aircraftking

Ok, I have a hobby zone super cub and im using the hz1013 battery it came with and I bought another battery just like it. Say I charge up a battery, then decide not to fly, then a few days later I do fly. How long should I charge the battery prior to flying? On the same line, if I go to the field and have a fully charged battery and don't fly, should I do a full discharge on it or just bring it home, take it out the plane and do I charge just prior to my next flight? Also, I wonder if discharging is necessary everytime before I recharge?

Sir Raleigh

Answering in reverse order of your questions:

If the batteries are NiMH, then you do not need to discharge them before you charge them for the next flight. However, if they are new, I would suggest you cycle them (charge/discharge) 2 or 3 times so they will obtain their full potential.

Always charge NiMH batteries after use. Once you charge NiMH batteries, and don't fly, you do not have to do anything until you are ready to fly again. Then you would put the batteries on the charger to "top them off" which usually only takes a few minutes.
If you are using a peak detection charger the charger will turn off automatically once the batteries are fully charged. If you are using a brute force charger (a charger similar to one of these wall transformers) then monitor the batteries temperature. When the battery starts to get warm it is charged up. Unplug the charger and go fly.
Also, batteries like to be used while they are still warm.

NiMH batteries will slowly self discharge over a period of time, usually in weeks, but they self discharge faster in the beginning than they do as time passes which requires them to be "topped off" to get them back to full charge.

Xpress

All batteries will lose their charge after a while. It is just a matter of time.

A few days might allow the battery to lose their charge of about 1-2%, nothing too significant. However, lithium batteries don't lose hardly any charge at all for months.

aeajr

My Feedback: (2)

Read the friendly manual. That is always your best first source of information.

Your Super Cub came with a "peak" charger. If you read the instructions you will learn that the charger automatically senses the charge in the pack and will add the right amount of charge automatically. No timing needed or recommended.

No need to discharge NiMh packs. If you wish, you can do it once a year for "good measure" but any more than that is of no value.

It is always good to "peak" the pack just before you fly. Warm, right off the charger, will give you the best power and the longest flights.

kofi1013

I have started using lip po's lately. I put together a e-flite P47 Thunderbolt ARF. with a 400 outrunner brushless motor. The recommended batery with this set up is a 2100 mAH 11.v battery. flying weight 21-26oz. I want to put in a 2 cell 1200 mAh battery to reduce weight. What will I have to trade off in perfermance? Will the plane be too under powered?

A second question. I ordered a cessna mix master. RTF. The battery that comes with it is a 2200 mAH 3 cell lip po. Can I use a 2100 mAH lip po? will flight time suffer significantly?

Thanks in advance for your help

Sir Raleigh

Although the 2 - 1200 mAh batteries will give you 2400 mAh capacity, which is an increase of 300 mAh over the single 2100 mAh battery, the trade off might be the additional weight of the 2 - 1200 mAh batteries over the 1 - 2100 mAh battery, if there is one.

In reference to your second question, the 2100 mAh battery should be lighter than the 2200 mAh one, so, even though you are loosing 100 mAh of capacity the less weight of the 2100 mAh battery may offset that loss and your flight time may not suffer at all.

A note: It's recommended that you not run your batteries down to no more than 80% capacity. If you follow this you might actually get more flight time from the 2100 mAh battery than you do with the 2200 mAh one because the 80% point of the 2 batteries will be so close the controlling factor will mostly be determined by the weight of the flight battery.

What is the weight of each of these batteries?

hellblastervolly

kofi1013.

Is there a reason why you want to make your P47 Thunderbolt lighter? Since the recommended batery will not affect the performance of it. I will not go with the 2 cell 1200 mAh if you like to keep enogh power for the motor. If you like to make it lighter go with a lower mAh on a 3 cell this will still give you the power you need but your fly whon't last as long as the 3 cell 2100 Mah. Offcorse it all depend in your trottle managment. The smaller lipo can last you at half stick as long as a bigger lipo at full stick.

Fernando

thailazer

Just about ready to order my first electric RC Ship but I have a question. How do you go about charging at the field after a flight? Do you have to open up the plane and disconnect the Deans connectors to connect up to the charger, or do you have an external plug to make it easier? Also, how long does it take to charge the batteries for a 40 size outrunner? All help appreciated.

hellblastervolly

Hi thailazer.

For safety reasons you need to remove your lipos from the plane every time you charge them. You can leave the NIMH or NICD in the plane but I still chose to remove them. Charging at the field you can use a 12V battery if your charger takes DC but if it's a wall charger you have to do it at home unles you bring your own power generator, lol. I have several batteries that I charge at home before a day Im flying but I still carry my DC charger and 12V battery just in case I stay longer at the park or field. The time it takes a battery to charge depends on the size of it and how drained they are at the moment of charging. Remember to not let the battery go lower than 3.0 V per cell. Any other questions feel free to ask.

Fernando

jdetray

If you charge a lipo at the recommended 1C rate, it will take a little over an hour to charge. This applies to a lipo of any size.

A pack that is only partially discharged will take less time, of course.

- Jeff

thailazer

Thanks for those answers. It sounds like the answer to my question: "Do you have to open up the plane and disconnect the Deans connectors to connect up to the charger, or do you have an external plug to make it easier? " is Open up the plane and put in new batteries...... Sounds like more hassle than just pumping in more glow fuel and flying again.

jdetray

You trade one set of issues for another when you move from fuel to electric flight. If your goal is to be able to fly more or less continuously, then you need to stick with fuel-powered planes or be prepared to own a bunch of battery packs. However, if your day at the flying field includes some time spent talking with other pilots, helping beginners, etc., you may find that three battery packs are sufficient. One will be charging, one will be cooling, and one will be ready to fly. With a bit of socializing, three battery packs is about right.

Some lipos can be charged at a 3C rate, reducing charging time to 20-25 minutes. Even so, safety dictates that you remove the battery from the plane to charge it.

On the other hand, at the end of a day of e-flight, you just pack up and go home. No mess and no clean-up required!

- Jeff

thailazer

Jeff, Thanks for the excellent answers. I did not know of the exact trade-offs so I appreciate your explanation. I usually fly when no one else is at the field, either aerobatics or lots of touch-and-go's, so I am thinking that the electric path is not something I should do right now. I try to get in as much flying as I can in the two or three hour slots of time I have. But.... for someone that wants to get a quick flight in at a local running track or park, the electrics sound ideal. Thanks again!