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Newbie LiPo Charger Question

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Old 07-27-2015, 06:27 PM
  #1
BJFlyer
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Default Newbie LiPo Charger Question

Hi everyone! I'm very new to RC flying. Got into it because I got my pilots license a few years back and have been too busy to get back into it.

I ordered an Apprentice S15 last week. I ordered a spare battery (OEM) and I'm trying to figure out a easier way to charge it rather than hooking up the jumper cables to my car. I ordered these two items from Amazon in an attempt to resolve my issue:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Problem is, the charger is only 1.8A output compared to the charger that came with the plane that is 3.0A.

Any suggestions for a charger that I can plug into my wall that will suffice? I've also read that you aren't suppose to leave a LIPO fully charged for over 48 hours. How are people monitoring the charge levels in each cell?

Thanks for the help! Very excited to get into this hobby!

Edit: Using the charger I bought of Amazon, I've been charging 1 of my batteries for about the last 45 minutes. I went over to the charger, and all 3 cell indicator lights were still green. I unplugged the battery and plugged it back in and they all turned red. Did I mess the battery up?

Last edited by BJFlyer; 07-27-2015 at 06:39 PM.
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Old 08-01-2015, 05:49 AM
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Quorneng
 
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BJ Flyer
The fact that the lights went red again was simply the charger had started charging again. As soon as the voltage rises back to the 'stop charging' level they will turn green.
That charger is a simple one. You have no way of knowing what is actually happening during the charging process.

My advice would be to buy one with a digital readout like this. Mains powered not only does this sort of thing charge (or discharge) virtually any sort and size of battery at a rate you can set but it gives you a continuous reading of the individual cell voltages whilst it is doing it.

There are cheaper 'clone' versions available if you want to risk it - I have had no problem with mine!
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Old 08-13-2015, 03:48 AM
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The problem can be that you don't know the batteries charge level with the LED only readout.
If you assume a 2200mah Lipo - - - and the battery was discharged to a safe 20% remaining level,
it would likely take a bit more than an hour to charge with 1.8A
~3.2v per cell, 80% of the charge used up.
4.2v per cell, fully charged 80% available for use, ~1700 mah
4.1v per cell no load, at least 90% should be available.
~3.8v per cell is a proper storage voltage.

Other tidbit. 3.2v per cell is considered the lowest "safe" voltage under full load.
As the Lipo cell discharges under load, the voltage has a fairly linear drop above 3.7V,
and drops more and more rapidly towards 3.2v. Under no load, the battery will recover
to about 3.7v per cell after a several minutes rest.
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Old 08-13-2015, 05:20 AM
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Hi,
You will need a better charger to properly take care of your lipo packs. Here is an affordable charger that is very straight-forward to use. You can monitor the individual cell voltages and it will automatically set the battery to storage levels if you are not planning to use the pack for awhile. As you stated it is not a good idea to leave a lipo fully charged but 2 days is not correct. You can leave it charged for a week but if you are not planning to use it beyond that you should set it to storage level as that prolongs the life of the battery and you can leave it at storage level for a very log time.
Here is the charger:
http://www.horizonhobby.com/product/...ger-p-kxsc1002
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