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Old 12-19-2009, 01:36 PM   #1
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Default Possible electrical issue

I might be having another issue that is just shown via this symptom.

I made this post thinking there was a problem with my brakes but I don't think it is the issue.

Brakes engage and won't disengage

These are the symptoms. I ran it for a good 10-15min and then all of a sudden the brakes were being applied even when I let off the trigger. They weren't being applied hard enough to lock the wheels up but enough to bring the cart to a stop pretty quickly. I noticed that it wouldn't hardly give the buggy any throttle either. The servo wasn't moving hardly. I turned the wheels and would turn left but wouldn't turn right. I picked the front of the buggy up and it was able to turn right and left. I set it back down and it wouldn't turn right.

I figured it was the buggy battery but according to the telemetry the battery was roughly 6.5V. I pulled it out and checked it with my digital multi meter and it said it was 6.542.

I plugged it back up and started messing with it again and it seemed to start working again correctly. I sat in the living room turning the wheel and the throttle for about 5 min and it started doing it again. Well something similar anyways (wheels would turn in one direction but the throttle and brake seemed to be working fine).

The remote battery is showing 5.4V but I wouldn't suspect the remote could cause this type of issue. If the remote is on I would suspect it would work. Could the remote cause this issue?
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Old 12-19-2009, 02:08 PM   #2
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Are you using a switch between the battery and the receiver? If you are, try a new one, the contacts in the old one will be worn out.
The bad connection will cause a voltage drop and the reciever goes into failsafe.
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Old 12-19-2009, 04:26 PM   #3
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Quote:
Originally Posted by Chris-s View Post
Are you using a switch between the battery and the receiver? If you are, try a new one, the contacts in the old one will be worn out.
The bad connection will cause a voltage drop and the reciever goes into failsafe.
Its a LOSI 8IGHT 2.0 RTR.

It does have a switch to turn on the electronics. The telemetry is showing the battery voltage drops from 6.4 to 6.2 when I turn the wheel which isn't much. The telemetry doesn't go offline which indicates to me that the receiver isn't losing power.

I just tried to bypass the switch but without getting another switch I can't tell if anything is going wrong or not as the battery is keyed and it won't go into the receiver.
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Old 12-20-2009, 01:08 AM   #4
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Battery plugs are slighlty different between manufacturer but are mainly a universal fit, the key your on about is easily removed with a file or modeling knife just note orientation when you plug it in.

Swithces do go duff but normally they just dont work or make a contact.

To me sounds more battery orientated than anything else or to eliminate it, how charged is your reciever pack or has it false peaked during charging, a simple check that has always worked is when its fully charged it will be warm.
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Old 12-20-2009, 07:41 AM   #5
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do you have a failsafe installed or is there one built into the radio?
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Old 12-20-2009, 08:02 AM   #6
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I assume you are using the dx3s? Have you ever dropped this controller? I dropped mine a while back and it seemed ok then about 10 min into running the car the front wheels started turning when i gave throttle inputs. meaning when i gave it brake it turned to the right and throttle it turned to the left. I tried binding a different controller to the receiver and that fixed the issue. It turns out that the controller was messed up in someway from me dropping it. not sure if your controller is messed up but thought i would give you something to think about.
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Old 12-20-2009, 08:44 AM   #7
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Quote:
Originally Posted by helivaguy View Post
do you have a failsafe installed or is there one built into the radio?
Yes there is but I don't think it was even being used because when I turned off the remote nothing happened. I rebound after I found this out and made made it put on the brake and turn the wheels straight.

Quote:
Originally Posted by fievel View Post
I assume you are using the dx3s? Have you ever dropped this controller? I dropped mine a while back and it seemed ok then about 10 min into running the car the front wheels started turning when i gave throttle inputs. meaning when i gave it brake it turned to the right and throttle it turned to the left. I tried binding a different controller to the receiver and that fixed the issue. It turns out that the controller was messed up in someway from me dropping it. not sure if your controller is messed up but thought i would give you something to think about.
Yes I have the DX3S but I haven't dropped the thing yet.

Quote:
Originally Posted by Bren Ralls View Post
Battery plugs are slighlty different between manufacturer but are mainly a universal fit, the key your on about is easily removed with a file or modeling knife just note orientation when you plug it in.

Swithces do go duff but normally they just dont work or make a contact.

To me sounds more battery orientated than anything else or to eliminate it, how charged is your reciever pack or has it false peaked during charging, a simple check that has always worked is when its fully charged it will be warm.
What is the best way to fully drain this battery? My battery charger doesn't have a drain ability.
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Old 12-20-2009, 10:04 AM   #8
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to drain your battery either leave it switched on, or real old school wire up a tail light bulb of a full size car as load will give the battery a work out. ( this was the only way to cycle batteries back in the 80's man i feel old.)
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Old 12-20-2009, 11:45 AM   #9
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I would borrow another battery or buy a second pack as eventally you would need a charged pack for emergency use.

Here is what I have seen several time the little tabs that are spot welded between your batt cells to make contact will break at the spot welds but still make a small contact & give a full voltage reading but can not supply full current.

Next would be the 6.5V your getting off the batt. Nominal voltage for a reciever pack is 6.0V meaning,if you were to kill the batts to the point that they turn the wheels slowly & move throttle slowly then let them sit overnight they will read close to 6V. Properly peaked voltage is higher like 7.0-7.4 depending on the condition of the cells.
As Bren said when propperly peaked you batt should be just a bit warm & should read at least 7V or higher. If they peak below 7V then something is wrong with charger or more commonly batts.

Could be a lot of things like bum reciever or burned pot in servo but these 2 batt issues are most common & I would check them first.
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Old 12-20-2009, 01:48 PM   #10
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Quote:
Originally Posted by butch man View Post
I would borrow another battery or buy a second pack as eventally you would need a charged pack for emergency use.

Here is what I have seen several time the little tabs that are spot welded between your batt cells to make contact will break at the spot welds but still make a small contact & give a full voltage reading but can not supply full current.

Next would be the 6.5V your getting off the batt. Nominal voltage for a reciever pack is 6.0V meaning,if you were to kill the batts to the point that they turn the wheels slowly & move throttle slowly then let them sit overnight they will read close to 6V. Properly peaked voltage is higher like 7.0-7.4 depending on the condition of the cells.
As Bren said when propperly peaked you batt should be just a bit warm & should read at least 7V or higher. If they peak below 7V then something is wrong with charger or more commonly batts.

Could be a lot of things like bum reciever or burned pot in servo but these 2 batt issues are most common & I would check them first.

Thanks.

Today I have been running it pretty much off and on all day cycling from 190 degrees to 240ish doing short bursts to break in the motor still. I have done this about an hours worth of total drive time. The only time I stopped was to recharge the RX battery on the buggy. My telemetry was saying it was at roughly 3.8V when I tried to turn the wheel. I charged the battery and it got warm as expected. I waited around another 10 min or so for the battery pack to cool off. When I put the fresh battery in the car the telemetry was saying it was at 7.2V. After all of the below (roughly 3 tanks of fuel) it is at 6.7V at idle.

I put it back into the buggy and started running it around. I went through roughly 1.5 tanks of fuel and then the transmitter lost control of the buggy. I was turning around with the throttle off luckily and the wheel stayed turning right. I ran towards it (it was about 40 feet away) for about 2 seconds and I regained control but I could only turn right, it wouldn't turn left. Throttle and brake seemed to be working fine but I couldn't turn the buggy left hardly at all.

I didn't do anything other than working the wheel back and forth and all of a sudden everything went back to normal. I ran the buggy down the street again and when it was on its way back I noticed telemetry was intermittent. It kinda glitched out for about 10. On off on off...on....off on. After that it worked fine for about another tank and a half of fuel. The total amount of time that this happened was about 1 minute worth.

So I believe you guys are correct. Either 1 the battery is bad or I have a loose connection which is more likely.
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