jun2_van

is it possible to use a lipo battery pack on an HPI Sprint 2 car?
thanks...

88NATE

iTrader: (7)

I don't know what the sprint car looks like but with the right esc and if the batt fits, now n days you can find the right lipo size to fit almost anything, hell losi made two saddle packs to = 7.4v lipo but remember bigger the mah bigger the batt so mesure and find out what you can do most sites list mesurements hope this helps

racer1812

iTrader: (31)

Yes you can. What you need to know is that the stock esc. doesn't have a lipo cut-off. If run a lipo below 6v it's junk, most of the time. Any esc that can run a 7.2v nimh or nicd pack can run a 2s 7.4v lipo you just need to make sure you don't ruin the lipo by running it too low.

jun2_van

so would it be okay then that with a lipo pack, when the car starts to slow down because of low power, i just take it out and recharge it?

and sorry if this is a stupid question, can i upgrade to an esc with lipo cut-off?

also, just trying to understand how lipo cut-off works..with it, does it mean the car shuts down at a certain point when the power is low?

thanks for the replies btw..

ray3619

the answers are yes,yes,and yes , you got it , ray

88NATE

iTrader: (7)

if your on a buget you can try to get a novac lipo cut off for about $25 or so to add to your esc but make sure that the lipo cut off is for the right batt and when its time it will blink, make a sound, and if you keep going it will cut off before it does damage if your batt go's too low it's all bad. but i never used it personally but thinking i might get one for my sons car.

Duster_360

iTrader: (21)

You don't want to overdischarge a lipo below 3v/cell or 6v for a 2cell , or 2S lipo. If you do, a cell may swell or puff as its called. Once puffed, the lipo is no longer safe to use and it needs to be discarded. The separate lvc will protect you from overdischarging the lipo and possibly runing it. I've seen mixed results running lipo without a cutoff and trying to judge when its time to quit and recharge. If you're racing where there are 10-15min heats, probably easy to do without an lvc. Bashing this gets hard to do since you can be easily distracted by so many other things and overdischarge it.

The Novak Smart stop is a good way to protect you lipo when the esc has no cutoff. The smart stop works by - quote from instructions -

"If voltage safety level approaches, throttle operation with short
periods of throttle blipping will occur along with flashing of the
LED warning that it is time to bring vehicle in-if vehicle is run
beyond this period, the module will bring to the motor to neutral
while leaving steering control".


Here is the 2S Smart Stop -

http://www3.towerhobbies.com/cgi-bin...?&I=LXPGM8&P=M

racer1812

iTrader: (31)

The Novak smart stop is a good idea without having to buy a new esc right away. It does need to be soldered inline though which I'm sure your LHS would do for you if you can't. You can run without a cut-off but like I said you need to be careful.

Thanks for the PM Duster.

jun2_van

thanks so much for the replies, guys..these infos are all very helpful...i will be going with the Novac smart cut off system..'just talked to the local hobby shop and he would install it for me...

Duster_360

iTrader: (21)

It'll be better running a lipo and not having to worry about time and knowing it is protected from overdischarge. Your lhs sounds like a good one.


racer1812 - you're welcome!