Custom charger and results.....
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ph2t
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Custom charger and results.....
I've been building a custom charger over the last month and I thought I'd share it with you all. Like most Bit freaks I've been looking for ways to get the longest runtime possible for the shortest charge. Since there is only 24 hours in a day and the human body needs sleep it's taken me a while to get all my sh1t together. I'd like to thank micro_amps for all his help with this since a lot of the success of this project has been to do with his advice, anyways enough of the award ceremony speech, lol!
The charger is based on two major parts, the timing circuit and the current/voltage limiting circuit. My goal for this project was to be able to have a fully custom charger for my cars that had variable time, current and voltage selection. From this I can charge singe/dual batt cars from a low 14H standard charge (5-15mA) to a more intense 45Sec 1.6A charge!
Before I go any further, here is a graph I generated from MS Excel outlining the THEORETICAL values of current and time required to charge various capacity batteries to 100% charge. Keep in mind that using most of these values in the real world will prolly blow up your car, doh! I used it as a guide only.
Here's a picture of the prototype. Once I'm happy I will build it into a nice little jiffy box with charge clip, push buttons and pretty lights.
As you can see in the diagram above the charger is currently charging my MS 49Mhz Skyline at 0.59A or 590mA. I used the multimeter to be able to measure the current I was sinking into this poor little guinea pig battery. With various testing I've been able to put as much as 1.6A into the car's battery for a VERY short period. I don't know about the long term wisdom of this though, will prolly end up killing a few batts this way....
The strengh in having a custom charger is the ability to be able to increase the charge time and current. You can get some really amazing results from doing this. Below is a table of my results so far.
As you can see the run time varies incredibly depending on the load. Charging at 1.1A for 54Secs gives me 21 minutes of runtime, for 5 minutes charge I get 50min!!! No load is the car upside down on my test bench. Fwd load is the car running fwd only with no steering, Fwd + Steering load is the car going fwd and turning to the left all the time.
How did I do this? I put the car on the end of some sewing thread and wound the string around a center pole. Check the video here of how I did this test.
http://www.prahranpianos.com/bit_g/char ... esting.avi
The car appears to run slow because in this particular video the steering is set to left, causing a lot of resistance to the motor. I did this because to gain an accurate runtime I needed to be able to simulate a normal play session as much as possible. Given the figures I've attained you will probably find that the realistic runtime of a car is 15%-30% greater given that you don't always have fwd+steering on all the time.
To keep the car going I butchered a controller and shorted the Fwd and Left terminals as shown below.
Keep in mind all the figures above are based on the stock 50mAh TOMY battery. Once I get it all in a neat little case I'll post some more pics. I might even start selling them if the interest is there, lol!
ph2t.
The charger is based on two major parts, the timing circuit and the current/voltage limiting circuit. My goal for this project was to be able to have a fully custom charger for my cars that had variable time, current and voltage selection. From this I can charge singe/dual batt cars from a low 14H standard charge (5-15mA) to a more intense 45Sec 1.6A charge!
Before I go any further, here is a graph I generated from MS Excel outlining the THEORETICAL values of current and time required to charge various capacity batteries to 100% charge. Keep in mind that using most of these values in the real world will prolly blow up your car, doh! I used it as a guide only.
Here's a picture of the prototype. Once I'm happy I will build it into a nice little jiffy box with charge clip, push buttons and pretty lights.
As you can see in the diagram above the charger is currently charging my MS 49Mhz Skyline at 0.59A or 590mA. I used the multimeter to be able to measure the current I was sinking into this poor little guinea pig battery. With various testing I've been able to put as much as 1.6A into the car's battery for a VERY short period. I don't know about the long term wisdom of this though, will prolly end up killing a few batts this way....
The strengh in having a custom charger is the ability to be able to increase the charge time and current. You can get some really amazing results from doing this. Below is a table of my results so far.
As you can see the run time varies incredibly depending on the load. Charging at 1.1A for 54Secs gives me 21 minutes of runtime, for 5 minutes charge I get 50min!!! No load is the car upside down on my test bench. Fwd load is the car running fwd only with no steering, Fwd + Steering load is the car going fwd and turning to the left all the time.
How did I do this? I put the car on the end of some sewing thread and wound the string around a center pole. Check the video here of how I did this test.
http://www.prahranpianos.com/bit_g/char ... esting.avi
The car appears to run slow because in this particular video the steering is set to left, causing a lot of resistance to the motor. I did this because to gain an accurate runtime I needed to be able to simulate a normal play session as much as possible. Given the figures I've attained you will probably find that the realistic runtime of a car is 15%-30% greater given that you don't always have fwd+steering on all the time.
To keep the car going I butchered a controller and shorted the Fwd and Left terminals as shown below.
Keep in mind all the figures above are based on the stock 50mAh TOMY battery. Once I get it all in a neat little case I'll post some more pics. I might even start selling them if the interest is there, lol!
ph2t.
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CaboWabo
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ph2t, you're a mad man and one hell of a mad scientist!
you amaze me man - frickin excellent work dude.
you amaze me man - frickin excellent work dude.
Dear Life Cereal, Where do you get off? Part of a balanced breakfast and delicious? Who do you think you are? By now you may have guessed I'm speaking ironically and have nothing but good things to say about what you do. Life cereal do not change a thing.
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payaso
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Agreed... The stuff I understand is kick ass, and the stuff I don't understand is still kick ass, just cause... lolCaboWabo wrote:ph2t, you're a mad man and one hell of a mad scientist!
you amaze me man - frickin excellent work dude.
silla
payaso...... 
"Imagination is everything. It's the preview to lifes coming attractions" -Albert Einstein
"Imagination is everything. It's the preview to lifes coming attractions" -Albert Einstein