Fred_B

iTrader: (1)

Raced with the new pack today and it wasn't a problem running 13.5 LiPo with the 17.5 4 cell guys. I think I need to add more weight to make things a little more equal but it was pretty close.

The Hobby King voltage booster worked fine all day for me and it didn't get hot or anything like that. If the Novak booster's bigger than what I have it's probably set-up to put out cleaner power to the receiver.

I was running a Tekin speedo and it did fall off some but I think it was just the pack running at lower voltage at the end of the run. I was able to catch the other guy running LiPo at the end of the run so it didn't fall off any more than his LRP did. Rolled out at a 3.35 in the main.

KHoff7

iTrader: (5)

Receiver pack! ..or until novak makes a real voltage booster...

Ran the car again this weekend. Same EXACT speed and still maybe a tick slower but I forgot to play with timing again. I run the same rollout for 4c 17.5 and lipo 13.5.....so that has a lot to say about the equality of the power output of the 2 systems.

trailranger

I was preparing my buggy for a race next month becuase I may be having a surgery in between now and then. I didn't want to be unprepared, but I already have all my ESC's tasked out to cars I run local excecpt for one ESC: GTB 4-CELL SS. I think the GTB without a massive fan or heatsink should handle 17.5 well, but as I was changing out the ESC wires for longer wires the thought crossed my mind to test my buggy on 3.7V to trouble shoot any weak links in that setup.

B4 Buggy 3.7V LiPO
Servo JR 8800T, GTB SpreadSpektrum 4-cell, 1000mah 4.8V RX (4x AAA), LRP 7.5Motor.

After about 5 mins of just doing figure eights I could not see any issues with the rx pack using a large powerful servo. I think those having issues with the RX or boosters may just have an undersized powerpack. I know 150ma should be enough for 5 to 8min, but really why chance your RX pack taking a dump with laps to go. IMO If you can afford the extra grams get a slightly bigger pack.

andrewdoherty

iTrader: (49)

I ran several packs of tests with my 2 SMC 1 Cell lipo's today. I ran them in both my 10r5 and my 12r5.

The SP GT LPF in my 10r5 ran perfectly without a receiver pack or booster for 5+ minutes using the 1 cell lipo. 9650 Futaba, 13.5 motor, spektrum micro receiver. At first I ran it with a 200 mah lipo 7.4v receiver pack and noticed no problems so I tried running it unplugged. I ran it with the esc turned on and off and felt no difference. It felt the same both ways for me. In a 5 minute run the car drained about 100-150 mah when I used then receiver pack. In the end I found the car to be fastest when I went up three teeth in gearing from what I run in the car with 4 cell/17.5.
I didn't add any weight to the car and ran the lipo in the back position. Car handled very well. I reduced the amount of the front tires I saucall day.ed as the car had too much steering with the lipo in.

The 12r5 with the original Sphere esc NEEDED the receiver pack to make 8 minutes. It drew about 150 mah from the receiver pack as well. The 12th scale felt a little too twitch for my taste with the lipo in and no adjustments. A softer center spring and a wider front width should help. I didn't get a chance to test rollout with the 13.5/lipo option, but it was with in .2 of what I had been running during racing with nimh and a 17.5

Chris Furman

iTrader: (118)

OK guys.. great news!

No receiver pack, no voltage booster, nothing.

SpeedPassion GT LPF 1.1 with Orion 13.5 motor
Futaba 603FS
Futaba 9650 Servo
Transponder - had to run Novak booster for this to power up

Ran for 8 minutes.. perfect, no problems... the last 5 laps started feeling flat, but I was still able to reel in others or be on par as other cars. Lap times were almost identical. 3 guys on the same lap for the qualifiers.

hanulec

iTrader: (28)

hi chris - thanks for the posting. what is the the part number of the novak booster you used?

on my testing, i was going to run a receiver pack test today but i ran out of the time during practice. i think in a few more weeks if we keep on getting good reports i might not have to run nimh for 1/12th club racing any more. keep it coming guys. the more data we can share with one another, the easier it will be for everyone.

andrewdoherty

iTrader: (49)

Good point about the transponder. I am running an MRT PTx and is working perfectly whether I run a receiver apck or not. Hasn't missed a lap on 1 cell voltage even when the esc's or receivers stop from too low voltage.

trailranger

I did some more testing with my buggy with the 3.7V battery. The GTB 4-cell should work well for anyone using a RX battery pack. I was using a SR3000 RX and a JR 8800T servo and a 4xAAA battery pack. After 6 minutes the RX pack only needed 80mah to repeak. The ESC siwtch was in the off posistion. A Switch was used inline with the RX pack to turn on/off the car. The 3.7V battery used only 1900mah during the 5minutes there the average load was 16maps with 50amp peaks under accelleration according to my eagle tree. I didn't have any pinions bigger than 27T, but the load should be similar to a dialed in 13.5 1:12. The motor was very cool and the esc too, so I would think 13.5 with 3.7V would be an easy go for launch.

I still reccomend a bigger RX pack than 150mah because as towards the end of a 8min race the RX pack will be on the DUMP side of the charge. A false peak or weak cell could mean problems on the last laps. A 400mah 4.8V rx pack is only 30x20x20mm. That is roughly the same footprint as a Spektrum Mico RX.

Please Note I am only using the buggy as a test vehicle since I can just head out my front door and see what what works and what does not for the radio power setup. I'm not testing buggy with 3.7V to make a replacement class. Tomorrow the buggy will be back to 7.4V with 17.5 motor.

Best of luck to all the 3.7V converts. My Tekin and GTB seem to work well when used with a good booster modual or rx pack.

Chris Furman

iTrader: (118)

Novak 5485 - transponder booster

Works like a charm! Everything works great!

Servo is still fast also! Maybe it's the Futaba 9650, I have to give it credit.

tfrahm

iTrader: (2)

I think Novak may have discontinued that part, because there is no listing for it on their web site... They mention it in the text about the GTB 4-cell version, but the part# itself isn't listed anywhere I can find...?

lidebt2

iTrader: (21)

https://www.ssl-stormerhobbies.com/c...=ns&pn=NOV5485

https://www.greathobbies.com/product...rod_id=NOV5485

http://h1072287.hobbyshopnow.com/pro...p?prod=NOV5485

fred kellner

iTrader: (25)

Novak 5485 - transponder booster
Works like a charm! Everything works great!
Servo is still fast also! Maybe it's the Futaba 9650, I have to give it credit.


So are you plugging the speedcontrol lead into the Novak booster then into the receiver? Then still using the switch on the speedcontrol?

Which will work better. This method or a receiver pack?

Chris Furman

iTrader: (118)

Fred - I am using the booster for the Transponder Only (from the receiver to booster to transponder.) Everything else (ESC and SERVO) is plugged in normally directly into the receiver. All I can say, is with this combination of electronics, everything works fantastic!

rcjunkie3000

iTrader: (94)

Has anyone completed testing a GTB 4-cell speedo? I know the 6-cell GTB, LRP, Tekin RS, and Speed Passion have been tested so far. The only mention of a 4-cell GTB was done recently with an off-road buggy. Has it been tested on a 12th scale?

trailranger

The GTB 4-cell should work in 1:12 using a RX pack.

The testing I did with my B4 buggy was not to test the buggy and speeds but to test the GTB with a RX pack with a test platform that could be used at home. The car should have no affect on the performance of the ESC being powered by a RX pack. I used a beefy servo to help drain the RX pack and look for any power issues.

What I discovered is that the ESC switch must be in the off posistion and a additional switch placed inline from the RX to the RX battery must be used.

What I discovered in using a ESC with a Booster modual is the same. The ESC must be in the off posistion. A switch should be used inline from the battery to the booster. I soldered a servo wire from my ESC Batt +/- terminals to my booster with a DTDP switch to keep things less cluttered. The booster works best if a 6.3V 3300uf capacitor or Glicth cap is plugged into a spare slot of the RX.

If you are happy with your GTB profile settings or using an Tekin or LRP esc, place a 1/2" or 5/8" heatshrink tube over the on/off switch. This will prevent the accidental turn on that can cause the RX pack to drain back into the Primary battery pack used for the motor. If using a booster, the drain back current could be high enough to overload and toast the modual.

I know a 150mah battery is enough to power 1:12 car that is dialed in. If your servo is working hard because of binding of pushy setup, then your RX battery may dump faster. Age and quality of the RX battery can also affect how you dump. So my opinion, is that when in doubt make it stout for the RX battery or modual to make sure you can drive that last few laps without the car powering off. If you are using NiMH cells, a slow trickle over night can help make sure all the cells are topped off on race day. During race day, 0.2 to 0.5A charge rates should be enough for repeaks.