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989 Tutorial

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Old 05-12-2008, 07:38 PM
  #1
boatcapt
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Default 989 Tutorial

Is there anywhere on the web that has a tutorial on the basics of charging different types of batteries? Specifically nimh and lipos. I haven't messed with batts in 17 years and alot has changed. I bought a 989 for a rc18t that I bought. I was running a 3s lipo. I charged the battery maybe 7 times and now its swelling. I don't think this was the charger, just maybe voltage got to low during the winter. All I have now for the rc18t is the stock battery that comes with it. For example, how would I charge this batt? Will the 989 stop charging when it detects full charge? Or will it stop charging when it puts 1100 mah in the batt? Sorry for the ignorance just trying figure out how to charged batts. Instructions seem to be a little lacking. Thanks.
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Old 05-13-2008, 12:55 PM
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Tim@MRC
 
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Default RE: 989 Tutorial

The problem with the LiPo could definitely be from it sitting too long with no charge. Every rechargeable battery has a self discharge rate. Which means, a fully charged battery left sitting for an extended period of time without being charged, will self discharge. With NiCds and NiMH this is not as detrimental as it would be with a LiPo. With NiCds and NiMHs, if they discharge too low, you can shock them, and then cycle them a few times and usually get most of the capacity back. With LiPos, once they get discharged beyond a certain point, there's usually no way to revive them. If you try to charge them at this point, then they could definitely swell. I've heard differing opinions on how to store a LiPo, whether to store them half charged or fully charged. The more popular and probably the one makes the most sense, is to store them at about 50% in a zip lock in the fridge. Check them once a month for voltage, and if needed do a slight charge to keep the voltages up. When you're done storing, let them come back to room temperature in the zip lock, and then cycle a few times to restore the capacity.
First I would set the individual profiles for all of the batteries you have. I would set the charge rate for the LiPo at 1C, and the charge rate for the NiMh for no more than 1.5C and 5 mv per cell. The charger will not charge more than 120% of the entered capacity, but it should shut off on peak. Let me know if you have any other questions.

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