try wireing a 100 amp fuse or circut breaker into your power input leads remember your controler might be 50 amps per motor but it will take in 100 amps and split it into 50 amps per motor so this way if the fuse blows or the cercut breaker cuts off your drawing too much current and at least youl save your controller rather than finding out the hard way
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Tim Team Reaper.

The fuse might save it from excesive loads but not from contiounious high loading i think is more likely geting hot from continued heavy loading ..... like Bret said the heat sinks are desighned to absorb heat from high peak loading quickly to get it away from the fets but they arent desighned to radiate the heat away from them selves quickly so iff a fan is fitted it will help a lot even a small amout of air flow will remove an enormous amount of heat much more than could just be radiated off the heat sink.

I have another question. Has anyone hooked up the invert feature so that it can invert when one pushes a stick up/down? What do you do to activate it?
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From what i understand you can do it that way or you can conect it directly to gravity type switch ie a mercury switch or modern equivilent so when your bot is inverted it will automatilcy switch the invert feature for you .Brett(Spockie) might be more able to help you on that but read the owners manual i'm sure its written in there some where .

The manual is a little confusing for someone like me. Which posts do you connect?
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if your heat sink it still geting hot from heavy loading or from excesive loads try fitting a bigger heat sink to keep the mosfets cooler like a t shape with air grooves filed in it or holes drilled in it with a fan bolted about 10mm above the heat sink http://www.hotkey.net.au/~acerules/pictures/mod.JPG
having more mass on the heat sink will absorb more heat quicker and will take longer to get hot becouse the heat is spread out over a bigger aria
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Tim Team Reaper.

Theres no room above the heatsink and I dont want to accidently mess up on something. I dont think its really going to matter because after this Saturday I am changing to smaller motors and smaller speed controllers.
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Tims idea is the best type of thing to do if you want to increase the IBC's continuous power handling capability. you need to improve the radiative ability of the heatsink to get rid of heat quickly after it has absorbed it from the fets..although you dont need to go as far as actually changing the standard heatsink (since that would involve re-fitting all the fiddly insulating washers and bushes)

Our solution to that was to stick a small CPU-size cooling fan on top of there. If you want to really improve things and have the weight, you can keep the heatsink with the fan from the CPU fan, and with a little thermal grease, press it up against the IBC's heatsink. that way you increase the thermal mass, increase the radiating surface, AND give it cooling airflow. that should handle nearly anything (within the FET's limits).

Why doesnt the IBC come with a cooling setup like that ? because 95% of bots (that the IBC was designed for) dont need it. it does just fine on its aluminium bar. Even 4 drill motors at 24v it will cope with. its only when occasional person really starts working it hard that it has that much heat to deal with, and we wanted to keep weight (and costs) down so it would be more useable to the majority of bots. Only the hot-rod guys who are really sucking the amps need to put a little more attention into cooling (like it says in the manual).

To easily use the invert/flip function, (if you arent using the third radio channel), just hook up the third channel to your receiver, and connect either the aux-hi and/or the aux-low output pin straight back to the Flip input pin..

voila. radio-controlled flip. move the third channel (whatever it may be on your controller) into the auxillary activation zone, and the aux-output will activate the flip input, and you are driving backwards.

If you are already using the 3rd channel for your weapon, you can use the "other side" of the aux (aux-hi if you are using aux-low for your weapon, or vice-versa) to still activate flip using just 3 channels, but you wonbt be able to activate your weapon AND flip at the same time, so no firing the weapon while upside down and continuing to drive backwards. only 1 auxillary output can be on at a time.

If you need bi direction weapon capability (ie, you are already using both aux-hi and aux-low), or you need to be able to fire and drive inverted simulataneously, then you will need to either 1, get a 4th radio channel and switch decoder (available from hobby shops), *or* 2. fit a manual flip-sensor to your robot like a tilt-switch that automatically activates the flip input whenever you are upside down.

Does that help clear things up ?

Last edited by Spockie-Tech on Tue Jul 27, 2004 11:24 am; edited 1 time in total

What would I use to connect the pins? Would a simple wire soldered to each connecting them work or would it be an accident waiting to happen.(shorting the system) Thanks for your help!
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That depends on your soldering skills

The IBC comes with a connector designed to suit those pins, but its in a disassembled state, and can be quite fiddly to put together for those without much experience in soldering..

If it seems too fiddly, then enlist the services of an electronics techie to pop some wires on it for you, then you can join the appropriate wires and insulate them without risk of damaging the board through accidental short circuits.

yes my haetsink mod idea is for people realy sucking the amps
but only attempt it if you have the patients and skills to remove the old heatsink and refit the new heatsink and all the insulating washers and bushes its just a more solid solution then sticking a fan on top with glue or whatever.
what i have done with my ibc is fit just a larger heatsink for more thermal mass and i have allso put all my electronics in one box with a large pc fan on top blowing cool air threw the box and out the top because hot air rises.
the reason why i havent used my other idea was because i had the space and wieght to put all my electronics in one box and have a fan cool the lot but if you dont have the space or wieght then i suggest my other idea or what Spockie-Tech sed with the thermal grease but im not sure how solid it is if the grease holds it on tight but im not putting down other peaples ideas as i havent tried them but anyway these are just some of my ideas do wahtever suits you best
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Tim Team Reaper.

I just had a thought about my 100 amp fuse theory if i put a 100 amp fuse on one of the power inputs on my ibc it would protect it if both the motors pulled over 50amps each .

but what if one motor pulls 70 amps in a stall and the other is only pulling 10 amps while running that makes 80 amp going in to the ibc so the fuse will not blow as it is 100 amps but because one of the motors is pulling 70 amps threw one channel or one side it will fry that side and then fry the rest of the ibc is that right?
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Tim Team Reaper.

Fuses are generally not considered a great idea in a combat robot.. they seem like it to start with, but there are a few objections.

Like all motor controllers, the IBC's "50 amps per channel" is a measure of its *average* power-handling capability. In actual fact, it will handle short power surges much higher than this (we've tested it at 120 amps for a few seconds), but a sustained 50 amp draw for ages will overheat the heatsinks without good cooling airflow.

The only controller manufacturer who rates their controllers in "continuous all-day amps" is Vantec (which is why their controllers have lower specs than most others for the $). Hobby controller manufacturers are terrible, they seem to rate their controllers according to the theoretical maximum the fets datasheet say is hypothetically possible before exploding into a cloud of plasma, and promote their products based on that.

So, a fixed 100 amp fuse is both too much and too little at the same time. It will limit your momentary surge power that the IBC is capable of providing, yet wont protect you from a sustained overheat situation at 90a mps combined. It will offer you more protection than nothing would though, but..

the 2nd problem is that they are glass (or plastic if the blade type) with a fragile metal filament in the middle that typically runs fairly hot (especially when close to its blowing limit). This means that any sudden impacts will quite likely cause the hot wire to seperate under the shock, even although the overload point has not been reached. the effect is a dead-bot, and unless you tap out quickly, if you are fighting some uber-spinner you will likely be up for far more in bot-repairs than you would have been *if* your controller had smoked in some momentary overload. For this reason, most builders who run fuses only do so in testing, and then bypass them with a wire for combat.

If you really do want to give your controller a bit more protection, then I suggest the Thermal-Auto-Reset circuit breakers available from Bursons or Repco (they're a Narva part), since at least once things cool down after the overload has gone, they will kick in again after a while, although I ended up bypassing them on Scoopys Saw at marayong because they were taking too long to reset - if the saw momentarily stalled, it would be out of action for the next minute or so.. a long time in a 3minute match.
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thanks for that brett i think i will give the fuse idea a miss this time
the stall is only if your motor stops moving totally isnt it?
Any way its just that iv herd of a few peoplez that have fryed thier controller.

AND I DONT WANNA DO THAT ha ha ha
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Tim Team Reaper.