Charging station

[lowerdfool]

i'm going to build a stand alone charging station that has both a zip zap charging pad and a microsizer/bitchar-g pad. with a flip of a switch i'll be able to either run 1.5/3/4.5 volts of charging current to either pad or both at once. I decided to use c size batterys for longevity and feild use instead of a plug in type although I may add that option later down the road. I'll do a write up on it when i'm finished.

[Namuna]

Sounds good!

Good luck with it!

[lowerdfool]

well, I finished it today. I've got 4 charger pads(2 zz's and 2 microsizers) and two swithes on the side that allow me to either charge at 3 volts or 6 volts. I'll try to get some pics today of everything I've got.

[d00kie]

Wow, four charging stations in one. Good job there. Now we wait for the pictures!!!

[DriveWRX]

You guys seem to knowledgable...

I have a Bit modded with two 150mAH NiMH cells. Since the controller can't charge the two cells, I charge it using a stand alone charger hooked up to 3 AA's.
I figure that's 4.5V right?

I built a plug-in charger that runs on 3V. Here's a link: http://tinyrc.com/forums/showthread....+Alone+Charger

My question is could I get a 4.5V or higher power supply, hook that up to the plug-in charger and use the that to charge my twin cell Bit?
Is it safe? I won't blow anything up?

[lowerdfool]

it should be safe. You might even be able to find a switchable current, plug-in adaptor. they make them for cars that plug into the lighter. I'll do some searching and see what I can find.

[DriveWRX]

Thanks lowerdfool,

I went to Radio Shack to check out what they had power supply-wise.
I found a switchable power supply rated from 1V - 9V (I think).
The box also said 2.5A. I didn't buy it, since the power supply I already have is 700mAH and I don't know what those numbers mean.

Could someone explain mAH and A?
I know that 150mAH puts out more power than a 120mAH etc...,
but how does 2.5A compare?

Help!

Originally posted by DriveWRX
Could someone explain mAH and A?
I know that 150mAH puts out more power than a 120mAH etc...,
but how does 2.5A compare?

Help!

I'm no expert, but I believe "mAH" stands for "milliamp hours", which is a measure of how long the battery will last under a given load. A 150mAH doesn't put out more power than a 120mAH battery, but it can hold a larger charge capacity, for longer battery life.

"A", or "amps/amperage" is a measure of electrical current. The amperage rating of 2.5A means that that particular power supply is rated to be used with equipment that will draw no more than 2.5 amps. Drawing higher than 2.5 amps will probably damage it.

{edit}
I guess I should have added:

You say that your current power supply is rated at 700mAH, (probably 700mA). I am very positive that charging a mini r/c car is not drawing anywhere near 2.5 amps, especially if your 700mA is working, so the one you were considering at Radio Shack is more than enough to handle the job....

[rrvbl]

loweredfool .. sounds great .. are you going to give us step-by-step instructions??

Please.........

[DriveWRX]

Originally posted by OLDS442
You say that your current power supply is rated at 700mAH, (probably 700mA). I am very positive that charging a mini r/c car is not drawing anywhere near 2.5 amps, especially if your 700mA is working, so the one you were considering at Radio Shack is more than enough to handle the job....

OLDS442,

Thanks, I think I get the meaning of mAH, battery-wise.
BUT , I'm still having a hard time understanding amps.
I'll reword my question:

What is the difference between charging with 3V @ 2.5A and 3V @ 700mA?

Does 2.5A make it charge faster?

Originally posted by DriveWRX
What is the difference between charging with 3V @ 2.5A and 3V @ 700mA?

Does 2.5A make it charge faster?

There is no difference really. It won't make charging necessarily faster. The amperage rating is to let you know how much current draw the power supply can handle under load, without failing. So, you wouldn't want to use a power supply rated at 2.5A to run a piece of equipment that draws more than 2.5A. If you do, the power supply will likely fail, (i.e. smoke, burn, blow up, etc. ) Basically, you want to make sure that the amperage rating of your power supply will be greater than the actual load that you draw from it.

As I said before, I believe your 700mA rated power supply will work fine, (assuming it is at least 3V). I don't know the exact draw of the batteries when charging, but I doubt it's very high. My stand-alone charger uses a Radio Shack 1.5-12V 300mA AC to DC Adapter, (cat #273-1662), that was salvaged from my junkbox. I soldered it into a Motor Works charging base. It charges all of my cars, including my dual 110mAH NiMH battery MicroSizer + 3.8 motor. I've used it multiple times every day for over a month now and it's still going strong....

[gRC]

Originally posted by DriveWRX
What is the difference between charging with 3V @ 2.5A and 3V @ 700mA?

Some info about charging with different adapters was posted in another thread.

[DriveWRX]

Thanks for the link gRC!

Still kinda intimidating, but I think I'm starting to understand!

[lowerdfool]

Here's the wire schematics for a charging station like what I've made. I haven't yet tested the voltage when 4 cars are on but I can successfully charge 2 at the same time without any drop in voltage as long as the batteries are new. I will probably in the near future get an ac/dc adaptor to plug into a wall that way I don't have to continue to change batteries as long as I'm at home or somewhere with an outlet.

and for the pic....

[Namuna]

Off to Bit Science...

[TheFanMan]

I think I may have to build one and have it built right into the pit stop of my track, that way all you have to do is pull up and charge, plus I already built in jacks so that you can run your car dead b4 you charge it, then just build the seperate charger in next to it, and BAM! quick racing action

[nbnby]

Hello,

I'm new to this forum but totally addicted to micro r/c. I found a cheap bit clone at Wal-mart that comes with a stand alone charger that holds three AAA's. I'm thinking about modding it by taking out the original charging posts and grafting my zipzap charging pad onto the top of it. The Walmart clones were about $13.00 each and come in a bullet shaped container.

Well, again, hello to everybody. I'm sure I'll get to know everybody pretty well.

[Azimov]

mA and A are the same thing. Just a different level of measuring current. Like inches and feet. 1000mA is equal to 1A. 500mA is the same as saying .5 A. They are both measured by time. Hence the h at the end of many spec write ups. Why it is called miliAmps rather than kiliAmps as in Ohms is beyond me.
Current flows, just like water. The way you measure it is how much flows past a given point in a certain amount of time. Again, just like water flowing over a dam. Voltage is pressure. Or, how much force is applied to pushing the water over the dam. Which is why when you raise voltage (pressure) more current can flow over the dam faster. And resistance is holding the current back, like the dam itself. If you lower the top of the dam, at a given pressure, more current flows due to less resistance, raise the dam until no current flows and you are said to have maximum resistance or no current flow. Materials with this property are called insulators. This water analogy works well for me as electrons in a wire behave the same way as water molecules in a pipe. Not really though, it's like saying the sun sets and rises rather than the earth going around the sun causing the illusion of the sun moving. When water flows into a pipe, the same water molecules flow out the other end. In a wire, electrons smack into one another like those executive desk toys that bang steel balls together. The first one strikes the next and so on until the last one pops out of the wire to feed your circuit. I'ts not the original electron that you pumped into the wire. This is why copper is such a good conductor. It has more free electrons to supply this chain reaction. It's also why it's so soft. Gold is the best conductor for the same reasons.

[DriveWRX]

Thanks Azimov,

You're analogy makes this so much clearer!

[Pojo]

sahweeeeeeeeeet......