Should I be getting extra oomph from dual cell?

[Kerosene]

I tried to dual cell my old Tomy today – added an extra battery (from a Panther? clone) and it seemed to run for a longer time – but not any faster. Should it go faster?
The car I put it in is a Compact Char-g (with original battery) with a 3.0 motor.

[ph2t]

How did you charge it? If you used the controller then yes, you won’t get an improvement.

You need to make a custom charger using 4*AA batteries. Preferably a 5W 1 Ohm WireWound resistor as well just to limit the current a bit and protect the AA’s and you car’s battery as well.

ph2t.

[betty.k]

what you’ve done is wire up your batts in ‘parallel’. this means the two + terminals are connected and the two – terminals are connected. as you found out this doubles play time but not speed as they are still giving 1.2V, just for longer. you want to wire the batt’s in ‘series’ which means end to end. this gives you insane speed and the same play time.
so,find the negative (black) wire, attach it to the – on one batt. then run a wire from the + to the – of the second batt. then attach the + of the second batt to the + wire (red) from the pcb:8ball:

[Kerosene]

Betty – I did it end to end. It must be the charging I’m doing wrong.

ph2t – is it possible to mod the controller to charge the batteries? The guide I followed (http://tinyrc.com/qfm/racing/mod_07.htm#25) had instruction for doing this – which I did – and it didn’t work.

If not, is there somewhere I can get a diagram or something to make a custom charger?

[betty.k]

it’s definately the charging. you need 6V and the controller only puts out 3V. you can tape some batteries together and attach them to the charging plate for a quick job or go to dick smith and buy a 4 x AA battery holder. they even have ones with an on off switch and case:8ball:

[Kerosene]

So I can just tape 4 AAs up and wire them directly onto the charge plate?
How long should I charge the car for?

I’d like to try this and see what sort of speed increase I get before I bother buying a battery holder and making a custom charger.

[micro_Amps]

Kero, 4 x AAs have the correct internal resistance to limit the charging current automatically. If you have the two cells in the car in series you can charge it with 4 x AAs (6v) connected straight to it. 90 seconds is a good charging time, 2 minutes maximum. At around 2 minutes you might notice the car’s cells starting to warm up a bit, if they get hot you have gone too far. A 4 x AA holder and a charging plate work very well as a dual cell charger.
:)uA

[Kerosene]

🙂 Thanks everyone. I’ll give it a go tomorrow.

[twizm]

i left my single cell bit on my custom 2AA charger for half hour and the cells were hot. been running over 20min now. this a bad thing?

[betty.k]

yes, definately way too much charging. i’ve seen pics of a bit that was left on a charger for 2 hours and the middle of the chassis melted!:8ball:

[HACHI-RYOKU]

Remember also, if you’re using nimh, then the batts hold in the heat where a nicad pushes the heat out. So, if your nicads get warm, it just means they’re done or close to done. If a nimh gets warm, then that means the inside is cooked and it was already done way before. Don’t wait for nimh to get warm. Just test with run times for best performance. Cooking the inside of a nimh will reduce it’s life-span as well as lower the volts and ma (current) it puts out. May also make batts (almost all batts can explode with enough heat) explode. The good thing is that they are pretty resiliant and you’ll have to do some serious cooking to see negative results. Most bad nicad & nimh will work normally if you fully charge and discharge it about 4 times in a row.

[leonli17]

mmm…I left one of mine dualcell on Custom Charger for like 8 hours and nothing broken. I must be lucky.

[twizm]

update on my over charged bit:
ran for an hour non stop and a half at full power, then stuttered to a stop. it runs perfectly fine now. it used to have 1min runtimes, now its better than when it was new. couldnt be too harmful for it if its increased runtime and power output

[Kerosene]

Well I tried it and it didn’t seem to make much speed difference. Maybe it was the junky second battery I used.

[HACHI-RYOKU]

If it was nicads, then it doesn’t surprise me.

I just remembered something. Don’t use batteries from different makers. They may not work well together. Try the same thing with same type batteries. I.E. tomy stock + tomy stock, or panther stock + panther stock, or even better 200mah nimh + 200mah nimh. Don’t mix nicads with nimh either.

Edited by – HACHI-RYOKU on 12 December 2003 23:46:49

[Kerosene]

I’ll go get some matching batteries and try again.
I suspect the battery from the clone I used is junk anyway.

Can I get these batteries from electronics stores (Dickheads/Tandy etc)? Or do I have to buy them from mini RC sites?

And in the end… is dual cell really worth doing?

[HACHI-RYOKU]

Yes! dual cells are definately worth trying! You’ll see when you get it going. It’s a little better with certain cars. For example, I know “Cyclona” cars make sucky duall cells, because the pcb is crap. Too many high resistance components. Original bits are very good. I’m sure you could ask around for other good cars to dual cell also.

Although, if you have a clone that doesn’t get a large increase in speed, then I would sugjest sending it to microamps for fet modding. Any car for that matter. Original bits included. The torque increas you get from his mod is unreal. I use dual cell cars with the fet mod (and 3:1 gears) and the performance is a little mind blowing. I need about a good 20 feet to race with someone. They’re so fast that small race courses don’t pull out the full potential.

The best place I’ve found for batteries is “Toyeast”. I live in Japan though, so the shipping is cheap for me. It might be a lot more for you. Look for 200mah nimh batts. There only a few (u.s.) dollars each. Although I will say that regular stock nicad batteries are still just as fast. nimh batts just last longer. Although you wont notice unless you have a way to charge them up all the way.

[Kerosene]

I’m using a Compact Char-G for all this – they’re the same pcb as BCGs I think?

Are LXX boosters worth dual celling? I’ve got a couple of spare cars floating around that need a good kick in the whatzit.

I’m ordering some more stuff from ToyEast pretty soon, so I’ll get some batteries and go nutzo.

Thanks for all the help and advice everyone.

[HACHI-RYOKU]

I would say yes, they are worth dual celling. If the car has good speed and torque, than it’s probably going to get a decent increase in performance. If it’s slow, like cyclona cars, then it probably wont make a good car to dual cell.

[mastercool bowker]

I did a triple cell mod 2 days ago and it went fine. I did a dual cell mod today and the wheels only move when i press forward while the car is charging. I take it off and it doesn’t work. I cheched the PVC to check for broken wires and i’ve wired up the charging port to the right place!
???????????????????i’m bafled?????????????????????

---

Eat right, exersize…die anyway!

[mastercool bowker]

I did a triple cell mod 2 days ago and it went fine. I did a dual cell mod today and the wheels only move when i press forward while the car is charging. I take it off and it doesn’t work. I cheched the PVB to check for broken wires and i’ve wired up the charging port to the right place!
???????????????????i’m bafled?????????????????????

---

Eat right, exersize…die anyway!

[betty.k]

i’m no techo, but it sounds like a dud battery. does it go in reverse when charging? or just forward. does the steering work? it could even be a blown transistor. do any of the pcb components get hot when charging or driving? just answer these questions and someone with more electro smarts will give you a better solution:8ball:

[merc-blue]

my experience tells me that u have stuffed up 1 of 3 things… firstly are they all got the same mAh rating . secondly ur method of charging could be whong u can shove a dual cell on a standard controller and expect it to charge . finaly wat betty said may have a screwed battery

[HACHI-RYOKU]

Or it may just be a certain battery position. Make sure that the wires aren’t only touching, but that there is something pushing it into the battery. Soemtimes it just takes a little pressure to get good contact on the batteries.

Also, merc probably meant to say “can’t, not “can”.

[Kerosene]

Is it possible to replace the single stock battery with a single 2.4v battery (if such thing exists)?

[HACHI-RYOKU]

Of course. I’ve seen people replace the batts with lithium-poli batts. I think they were about 3.7 volts. They are a pain to charge and maintain though. You could replace the batts with any power source (within reason). I took my ambulance and threw a 3 volt lithium camera battery in it. It worked, and was very fast. I took it out though, because the battery was very heavy and it would tip the car on almost every turn.

[Kerosene]

Ah ok. I thought there might be a battery the same size as the stock BCG battery, but with double the power. But I guess that would be too easy.

[betty.k]

they do exist, just look around. you’re looking for a 1/3 AAA 2.4V batt. i’ve seen 12V batts the same size, but i wouldn’t use that unless you like to see smoke:8ball:

[Kerosene]

If I ever find this magical battery – can I just charge it with 4 x AAs?

This sounds like a much better option (for me anyway) than soldering up an extra battery and trying to work out how to fit it in the car.

Edited by – Kerosene on 18 December 2003 19:09:16

[betty.k]

yes, 4 x AA should be fine. i might have a little hunt for some, cos i agree. much simpler upgrade:8ball:

[Kerosene]

I had a bit of a look, but could only find massive Nokia batteries. I guess I could tape one onto the top of my car 😀 :dead:

I’ve decided to take the plunge and get some of my other cars FET modded – cause I know it will take forever for me to get this dual cell working.

[HACHI-RYOKU]

Hey Kero, I say send some cars to get fet modded and practice dual celling too. When I first started messing with these cars I thought I was going to pull my hair out just trying simple dual-cell operations. Now I’m doing fet mods with shakey hands. Especially after a few cups of coffee. It’s kinda funny to watch. Anybody elses hands shake alot?
It seems more difficult than it actually is. You can look on the internet to learn alot about soldering, electronics and body work. It just takes a little patience and practice. A dremel is extremely usefull for chassis work, but alot of people swear them off too. They take a bit of practice to use efficiently.

As far as batteries go, that’s something that every modder with any rep has probably searched high and low for. I’m not saying to stop looking, but I would definately advise against waiting. My guess is that someone will eventually come out with something useable, because battery technology is ever growing, but it may not be in the immediate future.

P.S. I think MA offers dual cells too.

[Kerosene]

Yep. I’m sending at least one car to MicroAmps to get fet modded. And will keep my Tomy to experiment on myself. It’s already pretty trashed, so I won’t get too upset if I wreck it completely – which is probable.

Just waiting for my batteries to come in from ToyEast …. then the madness begins 👿

[HACHI-RYOKU]

MUH-HWA-MUH-HWA-MUH-HA-HA-HA-HA-HA-HA!!!!!!!

Oops, got a little carried away.

Good luck!

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