which speed controllers are better

[Anttazz]

Re: which speed controllers are better

antazz - tried a higher voltage?

First free day i'll have is tomorrow since I saw this, I will try then.

Shoot an email to sales@botbitz.com , we'll work through troubleshooting it with you

Will do, thanks

[leorcc]

Re: which speed controllers are better

Did the higher voltage work?

[Anttazz]

Re: which speed controllers are better

Haven't had the chance to test it yet, been working constantly since starting a new job. I'll try to get it done very soon. At the moment my next day off is on tuesday, so i'll try it then and get back to everyone.

[Ellis]

Re: which speed controllers are better

Haven't had the chance to test it yet, been working constantly since starting a new job. I'll try to get it done very soon. At the moment my next day off is on tuesday, so i'll try it then and get back to everyone.

That would be great. We're at the stage with Tormenta 2 where we either need another Electronize 30a or for a similar price get 2 of the 25a BotBitz. Having just done a test drive the precision (or lack of) with the Electronize is an issue.

[psycho_fling]

Re: which speed controllers are better

If your after better control why not invest in a dual speedo ?

[craig_colliass]

Re: which speed controllers are better

In my time making robots I have had:-

Sidewinders.
Electronize 30 amp.
Wotty 360, 180 and 100s.
Sabertooth 12 and 25 amp.
Victor 883.
and some cheap blue E bay stuff!

For cheap go for E bay expect problems,

Electronize and Victors are very good strong speed controllers they can lack finesse but this is war! they are single channel and so you may find they work best in a 4 wheel drive setup.

For better control go for dual channel speed controllers, two drill motors or Gimson drives the 25amp is very good. I have the 12 amp with these motors in Gabriel. :shock:

For ultimate power in a feather go for a Wotty 100 or find a Sidewinder. these seem to take anything you give them Seraph has a Sidewinder and Tron has a Wotty 100.

[Ellis]

Re: which speed controllers are better

Thanks for the help guys. We really can't afford to buy something flashy for this thing, we just don't have the money, so like everyone I suppose, I'm trying to find the cheapest option!

The 25a Sabertooth has crossed my mind more than once, but it's really over what we can pay, and I can't say I have heard 100% positive results when run with 2 drills each side. Can't afford to pay for something that won't be reliable and handle the needs, at least within sod's law.

The exact issue is that, one side seems to react far less if at all for up to around 25% throttle whilst the other does. But, it isn't consistent. Sometimes it's the other side that is delayed. And, it isn't just a little bit, it's very noticeable when driving. That, coupled with the time it takes for the relays to switch, makes it really not great. Turning at low speed with any precision is almost impossible. When racing around at near full throttle it's fine, though.

Of course, if anyone has a suitable ESC or ESCs (dual or not) up for grabs, we may well be interested. Thanks.

[PJ-27]

Re: which speed controllers are better

Could be the motors. Most drill motors have advanced magnets, so you get more power one way than the other.
Apply the same voltage to the motor either way and you'll hear the change in tone from the different RPM.

[craig_colliass]

Re: which speed controllers are better

With the robot is on the it's cradle and powered up, by operating just the forward trim on the Tx do both sides move very slowly at the same setting? If not then swap the speed controllers over and try again, if the symptom changes the problem is with the speed controllers or the controls Tx Rx or wires, if the symptom stays on the same side it is the motors or transmission.

Are the wheels free to move are the motors stiff? If the robot has been in combat things get bent and this can cause problems.

Some motors are configured to work better in one direction than another, this is done by magnet position I don't think this is a problem for you at this time.

dose the problem only seem to occur when the motors are under load? so on the cradle it's ok but on the ground it causes problems. If so it is down to the power being delivered to the motors this could be the speedo is bust or the circuit resistance is for some reason too much.

The wire and plug connections can be a problem Tamiya plugs can cause problems I am getting rid of these on my robots also check for damaged insulation on wires also check soldered joints and avoid using screw connectors (choc blocks) as they can cause problems.

Keep trying different things and soon you can narrow the cause of the problem down.

[Hoppy]

Re: which speed controllers are better

Relay based controllers are best suited to slower EV's such as mobility scooters where fast forward / reverse is not required. ESC's using relays need to reduce motor current to a very low level before switching in order to avoid contact burning / pitting, which eventually results in unreliable operation. ESC's such as the Sabertooth which uses 'H' bridge solid state switching arrangement are far better suited to combat robotics where fast direction changes are needed. However, as these controllers switch with Mosfets, high voltage transients can easily damage an ESQ. Keeping motor and battery leads as short as possible and tightly twisting their respective wires together helps to avoid damage. Avoid using any type of screw type terminal to connect motor and battery to the ESC. Most importantly, follow the manufacturers guidelines on the loading of ESC's and keep within the recommended working voltage, not the absolute maximum working voltage, which is usually a fair bit higher.

Hoppy

[Ellis]

Re: which speed controllers are better

Thanks guys. We're looking into the issues and thinking of potential replacement ESCs.

One thing, though, when you say screw-type terminals, do you mean contact block? Surely not? We wind the wires together and merely use the block to hold them twisted with each other, not in the conventional wire-in-one-side-wire-in-the-other-tighten-screws-for-contact.

Edit: by contact block I mean these things:

[Hoppy]

Re: which speed controllers are better

Twisting the wires together tightly or preferably soldering together and then using a screw terminal to hold in position is OK. Leaf type clamp screw terminals are better than straight screw terminal blocks but not IMO safe from loosening through vibration.

Hoppy

[plargen]

Re: which speed controllers are better

i found these quite usefull u can get 2,3 and 5 pin connectors

http://www.ebay.co.uk/itm/2x-Wire-Sprin ... 078wt_1142

[psycho_fling]

Re: which speed controllers are better

Avoid using terminal blocks, maybe for testing and getting all the wiring sorted buty after that just make a longer wire or use soldered connections

[PJ-27]

Re: which speed controllers are better

We use Terminal blocks in our robots no problemo - although the wire gauge we use in BitzaMk2 limits us to only a couple in each side and we did find some blocks the screws can works loose.

But as a convenient way to, isolate, distribute and mount I can't think of A better alternative.

Often considered a nut and bolt, but hard to isolate.
Connectors come apart too easily and have limited distribution.

What do most people use?