surjer

I am curious if I have to DeCharge my battery on my plane. I have a HobbyZone SuperCub and a few times I have charged it up in anticipation of flying it but didnt make it to the field. So 2 weeks later I am wanting to go to the field again and I remember the last time I charged the battery but never used it. Is the battery still charged? Do I put it on charge? Do I have to connect it all up and run it dead and THEN charge it?

Im sure this is a dumb question but I have learned the only real dumb question is the one that was never asked... (Thas how I make myself feel better for asking it lol)

Pacific Planes

The battery would still have a full charge. Companies say that you shouldn't keep them charged for an extended period of time. If you do it could effect the life of the battery but you are fine. It is never a bad idea to throw it back on the charger for 10 minutes to make sure it has a full charge though. Hope that answers your question.

surjer

Thanks Pacific Planes... I didnt want to destroy my battery before it even had any real use!

bruce88123

If it was fully charged when put up I'd put it on the charger for an hour myself. 10 minutes won't really do much IMO.

And just for the record the term is discharge and not DeCharge. Just part of the learning process. And as for the charging time, everyone has there own methods and opinions there too.

surjer

Doh! Thanks again! Much to learn... Gotta start somewhere right?

bruce88123

Exactly. Next time you'll know. Using proper terminology just makes everything easier to understand.
Have you seen this: http://www.rcuniverse.com/community/glossary.cfm

opjose

It depends upon the chemistry of the battery.

LiPo's have a self discharge rate of under 3-5% per day, and you can easily "top them off", prior to going out flying.

NiCD's and NiMH's have much higher self discharge rates and will often discharge in a week or more.
Longer than that may result in a deeper discharge.

The NiCD's could then be helped by a full cycle. The NiMH's would probably stand a "top off" charge to bring them up depending upon the amount of time that has gone by.

scratchonly

Google "RC battery Clinic" lots of good stuff there including your question.

bruce88123

http://www.rcbatteryclinic.com/

This is where he's trying to send you.

surjer

Awesome site guys. Thanks...

surjer

My battery is a NiMH which according to the site has a self discharge rate of 3%-4% per day on average. This means it should actually be pretty dead after 2 weeks. I will put it through a full slow charge before flying on that battery. After that its off to calculation to determine what my plane drains from the battery per minute of flight. Then Can use that info to Calc how long "Top-Offs" should take...

bruce88123

I usually just put mine on charge the night before I'm going to fly and they're fine. Using the charger that comes with them you will NOT harm them by leaving them on that long. I have a friend that plugs his in when he gets home from flying and NEVER takes them off charge. I'm not recommending that but just trying to show that they are hard to hurt with a standard slow charger.
One of these, along with the proper leads should be one of the first additions to your field kit. Then you will know the condition of your batteries better.
http://www2.towerhobbies.com/cgi-bin...?&I=LXNK81&P=7

surjer

I hate to ask but is that different than a standard MultiMeter? I have a really nice MultiMeter that measures Volts/Current/Amperes/Etc. I am assuming its different because these are multi cell packs?

flyhi

My Feedback: (28)

any good voltmeter will do, you are measuring output, not number of cells. if i haven't flown in awhile, week or so, i'll put the battery on quick field charge and charge it while driving to the field

bruce88123

Not true. The difference is that an ESV puts a measured constant load on the battery pack. This simulates the load the radio system will place on the battery pack and gives a truer measure of the health of the pack. DO NOT use a regular meter.

BTW - I have knowledge on this. I'm an Electrical Engineer and been working with electronics/avionics for 40 years now.

surjer

HA - I would have almost put money on it being different! Glad I asked. (Guess these arent such stupid questions)

bruce88123

If you don't know the answer, it isn't stupid. Even if just not sure, ask away. That's why we're here.

mbilar1

I've never met a stupid battery; but I do know a couple of dumb thumbs.

j.duncker

My Feedback: (2)

I have been flying a long time and seen a lot of crashes caused by flat batteries.

Can't remember EVER seeing one caused by an overcharged battery. Yes you can fry a battery, but hey there cheap, get another.

A word of warning on NiMh if you mistreat them they do fail sooner than NiCads.

spiral_72

Really!? is that true? I've never noticed THAT before.

piper_chuck

My Feedback: (12)

I use NiMH batteries for a bunch of stuff around the house (remotes, cordless mouse & keyboard, cameras, etc) and I'm certain I do not have to recharge them every 2 weeks.

opjose

It's never the less true though.

Take a fully charged NiMH battery and let it sit for a few weeks, then put it on a charger that reports back battery capacity.

You'll find that the self discharge rates cited are not very far off.

As the battery is used more, the self discharge rate increases.

ag4ever

I typically keep my plane and transmitter on the wall wart all the time. Mainly because i don't know when I will fly next and I want to be ready for that perfect time I did not know I would be able to go flying.

I also have a multi purpose charger that I can use to stuff a charge int he packs in almost no time if they are flat, but the slow charge is the best for pack longevity.

piper_chuck

My Feedback: (12)

A strategy I've seen is to put the charger on a timer so it only runs part of the day, perhaps an hour.

Big feet

surjer,
The one suggestion I would like to put forward here is to get yourself a better charger, funds permitting.
Reason:
Just because you put the battery on charge over night in no way tells you how much charge is in your battery. For example. you charge a battery for 10 hours on the standard charged you get with the Tx. The output of the charge is, lets say to keep it all easy, 100mah. So, if we ignore the loss durning the charge cycle in this example, you should have put 1000mah into your battery. If you have an 1000mah battery in theroy it is fully charged.
But is it?
If you have a defective cell in the pack you will not have the charge you think you have. The battery checker will give you top green if you plug it in , look at the green led, and unplug it. The ghost charge is still there. The defective cell may have some charge in it so the 4.8 volts is still present for the checker to 'see'.
result, short flight and expensive crash.

Or, I have read of one guy that later, after two wrecked planes, discovered he had a power cut during the night and so the batteries did not have the charge he thought they had.

If you get one of the charge/discharge chargers, they give a display showing the amount of current that went into your battery.
If this is very low, the battery may be faulty. Or, it may need cycled a few times.
Either way, you don't fly with it.

As I say, its only my suggestion.