Dual Batt. Mod

[stevensmd3]

Can someone tell me how to do a dual batt. mod to my zz and does anyone have a spare batt. to give me if you can help thanks

[go_zz_go]

no spare batt sorry check the faq for some good directions i belive it is found in the sticky on the top of the posts, also you will have to mod the charger to get it to charge properly


sorry for the lame response i just dont feel like typing it all and i would usally forget something important,, i know there is a good thread here i will try and find for ya

[Stridex]

This brings up a good question...

Does Radio Shack sell the batteries by themselves? I know they have everything electric, but I never thought to look.

[go_zz_go]

my local shaq dosent and i have heard others say theirs dont either at walmart you can get the kit racer and it has o nicd tomy batt put that in one zz and use the other stock bat for the dual mod eight bucks for a motor and batt not to bad plus they are fun to use cause they are smoking fast

[caver01]

I don't think I would really be excited about a ZZ WITHOUT a dual batt mod. The process is documented in other threads here. Do a search for Dual Batteries, or Dual, and you should turn up all sorts of suggestions, but I will outline mine for you.

First, you need the batteries. I bought a few from good old TinyRc, right here, by clicking the PARTS SHOP link above. Arrived quickly and without issue. These are 150mah NiMH batteries. They will work just fine!

The next thing you need to decide is what you really want out of a dual setup. Do you want speed? Most people want speed. For that, you need to configure your batteries in series. If you want run-time, you should configure them in parallel. Note that for me, speed was what I wanted, and I DRAMATICALLY increased run-time by using upgraded batteries anyway, so I got both.

Ok, so since this is my description, I am going for speed. I setup the batteries in series. First, I replaced the stock battery with a new one. That was easy enough. Next, I had to add a second battery in line with it. Obviously, there is not enough room for a second battery between the contacts. It only fits one battery, but there is plenty of room for another somewhere else, you are just going to have to wire it correctly. I first created two small leads out of wire and copper tabs that were about 3 inches long. I taped one lead to each end of the second battery. This "loose" battery can then be "inserted" behind the existing one using the wire leads.

The next step, inserting the spare battery, is a little tricky. Basically, you need to slip the wire from the spare's "+" into place so it touches the existing battery's "-" contact. Next, you need to put tape, or a piece of plastic over that. The idea now is that you are trying to insulate the orginal battery's "-" from the car's metal contact. Then, on top of that insulation, you insert the wire tab from your spare's "-" and make sure it DOES touch the car's metal contact.

The effect is that you are, with wires, adding two batteries, end to end. Now, take the spare and put it inside the chassis if you can find room, or above the circuit board under the car's body.

Now, charging--
By putting two batteries effectively end to end, you doubled the voltage. You are going to need to increase the volts to charge this setup, and since the replacement batteries are higher capacity, you will want to increase the charge time as well.

You can create a separate charger from spare parts as other threads suggest, or you can modify your controller to charge directly off the batteries (instead of through the timer-controlled circuit). To do that, you need to open the controller and connect the wires from the charge pads DIRECTLY to the battery wire contacts. This lets the batteries connect to the charge pad directly.

Now, since you are still charging the wrong voltage, you have to devise some way of getting 3 batteries ganged up in the controller. It's not going to hurt the controller, but you will increase the voltage to the charge pad, and thus, increase the charge to the car.

The downside to controller modification is that you have to watch the timing! You need to remove the car when you want to stop charging, since it is wired directly--the timer will not shut off the charge!

How to modify the controller batteries? I added a wooden slug, wired to a plastic holder for 2 AA batteries. The effect was that I had 3 batteries total powering the controller. This gave me 4.5 volts to my charge pad, and after charging a car for about 2 minutes, I got nearly 15-20 minutes of run time, and that was with my car batteries in series! Of course, the car absolutely screams too!

After performing this mod the first time, I later went back and used soldered copper tabs DIRECTLY onto the batteries. This is risky because heating the batteries too much can ruin them, but I was successful. Eventually, I broke my circuit board and had to rebuild a coil, but in the end, I now have my second battery inside the chassis under the PCB, and everything seems to work just great!

I highly recommend a dual mod for the Zip Zaps. The batteries are cheap. The car has plenty of room for 2 inside, the added runtime is incredible and the speed makes it all worthwhile. There is no comparison to running with that extra battery. It outperforms my Bit Char G car and has better range. My controller looks a little strange with the extra batteries outside, but I can work on making that cleaner over time. There might be room for an extra AAA battery inside, but I think I will eventually opt for a stand-alone charger at some point anyway. I'd like to set it up so that I can charge my bit with a standalone charger, as well as the ZZ and throw a switch to change volts if I want to. That would be ideal. Then I can put the controller back to original state.

Good luck. Take a look at other threads for pictures, or look at the questformadness.com website for the dual mod on a Bit Char G. That has nice pictures and lays it all out. It's for a Bit, but the idea is essentially the same. Just ignore the parts about hanging the battery off the back end since the ZZ is big enough to keep it inside.

[ejaf]

Thanks for the excellent summary, caver01...

I am looking into this mod myself, since my searches have proved that it's probably the easiest for improved speed (as compared to a PCB swap, and also less expensive).

I saw alot of posts from some of the EE gurus here though, about charging trobles (Axel and someone else). Those threads were related to the fact (I think) that since the batteries are in series, when you charge them up, the current is going through the first battery, and then into the second, so that the charge was really only getting to the first battery in the series.

With that said, does increasing the voltage (i.e. 3rd battery in series on the controller) for the charge actually stop this issue? Or are you really charging up the first battery to 100%, and then the charge is getting through to the second battery. Or is the increase in voltage without the increase in resistance actually pushing the current through to both batteries at the same time.

Apologize to anyone if I'm repeating other posts, but my exhaustive search about this never really answered that technical question.

As an aside, can I assume that if I do a dual battery mod, and also increase the voltage x2 in the controller, that the timing constant being used by the controller to time the charge would effectively increase by 2, thus giving same running times between 1 battery 3.0 V and 2 battery 6.0 V?

E

[stevensmd3]

thanks alot ! But in stead of doing the controller mod can't i just charge it like 6 times. wouldn't that make it a little simplerbut what i am asking is can't you or can you just charge it 6 times to create the same effect

[grimoire]

Charging

Tieing two threads together...if you modify your controller to use an AC/DC adapter as its power source (described in this forum's sticky), you could use an adapter with a switchable voltage. I just picked up one at the Shack that can be switched between various voltages, the two I'm most interested in being 3 and 4.5. Using the 3V setting would be the same as 2 batteries, 4.5 would be the same as 3 batteries. Of course, this means that if/when I put in the dual batt mod for the car (just running one now), I'll only be able to get a full charge if I'm close to an outlet ;-)

I'm planning to mod my controller this weekend (if I get some spare time).

[caver01]

Using the external power is a neat idea, but don't you still have to install bypass wires to the charge pads to charge DIRECTLY? I have not read the power supply thread yet, so I am not familiar with that mod. I wouldhope that it includes wiring power directly to the charge pad.

As for the previous post regarding "can't I just charge like 6 times" the answer is: Probably not. You will not be pushing the correct voltage. Charging too low of a voltage 6 times will not help. You need to increase charge volts to fully charge a higher voltage battery.

As for the multiple batteries and resistance, I too have read a lot about this. For a while, my re-worked dual setup was only drawing power from one battery. I cannot explain why, but eventually, after careful insulation from other PCB components, I have the dual battery mod working just fine and charging goes to both batteries. It doesn't seem to make a difference on my setup if I had taped wires to the batts, or if I soldered on copper tabs. In order for a charge to work, it obviously must connect to both the positive AND the negative terminals of the ganged batteries. So, one pole is on one end of battery 1 and the other pole is on the other end of battery 2. It seems to me that you cannot avoid sending electricity through both batteries. I found that I had to be extremely careful about insulation to keep the PCB from shorting on the wires or tabs, to keep the connections in the proper order etc. When everything is setup and properly isolated, I have not found that one battery charges more than the other.

Finally, with respect to the right voltages or timing, I'm no electrical engineer. It would help to have input from someone who really knows about this whether 4.5 volts or 6 volts are best for 2-150mah NiMHs and what the timing should be to extend the battery life. Can someone chime in here on that subject? Everyone should know the correct answer for this both on the ZZ forum and others.

[ejaf]

So, one pole is on one end of battery 1 and the other pole is on the other end of battery 2.

OK...it's in true series, both for receiving the charge and for powering the motor. At least that's how I'm interpreting that statement. I don't have to do any fancy wiring to get the - from the charger to the + on both batts, and vice-versa (oh boy that would be tough)

Finally, with respect to the right voltages or timing, I'm no electrical engineer. It would help to have input from someone who really knows about this whether 4.5 volts or 6 volts are best for 2-150mah NiMHs and what the timing should be to extend the battery life.

I definitely second that...the guys here a great at this kind of stuff. This would help out a great deal for my quest of "stealth mods" (i.e. if I can pack in 6V under the cover of the controller, noone will know...yuk yuk).

I know that the timing constant used is some function which works out to ~ 68%, but that obviously doesn't take into account dual batteries and higher voltage on the controller.

[ejaf]

caver01...

Found these threads....but still leave me with questions.

http://tinyrc.com/forums/showthread....referrerid=984
http://tinyrc.com/forums/showthread....referrerid=984
http://tinyrc.com/forums/showthread....referrerid=984

[stevensmd3]

so i do the same thing like the minus wire except don't Tape the Positive end right .If Not Please correct me because i just bought my soldering Iron And My Batts.Are In The mail. i am trying to do this mod by the end of the week . because i got a race that i know i will win with this mod but if i Don't i will most likely lose and i will lose my car (ZZ). So I really Need your help my batts should be in tomorrow. thanks for your help ahead of time......

[stevensmd3]

does anyone have a some pics

[caver01]

BDrift has some pics from his dual Bit Char G. THe idea is basically the same on the ZZs, only you have more room inside the chassis for the extra batt.

http://www.endlesswaltz.net/bdrift/2batt.htmc