I just got an email from jim from team knightmare and he sed he got 10-15mins easy runtime out of a 14v 4.8amp c pack running two ev warriors without slowing down much at all btw jim used a separet battery for his weapon motor which was a AME D PACK motor and he only got about 3 mins out of it

This was in his robot backlash so i dont know why Hellbringer 3 had a run time of only 1 minute with a 2.3Ah SLA?
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Tim Team Reaper.

SLAs get really knocked around by high current drain compared to NiCads.

You end up losing a lot of the energy as heat in the battery. Also, most of the cheaper SLAs are really only designed for alarm backup type purposes, and have pretty high internal resistance.
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The Engine Whisperer - fixer of things

As stated earlier, Hellbringer 3 had an Effective run-time of approx 1 minute off 1 x 2.3Ahr SLA. The robot was tested with a single 18v 3Ahr (is that right Philip?) and lasted more than 5 min.
This is because a SLA's capacity is dependant on the curent drawn from the battery. If a large amount of current is drawn from the battery for a short period of time the voltage supplied by the battery will drop well bellow the origional voltage but will rise again if the battery is allowed to settle.
I always test my robots by driving them hard with lots of sudden changes in direction placing the maximum possible strain on the drive-train, electronics and batteries. If the robot can't survive this then there is no point taking it to a compitition. This is where I got that 1 min effective run-time. At this time the voltage on the battery is so low that the victor speed controllers are cutting out. After the robot was allowed to settle for a minute I was able to run the robot for a further 30sec or so.
Ni-cad or Ni-Mh packs will not have this characteristic as the voltage will only drop once the cells ae completly drained. This means the robot can be run longer without needing to "settle".
But remember, SLA's can supply much more current than Ni-cads or Ni-Mh's (up to 3000A in some cases compared to Ni-cad max of 80A) and are easier to charge, not to mention the cost. But we will change to the dry cells soon.
Also Backlash has a 5:1 reduction onto 100mm wheels while Hellbringer 3 has a 4:1 reduction onto 200mm wheels therefore placing more strain onto the motors and causing them to draw more current (70A average).
And I reckon that I drive harder than Jim.
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Get Some!!!

Secretary of the Queensland Robotics Sports Club inc.

That is right. That was their first use. They should perform better with a few uses.

To turn on my ev motor i was thinking of a 24v selenoid but i was told by the guy at the marketplace they need at least 6v within there rated voltage to turn on which means if i have a 18v battery pack and it gose under 18v i cant turn on my weapon and if i use a 12v selenoid it may be able to take 18v i will prob blow it up as nicads give out more volts then they are rated

Any ideas on how to turn on my motor?
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Tim Team Reaper.

www.teamwhyachi.com

nick recently brought an 18v contactor to turn on his magmotor, BUT remember, you will have to have a 12v coil on your relay etc as the IBC will only output 12v through the aux connectors.

so basically just get an 18v contactor and use a smaller 12v relay from jaycar to turn the bigger one on.
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Where can i get one of them from?
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Tim Team Reaper.

www.teamwhyachi.com
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

why not use one of jaycars 60 amp relays with microswitches. Unfortunatly their peak current is not mentioned in the catalogue and the raly hasnt been added to their website yet.
from chris
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Mr "squirt"
Team Blazing Star

I would but i have nicad packs rated at 18v more when fully charged.
The 60amp relays are 12v id blow em up

Any one got any more ideas on how to turn on a ev warrior motor running at 18-21v ?

Dose anyone know of a 18v selenoid or relay about 70-80amps or more?

I would have used a selenoid from the marketplace but 24v versions dropout at 6v under the rated voltage and the 12v would blow up at 18-21v
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Tim Team Reaper.

If you can be bothered fiddling around with FET's you could make a solid state switch to ground like jake from Plan-B did..

an EV warrior at 24v has a stall current of around 200 amps (even at 12v, they're 100 amps), so you would need a few well-heatsinked fets in parallel and a small relay to change the IBC's open collector output into a switched 12v to drive the gates on the Fets, but at least you wouldnt suffer welded-shut relays like myself and many others did recently. (you might get some magic smoke, but hey its different. )

To switch that sort of current at an odd voltage like 18v, you're going to need to fiddle about a bit no matter what you do.

A solenoid is the simplest, but you will either have to risk burning a 12v coil at 18-20v (possible, but not likely in just a few minutes), or else come up with a 12v regulator with enough current to supply your solenoid. (a 7812 might do it)

Finding a normal relay that will cope with 100-200 amps is not going to be easy, and all relays have 12v or 24v coils anyway, unless you like fiddling with electronics, I'd go with the solenoid and either overvolt or regulate the coil supply.
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Great minds discuss ideas. Average minds discuss events. Small minds discuss people

I have sorted it out

The guy at the marketplace sales n stuff told me the volts that pass threw the coil if they go 6v under the rated voltage the selenoid will drop out
BUT!! it is the voltage you use to turn on the selenoid in which that is the case

So i will use a servo "as i am using one of the aux outputs to radio controle the flip input" a micro switch and the 12v 100 amp contin 200amp surge selenoid now
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Tim Team Reaper.

fet switch would probbly work
say 3 fets to make it nice and comfy (150A theoretical)
mosfet driver for a nice crisp switch on so you dont toast anything there.
inverter chip if you connecting it to the IBC (or use an inverting mosfet driver)

should be around $20-30 in parts probbly less

Can you send me a diagram on how to make one
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Tim Team Reaper.

quote:

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Originally posted by TEAM HELL BENT!:
So i will use a servo, a micro switch and the 12v 100 amp contin 200amp surge selenoid now

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