Lipo's in a TLT?

[pullstarter]

howdy guys, has any1 tried 2 or 3 cell lipo's in a TLT with a T600 motor? I'm very interested to know if anyone has as i'm thinking of giving it a go, the weight and size reduction of lipo's is very attractive.

cheers
simon

[gregrocks90046]

i haven't tried lipo's, but now i'm using venom 1200 mah/7.2v packs designed for the RC18T. physically about half the size, and the same run time i was getting with matched sanyo 2400 mah sub c's.

[pullstarter]

i was speaking to ronbeck earlier and he tried out a KAN pack today, he said was ok but runtime was of course down on his 3000mah packs, lipo's i think would be great if they work coz they take up so little room and are so light it wouldnt really matter where u mounted em, i was also toying with the idea of using a mamba brushless motor, the ones they make for 18th scale, but i dunno if they'd have enough torque.

Do you run the t600 with those cells?

cheers

[gregrocks90046]

i use a integy 55 turn lathe motor. they are inexpensive and pretty much the standard crawling motor for TLT's. the brushless motors have too much RPM for crawling. i'll post a pic of the batteries i use compared to a normal pack later today. like you, i wanted to find something smaller and lighter so i could get the CG even lower.

[NitroRC Ed]

I run a 3 cell Kokam LiPo pack with a lathe motor and pede trans. Have great run time from the few runs I have done. Have this thought that it might be a little to light in the front end for steep climbs though. Need to do some experimenting on placement to see what happens.

Ed

[romeo26]

whats a lipo(i know its a batt.)?
which charger do you use for the lipo's?
were can i get lipo's?

[rcguy]

umm, not really sure where you can get them... probably any hobby shop could order one for you..

but i put one in my heli and got a 3x or 4x longer flight time.. if that helps any..

any nicd or nimh charger WILL NOT WORK... it needs to be a lipo charger.. the duratrax ICE charger does it... im pretty sure

http://www.duratrax.com/caraccys/dtxp4170.html link to the charger that will work

[romeo26]

thanks rcguy.
what company makes them?
and how much are they?

[Plays_with_Toys]

I don't want to put Lipos on my TLT until they figure out the whole blowing up thing first.

[Bsmooth]

Originally Posted by Plays_with_Toys

I don't want to put Lipos on my TLT until they figure out the whole blowing up thing first.

The whole explosion thing is due to improper use of the batteries. Lipoly packs can only be discharged to 3.0v per cell. There are specific speed controllers for Lipoly use to prevent loss of equipment.

For example, a 7.4v(2 cells) 2100mah pack can only be discharged to 6.0v before damage is done to the cells


They must also only be charged at 1xCapacity or lower by a lipoly specific charger.

the aforementioned pack could only be charged at 2.1 amps or lower

Lipolies do give warning signs before the explode, they puff up. I have used them in my R/C planes for a good while know with out issue.

[Madkoifish]

I heard the exploding bit is during charging cause of iss handling. The requirements of the batteries themselfs dont lend to easy intergration into a bashing RC I have heard amp draw is a issue too. As well as life. Neighbor is a plane heli nut and has mentioned they baloon up over time even with proper use. He says some guys are only getting 6mo out of them. Granted some of these guys prolly fly at least 3 or 4 times a week.
For the more simple questions regarding lipoly or similar types a quick use of the trusty google will answer these. kokam I think is one company making them for RC cars. Entry costs arnt cheap.

for me Ill stick to regular nicads or nimh Looking at those smaller cells used in the little 4wd trucks of late. Or hell some of my AAs for my digicam 2300mah >_>

[pullstarter]

thanks for your comments guys, i was also thinking they may be too light to get the suspension working properly as NitroRC says, might experiment with the 2/3a's first and see what the weight difference issues are like. PWT, they dont explode unless u treat them in the wrong way, by using the wrong charger or the wrong electronics as Bsmooth says, Its essential that u use a 6.0v cut out on a 2 cell pack, otherwise they may well go bang lol.

cheers

[gregrocks90046]

here are some pics, pullstarter. i think you may have misunderstood nitrorc's comment. he means that the batteries may have been too light for him because the front axle was lifting during steep climbs. your suspension will work better the lighter the vehicle is. anyways, here are some pics comparing the size of the 1200 nimh's versus the 2400 sub-c's. big difference but same run time. anyway i can make my crawler lighter and or lower i will do it.

[Madkoifish]

you know now I gotta full screen this across 2 monitors to even read the forum???

[gregrocks90046]

Originally Posted by Madkoifish

you know now I gotta full screen this across 2 monitors to even read the forum???

sorry! photobucket was supposed to automatically size the pics down!

[pullstarter]

thats massive lol, i suppose u would need to adjust the suspension accordingly for the lower weight, just a matter of wrenching i guess. I might get a cheap 2/3a pack and test it out, thanks again for ur help guys

[FritoBandito]

Originally Posted by Plays_with_Toys

I don't want to put Lipos on my TLT until they figure out the whole blowing up thing first.

They have. Dude, I run lipos in everything I have and have yet to have a single incident. I have seen other folks lipos flame out or puff but in every case it was due to user error. Also, lipos don't really blow up. They're in a soft packaging so they flame out which in some cases is worse than an explosion. Think bigass match head which is more likely to start a fire. The important issues are

#1 CHARGING
Use a good lipo capable charger with all manual settings or at least a manual confirmation before charging. I don't trust automatic chargers. I've seen em detect the wrong number of cells and the lipo flames out. Charge at 1C which as stated above is the same rate as your battery capacity. Do not "peak" your lipos before running. Lipos don't "peak" and you're likely to flame out if you try.

#2 AMP DRAW
Do not exceed nominal rated amp draw period. Personally even if a manufacturer says I can burst up to XX amps I don't. If the nominal amp rating won't handle my highest, I go to a bigger battery. Too much draw will certainly puff a lipo and possibly cause a flame out. A Sears Clamp On Amp Meter works very well and doesn't require you to modify your battery leads.

#3 DISCHARGING
Do not over discharge below 3 volts per cell. 3.2 is safer. You likely won't flame out if you do but you'll certainly damage the lipo and lower its capacity. Bad enough and you'll puff the battery. Unfortunately not too many car speed controls have an adjustable low voltage cutoff option. Castle Creations (best speed controls period) are completely programmable. Too bad they don't make a brushed controller for cars. :(

#4 SAFETY
Don't ever charge a battery unattended. Even with the best chargers, sh*t happens. People have lost their houses and cars this way.
Don't leave lipos in a place where they can get hot. Lipos are heat sensitive and sitting on your dash in the hot sun can trigger a thermal runaway and flame out. Again folks have lost their car this way.
Don't try to charge a puffed or otherwise damaged lipo. You'll risk a flame out. Consider it gone.
Don't charge in your model. Take the lipo out for charging.
Don't just throw a lipo in the trash. Even if damaged it can still be chock full of energy and flame out in your trash. Best to drop it in a bucket of salt water for a couple hours. That'll completely discharge it and then you can toss it in the trash safely.

All this sounds like a hassle but it's not. Remember that it's mostly stuff you don't do. Also remember that in 3 years of using lipos constantly I have NEVER had a single issue. Not even a puffed cell. Kind of surprising considering I've crashed two of my lipo equipped planes HARD. Somehow the batteries survived intact. Go figure.

[K_B]

I've been haunting these forums for awhile, soaking up all I can. I have a PTI MMT and would love to use my RC18T batteries! But... isn't there a problem with amp draw when you use 540 size motors with 2/3a cells?

[Bsmooth]

Originally Posted by K_B

isn't there a problem with amp draw when you use 540 size motors with 2/3a cells?

Maybe if we were using a motor with less than 27 turns. Most of us use a 55t motor for crawling.

[Madkoifish]

I would think the more toruquey motors would draw more amps. IE under load etc.

Im sure a 55t isnt a worry for those size batteries. I have run 16Tri on a set of reciver batts and not had issues. I didnt do banzai runs or anything just was used for a TC i turned into a 1/18th monster truck.