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Lithium Ion charge or balance

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Old 10-14-2010, 03:29 PM
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fastplane
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Default Lithium Ion charge or balance

I am considering using Lithium Ion batteries for the receiver in my planes. Safety aspect of the Lithium Ion would be a big advantage over the Li-Po. I need something to charge that is safe to charge without removing them from my planes. I like the higher voltage and very low self discharge.
I am not sure what is best way to charge them.
I have a Hobbico Accu-Cycle charger. It does most of the different battery types including LI-Io and LI-Po. I currently use this for my Nickel metal hydride batteries. Also can charge two batteries at once.

For my planes I would want a 2 cell Li-Io. I think to protect the receiver and servos would also need a voltage regulator to step down to maximum 6v.
The question is about charging Li-Io. Do they get out of balance like my Li-Po and need a balance charger.
I currently use a Tenergy TB6 charger / balancer for my Li-Po and it does great job. It also can charge Li-Io.
But, what to use for the Li-Io.

Thanks.


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Old 11-02-2010, 07:22 AM
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ACKopter
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Default RE: Lithium Ion charge or balance

I use Fromeco Lithium Ion Rx batteries in my heli and I do use a voltage regulator to reduce/regulate voltage to my Rx. Here are some basic instructions on charging Fromeco packs,
1. All FROMECO receiver packs must be charged with a lithium charger set to “2 series” or “7.4 volts”, this includes the 4 cell 4400/4800/5200mAh packs.
2. After charging, FROMECO receiver packs must not exceed 8.4 volts
3. Charge FROMECO receiver packs at a rate not to exceed 1C. Use a lower rate (0.5 to 0.8) for longest life.
4. FROMECO packs should be charged at temperatures above 50F (10C)
5. Do not store lithium packs at temperatures above 140F (60), because cells may degrade.

There is no mention of actual balancing of the packs ( there is no balance tap anyway) there is however a disclaimer warning of the dangers of "out of balance" conditions so take it for what its worth. Also disclaimers on charging the packs in the model but that just falls under normal guidlines and I have always charged mine in the model. Yes there is some risk but what in life is actually risk free anyway.

Warning Safety Precautions
1. Never charge Lithium Ion cells/packs at any rate unattended.
2. Only charge Lithium Ion cells/packs with a charger designed specifically for Lithium Ion chemistry.
3. Lithium Ion cells can ignite because of unmatched cell capacity or voltage, cell damage, charger failure, incorrect charger settings and other factors.
4. Always use the correct charging voltage. Lithium Ion cells/packs may ignite if connected to a charger supplying more than 6 volts per cell.
5. Always assure the charger is working properly.
6. Always charge Lithium Ion cells/packs where no harm can result.
7. Never charge a cell/pack in a model. A hot pack may ignite wood, foam, or plastic.

I cant find the information right at this moment but I recall information directly from the Fromeco site stating it is fine to charge their packs using a standard lipoly charger provided you dont exceed the specified voltage and charge ratings. I have thus charged mine in this manner for over a year with no ill results even though it is in contradiction to #2 of the safety precautions.
Here is a link to the Fromeco site for more information,
http://www.fromeco.org/
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Old 11-02-2010, 08:52 AM
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fastplane
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Default RE: Lithium Ion charge or balance

AC, thanks for the response. Good info. I always charge my Li-Po batteries in a metal tool box. it seems odd that Fromeco would note about out of balance cells but provide no leads to balance them with. It is likely that I am not up to the advance of current battery technology.
It may be best for me to just continue using my NiMh and Li-Po batteries.


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