My plane was eaten by a tree and spent the night + a little there, how can I check it to see if it discharged too much over that time period. I have a Great Planes Triton charger and it seems to charge up. I haven't gotten a new plane to put the equipment in yet so I can't run it to check it's "life". The equipment is...

Fieago 2015 can type motor w gws "D" gearbox
Castle creations Phoenix speed control
Apogee 1570mh battery
hitec HS55 servo's

also any suggestions on what would fly well on this setup

Thanks

If you don't see any swelling on the Lithium pack then you are probably fine.

It sounds like you got the plane down already so I'll bet you'll be back in the air soon.

Good luck!

Bigbird


My Wingo on floats was stuck in a 50 ft Pine for over 2 weeks through wind and rain. When it finally blew down, I glued the pieces back togather and it flew the next day.

If you were using a LiPo, its probably toast. I did the same thing a while back and ruined a nice 3cell pack.
Depending on what LiPo you were using, I would measure the individual cell voltage. Its possible to blow the pack up if it trys to charge one cell up to full voltage if the other cell is bad.

Unfortunatly most chargers dont charge individual cells. They just try to pump the voltage in.

Example

A 2 cell pack should have roughly 4.6V per cell on a full charge.
If one cell is bad and will only hold 3V, the charger will try to put the remaining charge in the good cell.

Just so we're clear, it's 4.2V per cell. I wouldn't recommend charging to 4.6V. Might not do anything bad, but who's gonna go out and try it?

The thing to keep in mind here is that even if the motor is off, the ESC is still draining power. So are the receivers and servos. You can't unplug the battery because the plane's in a tree. When you get your plane back, the pack will be pretty thoroughly drained. A NiCd or NiMH pack might be rechargeable, but the LiPoly is almost certainly going to be down below 3.0 Volts per cell "safe zone," and probably below the 2.5 Volts per cell "serious damage" line. It may be possible to recharge the pack, but it will only be a shadow of its former self, and there will always be a shadow of doubt looming over its stability. If it were my pack, it would "sleep with the (salt water) fishes" tonight...

That was my thought but wondered if there was any way to test it. What I'm getting from the replies here is that there is not, other than putting it in a plane and trying it out. It did seem to fully charge.

Correct me if I'm wrong but with the Triton charger and temperature probe it's not possible to damage the battery as the charger will cut off if there is too much temp change.

Thanks for all the replies

The Triton charger should have shown you the initial voltage before you charged it, so you should have been able to determine how low it got.

If you've already recharged it, I'd check the balance on the cells with a voltmeter. If your pack doesn't have individual cell taps, you'll have to cut the shrink wrap off of the pack to get at the PC board to probe them. If they are still balanced, then just cycle it a few times with the Triton, and note the capacity you get out of it. If it's close to the rated capacity, then I'd say use it.

If the Triton says the battery charged, fly it. The Triton checks the battery out prior to and during the charge process. The several LiPos I stuck in trees were toast and my Triton told me so.

Cool... I didn't know the Triton did that... I've been lucky enough not to "toast" any of my packs so far, though! [8D]

Yeah, I even tried to cheat by telling the Triton the packs were something other than LiPos. In every case, LiPo or otherwise, the Triton beeped after a few minutes with an error message.

Thanks everyone for the replies, I'm still looking for a little more durable plane that can use the can type brushless motors with the GWS stick type mount. I loved the "tantrum" but boy was it fragile. You had to pick it up with two hands or you'd break wood!

Any Suggestions? I guess the Shock flyers need an outrunner style motor.

Thanks again to all

bigbird

Foam is the way to go IMO. Look for some plans to build a foamy out of Bluecor foam... readily available, cheap, can survive mild crashes, easy/cheap to repair. Check out the foamy forum here on RCU... there are posts with plans and links to plans for foamies...

Depending on chemistry and construction, Lithium chargers provide 4.1 or 4.2 volts per cell. The following is from a Poly Quest data sheet:
"PolyQuest engineers designed the Protection Circuit Module (PCM) to greatly reduce the chance of accidents while charging lithium polymer batteries. It is critical that each cell is
limited to a maximum charge voltage of 4.2 volts per cell and that only chargers approved for lithium polymer batteries are used."

There are no chargers that charge individual cells, except single cell chargers (that is a pack with only 1 series cell in it). Things like the Poly Quest PCM Guard monitor each cell's voltage to protect against exceeding the 4.2V per cell limit. If the PCM Guard detects a cell inbalance, it disconnects the pack from the charger. Again from Poly-Quest:
"If the PCM Guard detects that any one cell in the pack exceeds the limit it will electronically disconnect the pack from the charger and the warning LED light will go out on the PCM
Guard. Take a 3S for example. Even the best lithium polymer smart chargers, set properly by you, would want to charge this 3S pack to 12.6 volts. What happens when 2 cells
reach 4.2 volts each (ed. and the third cell doesn't)? The charger continues to charge trying to reach the 12.6 volts. Meanwhile, the 2 charged cells are being overcharged since the
charger doesn't think the pack is charged yet."

If you have a pack, like the Tanic packs, with individual taps for each cell, you can set your charger for a 1S pack and charge each cell individually. The recommended way to balance packs quickly, is to charge the whole pack to about 80% of it's max voltage, and then top off the cells individually.

The Poly Quest also have taps.

so, I just got my plane back from it spending the night in a tree... the battery is a Kokam 3s 1500, it was down to 4.6v overall after recovery. On my vision peak charger, I tried it on lipo, and it only went to 8.4 like it thought it was 2cell. so I hit it with nimh charge for about 30sec, brought it up just over 9v, then hit it with lipo charge again. pack charged all the way up, but overnight dropped back to 12.15v.

after reading this thread, I went and cut off the casing, and measured the individual cells, getting 4.04, 4.04, and 4.03. Does that mean the pack is still safe to use?

I don't have any advice on the battery, but next time try doing what I do, and hit the tree fast enough that it just rips the wing off and the fuselage comes on down.
Mark

While the Triton is almost "un-decieveable", It still cant tell if a multi-celled lipo is unbalanced.
And Ive got a 3cell battery here to prove it. One bad cell and two good ones. Basically it knows something is wrong, it just doesnt know what. The Triton is a superb charger, but not perfect.

Basically the triton will adjust amperage rates to keep the pack from overheating and to maintain max performance. So with this one bad cell lipo I have, it just tries to charge it at a low amperage rate.....for a LONG time. No error messages, etc. I wont fly it again, but I do use it as a test battery when Im just tweaking on my planes at home. I figure one day, Ill take it out back and do one of those lipo explosion demo videos. Crank about 5A to it and watch it go boom. Get it all on video

Most chargers cant tell if the cells are imbalanced. Thats why Tanic and a few others put taps on each cell, so you can manually check them.

Each cell, fresh off the charger, should measure 4.1V. After a period of time the batterie's internal resistance may drop the voltage some. Sounds like your battery is OK, give it a spin.

I beg to differ. You said it yourself "Basically it knows something is wrong." Is the Triton's failure to complete the charge cycle not an error indication? The Triton charges for a few minutes then monitors battery voltage then starts charging again. If you watch the display you can see this happening. It is this mechanism that keeps from overcharging the battery assuming the user sets the charger properly. If the taps on batteries you mention are for manual cell monitoring, they shure aren't user friendly. The taps are for connection of safety devices that prevent each cell from being over charged. It is possible to measure each cell's voltage with the taps, but that is not their primary purpose.

well, after 3 charge cycles, and 2 uses, my battery seems right back in form. My experience with NiMh batteries was that when they went bad, they would still charge up to normal voltages, but didnt put out much real power in flight. My Lipo put out just as much as I would expect from it, and is now holding at 12.28v after 24hrs. Its a Kokam 3s 1500 (8-10c)