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Old Feb 05, 2013, 12:46 PM
jsf135pal1 is offline
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LiFe battery questions


Using a 12 volt source and a turnigy 6 cell charger with the right plug, can you charge a LiFe receiver battery while it's in the plane connected to the receiver?
Last edited by jsf135pal1; Feb 06, 2013 at 08:24 AM.
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Old Feb 05, 2013, 06:13 PM
wellington53 is offline
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why would you want to do that rather than take out the battery?
Old Feb 05, 2013, 06:27 PM
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Yes, no problem. Have been doing it for a long time.

BUT, When you say 12 volt source what do you mean.

You have to charge Life batts with a proper charger capable of Life charging. You can't just apply 12 volts to the batt to charge it.

Also, I'm assuming you have a standard switch to turn the RX on and off. This switch needs to be off when charging.

If you are not sure what you have ask more questions before you proceed.
Old Feb 05, 2013, 06:39 PM
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Originally Posted by tacx View Post
You have to charge Life batts with a proper charger capable of Life charging. You can't just apply 12 volts to the batt to charge it.
Isn't that essentially what zip charging of 3S LiFe is? Granted you have some resistance introduced to limit current. But it's basically just a wire of the right size and length.
Old Feb 05, 2013, 06:57 PM
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It has to be 3 cells to use a 12 volt source.

You cannot do it with 2 cells, which is a typical LiFe receiver pack.
Old Feb 06, 2013, 06:55 AM
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Originally Posted by wellington53 View Post
why would you want to do that rather than take out the battery?
The plane I'm building is a YAK and the battery needs to go behind the cowl and I don't want to take the cowl off every time to charge the battery.
Old Feb 06, 2013, 06:58 AM
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Originally Posted by Ken Myers View Post
It has to be 3 cells to use a 12 volt source.

You cannot do it with 2 cells, which is a typical LiFe receiver pack.
My source creates about 11.7V and I'm using a Turnigy 6 cell charger. The receiver battery is 2S 6.6V 1100mAh and I have the J plug going to the charge jack on the plane. So this is a hazard?
Old Feb 06, 2013, 07:03 AM
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Originally Posted by jsf135pal1 View Post
Using a 12 volt source and the right plug, can you charge a LiFe receiver battery while it's in the plane connected to the receiver?
My apologies. I should have included I am using a turnigy 6 cell charger as well.
Old Feb 06, 2013, 07:17 AM
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You didn't mention that you were using a charger capable of charging a 2S LiFe battery. It should be no problem to charge it onboard.

I use "A123" 2300mAh LiFe batteries in 2-cell through 6-cell configurations as the power batteries in all my planes. All are always charged in the plane as there is a dedicated pack in each plane. No problem.
Old Feb 06, 2013, 07:48 AM
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Agree with Ken's approach. On-board charging of LiFe packs is no problem.

This is different from Lithium Polymer ("LiPo") - LiPo batteries should be taken out of the plane and charged in a fire-proof bag or box, or other safe environment.

For both LiFe and LiPo batteries though, I recommend watching over the charging process just in case something goes wrong. With LiFe charging you do not have to be as vigilant though. Every few minutes make sure the numbers on the charger seem reasonable and that nothing is getting hot.

Good luck with the build,

Paul
Old Feb 06, 2013, 08:18 AM
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Thanks everybody for your help.
Old Feb 06, 2013, 10:51 AM
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I have your exact equipment in 6 planes and have been charging the batts in the planes for a long time. No problems.

You will also need to access the balance connector from the battery. Being that you have the battery in the cowl you can take a balance lead extension from your battery and mount the connector somewhere on the plane so you can plug in both the charge lead and the balance lead without taking things apart.

I take a spare switch mounting plate and epoxy the balance connector in it, then mount the plate to the plane fuse. Here is an example of what I did to my Sig Hog Bipe. I never take this plane apart. You can see the black switch and right below it is the balance connector with a white rubber rod protector over it. Works great!
Old Feb 06, 2013, 12:34 PM
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Originally Posted by tacx View Post
I have your exact equipment in 6 planes and have been charging the batts in the planes for a long time. No problems.

You will also need to access the balance connector from the battery. Being that you have the battery in the cowl you can take a balance lead extension from your battery and mount the connector somewhere on the plane so you can plug in both the charge lead and the balance lead without taking things apart.

I take a spare switch mounting plate and epoxy the balance connector in it, then mount the plate to the plane fuse. Here is an example of what I did to my Sig Hog Bipe. I never take this plane apart. You can see the black switch and right below it is the balance connector with a white rubber rod protector over it. Works great!
Thanks. Good idea. Nice looking bipe!! What size motor?
Old Feb 06, 2013, 10:27 PM
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OS 91 4 stroke


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