts
will give you more WATTs output then the best 2 cell LIPO
in a 8 second run.
I have tried it, it does not work.

Larry

[chromey]

Hey Larry will that also work for carpet pulling?

[dpero]

Any LiPo I have raced off-road with has always been faster than my crappy NiMh packs. Internal resistance has always been much lower (than NiMh) in all the LiPo packs that I have tried.

Might be 10 volts at rest but under load it's much less. This would be a good test for my data logger. Maybe I'll try a comparison at the Hangar Pull.

What about allowing any chemistry in Insane? Voltage doesn't matter there. Would be interesting to try some LiFe cells in that class. The high voltage will keep the current lower.

[nrctpaXpres]

the guys from TN (with that sled) are using lipos on carpet in thier tractor class pretty much a insane with a brushless motor on it...they run the tires backwards so they don't over bite the track and like them fine ....my guess is the motors over power the track and allow the batts to breath a little and not lug it out....

[Ball Racing]

Originally Posted by MR TRUCKPULL

Daniel

Lipos can NOT be charged above there set voltage.
High C rating or high capacity will not be better then
the sub C's we use now.


A 7 cell pack charged to about 10 volts


Larry

A li-po off the charger at 8.4volts a month from now will be at 8.40 volts.
7 cells charged to 10 volts will be 9 volts in 5 minutes,
then when the amp draw hits, it really falls.

Lots of good batteries , you don't want to see really high voltage on max charge...
10volts on 7 cells is charging to 1.42 volts a cell, which is great, but only if it stayed in the cells after it came off the charge.

I used to run my clods on 8 cells but , I am just as fast, and am faster longer with a 7.4 li-po..


I am not saying that a li-po contains more static voltage,from 7 cells to a 2S pack, but is much better suited to the amperage that is loaded upon it.

And if a ni-mh is more than enough, you classes need to let you use bigger motors, that really make some HP..Or at least place more load on the motors you have..
If the motor can stand it, and not burn up the more load placed on it the more amps it will draw, and in turn the more amps you provide , the more watts you produce which is HP, so for split second you have crazy HP spikes...

I used to race brushless boats, and I know that for all out speed I would over prop it, and really get down,
but to do that for more than a lap it would melt the heat shrink on the batteries, and the ESC, then the motor will get cooked...
So you had to unload it as to not burdern other parts.
I stepped up to a battery that had a High C rating with higher mah, and the batteries then, were not in harm.
It was then up to the ESC, and the motor..

[MR TRUCKPULL]

Daniel

I have been racing boats for about 10 years,and Offroad trucks and cars for over 20 years. I agree that Lipos give you more power and speed for racing of any kind.

We are talking here about a 8 second run on dirt.

I have tried my race packs Enterland 2S - 35C - 5,000 mA that cost about $100.00 each pack.
A good 7 cell pack of sub "C" cells will win every time on dirt, I have tried both.

Chromey - HELLO -

With a 1 minute run on carpet, Liops may have an advantage.

I think it would be best, first to reduce the classes from a multiple
of 7 cells to a multiple of 6 cell.

Larry

[BCCrawler]

All this talk about power is good and well but the advantage of lipo in pulling is not the power it is the ability to put more weight on the vehicle and where you want it.

[MR TRUCKPULL]

Originally Posted by BCCrawler

All this talk about power is good and well but the advantage of lipo in pulling is not the power it is the ability to put more weight on the vehicle and where you want it.

We do that now, so how are lipos an advantage????
All classes are a set Max weight.


Larry

[dpero]

Garden Tractor is 6 cell. So is Digger.

[BCCrawler]

Originally Posted by MR TRUCKPULL

We do that now, so how are lipos an advantage????
All classes are a set Max weight.


Larry

Lipos weigh less.

[MR TRUCKPULL]

So what you are saying is that you do not have your batteries in the most optimum position in you truck for pulling.

In my chassis, if I switch to lipo, I add more lead at the same location,
So lighter batteries is NO advantage.

Larry

[dpero]

Some chassis could have limited battery placement. My GT is one. Would like a lighter battery in it. My 4x4 is somewhat limited. Pro stock tractor is another. I see his point.

[dlmealy]

If lipos are brought in you can't give that advantage to the ones that have them or afford them. If this happens a nicad style pack would need to be weighed and the lipo pack would have to weigh the same. If something like this is not done to protect the competitors as a whole you will see a lot of people lose interest. Just my thoughts. Larry and Derrick are both right one. Some classes will make no difference and some will make a huge difference.

Darren
Team BNB

[hellbounder]

in drag racing we'll take 2 lipos [40cor bigger thunder powers] and link them together .volts stays the same amps goes way up.ive been running a 4 cell a123 pack in my pulling truck. testing motors and esc's. awesome power.[14.4 volts] on concrete with over 100 pounds. trying to 1 get the esc to fry or 2 destroy the batts. nothing. motor got hot first.but kept going[basic lenear][sp] weve gotten the a123's so hot the batt bars popped of. no cell damage.oh and wasted a good set of cut tires.