ESC - any good? (GM) - HobbyTalk
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post #1 of 41 (permalink) Old 08-21-2003, 12:17 PM Thread Starter
MrFixxiT
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ESC - any good? (GM)

I'm rather new to R/C. At the moment I have a 3 or 4 year old TL01 of Tamiya with standard 540 motor and some standard Mechanical Speed Control.

I would like to buy myself an ESC and have some opportunities.
First one is a GM ASP. I can buy it with more than 50% discount and it looks pretty good, but I'm new to this ESC thing, so I want anyone's opinion about this thing. Specs are at www.gm-racing.de (in english)

Another one which will require me to pay more money is a T2M No Limit. Does anyone know anything about that one?

Is GM any good and would it be a good ESC to drive with the next 1, 2 or 3 years? Will it work ok with the standard 540 motor? But will it work as good or even better with a 19T stock motor (hand-out at dutch national championship races)? I will probably buy myself another (better) (stock) motor in the near future.
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post #2 of 41 (permalink) Old 08-21-2003, 01:25 PM
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FixxiT-
I have & use a GM speedo (V4). I must say that they have some really good stuff. If you can get a GM ASP at the price you mentioned,then by all means-get it! It should be all you need for the next 2-3 years. Another one to look into (seeing that you're in Europe) would be the LRP line of speedos,such as the Quantum line. But at least,get rid of the mechanical speedo!
-George

Last edited by irvan36mm; 08-21-2003 at 01:26 PM.
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post #3 of 41 (permalink) Old 08-21-2003, 01:32 PM Thread Starter
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Thanks for the quick reply. (More replies are welcome of course!

One thing to mention: the GM ASP weighs in at 64grams.

I know I have to get rid of the mechanical speedo, but I still want to keep it, because at the moment the only cup I could enter in with a competitive car is the Tamiya Euro Cup Stock touring car class. That means using an Mechanical speedo.

After some time if I like racing competitive I need to buy myself a nice 'pro' chassis.

Also, when I want to drive competitively (not internation, just local and maybe national sub top) do I really need to have these matched cells (or equipment for it) and use good dischargers and stuff? I use just one car bulb to get the final power out of the stick and then recharge them with a simple peak detector charger (3A). I have Sanyo RC2400 sticks.

Last edited by MrFixxiT; 08-21-2003 at 01:34 PM.
post #4 of 41 (permalink) Old 08-21-2003, 01:33 PM
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Im with Irvan.....i run oval and i love my V4......all Gm speedos are very smal and lightweight.....could they be another option instead of a quantum, no doubt about it!
Dave
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post #5 of 41 (permalink) Old 08-21-2003, 02:36 PM
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I must agree with the above. I have two GM4R and a GMV12 on the way. The two 4R's are mounted in both of my legands cars and run a street spec motor(i think it's 21turn)and i run 4 cell batteries. I've had these two ESC for 1 1/2 years with no problems. I would recomend to use the GM racing product line to anyone.
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post #6 of 41 (permalink) Old 08-21-2003, 03:50 PM Thread Starter
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But what about the 64g weight?

And what do you think of the ASP (Active Steering & Power control) function?
post #7 of 41 (permalink) Old 08-22-2003, 08:53 AM
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FixxIt: I will look into its specs and get back to you....but to be competitive on a semi-national level means matched batteries. People could blame a lost race on the .003 difference in their cells.......you dont need them for club level. as for the equipment, it would be much cheaper to buy matched than buy a brick of cels and trying to get the even ones. Matched cells used to be about equalizing the cells, now many matched packs come with over the top voltage with out the over the top price. For discharging, pick up a trinity real time 2 discharger or somthing like it. Bring the cells down individually. if you have to run stick packs for that class then dont wory about it. As for chargers/dischargers here are a few that are not $400....LOL...the duratrax digital parahinna charger has a adjustable peak meaning you can get rid of false peaks and charge 4 and 6 cell packs to their best.....the novak millenium pro and the CE pitbull are both great chargers, but you would want a discharger also....i think it is integy that makes the Reactor series of dischargers..........what charger do you have now? Hope this helps
Dave
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post #8 of 41 (permalink) Old 08-22-2003, 11:21 AM
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Quote:
Originally Posted by MrFixxiT

Also, when I want to drive competitively (not internation, just local and maybe national sub top) do I really need to have these matched cells (or equipment for it) and use good dischargers and stuff? I use just one car bulb to get the final power out of the stick and then recharge them with a simple peak detector charger (3A). I have Sanyo RC2400 sticks.

first i would get a charger that charges more than 3amps,, get you a good charger like the new lrp or the competion electronics pitbull both with peak detects and will help you in the future when you go to NIMH batteries. Right now your running 2400s that is NICD batteries in a stick form,, if so make you a simple discharger that brings the packs down at the amp you are racing at out of a series of car light bulbs. one equal 2 amp {1157s} so ten will make a 20amp dumper, but if you go racing more compitively you will get packs that are matched and side by side then you can use a charger {ex. T35 ,GFX, or Homemade dumpster until lights go out } to bring cells down to .09 and then place on a equalizing tray and bring on down each cell,, and dead short if you perfer { which i do }. as for speedos George is right,, and i also race with George on several ocassions. hope this helps .

BigDon
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post #9 of 41 (permalink) Old 08-22-2003, 11:43 AM
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Main things to look for in a charger:
1-Variable peak detect from .03mv to .07mv
2-Vari charge rate from an amp tp 6 or 7
3- 4-6 cell ( You never know when you'll need a 4 cell pack if you run 6 cell: Comm lathe???)
4- NiMH compatibility

Bigdon is right about the bulbs, they work fine, but watch them as they go out, dont leave them on too long......im still looking at the gm speedo you mentioned, get back to you soon on it
Dave
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post #10 of 41 (permalink) Old 08-22-2003, 12:19 PM
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also, they are cut off boxes that you solder into homemade dumpster that stop the discharge once the packs reach 5.4 volts which is good for someone running six cell packs,which you are if you are racing touring cars,, if that is the way you decide to go. that way you can hook them up and not have to baby set your packs while they discharge them ,, you can be doing other things,,, working on setup on the car, working on a motor, running the next heat , running in the amain,, or taking pictures with the hooters girl which is very blessed after winning the main .. ok,ok, ok i got carried away just alittle bit,, but you get the picture .

BIGDON

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post #11 of 41 (permalink) Old 08-22-2003, 04:48 PM Thread Starter
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You guys are really helping me with this. Thanks!

Some more questions:
1-Variable peak detect from .03mv to .07mv
what is mv?
2-Vari charge rate from an amp tp 6 or 7
what is amp tp? I guess this just means I need at least a 6 or 7 amp charger, huh?
I guess it's best for me to buy a charger with discharging abilities. Do I really make my batteries bad when I just use one car bulb for discharging? Maybe it's even better not to discharge at all then?
duratrax digital parahinna will be best for me then? I don't have the money to buy it yet though. Will any charger/discharger with the specs mentioned by speadfreak be ok, no matter the manufacturer?

I really don't know much about electrics, so I don't know what to do with things like 'bring cells down to .09 and then place on a equalizing tray and bring on down each cell' or is that for matching yourself?
What about 'adjustable peak meaning you can get rid of false peaks'?

Man, I must sound dumb here!

I see that I won't be racing competitively soon. I need to learn a lot more than I know right now. First I need to run for fun and maybe at club level. Although a good charger/discharger is needed I see.

Btw. I already ordered the GM ASP, so I hope your verdict will be good!
post #12 of 41 (permalink) Old 08-22-2003, 05:21 PM
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mV stands for millivolt. I don't know what tp stands for, though!

Adjustable peak detect: When you charge cells, voltage raise up to a certain point and then drops back. The peak detecting sensor in a charger will monitor for that drop and stop charging. So, when the voltage starts dropping, your batteries are almost full charged. The amount of voltage drop you want is what you want to be able to adjust depending on the type of cells and the number of cells. NiCads were charged until voltage had dropped by 15mV per cell (thus 60 mV for a 4 cell pack) while NiMh are charged until the drop is 8-12 mV per cell (30-50 mV for a 4 cell pack)

As for discharging, common wisdom is that you should discharge your batteries to a rate that is as close as possible to what you are discharging them on the track. Leaving a charge in NiCads is bad since these batteries tend to developp a memory and at some point, they will not perform well because they will get "lazy". For NiMh, it is said that they don't have a memory but I can't confirm because I've never tried to leave a charge in them...

If cost is an issue, as it was said previously, you might not need a sophisticated discharger. 10 car lightbulbs wired in parallel and a voltmeter will suffice. You will have to monitor the discharge and be sure that you stop at 3.6V for 4 cells and 5.4V for 6 cells. And to do that, you don't need an expensive voltmeter. I don't know what you can find in Netherlands but here in Canada you can find a few models that would be suitable for 25-30$. I'd be very surprised if you couldn't find some equivalent near you.

When you discharge, you want to bring the average voltage of each cell to 0.9V. That is how you know they are almost completely discharged. But this is an average because each cell, no matter how good is the match, will be at a sightly different voltage, and if you continue to discharge the cells as a pack passed that 0.9V limit, you might come to a point where some cells are completely dead while others are not and this will damage your pack. Thus, you want to continue to discharge each cell individually and that is what a tray is for. Once every cell is down to 0, then you might want to dead-short your pack by running a wire between the positive and negative poles of your battery. This helps to maintain the voltage as high as possible.

But, those last 2 step is optionnal and you might not want to bother with them unless getting every drop of possible performance is crucial... You will gain much more by spending time on the track that fiddling with your batteries. Just make sure that you discharge your batteries to 0.9V per cell and that is usually enough.

A last bit of advice, get the best charger you can afford. A good quality charger will last for years and will help to maintain your batteries in good shape.

I hope this helps,

Martin Paradis

Last edited by rhodopsine; 08-22-2003 at 05:46 PM.
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post #13 of 41 (permalink) Old 08-22-2003, 07:58 PM
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Dont worry about sounding dumb, we all started somewhere.....its better you ask about this stuff then it go unknown.......the amp tp was ment to say TO, not TP, sorry about that. I would save up for a set of discharge bulbs, an auto cut off device for them, and that duratrax charger. It has a variable peak and charge rate, and can also charge one cell ( i believe) which you can do a glow starter cell for nitro it needed....it can charge NIMH and NICAD pretty well. I know racers that are competitive with them in 4 cell oval, so they cant be bad at all. they run about 55 bucks, and its ac/dc, so its a good charger for the price. I may buy one as a backup for my T35 Stealth, either that or a Pitbull or a Pulsar, but this is the cheapest by far!
Dave
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post #14 of 41 (permalink) Old 08-23-2003, 06:42 AM Thread Starter
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The Piranha Digital Peak charger is a 110VAC (and 12V DC) charger. Here in the Netherlands we use 220V or 230V with other plugs...
I also saw that this charger only charges at 3A max with AC, which is enough for now, but not when I change to (3300) NiMH right?

As for discharging, I think it's easier for me to have discharger or even better a charger with discharging capabilities.

When looking in LHS I should probably stick to the 4 tips speedfreak gave me right?
1-Variable peak detect from .03mv to .07mv
2-Vari charge rate from an amp to 6 or 7 (Isn't 5 enough?)
3- 4-6 cell
4- NiMH compatibility
post #15 of 41 (permalink) Old 08-23-2003, 07:19 AM Thread Starter
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I ordered it yesterday and I got it in today! Wooho!

The only thing is that it's probably pretty hard for me to put it in and make it work. I guess I have to solder quite some things and/or get the correct plugs.

If anyone have some help on using the speedo, I would really appreciate it. My motor is a standard Tamiya RS540 thing with Tamiya plugs. The speedo just has some wires with thick metal wire coming out of the end. Do I need to solder it or can I get some plugs and put it on them?
I also need to solder one of the schottky diodes on it right? Is this difficult? I will use the transistor type; do I need to solder it as near as possible to the speedo itself or is anywhere on the wires ok?
And is there a special way to connect one wire to the motor+ AND the battery+?
The plugs for my receiver are in white-red-black color; the wires that came with my radio are yellow-red-black. Do I need the same order, but the white one for the yellow one? I need to change the plug of them too, but those were shipped in the package.

Thanks in advance guys. You're helping me a lot already.

I also need to use a jumper on this thing to program it, but that won't be a problem, because I'm used to jumpers and stuff (computer nerd?? almost! lol )

Last edited by MrFixxiT; 08-23-2003 at 07:49 AM.
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