** LIPO BASICS ** Read me first!

[REVOJohn]

yah the PO = polymer was supposed to be a solid polymer electrolyte which was all the rage in the early 90's but never successful except for the japanese. increased safety due to dry solid battery.
lithium ion and current li-polymer cells have the same energy density. rc cells are less energy dense due to the higher c rate. higher the c rate, the heavier the cell for the same capacity.
the current pouch format is merely an aluminium pouch/bag which yes its insulated but thats it.

[nuttzzy]

I wish I would saw this a few hrs ago before I made a battery specific post


Beep, Beep, Honk, Honk, Over and Out Rotorhead

[josecr]

Hi there

I bought 4 brand new nano tech batteries. I am about to start the break in process. How long should I wait in between each charge and discharge procedure? Can I do it back to back or is it more advisable to leave them resting for a few minutes or hours before the next round?

Thanks!
Jo

[Slyster]

I just do 5 cycles back to back... and I use one pack to power the charger for the other so I can do them in pairs.

[Kendo]

Originally Posted by REVOJohn

fyi guys

i can confirm hundred percent that there is no such need to run in lipo batteries.
merely buy, charge and play. the mere formation process of lipo batteries will bring the battery to a state of ready to run. not the case for lifepo4 though.. they get better on running in. if anything you are merely shortening the life cycle than anything else. anyone who tells you that you need to run-in lipo packs either had bad quality packs that have not been through a proper formation process or does not know what they are on about. happy flying guys

oh point 2. there is no such think is rc hobby are lithium polymer battery. there is no polymer. its standard lithium ion. the polymer is another misconception in the industry

Cool. What about the common advice not to parallel charge lipos until after a few cycles?

Although not completely intentional, I tried parallel charge some brand new small 1s lipos and the charger took them up way beyond 4.2v. Now, this was on a charger that shouldn't be trusted. I'm sure things would have been different on a proper charger but the fact remains, something about parallel charging new lipos confused the charger, unless it was just a coincidence. Much can be said about the quality of that charger, it had some issues, but it never acted out this quite this much before the incident.

No, I'm not using that charger any more. I retired it faster then you can say turnigy.

It would be very appreciated with some more of your insights.

[Rototerrier]

Originally Posted by Kendo

What about the common advice not to parallel charge lipos until after a few cycles?

I can answer this one. It's all about the numbers. If you hook up each battery and ensure they are all at around the same voltage per cell, then there is absolutely no reason they won't parallel charge. The key to parallel charging is that each battery needs to be close to the same level and balanced. If they are new, there is a chance this won't be the case. The total voltage could be wildly off between packs and/or the individual cells won't be properly balanced.

If you have a way to check the packs, such as the monitor mode of the iCharger 306B, then there is no reaon you couldn't check your batteries FIRST and charge them all together if they are all good and within acceptable tollerances.

[REVOJohn]

yup fully agree.

anyway every so called polymer cells is just many anode and cathode plate stacks inside. parralleling cells is the same as just adding more stacks. the only different as mentioned is the state of charge. cells/packs in different state of charge will load amps from the higest to lowest for sure once parralleled but your charge smells fishy here.......

[nuttzzy]

Ok when do I know to balence? Just periodically do it as a preventative maintanece?


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[Slyster]

Always balance charge. In fact with FMA chargers you cannot NOT balance charge it won't let you.

[nuttzzy]

Mines got a spot for the balence port then the main leads. I been charging threw the mains. Is that's right??


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[s0laris]

For parallel charging, as long as you hook up the MAINS 1st, let it stabilize you will be fine charging.

even if the packs are not same voltage they will stabilize.(within reason)

[SeanM]

Unless you're using the fused FMA Safe Parallel Adapter.. Then you would plug in the balance leads before plugging in the mains, so the pack can stabilize with limited current transfer. Correct?

[s0laris]

Well i do the mains first as they are capable of a lot more current than balance leads. At least that's my theory. I could be wrong

[Slyster]

I would assume a fused parallel board has fuses that blow when the current is too high? To safely connect the balance leads first you would need some sort of resistance to limit the current flow if the packs are unequal.. I doubt they have that.. instead I bet the fuse would blow... and that would get you no where. So I say main leads first.. always.

[SeanM]

From my understanding the FMA board uses 'polyfuses' for the balance connections, aka resettable fuses. They're supposed to turn black from red when there's too much current. I've never had this happen, but I believe they will turn red again after you remove the pack.

EDIT: here's a link to explain it in more detail. http://revolectrix.com/faqs.htm?category=54

[vmmattil]

What would be a good charger (with storage level feature) for the e-flite 2 cells with the UMX connector? (The one Carbon Cub and Blade 130x uses)

[Slyster]

Any charger would work. Just get the right cables... or make your own.

Good charger for small packs.
http://www.hobbyking.com/hobbyking/s...dProduct=18066

Good source for cables.
www.progressiverc.com

[BrettOssman]

One of my manuals says that repeated flying to LVC is bad. I assume this is correct?

[Slyster]

Yes LVC usually results in packs ending up at 3.4v (or lower!) in my experience. Voltage is important, but it is more important to know how much you are putting back. What batteries and what charger?

[SeanM]

Yes, that's true. Just once is more than enough to cause permanent damage. It may still work afterwards, but it will have lost performance and life expectancy.