Batteries

[FotoPlasma]

Originally Posted by sanddrag

As for the issue of starting a car, it is possible to do with a FIRST robot style battery. http://www.harborfreight.com/cpi/cta...emnumber=39954 I have one of these things and you can jumpstart a car at least 4 times before it doesn't have enough power to do it again. Also, what about those things you plug into the cigarette lighter to jump a car. How do they work and what batteries do they have?

As far as I know (and beware, I am no expert), the cigarette lighter circuit is connected, via the ignition system (as a switch), to the positive and negative leads on the car's battery. On most cars I've had the privelidge to replace a fuse in, the cigarette lighter circuit is fused at 10Amps, but I think most cigarette ligher male plugs have integral 3Amp fuses. As long as there's enough limiting resistance, the car needing the jump will be charged safely.

This is just what seems to me to be going on. I've never done it and, until now, haven't really been familiar with the practice. If I'm wrong, please correct me.

[echos]

I've been looking for a place in San Diego that sells TLP 4000C IntelliChargers like the one pictured below.

[Adam Y.]

This is why it's an engineering design challenge!
If you want it to be easy, go do battlebots .

Yeah but those guys use NiCad's and NiMh batteries in their robots. There really are disadvantages and advantages to all three of them. SLA's have high internal resistance which results in large and sudden voltage drop.

[Wetzel]

Originally Posted by KenWittlief

...
weight is not a primary concern for our bots ... If they gave us $200 batterys that were half the weight, you would hardly notice the difference in the performance (speed and handling) of our robots...

What competition are you competeing in? Have you never had to make swiss cheese?
An extra 6 lbs to play with would make a big diffrence in what we could do.


Wetzel

[KenWittlief]

only if you failed to plan out your weight budget.

there is no reason FIRST could not increase the weight limit by 6 lbs if it were really a serious limitation

its not.

[JVN]

Originally Posted by Wetzel

What competition are you competeing in? Have you never had to make swiss cheese?
An extra 6 lbs to play with would make a big diffrence in what we could do.

Then... within 2 years... someone would be calling out for 142lbs, because:
"An extra 6 lbs to play with, would make a big difference in what we could do!"

Then... within 2 years of that... 148lbs, because (you guessed it):
"An extra 6 lbs...."

This is why it's an engineering design challenge!
If you want it to be easy, go do battlebots .

Besides Jeff,
would you really WANT to give Wildstang 6 more lbs of aluminum?
I mean... jeez.


John

[Jeff Waegelin]

Originally Posted by JVN

Then... within 2 years... someone would be calling out for 142lbs, because:
"An extra 6 lbs to play with, would make a big difference in what we could do!"

Then... within 2 years of that... 148lbs, because (you guessed it):
"An extra 6 lbs...."

This is why it's an engineering design challenge!
If you want it to be easy, go do battlebots .

Besides Jeff,
would you really WANT to give Wildstang 6 more lbs of aluminum?
I mean... jeez.


John

Exactly... no matter how much FIRST would increase the weight limit (or lighten batteries, as the case may be here), people will still complain that they need more weight to work with, because they didn't budget their weight, or are trying to do something too large and complex. Being able to fit everything into the constraints is just part of the challenge of FIRST.