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I am sick of using lithium polymer batteries lately. After using a battery (for a well known manufacturer) for one month, it discharges faster than before. Also, while recharging it, I need to stay close to it for safety reasons (overheat, overcharge, explosions: as recommended on many blogs). And finally, each time the voltage on one of the cells drops below a certain threshold, I throw away the battery (NimH charging is damaging the batteries).

Do you have any suggestion other than LiPo batteries especially for drones? If no, what should I do to prevent all of these issues?

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    \$\begingroup\$ Get a proper LiPo charger ... "NimH charging is damaging the batteries" <- this is to be expected (and is dangerous). \$\endgroup\$ – brhans Mar 7 '16 at 21:11
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    \$\begingroup\$ Also, while recharging it, I need to stay close to it for safety reasons Then you're not treating the batteries the way you should be treating them. Like brhans says: get a proper LiPo charger \$\endgroup\$ – Bimpelrekkie Mar 7 '16 at 21:13
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    \$\begingroup\$ I second both brhans and FakeMoustache - get the right charger. Why in the world are expecting a NiMH charger to do the job? If you're sick of your batteries failing because you're abusing them - stop abusing them. \$\endgroup\$ – WhatRoughBeast Mar 7 '16 at 21:22
  • \$\begingroup\$ NimH and lipo chargers have different charge voltages and timing, you would be insane to use one with the other. Lipo's aren't dangerous unless 1) they have manufacturing defects 2) you aren't charging them right (using the proper charge cycle, with the correct voltage). I've been charging the lipos in my phone for years with no problems \$\endgroup\$ – Voltage Spike Mar 7 '16 at 21:35
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    \$\begingroup\$ "I'm sick of buying new cars because they keep getting damaged every time I drive them into a concrete wall." Then stop running your cars into a concrete wall! You need a LiPo charger. Otherwise you're just being stupid. \$\endgroup\$ – DerStrom8 Mar 7 '16 at 21:36
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You are abusing your batteries. Stop doing that, and they will last longer and stop blowing up.

If you need to stay close while charging, then your charger isn't doing its job right. You can't just get a random lithium battery, charge it with a random lithium battery charger, and expect all to be fine. You really can't expect "NiMH charging" to work properly for lithium batteries. That one should have been obvious. Each battery has its own specs. Most likely your charger is applying too much voltage or current.

Lithium cells can also be damaged by discharging too deeply or too quickly. You have to make sure whatever device you run them in contains smarts to shut off when the batteries get too low.

Get good batteries, get the right charger that is matched to those batteries, and make sure your device handles the batteries properly during discharge. Then lithium batteries should give you good service.

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  • \$\begingroup\$ I'd warn most inexperienced people away from LiPo's, used incorrectly or correctly. Too much worry about recovery from deep discharge, and you never know if the protection circuit is good. There's a reason why the hobby market sells fireproof bags for them. They also can offgas HF during failure. \$\endgroup\$ – Scott Seidman Mar 7 '16 at 22:58
  • \$\begingroup\$ @ScottSeidman: He's flying a drone. So most likely he's using raw lipos without protection circuits. It's common in the hobby since we need to maximise current output (depending on drone size that's anywhere from 10A to 40A - drones typically consume between 500W to 1kW) \$\endgroup\$ – slebetman Mar 8 '16 at 4:26
  • \$\begingroup\$ Check comment on main question :) \$\endgroup\$ – Nick Mar 9 '16 at 10:43
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NimH charging is damaging the batteries

STOP! Really stop flying you drone NOW until you get a proper lipo charger.

A lipo charger is not expensive. An cheap Chinese charger is anywhere from $5 to $30 (depending on how many cells you need to charge). Even the cheapest lipo charger would be significantly safer than charging with a NimH charger no matter how expensive that NimH charger is.

With a lipo charger you should be able to simply charge and leave it. Literally millions of people charge their lipo powered iPhones and Samsungs without waiting.

A lipo battery that's being used a lot should last two years. Unused lipos should last ten years or so.

Also, buy a low voltage alarm or learn to time your flights. DO NOT drain the batteries to lower than 3.2V if you want them to last two years. If you do their lifespan will be reduced significantly. My personal limit is 3.4V and I usually fly until 3.6V (which may be 3.2V or less when in flight).

Sometimes you will get a bad lipo. It could be manufacturing defects or badly stored or it could just be old stock. But it should not be more than 1% of the batteries you buy. I've personally have only ever gotten one bad battery.

Finally, if you're worried about fire hazard make sure you charge away from anything combustible. You can get fireproof bags at hobby stores. Or you can just get a metal toolbox to charge your battery in. Lipo fires burn hot and spark a lot but they don't last long. So your main concern should be to limit the spread of sparks if the battery combusts. I personally charge outdoors or in a corner of the room away from all furniture.

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  • \$\begingroup\$ Frankly, leaving lipo chargers unattended isn't a great idea. You don't have to sit over them watching, but you should be around \$\endgroup\$ – Scott Seidman Mar 8 '16 at 12:02
  • \$\begingroup\$ There's also an HF gas hazard. \$\endgroup\$ – Scott Seidman Mar 8 '16 at 12:18
  • \$\begingroup\$ Check comment on main question :) \$\endgroup\$ – Nick Mar 9 '16 at 10:43
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Any proper Lab supply can be used as a Li-Polymer charger. Only READ THE DATA SHEET and you will find that the batteries must be charged in so called Constant current / constant voltage mode. (CC/CV) Set the current to the maximum permissible charging value or less and the voltage to the maximum permissable voltage. During charging the current drops to less than 100 mA after the max voltage has been reached. Interupt charging after the max. time as indicated in the datasheet. No problems with overheating or exploding So there are three limits. One is the maximum voltage and the other the maximum current and finally the max. charging time at the end of CV mode. Warning: When using this method please know what you are doing and still comply with general safety rules when working with Li-ion batteries.

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  • \$\begingroup\$ Concerning the tech level and unwillingness of OP to comply to general rules of safety and good practice, your advice is essentially dangerous. \$\endgroup\$ – Ariser Sep 5 '16 at 9:23

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