receiver packs

[Mark Stiles]

How many people run receiver packs in their 1/12th cars?

At most of the meetings I've done, I've run around 36 or 37mm/rev gearing, and just managed to last 8 minutes without using a receiver pack (using 3000 batteries). I now have 3300's, but haven't tried them yet. Will running a receiver pack affect the handling of my car, and how much extra runtime would I expect to get as a result of using one?

[KRob]

The difference is minimal really.
I think it works out about 10secs extra time, but then you have to carry about 25g extra as well.
Some people use them to get the car to the weight limit.
Swings and roundabouts.

Jim Spencer does well enough without one.
I run one because I bought it so I will use it ;D

Causes problems if you don't remember to charge it though :o

If you can last the 8 mins, that's fine, a reciever pack is (unfortunatly) not a miracle cure for duration.

[PUASHP]

I have run a receiver pack for the last couple of seasons, although I have also tried the car without.

Not sure if it really helps with run time but I did find it gave the car a bit more punch over the last 4 minutes of the race.

I will continue to run one as the car would be underweight without

Paul

[rice98w]

i have tried back to back runs with mine.

with reciever pack, the car has quicker steering, due to the extra 1.2volts, duration is basically the same as the extra weight i think cancells out the duration plus point.

without receiver pack, the car seems alot smoother, i think the extra 1.2volts makes the car too twitchy (with my servo anyway, as with the 5 cells it simply is just too fast, its the KO one. i could change the servo speed on my tranny but why got through all the hassle when i can save weight?)

my car race ready is 806 grams, with receiver pack, switch and wire, is 830g

with the invention of 33's, im going to try and race the season without resorting to a reciever pack...

matt rice

[KRob]

I will continue to run one as the car would be underweight without


Bah! Humbug.

[rice98w]

so in conclusion, if you have a slower servo, eg a futaba s135 or a s9601/2 maybe you should run an rx pack, but with the KO, try it at your own descresion.

matt rice

[rice98w]

kieth is your car a bus or something? lol.

i think paul runs small tires, i tend to use larger ones (although this season at the start they will be huge, im talking like 52mm!).

not sure on kieths

matt rice

[KRob]

It'a a Corally, not known for their lightweight, although I bet Andy Sawyer's and Robin Hammett's are near the limit (not to mention Griff).

Mine last year with reciever pack was about 850g. :P

It's maybe worth mentioning that you need somewhere to plug it into the reciever, not a problem normally, but if/when personal transponders become the norm, they will need to plug into the reciever as well.

[Mark Stiles]

If you were to run a KO receiver, then couldn't you plug the transponder into the channel 3 plug? That would leave the battery plug free for a receiver pack.

[marcoski]

yes you could

[KRob]

I think some KO reciever's only have 2 channels and a battery plug.

Just had a look at mine and it is as above, and it's only a couple of years old.

If you have plenty of plugs available, result ;D

[rice98w]

thats one of the points of the new receivers!!! :D ::)

the new phasar has 3 + batt, KO, nosram, the list goes on...
wow kieth your car is fat!, i didnt know corallys were renound for being heavy, although i cant see griff, sawyer or robin using buses for cars! lol, im sure they have every gramm shaved off that they can...

matt rice

[Mark Stiles]

I have the latest one (I think its the KR-301F or something), that has three channel compatibility.

[KRob]

Yeah, that's FAT and not PHAT :-[

Can I be bothered to do anything about it, those who know me will know the answer ;)

A good point was made earlier that if your race cells do go flat, the reciever pack will still supply enough power so you can still control the car (provided that doesn't go flat as well :P)

[lewist]

when my packs dump the car is totaly uncontrollable!!! at least with an rx pack you still maintain controll!

[MattW]

It's true that Keith and I aren't going to need a reciever pack to make our cars up to weight ;D especially with 3300's, it's going to be even heavier. I did have a go at getting some weight off it, but then got bored ;D

Older KO 297/LRP recievers have 2 channel and batt socket. New 301/LRP have 3 channel + batt. My GM is 4 channel +batt :)

[Andy Sawyer]

I only ran the rx paxk at the Euros (where the car needed to be 840g)

The rest of the season I ran without and needed at least 5g of lead
(so you can get a Corally light)

This year I dont plan to use one, but I will have one ready just incase.

[Glenn Atterton]

To all,


I think some KO reciever's only have 2 channels and a battery plug.

Just had a look at mine and it is as above, and it's only a couple of years old.


If you only have 2 channels + batt, buy (or make one from old wiring) a Y harness www2.gpmd.com/image/h/hrcm4701.jpg (http://www2.gpmd.com/image/h/hrcm4701.jpg)and plug rec batts & personnel transponder into it before plugging into batt channel on the receiver.

Ads a few extra grams so could help if your struggling to meet the class weight limit

[MattW]

Note to anyone who used GP NiMh reciever cels last year:

check that they are still ok before you try and use them. Just checked mine and have one cell that is no longer playing the game :o :o

[Dave Treacy]

Ads a few extra grams so could help if your struggling to meet the class weight limit



Anyone struggle with the weight limit in 1/12th...? Not me!

[rice98w]

i have to add some weight to get it legal...muahahahaha!!! ;D ;D ;D

but at the moment im not running an Rx pack

[ian plimmer]

what a load of old ladies you are,ditch the r/pack and train your thumbs lol

[Mark Stiles]

How do you guys get the weight down that far. My car weighs 846 grams, and i can't see any way of reducing that! (i don't run an rx pack) ??? My car is an associated L3

[Big Jimmy G]

Hi

Here is some information that you lot may find interesting....

GP do good reciever pack cells (1/3 AAA at 160mAh capacity). You will need 5 of these cells at 3.75g each, plus the wiring and plug, call it 20g in total.

That you probably already knew.

GP also do Li-Ion cells (part no. GP1029L15) which are 2/3 AAA size and still 160mAh capacity, but 3.7V and only 5.45g each. As thair voltage is higher you will need only 2 (plus the same wire and plug etc) which gives a weight of about 11g

An easy way to save 9 precious grams.

According to Marcus charging may be a bit of a mare tho.....

James

[Big Jimmy G]

Hi again,
By the way, what speedo and servo combinations need reviever packs?

I've got the Futaba S9602 servo and I'm sure that that is prety quick enough for me on the plain 4 cells. I also run a Nosram Missile that claims to only need 4 cells, but I have heard from several sources that even if it says "4-7 cells" on the box it doed not mean that it runs at full efficency on 4 cells.

Can anyone throw any light on this particular speedo or recomend a good one that really really really works on 4 cells please?

Ta,

James

[rice98w]

if it works..it works!lol ;D

if it didnt work then obviously it would need more Volts....but if it does even show an LED with 4 cells then it works fine mate

[marcoski]

Thats rather a sweeping statement! Not all fets are fully driven on 4 cells, especially as they fade away towards the end of the run. Efficiency will suffer. There are some speedos specifically designed for four cell use, with an inbuilt switch mode supply to provide an always 6 volt rail for the reciever and servo, and of course proper FET drive.

Damned if I can remember the name of one though, chemo moment!

[rice98w]

sweep sweep sweep

i've never had a speedo that wont run right on 4 cells. i've ran an

atom
cs rocket
robitronic

all with no rx pack...

but then again...i never fade away with THESE cells....hahaha ;D ;D ;D

[marcoski]

OK the fets used in the novak cyclone will struggle on 4 cells, and the regulator for the reciever gives 4.2 volts on 4 cells, and that is fully charged. But, it claims to work on four cells.

[rice98w]

ah...never used a cyclone! i know people that do though and run absolutely fine! kev used to and DJ still does.

so are the fets different from atom to cyclone then? i was under the impression the atom was just smaller and had less fets?

matt

(bed calls...shut eye is needed ;))

[marcoski]

They are.

[Big Jimmy G]

According to the blurb on the Aton instructions the internal workings are designed to work at 3.0V. I guess that implies different FETs and / or switch mode thingy doodahs....

Anyone tried the LRP or Nosram range yet?

James

[MattW]

The Quantum comp/Dominator Power is fine. I would guess that this was the most used ESC last year.

[steven bough]

i know that KO 947 sevo needs a receiver pack to work at its best..

when using a receiver pack with a LRP Quantum speedo-is it o.k to leave the speedo on/off switch on.

Im sure ive hear's that people take the positive lead of the speedo out.but i would sooner not do that if the Quantum is o.k left has it is?


ste

[jason]

steven,

last year I ran a nosram (same speedo) with a reciever pack, plug it in as normal ie all leads but dont switch it on, turn on the reciever pack and it will power up the speedo.

Jason

[Jim Spencer]

Steve

Ran that KO servo all year without a rx pack, seemed fine to me.

Jim

[rice98w]

same here! :P

[Oliver]

Would i then be right in thinking that an Rx pack is really only needed to power a fast servo??

I have been running a KO 1100 speedo in my 12th on 4 cell and had no probs - that was with an (almost) standard servo.

OLI

[Big Jimmy G]

What is the difference berween switching the speedo on/off?

I usually switch mine on (unless I forget.....). I have all the leads from the speedo pluged into the reciever too. Does this make it more / less efficient or what?

James

[marcoski]

Actually it makes no difference as the regulator in the speedo will be over-ridden by the RX pack, and will block any attempt by the RX pack trying to charge the main cells through the speedo.

[Jim Spencer]

Oli

As mentioned earlier Matt and I are both running the KO PDS947fet, with no rx pack, and no problems, theyre normally well quick enough ;D

Jim

[Big Jimmy G]

Hi again,

Just tried the car with and without the reciever pack in. There was little or no noticable difference even in back to back runs. Each time I came back with 110 - 120 seconds of runtime in my 3300s so there was no dumping issue and the speedo / servo seemed to work just fine.

One interesting point tho. As we have no marshals during a race, reverse is very important. With the pack connected I could only reverse at a snail's pace. When I was only running on the main 4 cells I has full speed reverse - scary! Why?

Next meeting I will try the trick of a 14x2 and 3000 Panasonics and keep the pack in my pit box...

By the way, on the IRS site they also do reciever packs, but if you look closely at the cells they are marked 160mAh and only 1/4 AAA size, not the usual 1/3. I guess these will be even lighter..... Anyone got these ones?

JAmes

[steven bough]

Am i right on thinking that some speedo's do require you to take the positive wire out of the lead when using a receiver pack?

Regarding the 947 servo im sure it says it needs to run at 6v -so at 4.8 it would not be at its best-but who cares,has i have to use negertive steering curve anyway,because its to fast for my thumbs...

[B_Final_Bob]

I used a KO 947 servo at the NE Carpet Champs for the first time without a receiver pack... way better than the Fruitaba servo I was using ;D

It probably does say 6v use, but using it on 4 cells probably slows it down and makes it a bit easier to drive ??? ???

[rice98w]

the 947 with 6V is crazy fast! havent tried it on the track yet but on my workbench its amazingly quick!

might try it sometime ;)

[B_Final_Bob]

ooohhh! workbench! very posh! Must be a big workbench if you drive your car on it :P

[rice98w]

ROTFPIMP nice reply...i like it! ;D ;D ;D

[steven bough]

in the past ive been using the Futarba-has i felt the Ko was a bit more firsty on the batts..
But im going to use it for this season has im going to use a receiver pack.Unless i find it to quick,if so i will go back to the Futarba