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Please help!!!! my Li po pack won't charge

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Please help!!!! my Li po pack won't charge

Old 06-04-2007, 09:25 PM
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cbreeze
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Default Please help!!!! my Li po pack won't charge

Greetings,

I'm a experienced RC guy but Electric newbie who needs help.

Set my first airplane (Precision Aerobatics mini Katana) up, bought two 3 cell 2100 mah li po's and went flying. I made certain that my Phoenix 25 speed controller cut off was set at 9.0 volts. I flew my first flights with a Thunder Power li po and everything was fine. After a few flights, I started a take off and the motor died. Figured that the battery was pooped I switched to a True RC pack, made another flight and went home because of the weather.

Tonight I tried charging the Thunder Power and my Triton 2 read battery low voltage and would not charge. I then tried charging the True RC and it charged fine. I went over the instructions on the controller but discovered that there was apparently no way to confirm the settings that had been programmed. I re-entered the settings and am now sitting here with a battery that won't charge and trying to figure out what happened. Is my battery gone? is there anyway to bring the voltage up? Sure would appreciate some help here. Thanks in advance.

Chuck B.
Old 06-05-2007, 12:54 AM
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Default RE: Please help!!!! my Li po pack won't charge

I would start out by checking each cell's voltage and if they are all 2.5 or more then maybe you can carfully start a slow charge on a nickel setting or the 2S setting until the voltage rises slightly. Then remember to reset charger to normal setting.
Old 06-05-2007, 07:44 AM
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Default RE: Please help!!!! my Li po pack won't charge

guver,

Thanks for responding. Looks like this might be my only option. I sure wish I knew what happened. Right now I see two possibilities. Either my speed control is not working properly and since this was the batteries first flight, perhaps a defective TP battery pack. Is there a way of making sure your speed control low voltage cut off is working?

With all the warnings about li po's and with the batteries being so fragile, I am wondering if going e right now is worth it. I just can't believe that I might have wasted $69.00 (battery) so fast and easy.

Chuck
Old 06-05-2007, 08:48 AM
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Default RE: Please help!!!! my Li po pack won't charge

When you come down and land, between flights, did you remove the battery and turn everything off? I am not 100% sure if the Phoenix 25 does this or not, I am pretty sure it does, but I know for a fact that some other ESC's do. They use a percentage number of the total supplied voltage to estimate the low-voltage cutoff. So when a pack is connected, that is fully charged, the low-voltage cutoff will be programmed correctly. If you fly, land, turn all the gear off, then reconnect the battery without fully recharging it, that percentage for the low voltage cutoff will now be incorrect because you are connecting a battery that is no longer fully charged. So the low-voltage cuttoff theoretically drops lower than it should.

The pack is most likely not ruined. You need to find someone who has a charger that will recognize the pack eventhough it is below 3.0 volts per cell. Then you charge it at a very low rate, 0.2 amps or 200 ma, it should slowly recover and get over 3.0 volts per cell.
Old 06-05-2007, 01:35 PM
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Default RE: Please help!!!! my Li po pack won't charge

CBreeze,

If you are using the BEC in the ESC it does not cut off the batteries. That would not be a good thing because you would lose control when your batteries reached LVC. The LVC only cut power to the motor. This could cause your batteries to drop below the LVC (Low Voltage Cutoff) if you do not turn everything off.

I would suggest that you disconnect your batteries between flights.
Old 06-05-2007, 02:12 PM
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Default RE: Please help!!!! my Li po pack won't charge

Maybe I was not completely clear. I would recommend removing the pack after each flight, I would not recommend, landing, taking the pack out, not charging it to full, and just reconnecting it.

I Just read the manual on a Phoenix25, and the LVC is programmable for 9.0 volts with the usb link. However, stock setup I believe is on auto, and flying then landing and reconnecting the battery without re-charging it to full, may be causing the auto function to lower the LVC based on a set % the supplied voltage. If that supplied voltage number is lower than a full charge voltage, it may be functioning improperly.

You should order the usb link. The easy fix is to just fly the plane once and figure out how much time you can get without getting close to the 9.0 volts. Remember, that is under load, when the motor is running. You should be above 9.9 volts or so once you land and take the battery out, once the pack has had time to rest and bounce back in voltage.
Old 06-05-2007, 09:35 PM
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Default RE: Please help!!!! my Li po pack won't charge

Thanks everyone for the help.

I did order the USB link. Between flights, I just turned everything off and did not remove the battery.

On a more positive note, I took the battery to my LHS where I bought it and explained what happened. A youngster, with spiked white hair, who works there and talked like he knew something about this e stuff said "no problem, I can fix this." He took my battery and connected it to the Triton 2 in the shop. He set the voltage at 3.0 volts. The battery started charging and showed 8. something volts. He said if it doesn't shut off it will be fine. The higher voltage stayed on for a minute or so and brought the battery voltage up to 9.0 volts. The charger then started charging the battery normally at a 2.0 volt rate and approx 50 minutes later completed the charge. All the time I was leary and was standing there waiting for the battery pack to puff and explode but it did nothing. Did not even get warm. So for now, it seems alright. I am not going to fly again until I get my USB and I can make sure that my speed controller is set properly. I had also checked around on the web and there was at least one other thread where someone suggested attempting to charge the li po as a ni cad to see if the charge could be brought up. I was afraid to do that myself but maybe that might be another way to deal with situations like this.
Old 06-05-2007, 10:54 PM
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Default RE: Please help!!!! my Li po pack won't charge

Be careful when you use and charge that battery from now on. In my experience, batteries that have been brought back "from the dead" tend to lose capacity and/or the ability to properly hold a charge for extended periods of time.
Old 06-06-2007, 06:50 PM
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Default RE: Please help!!!! my Li po pack won't charge

I brought back a 3 cell TX Li-Po from the dead.......yup left the switch on..........used my Triton at .1 amps and charged fro two days nice and slow..........pack works fine to this day and it been about 4 months.
Old 06-06-2007, 09:19 PM
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Default RE: Please help!!!! my Li po pack won't charge

Jam Jam,

Encouraging news indeed. I called Thunder Power today and they told me that they sometimes do the same thing and one possible consequence would be a shortened life span. I also learned that you are supposed to charge the batteries before use. Something I did not do with this pack. I was also on the phone with Castle regarding my Phoenix 25 controller. They told me that the controller cuts off at whatever low voltage point is selected. For me it would be 9.0 v and that number is precise. I doubt that there is/was a problem with my speed controller.

Also breezed through a model magazine today and saw an advertisement for a new li po that will not swell or catch fire. I guess as time goes on things will get better with the battery technology.

Jam Jam, I have the Triton 2 and am wondering how you got the battery to charge at the lower charge rate. All I got on mine was the low battery voltage warning.

Thanks,

Chuck B.
Old 06-07-2007, 07:57 AM
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Default RE: Please help!!!! my Li po pack won't charge

Chuck when I originally started to charge it at a normal rate I got the low voltage error also......so I just kept stepping the charge rate down when I got to .1 it started the charge sequence........It took a long time but it's all good now. And yup maost Li-Po's are shipped out at around 11.5 to 11.7 when new........charge em' up and then use.......
Old 06-07-2007, 08:12 AM
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Default RE: Please help!!!! my Li po pack won't charge

Jam Jam,

I tried that and went down as low as I could go but could not get past the voltage warning. I was wondering if perhaps you used a Triton which might work a little different than the Triton 2 that I have.
Old 06-07-2007, 08:33 AM
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Default RE: Please help!!!! my Li po pack won't charge

Yeah Chuck as I stated earlier " Triton"..........I only use it with a few of my stuff other wise I use the Hyperion EOS1210i.
Old 06-07-2007, 12:00 PM
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Default RE: Please help!!!! my Li po pack won't charge

ORIGINAL: cbreeze

I did order the USB link. Between flights, I just turned everything off and did not remove the battery.
With the pack connected to the ESC still? That is most likely your problem. Just because everything is off, does not mean that the system will not drain the pack when it is connected, very slowly, but it will still drain it. Always remove the pack if the plane is going to sit for a while to prevent it from draining.

I don't think the Triton 2 will allow you to recover packs. At least you found someone to help you out. Personally, I would not charge as a NiCd.
Old 06-07-2007, 12:53 PM
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Default RE: Please help!!!! my Li po pack won't charge

Ni-cad charing on a Li-Po is not a good idea and we at MaxAmps Do Not recommend it.
Old 06-07-2007, 01:26 PM
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Default RE: Please help!!!! my Li po pack won't charge

Ya.......that's what I said

He had mentioned that someone told him to try and charge as a NiCd to bring the voltage back up to an acceptable rate.

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