lipo batteries

[Hadi]

I've been trying to understand the concept of Lipo Batteries but there is still something that I don't understand:

What is the difference between the Lipo 11.4V 1300mAh vs 1800mAh?

Do I get a higher power or flying time with higher mAh?

Ps. is it safe to buy Lipos from Hobbyking?

[xed]

More mAh = more capacity = more flying time.

More voltage = more power.

[mitea_dan]

But it also means it’s heavier, and so the flight time isn’t that much longer, at least not proportional to the battery’s capacity.
In my opinion, the best would be the battery that lets you fly between 10 and 15 mins.

[Burning Head]

15 to 20C max its ok for your trainer Hadi:cool:

[RichR]

Hi Hadi,

Also keep in mind that greater capacity "Higher mAh" can supply you with greater sustained amps while maintaining a proper voltage level, meaning (In theory):

(mAh of lipo * C Value)/1000 = Continuous discharge Amps

A 20C 1300mAh pack = 20C *1.3Amps(1300mAh) = 26 Continuous Amps
A 20C 1800mAh pack = 20C *1.8Amps(1800mAh) = 36 Continuous Amps

Be sure to check your electric motor specifications and choose a lipo pack that can supply the needed amps. Remember, higher C ratings are good for high-power applications, however, they are simply overkill for many trainer type applications. Like it has been mentionned, the higher the C-rating the heavier an equivalent pack becomes! Let us imagine a 45C 1800mAh pack:

45C *1.8Amps = 81 Continuous Amps!!!!!!!!!!! (So, like BurningHead said, keep the C-rating as well as the capacity in mind. And remember, a higher capacity (meaning greater mAh)lipo will also maintain a higher voltage under load throughout your entire flight versus an equivalent voltage lower capacity lipo pack which in turn means more power because Voltage*Amps=Watts and the more watts, the more power. Watch the AUW of the aircraft, and find a suitable balance, meaning a battery that can supply the amps without going overboard with the C-rating and give you tolerable flight times without sacrificing weight (Although a bit of weight is good on windy days!). There is a lot more to this, anyhow...Hope that helps! Good Luck

[Hadi]

One more question: What is the best and most econmic charger I could buy? right now I'm using the Great Planes 3S LiPo Balancing Charger which came with my SkyFly Max,

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXVZZ3&P=ML

It charges in a current of 800mA maximum! but it would take a long time to charge my two batteries "1800mA" because it charges only One at a time,.

Is it a good Idea to buy another one of these chargers for $25 or I should go for a better one that charges faster and easier!

tnx

[Burning Head]

Invest in a good trainer Hadi, you will fly and lurn more my friend then with your Sky fly:).

[RichR]

Hi Hadi,

Don't waste your money on buying another Great planes 'wall adapter' charger, simply buy an Accucel 6 for $22.99 + Shipping from Hobbyking. A lot of people I know use them with great success. It has the following specs:

Features;
Microprocessor controlled
Delta-peak sensitivity (NiMH/NiCd)
Individual cell balancing
Li-ion, LiPo and LiFe capable
Ni-Cd and NiMH capable
Large range of charge currents
Store function, allows safe storage current
Time limit function
Input voltage monitoring. (Protects car batteries at the field)
Data storage (Store up to 5 packs in memory)
Battery break in and cycling.

Spec.
Input Voltage: 11~17v
Circuit power: Max Charge: 50W / Max Discharge: 5W
Charge Current Range: .1~6.0A
Ni-MH/NiCd cells: 1~15
Li-ion/Poly cells: 1~6
Pb battery voltage: 2~20v
Weight: 355g

This charger has a JST-XH charge plug, which makes it compatible with Zippy, HXT, TURNIGY and any pack with a JST-XH adapter.

[RichR]

Btw,

You will also need a power supply to feed the charger, you can use an old PC power supply (try not to electrocute yourself...lol) or an old wall adapter that supplies 12v in excess of 6 Amps (if you intend on charging packs up to 6000mAh, which I doubt!)

Later ;)

[Mick]

This charger would be limited by the total power capacity of 50W. This is great for small batteries ie low voltage or low capacity but if you intend to work up to medium to large batteries 4-6S at 3000mAh+ then I recommend a 150-200W charger. For example:

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7386&Product_Name=GT_A-6-10_200W_Balance_charger_&_discharger

[RichR]

The Accucel 8 (150 watt) is a better option to the GT Power chargers if he intends on charging larger capacity lipos, GT power has a bad track record of reliability it seems as per the forums. However, if you intend to pay $50 + Shipping for a Hobbyking charger, you're better off buying a Thunderpower 610C for $99.99 (DC only) or the new TP610C AC/DC for $119.99 (no need for external power supply). At $22 + shipping, the Accucel 6 is good for what he is using it for since he emphasized on the charger being 'economic', and it will charge a 4s 3000 mAh battery with ease. All depends on what you intend on charging, like Mick said. You have to supply us with more information on what you intend to do with this charger, as well as whether you will be wanting to use it to charge larger batteries than what you have on your Skyfly. There are many options, just spend the money once and buy a charger that will not limit you in the future, $25 here, $30 there is not 'economical' in the long run, you simply end up spending more. Spend $100 once on a quality product and forget about it, just my opinion! :)