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General control line discussion => Open Forum => Topic started by: Bill Little on April 28, 2015, 10:15:58 AM

Title: Li-ion 16850 3.7 volt, 5000-6000 mah single battery
Post by: Bill Little on April 28, 2015, 10:15:58 AM

Hi All,

Does anyone have experience with, or ideas about, using the 18650 Li-ion battery to power the ignition system on spark ignition engines?  Seems using only one battery will save some weight.  They are available in cylindrical or flat configuration, and are 3.7 volt.  And you can get them in up to 6000 mah rating.  Plus they are fairly inexpensive for the batteries and charger.  Wouldn't the 6000 mah rating allow the battery to hold its charge longer?

Any thoughts?  Thanks for the coming replies!

BIG Bear
RNMM/AMM

Title: Re: Li-ion 16850 3.7 volt, 5000-6000 mah single battery
Post by: Don Hutchinson AMA5402 on April 28, 2015, 11:12:52 AM

When running, the ignition system will pull about 750 mA, a 6 minute flight would use about 75 mAh, if starting wasn't real quick a flight could use 100 mAh. 6000 seems like way overkill to me. I still like the 2000 mAh Eneloop AA batteries. I have 3 in my Torp 32 powered Moitle, an Acme ignition module and an Aerospark Quality coil. All up weight is 35 ounces. Why do I like the Eneloop cells? They were charged prior to the 2014 VSC and they still today are well charged 1+ year later! A simple 200 mA charger does all I need for these.

Title: Re: Li-ion 16850 3.7 volt, 5000-6000 mah single battery
Post by: FLOYD CARTER on April 28, 2015, 12:36:33 PM

A single cell LiPo of 3.7 volts and 1200 mAh makes a great spark ignition flight battery (cell).  The simplest and definitely the lightest you can possibly use!

LiPo chemistry will deliver the high peak current required, meaning you no longer need an external "booster" battery used for that extra current while starting.

You DO need a special charger for LiPo. 

Floyd