MagLev C

[iwonder]

It seems to work for me, if everything's filled in and you put a Y in the column I assume it does nothing? What happens if you put a 1 or 2 in the competition violations column?

[bearasauras]

Works for me too. Can you show us what you put in?

[gdb182]

what is everyone doing for batteries? a typical 9V isn't really cutting it because i have to buy a new one almost every 2 days and it is costing me a lot.

[Schrodingerscat]

what is everyone doing for batteries? a typical 9V isn't really cutting it because i have to buy a new one almost every 2 days and it is costing me a lot.

You could use rechargeable batteries.

[FawnOnyx]

what is everyone doing for batteries? a typical 9V isn't really cutting it because i have to buy a new one almost every 2 days and it is costing me a lot.

You could use rechargeable batteries.

Also, the main reason alkaline 9V batteries run out so quickly is because they sacrifice capacity and current output for higher potential (9V). Most of them have 6 small 1.5V cells in series to get to 9v, which means they have really low capacity (550mAh compared to over 2000mAh in AA batteries).

In addition, alkaline batteries actually can't output much current at once, which is actually a big limiting factor for things like maglev motors. I found that after I switched to 6V NiMH and 7.4V LiPo batteries, there's plenty of current and the motors are much more powerful. It's really the amps that can make a big difference, not the volts.

So in summary I'd go for something that's rechargeable as Schrodingerscat said, but also has a larger capacity and current output. Getting 4 NiMH rechargeable AA's and a 4AA battery case from Radioshack would work, giving you 6V and plenty of current. If you want to go beyond that, then you can look into 2 cell (7.4V) LiPo batteries, which charge and discharge super fast and come in huge capacities. You'll need a specialized charger though which is added cost (around 20 bucks). If you're interested, here's a nice description of battery types.

[torqueburner]

It seems to work for me, if everything's filled in and you put a Y in the column I assume it does nothing? What happens if you put a 1 or 2 in the competition violations column?

Ahh - I was entering a "1", since you enter the number of competition violations in that column. A "Y" works for construction violation, while a "1" does not. Thanks.

[masser12]

What are you guy using to control the speed of you motor? is it working well for you?

[feynmanlover]

I was using a 7.4v 2 cell Lipo battery, and the motor was extremelyyy powerful. I decided to buy a 25 Ohm rheostat rated for 3 watts for the speed control, but I kind of fried it because at lower resistances (like 1o ohms) the current is too large. I cant find any rheostats that are rated for more power than that, so I am thinking about downgrading to a few AA batteries and and a less powerful motor. I think the rheostat would work with that. What do you guys think? Have any tips or solution for my problem?

[cnapun]

I have not yet rebuilt my car after frying a 25Ω 3W voltage divider from Radioshack. I do have a 5Ω 50W rheostat that I bought from Amazon, but I still have to build the cart to see if it will work.

[iwonder]

Yeah, I wouldn't downgrade to AA's, best option is probably to use a larger potentiometer (same thing), look at mouser for some large ones. I got a 25W that's working fine. Mew member you won't run the motor forever, so you can probably get one rated a little lower than what you need.