Cycles on LiPo's

[89x-cell60]

Hello to everyone,

I was not able to find the answer to a question that has been running through my mind on these batteries.

I have read that you can get about 500 cycles out of a good NiCad or NiMh pack, but I have not seen or heard of anything about the LiPo's.

I guess I need to hear that I'm getting the same fight times compared the amount of fuel spent for the same amount of flights? Or another way to put it, justifying the price of these batteries to Glow, or stick with NiMh/NiCad until the LiPo’s have been fully tested?

Hope this makes sense :?

Thanks for this great new site :D

David

[jwooten]

David,
I am assuming that you are talking about electric helicopters.
LiPos are very new. Not enough people have had them long enough to tell. I have heard 100 to 300 cycles. It will probable depend on how fast you discharge them and how deeply you discharge them. I have about 30 flights on mine and they are only getting better. Lipos will give the more power with less weight than the comparable nicads or nimhs.

Lipos are expensive. You probably won’t save money on fuel, at least with today’s prices. I expect prices to come down in a year. Then I have been wrong before.

Jimmy

[DavidH]

Lipos are expensive. You probably won’t save money on fuel, at least with today’s prices. I expect prices to come down in a year. Then I have been wrong before.



From what I have been told. You can expect at least 300 cycles out of the Li-Po batteries. That would be 300 flights at the least.
Now the average 90 size heli gets just a little over 6 flights out of a gallon of fuel. So that would take 50 gallons of fuel to make 300 flights.
Average price on 30% heli fuel on the low range is about $18 a gallon
50 X 18 = $900

To equip an IonX with 2 of the 8 amp Li-po packs is going to be less than $700.

So really your buying all the fuel up front for the E-Helis. That is why it looks to be such a high cost.

David

[Spitfire_mk5]

But there is also the conveinance factor of the glow fuel: you don't need to wait over an hour between flights, so you really 'need' around 2-3 full sets of batteries, to be able to fly compariable number of flights to a glow pilot.

But on the bright side you end up with more BSing time :D

[89x-cell60]

Thanks for the replies :D

I was trying to see if I wanted to go with the LOGO 10 or 14, or go with this new Zoom E-Heli. I would like to get the Logo, and getting 2 or 3 packs is about the same for glow if you they can cycle 300 times. The batteries for the Zoom 400 look to be about $120 to $150, which sounds better (Read cheaper :lol: ) Not to mention the fact that I only fly 60's with 15% fuel. :shock:

Thanks again,

David

[ChrisS]

The key to good Lipo life is to stay away from the limits of the battery. Unlike roundcells, Lipos do not have a memory effect, so you can run partial cycles without worry. Charging to 90% (1 hour at 1C) and discharging to 3v/cell or greater are real good ideas.

When you buy your batteries, size them correctly. You need to make sure the batteries you choose are fully capable of supplying MORE than the actual peaks you will see in flight. Ask the manufacturer about the continuous and peak discharge rates he has tested and confirmed the batteries to. Just buying a battery based upon it's C rate is not enough.

A battery that is always more than warm or hot (over 140 F) at the end of a flight will not last long. Batteries tend to warm up as they approach the end of thier cycle but can also heat up when exerted too hard.

Store your batteries over long periods at half charge, say 3.6 volts/cell, in a cool place.

Chris

[vaporlock]

I just read that lithiums have a rather short lifespan:2-3 years from manufacture.
See: http://www.batteryuniversity.com/parttwo-34.htm

So even though they may give 300+ cycles, if you don't fly enough, they may not be such a good deal. In spite of this, I am going forward with a raptor conversion. I just need to fly more to justify it :)


chuck

[Hellboy]

alright figure this out....i have 2 lipo packs i screwed the first one up by dipping too low on the voltage....the second one i bought was i 1600mah pack for my shogun heli, first charge brought the voltage up to 12.6 volts, after my first short flight (battery meter still showing green), the thing wont go past 11.3 volts . am i charging at the wrong rate? what is the ideal rate or charger you guys reccomend
your help is appreciated...

[fitenfyr]

The best plug it in and not worry about it charger on the market is the Astro 109.
Sounds to me like you lost a cell.
If you can send it back to the manufacturer to check it out.

LiPo's are expensive, but if you take care of them they will give you some great rewards.
They are not for everyone IMO. I think you have to be a notch above the average "flyer" to want to mess with these HV brushless setups now.
You need to have an abundant amount of patience with LiPo powered ships.
Sure you can buy 2-3 packs, but if you don't watch the motor/ESC temps and let the whole system cool down before you fly again the packs will be sitting there for nothing. :D
I will be keeping my Extreme for sure as "filler" time. That way I can charge my packs for the ION carefully one at a time (about 2:30 hours) and fly a couple tanks with the smokey beast while I am waiting. :D

[KillerBob]

Spitfire - you forget to mention the conveinience factor of electrics... it is sooo nice to ge rid of oil-mess (allthougt my Ion-X tend to rust :arggg: ) - and you never worry about mixture settings and so on. The conveinience is there - just different

MHW have been describing the life of Lipos recently - and it seems like a real lipo killer is storing packs fully charged @ high temp. If you store fully charged packs @ 20deg C (room temp) the cells will loose 20% a year. If you store fully charged cells @ 0 deg C (freezing point) they will only loose 2%... @40 deg C the will loose 35% a year :shock: These figures drops dramatically if the pack is only partially charged

So the key to long lipo life is to store them cool (fridge ???) and only partially charged. Anything between 30 and 50% should be good.

Most important - Chris said it....

best regards
Lars

[fitenfyr]

Oh great....
Now my wife is going to be nagging me to get my packs out of the feezer. :D

[Spitfire_mk5]

send them up here: the way the Wx has been lately -40* days aren't that far away


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