GoldenMotor.com Forum
General Category => General Discussions => Topic started by: hardmouse on July 25, 2012, 08:00:33 AM
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I just got BAC-0282P controller and trying to connect to motor, however, as soon as I connect to battery I figured something wrong. The red wire(+) and black wire(-) for battery is actually shorted. Is that normal? or what did I do wrong?
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Are you sure it is shorted, or could it just be the normal big spark that is very noticeable when you first connect the power?
This alarming spark is caused by the initial current surge as the battery instantly charges the capacitors in the controller up to battery voltage in a split second.
If, after the initial big spark, you can keep the wire connected without any heat building up in the wire, it is probably OK.
However, a direct short across a battery lead connection can instantly melt the copper terminals:
(https://i.imgur.com/Awuxv35.jpg)
(http://www.arhservices.co.uk/GoldenMotor/BurntConnector.JPG)
..and I discovered that it doesn't do your fingers any good either:
(http://www.arhservices.co.uk/GoldenMotor/Burntfingers.JPG)
If you have a 40 Amp fuse fitted to your battery, it should blow instantly if the battery power lead was accidentally short circuited.
Alan
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Yes I tried and tested. 100% sure they are shorted. I connect 6V battery and LED through the + & - pole from controller and I can light up LED.
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Testing with an LED will not indicate a short circuit, as the controller will allow enough current to pass through to light up a typical LED.
To prove this, I tried your test on one of my controllers using a 6V battery and a very bright 3.6V LED and what I thought was a 150 ohm resistor. I must have put the resistor back into the wrong bag last time I used it, as it was only a 15 ohm resister and the poor little LED was drawing 120mA through the controller instead of ~20mA. :o
Try using a mains voltage electric kettle or iron (switched on) in series with your bike battery and see if your battery gauge LEDs light up. If your controller is shorted, the LEDS would not light and the kettle element (or iron) should start to warm up.
If you have access to a voltmeter, try measuring the voltage at the battery connections on the controller with the appliance still connected in series. A very low voltage reading could be indicative of a short, a high voltage reading at the controller (and a very small voltage reading across the appliance) is what I would expect if the controller was not shorted.
Alan
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This is what was happening.
I connected 5 wires connector(the biggest white one) and 3 thick wires(Green,Blue,Yellow) to my motor, then I connect black and red wire to my LIPO battery(6Sx2). Last thing I saw is a vary large spark (or fire) coming out from connector and it almost burn my hand.
(http://hardmouse.com/robots/ask4help/burned.jpg)
Can you tell me which part goes wrong? Thanks for help.
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If the polarity of the battery wiring is definitely not reversed, then the controller must be dead.
Alan
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I use the same battery same wire on other machine it works fine. So, what do you suggest? Return the controller and how?
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Contact the dealer you purchased it from and explain that the controller is faulty and ask what needs to be done to obtain a working replacement controller, and then fit a suitable fuse into your battery wiring!
Alan
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I bought directly online. Try to connect them by email but never replied. Do you know any proper email I can contact with?
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Try sending an email to David (wyh@goldenmotor.com) and briefly explain the problem to him.
Alan
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Thank you Alan.
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Finally, David promise me to send me a new one and he did and he will test it personally before ship to me. Thanks! David!
However, when I got it today I can't wait to go home to try it out. Since the last bad experience it almost burned my battery I decide to try again if the battery connection are shorted. Unfortunately, it did. Yes, the battery wire comes out from controller is shorted. See image below:
(http://hardmouse.com/robots/ask4help/shorted.jpg)
I connect 10mm LED with 6V battery through the black- and red+ wire from controller. The LED lights up!!! Does it mean the wires were shorted? Or it's me who stupid enough to test it that way??
Hopefully someone could help me out of this. Thanks a lot!
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If the LED requires 10 milliamps to light, I don't think the controller is shorted, it is probably just the 5v system drawing power..... Now if the LED requires 3 AMPS to light, yeah, you have a short.
If you were "David", would you say you tested the controller and found it satisfactory if you hadn't actually done so? I don't have a clue who "David" is, but most of the folks I know wouldn't put their name to it without actually testing it.
So what to do? You surely don't want to damage your battery, and your experience so far has not been exactly wonderful.
First off, make sure you have the correct polarity at the battery. Is the positive marked terminal really the positive voltage source? If that is correct, then what?
Maybe follow Alan's suggestion?
So then, do you have a toaster or a waffle iron, or a clothes iron or something with a high power heating element controlled by a bimetallic switch? And a voltmeter? If you do, you can jumper wire the heating element in series with the controller, and measure the voltage drop across the heating element when you apply power. If the controller is shorted, you will see battery voltage across the heating element, and if the controller is ok, the voltage across the element should be very low. The high power resistor of the heating element will keep the current to a few amps, even if the controller is a dead short.
Please feel free to ignore every thing I have said, my wife does it all the time. But please pay attention to polarity.
TTFN,
Dennis
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Dennis is absolutely correct, that 10mm LED requires less current than the controller draws on standby, therefore the current flowing through the LED will be sufficient to allow it to light up.
Testing with an LED will not indicate a short circuit, as the controller will allow enough current to pass through to light up a typical LED.
Although that LED has a typical current draw of ~20mA (0.02A), a current of just 1mA is sufficient to visibly light up the LED, but if you try the same test using a 5W bulb instead of the LED, then the bulb should not light. ;)
As Dennis also mentioned, make 100% sure the battery polarity is correct, otherwise you would experience a virtual short circuit, as the current will easily flow through the controller's MOSFETs in the reverse direction, giving the impression of a short circuit on the power connections.
As your LiPo pack has no BMS to control the maximum current flow, I strongly recommend that you fit a suitable fuse or circuit breaker into your battery supply circuit, so you won't have to worry about your LiPo pack suddenly turning into an incendiary device should a short circuit or reverse polarity occur!
Alan
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I strongly agree with Alan about the fuse. One thing to consider when selecting a fuse is that the rated current is what it will carry indefinitely, and that a fuse will carry a short term over current far about its rating. A 30 amp fuse will easily carry 45 amps for a short time, or 35 amps for a long time, but if you short your battery, the fuse will blow in milliseconds.
I had a lead-acid battery explode in one of my Mini Coopers, and it sounded like a 40mm cannon going off in the boot. I do not recommend the experience.
TTFN,
Dennis
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Thanks Alan & Dennis,
Yes, my electronic experience is poor :P Gladly learned a lot from you guys online. I did a quickly test to try to connect 12V battery with 24V motor through the controller and it runs. I am not sure if that means anything.
I will get a 30A fuse or higher tomorrow and see if it will die after I connect it:o
Beside, I am pretty sure the polarity is correct from my battery and controller. Unless they label it wrong ::)
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Please explain exactly what you meant by "connect 12v battery ....and it runs". You have me concerned, but I'm old an misunderstand things sometimes.
TTFN,
Dennis
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Sorry for my bad English, here is the brief drawing:
(http://hardmouse.com/robots/ask4help/shoryDia.jpg)
Try left side setting to see if current flow over controller. The result is; that motor spins like half speed since the battery only 12V. (The motor is 24V 280W for e-scooter)
I got 30A fuse today which is not cheap from local store. So, before I burn that fuse. I wanna see if using larger Amp than previous attempt by using LED.
Now I am a bit worried because even I got a fuse to protect battery. That's BIG spark wasn't fun at all in my first experience.
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That is what I was afraid I thought you meant. Your English is fine, by the way.
I am really concerned that the motor is turning. That seems to me to be an indication that the controller is allowing a pretty good current flow, at least more than I would expect to be drawn by the logic circuits. (And I have never seen a BAC-0282P and am totally ignorant of its specifics.) Does it make any torque? If it is in really good condition, a motor may turn under no load with very low current, but can't make any torque.
I would not hook up the controller and 44V battery at this point. As Alan pointed out, reverse polarity to the controller makes the FET diodes conduct, and by using your 24VDC motor as a load you are limiting the current to a reasonable value, and probably doing no harm. But if you hook up that 44V battery, and it is the wrong polarity, there probably will be damage to the controller and battery as well.
You really need a voltmeter to be sure about the polarity. I'm afraid for you.
Can you show us how the 6Vbattery and LED were connected? One side of the LED base normally is flattened to indicate how to hook it up. Please note that in a drawing, if you can. How bright was it?
TTFN,
Dennis
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Hi Dennis,
6V battery and LED connected the same way as I connect the motor. just replace the motor as LED and replace 12V battery to 6V. The LED is not bright but visually clear.
There's something interesting. I try to connect 7.2V, 12V NiMh battery to the controller. I don't see any spark and anywhere become hot. I don't know if that means any thing. By the way I got voltmeter. What should I do with it to determine and help this situation?
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Regarding the LED, my question was about the polarity of the LED. Where was the lead adjacent to the flat on the diode base connected? Now that you have a voltmeter, it is of no concern.
You need to confirm the polarity of the battery before you hook it to the controller. You can do that by connecting the positive (Usually colored red) VM lead (turn the voltmeter on and select DC voltage before connecting anything) to the marked positive battery terminal, and the negative (usually colored black) VM lead to the marked negative terminal of the battery. The displayed voltage should be positive, if the battery is correctly marked. If it is, you should be OK to connect to the controller. My concern was that the battery was mismarked, or rather, incorrectly wired when it was assembled, and the marked positive terminal is actually the negative voltage source. I hope I'm wrong about the polarity, but I have read too many bad stories on this site about such errors from the manufacturers.
TTFN,
Dennis