Where is a good place to buy batteries online?

[Mike Palko]

I want to pick up some new batteries preferably individual cells so i can make my own battery packs. Are there any site's you guys know of that have a wide variety or good prices online? I have been away from electric's for a while, but how is the nickle metal hydrive (spelling?) technology coming? I know that they worked fine for model airplane use as long as you kept the amp draw down and charged them slowly. If you can give me any advice on batteries it would be greatly appreciated!

[pmpjohn]

Try Dynamo Electrics. They are listed in the E Zone sponsers.

[steve lewin]

NiMH (Nickel Metal Hydride) are getting better all the time. The new Sanyo 3000mAh HV cells are good for about 50A and can be charged in 30 minutes (note: you need the HV type, the older 3000s aren't as good).

If you can give us some idea of what sort of motor you're going to use or what sort of currents and durations you're looking for I'm sure we can give some advice (plenty of people round here who know about electrics, just not so many who know lots about C/L).

Steve

[Mike Palko]

This is the setup i am currently using. Astro cobalt sport 15 geared w/the standard gearbox. A Master Airscrew electric 12x8 prop. 10 Sanyo 1400scr cells. I have been using a 25amp fuse so i assume i am pulling between 20-30amps. This combo i belive makes 40-45oz of thrust.

Alright here goes with some of my questions/comments.

1.If i am right NiMH cells weigh less than Nickel Cadmium Batteries?

2.Since the NiMH cells are 3000mah would that theoretically double my current flight time from the 1400mah Nickle Cadmium cells?

3.What is a good charger for up to 12-14 cells and where can i buy it? Right now i have a cheap astro flight charger.

4.I want to pull as few amps as possible. I would like to get a minimum of 4-5min of full power from the motor battery combo. I would assume this would require 30amps or less.

5.I don't think i can get the flight performance from a cobalt motor that i need/want. I think i will need to go with a brushless motor.

6.What does sensorless brushless motor mean?

7.Do you need a motor controller for all brushless motors? Or is a sensorless brushless motor able to work w/o one?

8.How do you or i pick a motor? It seems there are so many motor, gearbox, prop, battery, cell number, mah ect combo's that it is almost trial and error to pick a motor that works for you.

9.I want to fly a plane that has about 480-560 sq in with authority! Total flying weight should be 40-43oz. Control line flying need tons of power! I guess you guys already know that control line takes much more power than r/c planes to fly so power to weight ratio is very important.

Any help you can give me would be great. I guess the first thing i want to do is stick with my old plane and just make up some new battery packs. I would love to try the NiMH cells. I really want to get the power train figured out before i build a new plane. If the batterys work out i think brushless is the way to go for maximum performance. I guess we will see. I am getting excited to go fly again. Sorry this was so long, Thanks again Mike Palko

[retiredVTT]

http://www.dynamoelectrics.com/


Great Batteries, Great Prices, Great Service......

A + B + C

Easy as 1 - 2 - 3.....

Talk with Jason or Chuck ......

Bill

[steve lewin]

Hi Mike, no problem with the loads of questions. It's a pleasure to see someone aiming to do some serious electric C/L.

Having said that some of your questions are covered pretty well in the Electric Flight FAQ which is worth a read even if it's not specific to C/L. YOu can get to it from the Ezone front page or direct here http://www.ezonemag.com/pages/efaq.htm

To answer your specific qs :
1. NiMH have greater capacity for similar weight. E.g. 3000s weigh little more than your 1400s. The same size/weight NiCds are now up to 2400 mAh.
2. Yes
3. It's worth checking the main electric flight forums for this. I like the Hitec CG340 if you don't want to spend much money or for a bit more the SuperNova 250 or if you really want a good charger that will last you forever a Schulze isl6-330. I'm on the wrong continent to tell you where to buy them.
4. 5 minutes on 3000s would be 30-36A

5/6/7 Brushless are likely to be lighter and more efficient. Yes they need a controller (brushless really need a controller to run at all, you can't just connect a battery direct to them, they're AC motors and the controller turns the battery into AC for them). Sensorless is covered in the FAQ but for practical purposes it means you can choose the best motor and controller separately from any manufacturer you like. With a sensored motor/controller they both have to come from the same place.

8 Most of us use programs called Motocalc/Electricalc to give us an idea of how a motor/gearbox/prop combination will work. But they know nothing about C/L planes. OTOH if you just put your current combination in against any old R/C plane you can then change the various bits around and if it climbs better or lasts longer those improvements should transfer to the real thing.

For now you have 2 good options. You can try some NiMH 3000s (make sure you get the HV versions) which will be the same size but weigh a little bit more than your 1400SCRs but give you around twice the duration. Or you could get some CP1700 NiCd cells which are considerably smaller and lighter than your old cells and will give you at least as much duration. There are plenty of other possibilities but either of those would be a good start.

Let us know how you get on.

Steve

[Mike Palko]

Thanks for all the answers. If anybody else reads this post and has other ideas/opinions ect please post. This will give me a start. Where can i get motocalc or electricalc? I have many more questions but i will try to find the answers to them myself. I will keep you posted. Thanks again.