I actually prefer to use my table saw (use a finish blade though) but figured most folks don't have one of those handy and they're a bit pricey to buy one for a servo mod.

I'm planning on switching over to lipo power this fall and I could use some help from some of you that have been running lipos for a while. I understand that I need a 1S lipo pack per ROAR rules. But what about power to the receiver and speedo? Right now I'm running a Tekin RS, Spektrum micro receiver, and a Futaba 9650 servo. Should I use a lipo rx pack or a booster? If I should use a receiver pack, what size gives sufficient power, yet is small enough for the chassis? I'm new to lipos and a little confused on how to wire up all the extra stuff.

Fuzzy -

You're thinking WAY to far ahead. We need to re-build the Gate first.

I'm considering the booster module, if only for the fact that it is one less battery to maintain/charge. Maybe someone will make one in a small case that can easily plug into your Rx using standard servo connectors, and solder it's leads to the battery posts on the ESC. Or better yet, incorporate it into the Rx case itself, without needing any special connections to be made. Just plug in your Rx, steering servo, connect the battery, and turn on the switch and go.

YOKOMO 12R5 World Champion option Parts

Magenta tires are 32 shore and are a natural rubber foam
White is 25 shore and is a low natural rubber foam (synthetic blend)

The number refers to a hardness rating when using a durometer. There are different scales, so if you are using a durometer to measure your tires, make sure you are using the correct scale, and keep in mind that thickness of the foam will effect measurements.

good luck.

thanks
 

thanks is it the lower the shore the stickyer to the track?

California, the state where men are men... :D :D

I've been runing the 1s for a few months now. I've tried the receiver pack and the booster and found that for me the booster was the easier way to go. I have the same electronics setup you have, you plug the booster into the receiver and attach the other end to the + and - of the esc. Currently you leave the esc switch off and when you plug the battery in everything goes hot. According to Tekin once thay fix the 198 update we'll be able to use the esc switch and utilitize the lipo cuttoff. Heres a couple of pics.
http://i414.photobucket.com/albums/p...9/1s_setup.jpg
http://i414.photobucket.com/albums/p...1s_booster.jpg

Thats how the TQ booster works, see my post above for pics

Or order the nearly identical booster from Hobby King for about 1/5 the price. You have to wait a bit (mine were here in about a week) and it has servo-type plugs at both ends. The receiver lead from the esc plugs into it at one end then the booster itself plugs into the receiver. Couldn't be easier. I ordered 6 of 'em when I ordered and they were less than $5 each shipped.

The TQ one runs about $25-30 if I'm not mistaken. The Novak one due out any second now is a whopping $40-45. In fairness the Novak has a higher output voltage and (I believe) a higher current rating, but neither are necessary for 1/12. The el-cheapo Hobby King unit has a 5v constant output and does 1 amp continuous / 1.5 amp surge...PLENTY for a 1/12 servo and PT.

With the lipo, a lot of esc say they have to use 2 or 3 cell lipos.

Is it still possible to run them on one cell?

A lot depends if you can toggle the low voltage cutoff on and off or not. For example the LiPo-capable Novaks you can turn off the LiPo mode and eliminate low voltage cutoff. The Tekin and LRP/Nosram esc's can also be run in a non-cutoff mode. I've yet to try my KO BMC's and am concerned they may not support 1s LiPo.

The 4-cell Novak (unfortunately discontinued) doesn't have LiPo cutoff and is absolutely "plug and play" with the boosters. The others that I've seen used with boosters all have needed work-arounds to function correctly. Nothing major, but not as convenient as the Novak. Now if the Novak didn't take up half the chassis area of my 1/12 chassis...

Well how about this esc, yeah racing brainless esc 35A? Has anyone tried this or know whether it works with one cell lipo.

Also i still don't understand what you mean by booster or receiver pack.:confused:

The single cell LiPo batteries (1s) are substantially less voltage than even the 4-cell packs we have traditionally used. The voltage is so low that most of our electronics (receiver/servo/PT) will not function at the voltage provided. Even those that WILL work (an example is the 4-cell specific GTB and Spektrum receiver) the voltage is so low that the servo is very very sluggish.

A booster is an electronic circuit that takes the voltage available from the battery and bumps it up. As an example, the King Hobbies unit I've been using takes any voltage 3.7-4.2 volts input and outputs a steady 5 volts which is enough to power the electronics.

A receiver pack is, anymore, a small capacity 2s LiPo battery that is carried on the car specifically to power the receiver/servo/PT. The down side to this is that this is a second battery that needs to be charged, etc. The 2s LiPo also is generally too high voltage for receivers/servos and have the potential to burn servos out, so a voltage regulator should also be incorporated.

Receiver packs can also be made from 4 or 5 very small NiMH or NiCd cells which eliminates the over-voltage situation but creates (arguably) even more maintenance in addition to the charging regimen that would be required.

Receiver packs are nothing new. Not too long ago before NiMH battery capacities grew to such high numbers as we've seen the last several years folks running 1/12 Mod ran receiver packs because the high current load of the low turn brushed motors could cause voltage in the main pack to drop low enough that the PT wouldn't pick up or the car would steer to one side or the other as the driver applied power when the receiver wasn't getting enough juice, etc.

My own feeling is that adding a receiver pack completely eliminates any and all of the convenience advantage LiPo batteries offer and, in fact, adds complexity to the point of "why bother". I HAVE used the voltage boosters successfully and am convinced they are the way to go.

How about the yeah racing esc. It says it can run 4 to 9 NiMh Cells or a 2-3 cell lipo. If i use the one cell lipo in association with the booster will i be able to run it.

Also i was wondering if i was to pair a 13.5t with 4 cell NiMh then what is the lipo equivilant?