keith 202

My Feedback: (1)

I'm old school. Cobalt 05 and Ni-Cad old. I've been trying to go brushless and li-po and I'm not doing well. I have two Li-Po chargers(Elite 5i-BC & Worley MCMR) and five batteries(Kokum & Enerland) that are no good. I need answers. Is there a book or a central clearing coloum that will help me?

jdetray

Sorry to hear about your difficulties. If you can provide some details, perhaps someone can give you advice.

You say the batteries "are no good." What is wrong with them?

Were they "no good" when you bought them? Did they ever work properly? Did you charge them at the recommended voltage and charge rate? Did they work for a while and then fail?

Is there a problem with the chargers as well?

The more info you can provide, the more likely it is that someone will be able to help.

- Jeff

Aerobat5

I'm new to Electric. I'm currently using a Power10 in my Katana MD, w/2100, 3C, 11.1v batteries. I only get 8-9 minutes duration, but battery size is a limiting factor since the Katana has a small battery compartment. Can I use something else, like a 7.4V 3000Mah without degrading motor performance??? And what is most important when choosing a battery, Mah, V???????

Dr Kiwi

You will very definitely degrade performance in going from 3s to 2s (Given the same prop, voltage of 7.4v instead of 11.1v will result in far lower amp draw, and thus power since W = V x I). You could increase prop diameter and draw a far higher current (if the motor could cope with it) and end up with the same power-in [but I doubt the motor would be happy]. In choosing a battery you need to look at its capability for delivering what the motor/prop will demand - for higher current draw you need larger capacity (mAh) or higher C rating. Look at the max amp/max watts for your motor... do not exceed either of them. You can choose whatever voltage you want, but to get the maximum power out of your motor you need to optimize both voltage and amp draw (suited to the motor Kv and the size of prop you wish to use, to get the correct balance of speed and thrust).

Aerobat5

Thanks for your input. I kinda figured that, but wanted to ask. Have you ever heard of a CD program called "Motocalc". Its supposed to figure out your balance between amps, draw, etc??????

jdetray

Hi Aerobat -

You can download a free 30-day evaluation copy of MotoCalc at:
http://www.motocalc.com/

If you like the program and wish to keep using it after 30 days, registration costs $39. If you want the program on a CD, it's $49.

- Jeff

danwes10

Hi guys, Im new to electric. I picked up an Impulse Power 3 cell 11.1 950 mahlipo from hobbypeople and i plugged it in for its first charge, and within a few seconds te charger gav the finish charging tone and so I plugged in to the receiver and got no servo control or anything, took it off and checked the voltage and it had lke 2.5 volts at the connector. The warranty says it wont cover under voltalge batteries. Im not sure if the store will take it back? Any fixes for this?

jdetray

A 3-cell lipo pack measuring 2.5V is almost certainly beyond salvation. A new 3-cell pack should be about 11.1V when you receive it and should charge to 12.6V when fully charged.

Since the pack was delivered to you severely under voltage, the vendor should take it back without any hassle. Tell them you received the pack, checked the voltage, and it was only 2.5V. You should receive a replacement.

- Jeff