Rechargeable Li-ion adjustable voltage mod

actofgod · #1 12-02-2002, 10:52 AM

This is just in the "idea" stage right now

http://www.mbi.panasonic.co.jp/oemba...t/ioc0108e.htm

This link shows a button-cell-size rechargeable Lithium-ion battery, 130mAh, 3.7v. This one is 30mm in diameter and 3.2mm thick, which seems a little too big to fit in a bit. It might be mounted on top of the pcb. There is another batt (click "lineup/specification") farther down that is 24.5mm and 120mAh. In a pinch, you could get several smaller ones (with less capacity) and wire them for more run time.

1) Has anyone found any other rechargeable Li-ion batteries that would fit inside a bit?

2) These would have the same voltage as a 3-cell mod. I was thinking it'd be nice to have some resistors or something to cut down on the voltage. It'd be even better if it was adjustable, like a potentiometer wheel type setup. It would be really handy to have a dial on the back/top of your bit that could basically adjust the top speed of the bit by changing the voltage allowed from the battery to the motor. This would work with those dual-cell mods too, but it'd be even more useful with this 3.6v mod. That way you could "dial down" the speed for tracks with lots of turns, and turn it back up for oval-type tracks.

Comments or suggestions?

akura · #2 12-02-2002, 08:07 PM

Ive been playing with some coin sized batteries, just a few non-rechargable 3.0v Li batteries and found that the best place they will fit is directly under the shell, on top of the PCB cover. This is with a R34 Skyline shell, so anything with a bit more clearence/width would fit it easily.

I really like your idea of the pontimeter, a variable resistance would be great for making your car truely race worthy if you are able to adjust the running power of the Bit according to the needs of the circuit. This will definately have to be investigated further... mainly it will the size of components that will always be the problem!

Keep us updated on this!...

Ovgron · #3 12-02-2002, 09:38 PM

I found this ==>http://sales.goldmine-elec.com/prodinfo.asp?prodid=4520

I have very little info on them

, but am going to try to wire some in parallel and see what happens. At 5 for $1, the price is right...so I got a few dollar's worth (along with parts for my adjustable 2 stage booster idea). They claim 3v DC, but im not sure the capacity. They say "We charged one up and it powered a flashing LED for about an hour before needing to be recharged" and "Has rating of .6 Farad". I'm not sure, but I think most FLEDs draw like 20 mA, so, each one might be like 3v, 20 mAh. I'm not sure how the Farad rating will work, I'm new to electronics. Even if i can only match stock capaciy, the voltage is still doubled.

Ovgron · #4 12-02-2002, 10:26 PM

Sorry for 2x post, but....

Found this ==> http://www.allelectronics.com/cgi-bi...-12&type=store

This==> http://www.allelectronics.com/cgi-bi...-10&type=store

and this==> http://www.allelectronics.com/cgi-bi...-11&type=store

Not too expensive if you dont mind breaking up packs to make your own

.

actofgod · #5 12-03-2002, 12:58 AM

Nice findings Ovgron. I wonder how you charge a rechargeable Polyacene battery though..? If it works well (and doesn't explode or anything) please post your results!

I need some help from the electronics people.. there are tons of potentiometers and trimmers out there and I'm not sure what I need. They have ratings like "10k Ohm" and range from 1k to 5M. I guess I need something with a pretty small rating. You'd want a possible range from the batteries between 1 volt and 3.6 volts but anywhere close would work fine. It just needs to have enough max resistance to slow the engine down, and small enough resistance at the min value to let it run at the batteries' full voltage.

I'm learning this as I go, so any help is useful. I may experiment with a leftover trimmer dial from a GBA Afterburner kit. The voltages may be comparable since the GBA runs on 2.4-3.0v. It appears to have "B2K" written on it, but it could be "82K". The dial itself is about the same diameter as the inner rim of a front bit wheel and is quite thin. It'd be an easy fit if the voltage works out right.

akura · #6 12-03-2002, 04:34 AM

Although my understanding of electronics is somewhat fuzzy, i think an 82k (minimum?) variable resistor will be a tad large for a power source putting out 3.7v and 130ma. Considering you want a great deal of the voltage coming from the battery to make it to the motor, the resistance range will have to be fairly low... somewhere in the realms of a few ohm to about 30ohm I believe.

However, perhaps someone with a sounder understanding of electronics could correct me.