Custom charger for ZZ SE's

ph2t · Post by **ph2t** » Sat Nov 01, 2003 6:09 pm

So has anyone built one yet?

I don't wanna be buying 4*AAA batteries every two days, that shiat's expensive...

I took some measurements on the battery tabs under the car and had a look inside the chassis. I seems to be that the best time to charge is when the switch is in the OFF posistion. Some reasons....

When turned ON, the battery terminals reported a -VE value, really weired. When turned off the same terminals reported approx 1.8V, this is OK considering that the car was "flat". I'm aussming that the switch takes the battery out of circuit with the PCB. This is what you want to happen (like my DIP switch mod).

As you all prolly know by now that the SE's run @ 2.4V. This is achieved with two VERY small 1.2V/70mAh batteries setup together in series.

I'm gonna use an old bit-g charging plate that has the two side tabs removed and centre nipple thing sanded/cut down as well. The +VE and -VE terminals are oriented the OPPOSITE way to bit's, be carefull of this.

Given this info, a simple 4*AA battery charger like most BitChar-G dual cell bettery chargers should work...

Yet to try this. Will bust open the chassis and have a futher look around and see what I come up with.

Any tips/sugegstions/shared experiences will be appreciated.

ph2t.

bdebde · Post by **bdebde** » Sat Nov 01, 2003 11:01 pm

Hey ph2t here is one that I did.

http://tinyrc.com/forums/showthread.php ... adid=13862

Also, I think the terminals are reversed from bits + and -.

hogjowlz · Post by **hogjowlz** » Sun Nov 02, 2003 2:59 pm

bdebde wrote:
Also, I think the terminals are reversed from bits + and -.

you sir are correct

ph2t · Post by **ph2t** » Sun Nov 02, 2003 7:34 pm

hogjowlz wrote:
bdebde wrote:
Also, I think the terminals are reversed from bits + and -.
you sir are correct

thanks fellas, noted and updated

cheers,

ph2t.

ph2t · Post by **ph2t** » Sun Nov 23, 2003 7:51 am

I've had a chance to continue on playing with this idea and have found out some truths.

First of all we are all wrong when it comes to the charger terminals. They are not the same as bits but flipped, no sir re bob, no. The centre terminal is the ground (negative -VE) and the terminal closest to the face of the controller is the positive terminal (+VE). So you can't even use a butched bit-g charging pad for this mod which is pretty shitty.

Have a look closely in the diagram below, paying attention to the circled area:

Notice that the -VE (negative) bettery terminal (at the top of the pic) goes over some plastic in the same location as one of the outer terminals. You can see in the area circled that some metal comes out from underneath the -VE terminal. This is the "channel selection" plate that is used during charging for the controller to tell the car what frequency to run on.

Not satisfied with just pulling apart the car I said "what the hey" and pullled the controller apart as well. To my suprise I noticed that the charging terminal now has 4 wires connected to it!

Now I just had to find out what the hell everything is so I pulled the charging pad apart. Tricky bugger, make sure you keep an eye on everything.

Notice that the centre tab has a metal plate underneath it. These two contacts connect to each other when you place the car on the charger. I assume that this is just a simple switch arrangment that tells the controller to start charging.

So to recap:

White wire = "car has docked" switch, goes to ground when pressed.
Red wire = positive battery source
Black wire = Ground, GND.
Orange wire = frequency set signal, sets car freq during charge period.

The photo below is the controller circuit board. You can see via the circles each function and it's corresponding wire:

So, now that's all figured out. All I did was solder a pair of wires to the charger pad for the Red and Black terminals. I then chose to feed these wires out of the back of the controller case.

To goal of this is then you can put a regular 4*AA battery pack on it or a 6V regulated source, whatever you want to charge the car with. The AAA batteries in the car are just crap for any output current to healthily charge the batteries in the car.

In my mod below, I'm running a 6V DC Regulator LM7806 from a 1.5A 16V power supply. In line to the car is a 1Ohm 5W wirewound resistor. This helps limit the current and not destroying the battery. You can see from the pic below I'm charging it at a little over 1A.

Cool!

crazydave · Post by **crazydave** » Sun Nov 23, 2003 9:02 am

Good work figuring out all them wires, ph2t.

I have this plan I have yet to go through with.

I've been planning to install jacks in all my controllers, so I can just plug my power source into the controller, and have one power source for all my controllers. Probably a 800-1000mA wall wart w/ selectable voltage.

For bits, and original Zip Zaps, I'd just wire the plug straight to charger base. For the SE I'd wire it to the controller's power source, and add a switch to shut off the batteries in the controller when the power source is plugged in.

I just have too many controllers, and that would be too much of a pain now to install all those jacks, but one day I'll get to it.

fook yu · Post by **fook yu** » Sun Nov 23, 2003 7:44 pm

Seen this one crazydave?

http://tinyrc.com/forums/showthread.php ... adid=13862

*edit* oops, guess it was posted earlier in this thread

Cheesehead · Post by **Cheesehead** » Wed Jan 14, 2004 8:43 pm

I would get a set of 5 cheap NiMh cells (sub-c's @ 1500mah can be found in 6 cell packs for 10.00) and a good charger. That way, you would'nt be attached to a @$@!$#!@$!@ Wall-Wart.