xDennis

My Feedback: (2)

Hi,
I just got a park zone t28, i flew it for about 5-7 minutes today (pretty fun plane to fly, i was pleasantly surprised) anyway I know the batteries are not fully dead.

Do I have to decharge them all the way before charge it up again, or can i just stick it on the charger and will it start the charge from where the battery power left off without doing any damage to the batter?

I have the factory charger that came with the plane, it doesn't have any special decharge feature or anything.

Thanks,
Dennis

Kilo.Hotel.Alpha.Lima

NO! DO NOT FULLY DISCHARGE LI-PO BATTERIES! YOU WILL RUIN THEM!

Assuming you are using the E-Flite 25A ESC that comes with the RTF kit, and assuming you're using the 'ParkZone' 1800mAh battery that also comes with the RTF kit, the ESC has a (programmable) low voltage cut-off that stops the battery discharging below 9 Volts. This is because if you discharge a li-po battery below a certain voltage per cell (varying reports from 3 Volts per cell and up), you will not be able to recharge it and, if I understand correctly, you may actually cause the battery to catch fire/explode if you attempt to charge a li-po that has dropped below the safe voltage per cell.

As a general rule, li-po batteries should be stored in a fire-proof container away from flamable materials (i.e. don't just drop them on the carpet in front of your linen cupboard!).

Common Sense RC has some good information on li-po batteries;

http://www.commonsenserc.com/most_life_lipos.pdf

I'm sure many other places do, too, including this site. Please be careful with your li-po batteries. They are potentially dangerous.

Cheers.

EDIT: By the way, I'm glad you liked the T-28. I've been wanting to try one myself, they look pretty cool.

xDennis

My Feedback: (2)

OH wow,
Thanks for the info! I did know that. I'm a nitro man.. this is my first electric that uses lipo.

So is it safe for my to just put it on the charger to recharge it? (on the 1.8amps setting) Yes, i'm using all the factory stuff that came with this RTF.

Kilo.Hotel.Alpha.Lima

Yes, you can just charge the battery once you've finished using it. It's recommended that you charge the battery at the lowest rate you can. Obviously, the lower the charge rate, the longer the battery will take to charge. So, in effect, the charge rate is somewhat dictated by how long you have available to monitor the battery while it's charging i.e. you don't want to set it on charge at the lowest rate and then go to sleep...

As I understand it, you should never charge your battery at more than 1C.

I don't know the relative charge times for your battery at a given charge rate. But I usually allow myself an hour or two to keep an eye my battery while charging it at about 250mA, say, while I'm watching TV or surfin' the 'net or something.

jzrf6c

NEVER EVER charge Lipo's unattended. By that I mean that you must continually check the battery as it charges (unless of course you have one of the better chargers that caters to Lipos). Watch for swelling or the battery getting HOT. I find it best to use a charger that has a timer to shut off charging after the battery is fully charged or a set time expires. The reason being, as I get older I forget things. It is very easy to forget that I started charging a Lipo and then go off to bed!

xDennis

My Feedback: (2)

All this negative talk about lipos has me second guessing them.. they sound very dangerous.

Kilo.Hotel.Alpha.Lima

Li-po's punch well above their weight in power terms. To the best of my knowledge, there's no other type of battery, literally pound for pound, that matches their ability to store and deliver power.

But they are a compromise.

For all that lightweight juice, you sacrifice durability. Li-po's are not inherently unstable but they do not take punishment well. You have to be careful to charge and discharge correctly, and to handle and store them correctly.

However, I feel that the number of people that use them and the number of manufacturers that are willing to recommend and supply them indicates that li-po batteries are a reasonably good compromise.

Treat them properly and you should get years of safe enjoyment from them, as I and many others here have. Just always be aware that they are potentially dangerous if damaged or mishandled.

EDIT: May I recommend that you do some research about li-po batteries? You will feel more comfortable and confident about using them if you know the potential hazards involved. You could start by browsing some of the topics in the 'E-Flight Power Sources' forum on this site, here: http://www.rcuniverse.com/forum/forumid_126/tt.htm

There is also a wealth of information on other RC 'boards, such as RC Groups, here: http://www.rcgroups.com/batteries-and-chargers-129/ and on various hobby store sites and supplier/manufacturer sites, including videos on YouTube: http://www.youtube.com/watch?v=mw8jb1KmAG8

The general rules I follow, as stated in some of the posts above, are:

-Store your li-po batteries in a fire-proof (or at least highly fire-resistant) container, away from flamable materials (I like my Army surplus ammo case, myself).

-Charge your li-po batteries in an open/well ventilated area on a fire-proof (or at least highly fire-resistant) surface, away from flamable materials. You can also get 'charging bags' for li-po's, such as a 'LipoSack' in the video above.

-Always monitor your li-po batteries as you charge them. You don't have to sit beside them and stare at them but check them intermittently to be sure they're not overheating and/or puffing up. Remove them from the charger immediately once they have finish charging.

-Always balance your li-po batteries. The charger that comes with you ParkZone T-28 Trojan RTF kit is a balancing charger, so you're OK there.

-Treat your li-po batteries gently! Don't toss them around, don't drop them and don't hit them against things! They are fragile and easily damaged/ruined.

-Never fully discharge your li-po batteries. Always stay above the safe voltage-per-cell limit (usually stated as 3 Volts per cell but always better safe than sorry, so stay above that if you can). In flight, when you feel the power start to wane, it is time to land and charge your li-po and/or swap it out for a fresh one (although, don't charge a li-po immediately after flight, while it is still warm/hot. Allow it to cool before putting it on charge).

-In flight, try to stay at 80% power or below. Flying at full-throttle for extended periods can potentially overheat (and hence damage/ruin) your li-po battery and possibly other components of your power system (although, short bursts at full-throttle are generally safe and one of the most fun parts about flying with such a powerful system! ).


Hope this helps. Keep researching li-po batteries and, to quote the Hitchhikers Guide To The Galaxy, Don't Panic. Treat your li-po's properly and enjoy them!

hellblastervolly

xDennis

I use to feel the same way about lipos so I did my homework and follow the safety guide and now I have tons of lipos with out any problem so far.

Fernando