I'm probably going to buy a 2 cell 1000 mah/7.4v 20C Li Po battery w/balencer. (1) what does the balencer do. (2) Will I have a longer flight with this battery or my 1100 mah 9.6v Nimh. (3) Will I have more power with the 9.6v nimh or the 7.4v Li Po. (4) How much more of an upgrade would it be to get the 3 cell 11.1v Li Po instead of the original. I'm wanting to get a brushless motor and it seems that most people are using the Li Po's with the brushless rather than the Nimh. (5) about how long would it take to charge the Li Po batteries I mentioned?

1. the balancer makes all cells in the pack the same voltage 2.well my guess is that it will be close, your nimh will hold more mah, but also at the expense of being a lot heavier, so considering the weight savings, you should get more flight time out of the lipo. 3.the more the volts, the more the power, so more power with the nimh. 4.my guess is that you should get the 3cell lipo, not the 2 cell, it sounds like that is closer to the voltage that you want to run, if you go with the 3 cell lipo then its a whole diff story, you will then BY FAR have more power than your nimh and more capacity as well, of course i dont know what the rest of your setup is. if your long range plans include brushless then 3 cell lipo is most likely what you will want. 5.you will be able to charge it at 1 amp max, im not sure off the top of my head what amount of time that eqates to, but just guessing.... maybe an hour or so.

if you give details of what motor and speed control you have, we can answer more specific.

1. The balancer assures that the cells in your pack are always at equal voltage when charged. If one cell has a higher voltage than the other, it may be damaged during charging. The balancer is designed to prevent this.

2. There are a lot of factors at work here. The two packs are similar in capacity, but the lipo is much, much lighter. So my guess is that flight times will be longer with the lipo. It depends on the current requirements of the motor/prop, the type of plane, and how it is flown.

3. You might make more power with the NiMH, but in practice there may be no difference or even an advantage to the lipo. While the "nominal" voltage of a 2-cell lipo is 7.4V, the actual voltage of a fully charged 2-cell lipo is 8.4V, not so far from 9.6V. The much lighter weight of the lipo will make a big difference in performance. It depends on the size and type of plane.

4. It sounds like you are presently using a brushed motor. While you can run a brushed "can" motor on a 3-cell lipo, the higher voltage makes it easy to burn out the motor. If you go to a 3-cell lipo, you must use a smaller prop and carefully monitor the current.

5. It takes a little over an hour to charge any lipo at the recommended 1C charge rate. For your 1000 mAh pack, the 1C charge rate is 1000 mA (equal to 1A). If your lipo charger does not have a 1000 mA setting, use the next lowest setting

You do have a lipo charger, don't you? You can not use your NiMH charger for lipos.

- Jeff

Hey

Sweet if finally worked, I typed what I wanted to say twice but it didn't word either time. Ok so this is what I put before. Right now I have a Slow Stick and want to get this brushless motor/speed controler setup. [link]http://www.rchotdeals.com/[/link]. Then I want to get one of these two batteries. [link]http://www.rchotdeals.com/Products/rc/Li-Poly_Batteries/1000_2cells_20C_7v.html[/link], or [link]http://www.rchotdeals.com/Products/rc/Li-Poly_Batteries/1000_3cells_20C_11v.html[/link]. Soon I'm hoping to get an areobatic plane and will put this equipment in it after I've had it in the slow stick. There are 4 different choices of motors for the motor/speed controler package which ones do you guys think will fit my needs best.

Also can you recomend a good lipo charger that isn't over 50$ that works really well. I don't think I need one that will charge 4 cells. just 1-3 cells.

I forgot to add that I need it too plug into a wall. I fly at my house so it's easiest if I can charge it in my house.

Go for the three cell batt. When you upgrade to a hotter plane later on, it will have the poop. In the Slow Stick you just have to throttle back. The Eflite Celectra charger works well. Nothing fancy but does a good job. Hope this helps.

Word to the wise...don't charge your lipos in your house unless you watch your pack while it charges or you have amazing home owners insurance if it burns down. Since you are pretty new to lipos, you need to read up on the precautions and dangers of them before charging them indoors.

wow didn't know they could do that much damage. I think I'll charge them in the barn instead then. With the Eflite Celectra charger do you have to hook it up to a 12v power suply? how does it get its power, or can you hook it into a wall socket.
The barn is more of an equipment shed with concrete floors so that would be an Ideal place to charge lipo's. If any one else has chargers they like for under 50$ please respond.

Most lipo chargers operate from a 12V DC power source, such as a car battery. For home use, you can get a separate DC power supply.

I've never used them, but both the [link=http://www.toddsmodels.com/Charger/DYN4053.htm]Vision Peak Ultra[/link] and the [link=http://www.hobbypeople.net/gallery/130116.asp]Watt-Age Charge It All[/link] are AC/DC chargers that use either 120VAC house current or a 12V power source.

There may be others.

- Jeff

As a general rule a 3 cell lipo will weigh about the same as a 7 cell nimh battery but have twice the capacity. For example, a 3 cell 2000ma lipo will weigh about the same as a 7 cell 1000ma Sub A nimh pack. This means about double the flight time. However, the lipo will also have a higher voltage for more power...and hold that voltage more constantly through the flight until just before low voltage cutoff kicks in, where as a nimh will constantly show decreased power as the flight goes on. Both do this but you will notice it more on the nimh.

Many brushless motors require a 3 cell lipo to really shine and show off what they are capable of. While you can power them with nimh packs, you tend to need an 8 or 9 cell nimh pack to get the voltage to where it needs to be, and of course as you add more cells to keep up with the lipo you'll gain more weight.

For the most part, one lipo charger isn't going to give you a better charger over a less expensive lipo charger. Lipo chargers have to follow strict guidelines to safely charge a lipo and as a result there isn't much wiggle room between charging methods. The only exception to this being chargers that balance the cells as they charge. I prefer a balancer that is independent of what lipo charger I'm using. That way if the charger breaks later on I can still you my balancer with another charger. I prefer the Blinky Balancer sold by Astro and promoted by Common Sense to use with their packs (they feature a balancing plug that Blinky plugs into). You can use the balancer before, during, or after a charge. It's about the size of a credit card, requires no power source, and sells for around $25. For a charger I very much like the Celectra 1 to 3 cell charger (They also sell a 1 to 2 cell version).

For lipos I go cheap as possible. Most lipos come from China and are slapped with a "brand name". Much of what you are paying for in the price is name recognition in my opinion. For bottom line prices try Common Sense RC, Dymond Motorsports, or for even cheaper ones try Ebay. Just make sure if you do plan to use a balancer to buy lipo packs with a balancing plug...and one that matches, or buy the proper adaptor to mate them with it.

Yes, lipos can be very dangerous...but so can nimhs and nicads if they are abused as well. Make sure your ESC has the proper cutoff voltage set for a lipo (Lipos don't like being overdrained). Make sure your charger is set to the proper number of cells and never go over 1C (1X2000ma=2 amps on a 2000ma pack). Charge the pack on a cement floor in the open where it can't throw a spark onto something. Don't dent or cut the pack. If the pack shows signs of bloating get rid of it right away. Always remove the lipo from the plane when not in use (the RX/speed control can continue to drain the battery down even if the motor isn't on). If you get your plane stuck in a tree make every effort to retrieve it as soon as possible or the lipo will be drained beyond repair. When not in use store your lipos in a fire box or in an open area on cement. Make every attempt to keep the battery leads from shorting, using heat shrink tubing and electrical tape for insurance.

That all being said, I've seen nimhs catch on fire, overheat, etc....due to overcharging or shorting the pack. Heck, even a D cell battery can cause a fire in your house if it's shorted. I won't be going back to nimhs for most of my planes. The flight times and power a lipo produces will spoil you for life. These batteries, along with brushless motors, are sounding the death bell for gas in my view.

By the way, if you are looking for a cheap brushless motor with great performance check out the BP21 from Balsa Products (Cheaper elsewhere). It's a good replacement for a 400 to 480 sized brushed motor and is going for under $20 now.

Whoops, my link for lipo safety didn't post:
http://www.fmadirect.com/support_docs/item_1197.pdf

I'm not one to push scare tactics like some regarding lipos, but I'm happy to help spread proper usage and care for them. They take a few more measures to ensure prolonged life and safety than nicads and NiMH.