Larry,
I take the battery out of the plane, because (I guess) I usually leave my plane in the car, and my charger is in the basement.
Also if you leave the battery in the plane, you might one day forget to unhook it from the ESC. The best thing that could happen in that case is that the battery is discharged to zero, effectively killing the battery. The worst of course is somehow the motor gets turned on somehow.
Now the folklore (which is probably true) is that you should store the batteries at roughly 40% to 50% of full charge, and then top them off before you fly. That should give you the longest life. So if you fly only on the weekends, then after a session, charge the battery to the "Storage Level" (my FMA 4s charger has that option). Then the night before flying, go ahead and top it off.
We have a field at work
, so assuming the weather is ok, I have the opportunity to fly almost every day. So I keep the batteries in a fully charged state. However since I haven't actually flown that often, my batteries stay pretty much at the fully charged state all the time. I haven't really put that many flights on each pack, so I am not sure how much lifetime I may be losing. One thing I am thinking is to drop down to keeping 2 out of my 4 packs in the fully charged state, and put the other 2 into storage. Usually after two flights in a day, my level of flying drops dramatically ---I tend to lose focus. One thing I am happy about is that my packs are a fair amount cheaper (~$65 per pack--FMA 4s2100 packs) than most people are using in CL, so if I am screwing them up, I have less to lose.
Another comment about Lipo safety. Sorry if I sound somewhat cavalier about it. You do need to take care. However I recommend looking one time at one of the Electric Power forums on RC Groups or RC Universe. My reading is that if you buy reasonable stuff from reputable sources, and if you know what is acceptable in charging and using lipo batteries, you won't see any catastrophic problems. Here are a few of my "rules"
1) Buy Good stuff. Not necessarily the best, but stay away from cheap stuff.
2) Buy a good charger (see #1 !) . The FMA charger is good and the balancer is built in. The Astro 109 is also good, but you will need to buy an external balancer (I have the ASTRO Blinky). Read the manual, and make sure the charging is going according to plan. Also keep records to note if the battery is changing its characteristics. These are the two I happen to have, and I can recommend either. The FMA can only charge a maximum 4s cells in series. The Astro can go higher. FMA does have a newer charger that works with a higher cell count, but it is also more expensive!
3) Buy a Wattmeter. This sits between the battery and the ESC. This is a good way (not "best") to make sure that you are not inadvertently abusing the battery, esc, or motor. My rule of thumb is that when you run statically, the current draw should be less than the rated constant "C" rating. Hopefully when you are flying, the average current is less than 10C. Remember a PA flight is less than 6 minutes of throttle on. If you would suck the battery dry in that 6 minutes, you would be drawing at a 10C rate. Good practice is that you leave 20% charge in the battery, so that implies an average discharge rate of 8C. So for my 2100 mAHr cells, my average current should be ~17A (which it is in my case).
4) I always feel the temperature of the battery after a flight to make sure it isn't over temperature. I just bought an infrared temperature sensor for ~$25 to get a more quantitative idea about the temps. You want the temperature to be lower than 135F after a flight.
Topic: Care of battries (Read 792 times)