FLIGHT TIMES ( simple Math, but mind blank ) HELP !!

[hghost]

Ok...I finally got some flight time with the Super Cub this evening

Had a Great time.

OK, so here is the question and forgive my ignorance and mindless moments

My memory at times, just seems to go blank

I used 3 Parkzone Batteries I bought a couple years ago. they have been stored charged and cycled

Now....I know a 3 S 1300mAh battery charges to 12.60V and 4.20 per cell

I could not remember what times I had gotten before...so to be safe, i set the first battery at 7 minutes.

At about 5:54 it seemed the plane was a tad sluggish. I had to throttle almost all the way up to keep her level
I assumed the battery was near LVC, so I landed.

I installed a new battery and re-set my timer to 6 minutes and went again...once again near the 6 minute mark, the plane
seemed to need almost full throttle to stay aloft ( it was a little windy -not bad tho )

Landed with a few seconds remaining

Installed 3rd Battery and flew almost 6 minutes and landed with 43 seconds left on the timer ( wrote it down )

Ok so hear was the Battery numbers ( wrote them down to )

Batt 1 was 11.1 and each cell was-3.72-3.71-3.75
Batt 2 was 11.9 and each cell was-3.96-3.97-4.01
Batt 3 was 11.9 and each cell was -3.96-3.97-4.00

I used one of those small battery checkers to check the batteries.

These numbers appear to be about HALF ? Should have another 5-6 minutes perhaps ?

I noticed when charging these Parkzone batteries, they seem to never balance perfectly...one cell in every battery is
always off and always the same cell on each battery.

I also wonder about the sudden, seemingly loss of power below the 6 minute mark...Always have to throttle up higher to stay aloft ( if that makes sense ?)

SO with those numbers , it seemed I could have flown longer ( but brain dead moments like mine, I can't remember )

I had thought at one time I flew 9-10 minutes before coming no where near the LVC , But again I can't remember ?

HELP....lol

[sham]

The numbers do indeed indicate about half left, but the problem is the park zone batteries.
I've binned mine as once they had a few cycles on they never balanced properly and the voltage sag was so bad under load that they would LVC even after 5 minutes in the Supercub.

When checked after, they showed to be above storage.

I bought OverLander brand 1350mah batteries because they are the same physical size as the Supercub stock ones and never had a problem since. Regularly get 14 minutes out of a battery.

[flydiver]

Do you keep your batteries fully charged so you are ready to fly?

As sham indicates, voltage READINGS are not the same thing as voltage SUPPORT/CAPABILITY.
A good battery maintains it's voltage during use and only 'sags' toward the end. A poor battery can sag from full voltage to LVC almost immediately and then show almost full voltage when checked.
Voltage ALONE is not a good indicator of performance capability.

Your best tool for this is a wattmeter. You hook it up, throttle up, and you can see what the battery voltage is doing. But a perceptive pilot familiar with a plane can do the same thing, just not as precisely....with numbers to back it up. That's what you are doing.

All batteries age and this inability to support voltage is a main symptom (ignoring puffing, and other failures). Poor quality and poor care are the main reasons for poor performance. The PZ batteries are not great. Finding good replacements is it's own trial since lipo quality is a moving target.

[hghost]

Thanks guys, I keep the batteries at store charge, I do not charge them fully until I am ready to fly.

I have three of those ParkZone ones. they always seemed to do well until now ( but they are older )

I also have a couple Turnigy Batteries, I use them in my Decathlon. They are just a tad longer than the ParkZone .
Hard to get in that battery box..I modded it the other day, so they should fit better now...i just have not used them in the Cub
because of their size..plus they have a XT60 end and I have to use a adapter means more wire to push in that small box.


Figure I will need to order better ones.

Will the 1500mAh 20C be Ok in the SC ? They are about the same size in length a tad difference
1300's are -Pack Size: 78 x 33 x 24mm and the 1500's are-Pack Size: 78 x 34 x 24m Turnigy's

I do not want to push that brushed motor, but I would assume the 1500 would give allot more flight time ?

But as you say fly...getting even good lipo's now days is a shot in the dark...even if one time you got great ones
the next they may be horrible.

overLanders are across the pond.

thanks Sham and Fly

[sham]

The 1500s will be fine if they fit, people use 25C 2200 with no issues. My Overlander are more than 20C I think, and each have many flights in the supercub with no issues whatsoever.

You will get an extra minute or 3 out of them, for sure.

[hghost]

When I get the chance i am going to push these Parkzones and see how far they go.

I fly several models when i get to fly, so I have a couple Turnigy batteries already, I can run in the SC

It has been awhile since these Parkzones have been run...after a couple cycles they may perk up
I had some Turnigy's that seem to be dying and they perked up after a couple cycles through a model

It was just odd and my simpleton mind sometimes fails me...I have to ask

Seems some of the 2200's are pretty long, will have to see if I can find some shorter ones
I modded my batt box by cutting the back of it out, it gave me about an inch and a half space i think it was.
Still tight fit , but allot better than it was.

Thanks Sham...

[sham]

Same mod I did to mine. I've never used a bigger battery, but the extra space is great. Makes life a little bit easier

[Knackered Sailor]

Wey Hey!  Things are looking up with a real discussion of a real problem.   This forum was having to become a ranting site against endless global wind, cold and rain. 

[flydiver]

2200 are long.  If you find shorter, they'll be fatter. Got to stick those electrons somewhere. The usual mod it to cut a hole in the top of the battery box and mount it vertically against the firewall. This can mean moving some components that are now mounted there which weren't long long ago before lipo and SAFE. That was before 2.4GHz......ugh, showing my age.

[hghost]

I started to Mod the top, but decided against it...went to the back instead

Well sort the battery issue out next time I get to fly...hopefully those batts will perk up a little
and even if they do not, No big loss.

[flydiver]

May 29, 2015 23:20:23 GMT 1 hghost said:

...hopefully those batts will perk up a little
and even if they do not, No big loss.

If they are old, it would seem unlikely. As batteries age their internal resistance goes up. Think of it as the pipe allowing power out getting smaller. As long as the 'draw/need' does not exceed the flow, all is well. Once the requirement is more than the pipe can deliver > failure.

When the battery is full it can 'push' a bit harder over coming the resistance somewhat.
If you make the draw lower (fly slower), it can work a bit longer.
But, ultimately it's a downhill slope from there as you are now working the ragged edge.

[hghost]

May 30, 2015 3:43:04 GMT 1 flydiver said:

May 29, 2015 23:20:23 GMT 1 hghost said:

...hopefully those batts will perk up a little
and even if they do not, No big loss.

If they are old, it would seem unlikely. As batteries age their internal resistance goes up. Think of it as the pipe allowing power out getting smaller. As long as the 'draw/need' does not exceed the flow, all is well. Once the requirement is more than the pipe can deliver > failure.

When the battery is full it can 'push' a bit harder over coming the resistance somewhat.
If you make the draw lower (fly slower), it can work a bit longer.
But, ultimately it's a downhill slope from there as you are now working the ragged edge.

TRUE

[hghost]

I did have a couple turnigy batteries that acted similar...seemed they lost punch after a bit...they had set for a long time at store charge

after using them a few times, they perked up and the times increased....SO...not sure what that was about
but they have done fine since.

maybe these Parkzones will do the same......?

[flydiver]

That's possible. Sitting a long time vs regular use can be different. It is suggested by those I've come to trust to do a few easy cycles on new lipos to break them in > low draw and not excessive discharge. This apparently can improve their performance and longevity. Without knowing exactly why I'd suspect a lipo sitting long at storage would be kind of 'creaky' and act somewhat like a new lipo at storage. If the PZ have sat for months, they might improve. OTOH if they are old already they are still signalling you may want to start shopping around.
That's different than a well used lipo 'going down the tubes' with routine use. I've had a lipo do OK on a flight at the field, be recharged right there, and crap out never to recover on the next flight. I've also had hard used batteries go on and on and on, but never completely discharged, kept in their operating range, and kept at storage, just not 'babied'. Go figure. There is a science there, but with so many variables it's just about as much art and voodoo....which I point out is distinctly different from ignorance, stupidity, and abuse.

[hghost]

May 30, 2015 22:05:59 GMT 1 flydiver said:

Go figure. There is a science there, but with so many variables it's just about as much art and voodoo....which I point out is distinctly different from ignorance, stupidity, and abuse.

....

best post thus far