i need help with RC CAR

petriodet

petriodet

petriodet

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Joined
25 May 2009
Posts
1,102
hi i think i need some help i got my r/c cars out the other day and discharge then charged the batteries i used the car this morning and found to have a completely dead battery one set on fire lucky i near the car when it happened and blew it out and removed the battery i put the last one in and it seem to be ok.the batteries are 1800mah 7.2v.
on the side of the box :
brushless motor
kv:3300KV
ESC:15A required
voltage:6-12v
current:0.6A(no load)
14A (MAX)
Brushless ESC
output: 75A

question i have:]
can i use a battery with more volts?
surely that ESC is too large?
why did my battery burn?
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That looks like either a faulty or damaged pack. Was it very hot when you unplugged it from the charger? What kind of charger did you charge it with? Does it cut off automatically when the pack is fully charged?
 
Dutch Guy said:
Is that needed for a basic Ni-CD battery?
Click to expand...

I thought if they were multi-cell batteries thay had to? Im not 100%, I know they are needed for my RC Planes Li-po batteries which are multi-cell.

My balance charger does various types of batteries including Ni-CD
 
I can't say why the battery did that but for you other questions, No don't use a higher Volt Battery but Do get a higher mAh battery pack, 1800mAh is **** poor, especially for a Brushless Setup, you want atleast a good 4000mAh. Size of the ESC makes no difference, it's fine.
 
Ni-Cads don't need a balance charger, the first chargers i had were just a case full of resistors and a timer on the front to kill the power after a pre-set time.
 
You wouldn't be able to fit a higher volt battery in, there wouldn't be anywhere for the extra cell.
The ESC has a very high out put but the motor will only draw it's 14A anyway, no matter what the ESC can supply.

Actually, saying that I don't know if brushless motors have a limit to what amps they can draw. On the old type if you had the wrong gearing on the motor could draw too many amps and fry the ESC.
 
The ESC/Motor is probably pulling more amps then the batteries can supply.

Change to some decent 5000mah Ni-Mh packs and you'll not only go faster due to the added amperage but have longer run times too.

If the ESC has built in low voltage circuitry then you can go with LiPo batteries which will really get it moving as they can supply a huge amount of amps.
 
If you go for Ni-Mh you may need a new charger. if you go for LiPo you will definately need a new charger and they are not cheap.
Also if you liked the Ni-Cd fire you'd love a LiPo fire!

Also looking at your pictures, you don't have the gap between the pinion and the main gear set correctly, you can see the wear on the teeth. That might be causing your problems.

Get a meter on the motor to see what it is drawing when running.
 
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ok thanks guys i don't know what balancing the charger is i use the one that came with the car it does not have a cut on the charger it has an output of 250ma my calculations say i shouldn't charge it more the 7 and a half hours which i stick to.the battery pack don't get hot when charging,the burnt battery and the working battery are ni-cd and the dead battery is ni-mh
i've just bought some 4500mah ni-mh.
i want a new charger aswell can someone spec me one.
 
SimonCHere said:
If you go for Ni-Mh you may need a new charger. if you go for LiPo you will definately need a new charger and they are not cheap.
Also if you liked the Ni-Cd fire you'd love a LiPo fire!

Also looking at your pictures, you don't have the gap between the pinion and the main gear set correctly, you can see the wear on the teeth. That might be causing your problems.

Get a meter on the motor to see what it is drawing when running.
Click to expand...

the car was pre built i don't have a clue what the pinion is but i'm guessing that it is the cog coming off the motor?
how do i adjust it?
 
I use the Imax B6 Balance charger for my Nitro RC Plane

Very good and only around the £26 mark

http://cgi.ebay.co.uk/IMAX-B6-Charg...sGames_RadioControlled_JN&hash=item19c0283704







The IMAX 6B is a very advanced charger, able to charge, balance and discharge Lion, LiPo, LiFe (A123), NiCd and NiMH batteries.

Features;
Microprocessor controlled
Delta-peak sensitivity
Individual cell balancing
Li-ion, LiPo and LiFe capable
Ni-Cd and NiMH capable
Large range of charge currents
Store function, allows safe storage current
Time limit function
Input voltage monitoring. (Protects car batteries at the field)
Data storage (Store up to 5 packs in memory)
Battery break in and cycling.

Spec.
Input Voltage: 11~18v
Circuit power: Max Charge: 50W / Max Discharge: 5W
Charge Current Range: .1~5.0A
Discharge current range: .1~1.0A
Ni-MH/NiCd cells: 1~15
Li-ion/Poly cells: 1~6
Pb battery voltage: 2~20v
Weight: 277g
Dimensions: 133x87x33mm
This charger has a JST-XH charge plug, which makes it compatible with Zippy, HXT, Loong Max and any pack with a JST adapter.
Note: Power supply not included.
ATTENTION: This is a GENUINE iMax B6.
 
In your 3rd picture, the pinion is the brass gear.
There should be a couple of screws holding the motor on in oval slots. you can move the motor to make the teeth mesh properly.
 
DJMK4 said:
I use the Imax B6 Balance charger for my Nitro RC Plane

Very good and only around the £26 mark

http://cgi.ebay.co.uk/IMAX-B6-Charg...sGames_RadioControlled_JN&hash=item19c0283704







The IMAX 6B is a very advanced charger, able to charge, balance and discharge Lion, LiPo, LiFe (A123), NiCd and NiMH batteries.

Features;
Microprocessor controlled
Delta-peak sensitivity
Individual cell balancing
Li-ion, LiPo and LiFe capable
Ni-Cd and NiMH capable
Large range of charge currents
Store function, allows safe storage current
Time limit function
Input voltage monitoring. (Protects car batteries at the field)
Data storage (Store up to 5 packs in memory)
Battery break in and cycling.

Spec.
Input Voltage: 11~18v
Circuit power: Max Charge: 50W / Max Discharge: 5W
Charge Current Range: .1~5.0A
Discharge current range: .1~1.0A
Ni-MH/NiCd cells: 1~15
Li-ion/Poly cells: 1~6
Pb battery voltage: 2~20v
Weight: 277g
Dimensions: 133x87x33mm
This charger has a JST-XH charge plug, which makes it compatible with Zippy, HXT, Loong Max and any pack with a JST adapter.
Note: Power supply not included.
ATTENTION: This is a GENUINE iMax B6.
Click to expand...

will that work with my batteries they have a tamiya connection.
 
You will need to solder some Tamiya connectors on to the ends of the charge connectors for that charger, or solder some compatible connectors onto the end of the lead cut from your dead batteries. Your choice.
Oh you will also need a 12v supply for that changer. You can't just plug it into the wall, although you can attach it to your full size cars' battery.

you can get a piece of paper and slip it between the gears, push the gears together and tighten the screws. then take the paper out. 1mm is probably too big.
 
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