Thinking of Trying a LiPo

[30YrsL8r]

Hi. My son and I are both running TB-02 cars and have a couple of Mtronics ESCs (Viper Auto Sport Tuned 20 and Viper Eco27). I'm convinced his no-brand 5300mah (yeah, right) NiMh is on the way out, and so I need a replacement. I'm fine for the time being with a 3300mah Sanyo pack.

So, I'm thinking about trying a LiPo. From what I have read, I _think_ the ESCs will be happy with a 2S LiPo (7.4v) and all I need to do is make sure the steady discharge current of the LiPo is greater than the ESC can demand. Trouble is, I don't know that the limit of the ESC is.

If it makes any difference, I'm thinking of putting a cheap HPI Saturn 27T 540 motor in each car to (hopefully) boost performance, as I have no idea what the silver cans are that are in them at the moment.

Has anyone run a LiPo on either of these Mtonics ESCs and, if so, did you use an external Low Voltage Cutoff?

[Gruntfuggly]

I'm no expert, but I don't think it makes any difference to the ESC - the motor is what affects the ESC as it will draw more current it it has lower turns. If you're current set up is working ok, swapping from nimh to lipo shouldn't make any difference. I'm using lipos with a sport tuned and a TEU101BK with no problems. The Viper 20 should be fine as it's rated for 20 turn motors, and I expect the 27 will be OK too.

I'm using a low voltage alarm and a cut off (both cheapies off ebay) in two different cars. To be honest the run times with lipo packs (4000mah) are so much better than my old nimh packs that I've had to stop for repairs before the packs get low!

Go for the lipo packs - I doubt you'll regret it - make sure you have an appropriate charger though...

[Percymon]

I've run 2200mAh 2S turnigy packs with 20C constant rating in my scorcher with the sport auto esc without any issues at all. The scorcher might be 2WD but it's no lightweight and 20C constant discharge rating was fine.

Look at hobbyking website, they now have a uk warehouse and are about the cheapest place for lipo. For the difference in price you may as well get a 30C pack. A 3000mAh pack will probably last as long in run time terms as your 5300NiMH anyway as the weight saving with the lipo will be significant if you use a soft case pack. You'll need to protect the battery in the chassis by wrapping in thin foam or thin plasticard.

I only use a low voltage alarm, hobbyking have those or eBay for under £2 - works fine for me but in a noisy area with lots of people it might not be so audible.

[30YrsL8r]

So, for about £20 I could get:

Turnigy 2S 3S Balance Charger. Direct 110/240v Input (UK Warehouse)

and

Turnigy 3800mAh 2S1P 7.4v 25C hardcase pack (UK Warehouse) 136mm x 45mm x 22mm

or

Turnigy 3600mAh 2S 30C Lipo Pack (UK Warehouse) 137mm x 43mm x 15mm - Softcase

with a cheap Low Voltage Cutoff/Alarm

I kind of like the idea of the hard case, having read horror stories about damaged LiPo's, to be honest. Having measured the battery bay, only the height might need some imaginative mods.

[DCLXVI]

Go for LiPo, I did I few years ago and I'm never ever touching a NiXX again, I even put a LiPo in my transmitter...(3S is aparently close enough to 8xAA)

[Percymon]

So, for about £20 I could get:

Turnigy 2S 3S Balance Charger. Direct 110/240v Input (UK Warehouse)

and

Turnigy 3800mAh 2S1P 7.4v 25C hardcase pack (UK Warehouse) 136mm x 45mm x 22mm

or

Turnigy 3600mAh 2S 30C Lipo Pack (UK Warehouse) 137mm x 43mm x 15mm - Softcase

with a cheap Low Voltage Cutoff/Alarm

I kind of like the idea of the hard case, having read horror stories about damaged LiPo's, to be honest. Having measured the battery bay, only the height might need some imaginative mods.

also look at their euro warehouse....

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8973

http://www.hobbyking.com/hobbyking/store/de.asp?fltDE=2s1p

as no import duty and postage isn't too bad. A piece of plastic under the soft case battery and some thin foam sheet around it is more than ample protection. Some of the problem fitting hard case lipo's is the square profile at the ends so double check the shape of the battery compartment.

[94eg!]

Nickle batteries actually have a higher peak voltage fresh off the charger than Lipo, so no worries about the ESC's voltage specs. Of course if your ESC is already at the borderline with your current setup, adding Lipo could be enough to push it over the edge. I ran into this problem in my Dyna Storm running a CPR P160-F & Acto Pink 14T 2WD motor. With nimh batteries, the setup ran flawlessly. But once I switched to an orion 2400mah lipo, the ESC would cut out randomly if I jammed the throttle too hard at lower speeds. This was caused by the large current demand of such a hot motor. The Nimh could never supply so much current. But since the lipo can, it quickly exceeded the ESCs built in current limiter and shut it down.

This isn't a big deal typically. And the performance boost from Lipo will easily out weigh any hassle of making the change.

[30YrsL8r]

So much for £20! I've doubled that, but I did buy two batteries and a better charger:

2x #T38002S-25HC/26806 Turnigy 3800mAh 2S1P 7.4v 25C hardcase pack (UK Warehouse)

http://www.hobbyking...DB-08F2D21D4C44

1x #ECO6/29047 HobbyKing ECO6 50W 5A Balancer/Charger w/ accessories (UK Warehouse)

1x #HKing-2S/26076 Hobby King Battery Monitor 2S (UK Warehouse)

http://www.hobbyking...6C-02C720B003D4

1x #AM1009x10/28432 HXT 4mm Gold Connector w/ Protector (10pcs/set) (UK Warehouse)

http://www.hobbyking...B0-BDBBF7D46EBE

Turns out hobbyking does a "buddy code" thing where people that use your code get a discount and you get a rebate, so I've included them above if anyone's buying this stuff in the next two weeks. Not sure why the ECO6 doesn't qualify.

[30YrsL8r]

Some of the problem fitting hard case lipo's is the square profile at the ends so double check the shape of the battery compartment.

Good point. I looked again at the TB-02 battery compartment and, although the bottom is "dished" to fit the standard pack snugly, the actual dimensions (and corners) will allow the hardcase pack to fit.

[tamiya monkey]

Lipo all the way, i was hesitant at first hearing all the stories, but after trying them i would touch a nimh or nicad again, you will be fine with your esc's, i have both and have no problems, i fitted a voltage cut-off so cut power to motor once it reaches the cut-off voltage, lipo alarms are ok but i preferred the cut-offs' search ebay for Hobbywing 7.4v 2s LiPo Battery Protector.

charger wise the one mentioned has an Output: 650mA per cell, this would be very slow, i use a imax b8, but found the b6 variety of chargers cheap and easy to operate.