Whats ever ones thoughts

So ive been pondering on getting a true 1 cell lipo that i dont have to use a silly booster with and ive foud this what do you guys think?
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My advice - AVOID!

Read the spec carefully - "These controllers will have their BEC circuit disabled - removed actually - so you will need an outboard 4.8 - 6.0 volt power source to run your electronics". In other words the units will "function" on 1s LiPo (lights will come on and you can make changes to the setup profiles) but they will not put out any sort of usable voltage to your speedo and receiver. If you race them on the tack you'll risk having a slow servo and receiver / PT brown outs as the cell voltage falls off during the race. Then they go on to suggest how to use a booster and receiver pack...

They are prety much the same as the Novak GTB2 in that respect. They CAN work, but you must have a rather lucky combination of receiver / PT and servo if you expect them to work reliably.

If you are truly after a booster-free speedo that gives a good 6.0V output to your radio gear there are only three I know of - LRP SXX Stock Spec, Nosram Pearl Version 2 and Hobbywing 1s.

James

i was really hopping to avoid going the hobbywing route till the agm was over and done with guess i dont have a choice now lol

Don't forget the SpeedPassion EX 1S speedo.

Rudolf,
Yes, I must admit that I have never seen of that one, but it sure looks nice! Ok, so it is a fair bit more expensive than the HW typebut the specs look impressice. Anyone tried one os 1s LiPo?
J

I recently bought a speedpassion V2.1 EX 1S

It works a treat and has built in dc-dc converter to run servo and receiver, but it has the same blinky esc issues as hobbywing.

I believe the speedpassion are very similar.

There appears to be a lack 1s esc's on he market with dedicated Zero timing. Blinky esc's are the way forward I believe because they are so universal with just a firmware change and they are readily available.

As per my video and others there is nothing wrong with a GTB2. Either with or with out a booster

True, Gary. Those videos look great!

It is true that Gary, and sevral others, have found the GTB2 unit will function on 1s LiPo power. However, it seems that you also have a particular combination of other electronics and race on tracks with a particular layout to get reliable performance. The GTB2, (as with the Mamba and Black Diamond units) does not actully boost the voltage to your receiver. Gary, you have done this test yourself and you've found that the voltage at the receiver is only whatever voltage the cells are at, ie lower at the end of the race than at the start, and a lot lower when you are needing power to accelerate.

To get a GTB2 to run reliably you seem to have to match the following set of additional requirements:-

1. Your receiver will function down to around 3.5V
2. You are running the newer AMB RC4 ("Harry") personal transponder (like yours Gary) or MTR transponders which work to about 2.8V.
3. Your serov is of the "low current drain" type, usually the high end KO or Futaba dedicated 1/12 units (or Savox 1357 like yours Gary).
4. The track is larger, more sweepy layout and the timing loop is not on the exit of an acceleration corner (Ardent fits this criteria).

If, on the other hand, you have receiver that need higher voltages, or you have any of the other types of PT, or you are not using a mini-servo or you are racing on smaller, more technical tracks that demand more acceleration, or the timing loop in in a place where the car is under higher load, a GTB2 unit will not work reliably. You risk slowing servo speeds and glitches, and PT missing your laps. Many, many others have found this, search back on the forum.

Now, I know Jamie well and have raced with him on several of the tracks I visit regularly. I know the rest of the gear he has and the sort of budget he is on for his racing. If you read his opening post he also specifically requires that he does not to run an additional booster too. Since he has an older AMB personal transponder (requiring at least 4.0V to work) and that he is using a touring car / standard sized servo that happens to have quite a high current drain, and that he usually races on smaller tracks which do not always have the loop in an ideal position I have advised that the GTB2 / Mamba / Black Diamond will not be suitable for him.

James

Mine gtb 2 cheapo servo new transponder mini one no problems runs a dream everytime whats are you trying to say seems its only you who has a problem GTB2 wicked esc
maybe you have some duff gear

Admin / Paul,

"new transponder mini one no problems runs a dream"

Yes, of course it will, that is exactly the point I am making - IF you are to run one of the new, mini transponders you are less likely to get the brown outs and missed laps.

"cheapo servo"

Again, IF your seovo has a low current drain you are less likely to get slow servo speeds and glitches when you run the GTB2. Now, I don't know what the specs for your servo are of course but I wouls guess it falls into that class.

As I have said before, IF the gear I used with my GTB2 has matched the list I posted, AND if I raced on a track with a wide, sweeping layout and that had the timing loop in a suitable place, I could get my GTB2 to run well too. I've never denied that. HOWEVER, to do this I have had to borrow other servos and PTs from friends (or add club handouts to my car) becasue a lot of the gear out there cannot work reliably with the low receiver voltges that the GTB2 produces.

By the way, did you ever get round to doing that voltage test at your receiver as I suggested last week? If not, please do so and let us see your results too.

Now, Jamie, and many others are in the same boat as I am. We both have the same, older version of AMB's PT that needs 4.0V to work (rather than 2.8V like yours does), we both have servos with relatively high current drains and we race the majority of our meetings on relatively small, technical tracks. So, to get our gear to work as reliably as yours does we either have to splash out more cash on new PTs, possibly change our servos too and race only on suitable tracks, or we choose to invest in speedos that boost the 1s LiPo voltages to 6.0V at the receiver. Some people don't have the luxury to be able to throw too much cash at their cars so buying just the speedo (HW 1s for £90) might be all that is possible. Jamie has given a specific set of criteria and asked for suggestions - I am advising that he goes for a speedo that will boost the input voltages as this will match is criteria without the need to spend more money to change the rest of his gear...

James

with the gtb2 running it o a large track would mean less drinage of power would it not? same with any speedo or have i got this wrong?

allso ive gone for the 1cell hobby wing speedo just hoping i dont get stung on inport tax but either way it will solve the power drain

Now i need to figure out what decent 50-60c 1 cell lipos to buy

Yes, Jamie.

On a bigger track, where the corners are wider and more flowing, current drain will generally be lower. That is why the GTB2 can work well on these types of track - lower current drain = less voltage drop = better functioning PTs and servos.

Shorter tracks that are more technical in layout and require more "pointy-squirty" driving will generally put greater demands on your electronics as you need more current to keep on accelerate from low speeds than you do to maintain a steady high speed. More current = more voltage drop and possible problems with PTs and servos.

As for cells, I am now running 5400maH / 45C ones but anything over 4000mAh and 25C should probably be ok. Get the best figures you can afford...

J