Problem with my lipos

workaccount

Hi,
I have an issue with both my lipos. The batteries Are 22.2v 5000mah Thunder power extreme v1.

I have the thunder power TP-1010c charger and the TP210v balancer.

As of writing now I have the one lipo plugged into the charger and balancer and if I check the reading of the cells they are all in or around 3.8v with the difference between the highest and lowest being 0.025v.

When I go to charge the battery it will start charging and after a very small time I get an error "Imbalance over 0.2v".

I am charging the 6s at 5 amps.

Nearly immediately after I start charging if I view the balancer info one cell will jump up to 4.1v. This is why it's erroring (over 0.2v) and won't let me charge. As soon as I clear the charging error screen and check balancer info again everything is all down at 3.8v??

I bought these battery used with a helicopter but the previous owner says there are only 40 cycles on it.

I'm not sure if there's a problem with the battery or the balancer. It's possibly the balancer as my other battery causes problems aswell albeit is is different. When charging it to 95% it errors saying something like cell over max voltage. The balancer perhaps is not working fast enough or is providing false information?

The only change I have made to the charger itself is upgrading the firmware to 2.3a to enable other types of battery to be charged such as NI-MH and to be able to recover a battery which has gone below min. voltage - my beginner mistake.

I know that when I bought all this equipment used it worked. I can't remember if I only started getting these problems after the 2.3a upgrade. Any help appreciated.

coolwings

workaccount wrote: »

.... I bought these battery used with a helicopter but the previous owner says there are only 40 cycles on it....

That is probably more cycles than the average beginner gets from lipos before terminally damaging them. Really determined beginners manage to do it in the first cycle.

Personally I would never buy a used lipo from anybody at any price other than absolutely free. Even then I would be considerate of the possibility of wrecking a good plane due to the unexpected failure of "the free pack", and still having a free pack cost me a bundle!
(But I appreciate this does not help you with the situation you find yourself in. It's so as to give you an idea as to how low I suspect your chances are of a good outcome to this.)

Speculations:
Either you have a pack with the weakest (usually middle) cell torched, and the other cells in varying states of remaining lifespan.

Or you have a funny charger balancer setup.

How about you run the pack under load for a short time? Depends on it being partially charged of course.
Then measure the temperature of the individual cells. If one cell has increased internal resistance, then that cell will be hotter than the others, and thus give you a hint as to where to look.

If the cells have a uniform temperature, then the charger-balancer setup is more suspect. That might be easier to correct.
In this case you should investigate if it is possible to reset to mfg settings, and undo the upgrade that you have doubts about.

coolwings

Independent test chart attached for Thunder Power Extreme new version lipos.

Remembering that lipos really hate going over 65 degrees, take a look at the temperature Thunder Power Extremes labelled 25C/50C reach on a discharge of just 20C as they get close to empty during a discharge/model flight.
The graph shows how a run at 30C, with multiple rest periods, (called pulse discharge) stays under 65 degrees, just. So there is temperature limit for continuous discharge of half the stated C rating. Exceeding the proper temperature affects lifespan adversely.

It is (in my opinion) an example of "creative" labelling, remember the cells can definitely do over 25C, BUT ONLY PROVIDED SPECIAL COOLING HAS BEEN ARRANGED IN THE MODEL, so there has been no falsehood on the label, just economy with the facts maybe.
Looking again you start to get an idea that to do 25C (as stated on the label) continuous, the batteries would have to be under a certain room temperature at the beginning of the flight.
Now you can see how a beginner who thinks these can do 50C, or even 40C, or even just 30C will kill them very quickly if they use that as a continuous discharge rate. Kill them by overheating them that is. The 50C would be for a couple of seconds max. I would guess 30C would damage them in 30-50 cycles based on the chart here.

The cells would rise in resistance due to being roasted, and still function, but not for high power. They would get hot when asked for high power after that time has been reached. This leaves them OK for slower models after that, but one power run would destroy them then.

Maybe that's why (some) makers sometimes don't show temperature on their battery discharge charts, and (some) modellers pay absolutely no attention to articles and reviews of lipo batteries unless they are done by known individuals!
A brushless motor manufacturer told me once ...for some Lipo makes divide the lipo C rating by three, and the others divide by 2!

syl77

Hi workaccount, have you tried cycling the packs....

coolwings

Did you get the charger cutoff to stop tripping?

workaccount

coolwings wrote: »

Independent test chart attached for Thunder Power Extreme new version lipos.

Remembering that lipos really hate going over 65 degrees, take a look at the temperature Thunder Power Extremes labelled 25C/50C reach on a discharge of just 20C as they get close to empty during a discharge/model flight.
The graph shows how a run at 30C, with multiple rest periods, (called pulse discharge) stays under 65 degrees, just. So there is temperature limit for continuous discharge of half the stated C rating. Exceeding the proper temperature affects lifespan adversely.

It is (in my opinion) an example of "creative" labelling, remember the cells can definitely do over 25C, BUT ONLY PROVIDED SPECIAL COOLING HAS BEEN ARRANGED IN THE MODEL, so there has been no falsehood on the label, just economy with the facts maybe.
Looking again you start to get an idea that to do 25C (as stated on the label) continuous, the batteries would have to be under a certain room temperature at the beginning of the flight.
Now you can see how a beginner who thinks these can do 50C, or even 40C, or even just 30C will kill them very quickly if they use that as a continuous discharge rate. Kill them by overheating them that is. The 50C would be for a couple of seconds max. I would guess 30C would damage them in 30-50 cycles based on the chart here.

The cells would rise in resistance due to being roasted, and still function, but not for high power. They would get hot when asked for high power after that time has been reached. This leaves them OK for slower models after that, but one power run would destroy them then.

Maybe that's why (some) makers sometimes don't show temperature on their battery discharge charts, and (some) modellers pay absolutely no attention to articles and reviews of lipo batteries unless they are done by known individuals!
A brushless motor manufacturer told me once ...for some Lipo makes divide the lipo C rating by three, and the others divide by 2!

Very interesting. How can I tell how manys c's the helicopter is drawing?

Is there a way to draw battery power at various loads in a test environment to compare temps at various c's to your graph for example?

coolwings

You can use a wattmeter to read live data in the model.

If you haven't got a wattmeter (get one) allow about 200 watts per kilo of model for the hover, weigh your model, and divide the total watts power by the voltage (3.0V per cell! not 3.7 or 4!) to get the amps, estimated.
Depends on an efficient setup, free linkages, german components, ... for cheap speed controllers and plug connectors add at least 10% more load, maybe 20% to the estimated power the battery must give.

Drawing different loads .... usually done by fitting smaller props. But for a heli you could drop rpm with the same prop and measure the different loads at each throttle setting. With a wattmeter it's simple.

You get my point though? After eliminating overcharge and deep discharge, it's not the volts or amps that matter. Cheap packs and mislabelled packs still give similar volts and amps.
It's the temperature rise (under load) caused by internal resistance that kills them.
The best cells have lower internal resistance. They are not the cheapest cells, but they are the cheapest cells over time by far. The quality control of different sellers varies greatly in this. At www.greenhobbymodel.com we have zero failed "quality" packs (not incl user abuse).
OTOH the cheap chinese packs are a whole different world, and I do not waste my own personal money on them. Then there are the relabelled rebranded chinese packs, and all the ads say it is wonderful ..... but they are the same crud inside .....

But even that is oversimplifying it, reading the makers internal resistance figures, because resistance rises. Some low resistance packs increase in resistance relatively quickly as you use them, and others don't, or increase in resistance much slower. Those have a far, far longer service life. This is the expertise you get in Green Hobby & Model , and some other LHSs like Fred where the staff actually use their stuff and have done so for a long time.

syl77

You can use a wattmeter to read live data in the model.

If you haven't got a wattmeter (get one) allow about 200 watts per kilo of model for the hover, weigh your model, and divide the total watts power by the voltage (3.0V per cell! not 3.7 or 4!) to get the amps, estimated.
Depends on an efficient setup, free linkages, german components, ... for cheap speed controllers and plug connectors add at least 10% more load, maybe 20% to the estimated power the battery must give.

Drawing different loads .... usually done by fitting smaller props. But for a heli you could drop rpm with the same prop and measure the different loads at each throttle setting. With a wattmeter it's simple.

Are we talking about calculating C's while heli is in the air, surely a wattmeter can not give a good reading during different flight menouvers, i.e. tic tocs, I think a system like the eagle tree system would give best results, but those cost a bit. It also has temp sensor.

The best cells have lower internal resistance. They are not the cheapest cells, but they are the cheapest cells over time by far.

very true, packs like flightpower and thunderpower are the best.

loopingfred

Hi Guys,

Agree with all of the above !
Invest in a wattmeter, maybe one of your best buy ! (Xmas is closing in ! )

very true, packs like flightpower and thunderpower are the best

I would add to the list Polyquest (The XP serie is brilliant !) and a relatively new comer in Zippy, with really good actual specs, a one to keep an eye at in the future I think...

For "reading" data in flight, there is another system than the Eagle Tree one (excellent stuff btw !) but I cannot remember the name ! I'll try to find that out... Reading is made on a 4 line screen "live" if I remember but not sure...

You can also have "recorders", but you will need a Laptop at the field to read the data.

Fred

syl77

Thought the following link would be a help in comparing all the different lipos on the market
http://progressiverc.com/Research.html

It also includes other electric components too.

workaccount

coolwings wrote: »

You can use a wattmeter to read live data in the model.

If you haven't got a wattmeter (get one) allow about 200 watts per kilo of model for the hover, weigh your model, and divide the total watts power by the voltage (3.0V per cell! not 3.7 or 4!) to get the amps, estimated.
Depends on an efficient setup, free linkages, german components, ... for cheap speed controllers and plug connectors add at least 10% more load, maybe 20% to the estimated power the battery must give.

Drawing different loads .... usually done by fitting smaller props. But for a heli you could drop rpm with the same prop and measure the different loads at each throttle setting. With a wattmeter it's simple.

You get my point though? After eliminating overcharge and deep discharge, it's not the volts or amps that matter. Cheap packs and mislabelled packs still give similar volts and amps.
It's the temperature rise (under load) caused by internal resistance that kills them.
The best cells have lower internal resistance. They are not the cheapest cells, but they are the cheapest cells over time by far. The quality control of different sellers varies greatly in this. At www.greenhobbymodel.com we have zero failed "quality" packs (not incl user abuse).
OTOH the cheap chinese packs are a whole different world, and I do not waste my own personal money on them. Then there are the relabelled rebranded chinese packs, and all the ads say it is wonderful ..... but they are the same crud inside .....

But even that is oversimplifying it, reading the makers internal resistance figures, because resistance rises. Some low resistance packs increase in resistance relatively quickly as you use them, and others don't, or increase in resistance much slower. Those have a far, far longer service life. This is the expertise you get in Green Hobby & Model , and some other LHSs like Fred where the staff actually use their stuff and have done so for a long time.

If I did get a watt meter does it record highest load that I can read once landed? That would be great.

The reason I would still like to setup a test enviroment to test the batteries temp at different loads is to estimate where they are in their life now. If there still not capable of running 20c continuous like they would have been new they may still be capable of running at 17c continuous for alot of cycles so I could adjust to chopper head speed to not draw anymore thus keeping the temp. under 65 degrees for many cyles to come.

My charger only lets me discharge up to .9 amps!

coolwings

Tether the heli to the ground. Put a wattmeter on the side where it's visible from 5 feet away.
Start and run the motor up to the expected headspeed/throttle.
Now just look at the wattmeter and read the screen.Wait 45 seconds to see if there is battery voltage brownout/fade on this load which might lower the rpm. If there is, read the new power consumption.
You see all you need to know. Running on the ground increases your power demand, so you see a maximum reading, that should not be exceeded while in flight at the same throttle level.

Of course you can get a data logger with sensors, fly the model, land, hook the log up to your computer and download the nice little graph.
I might do that if I had a spare lifetime to waste and believed the reviews for such things. But my wattmeter is effective and simple and does everything I need.

syl77

Tether the heli to the ground. Put a wattmeter on the side where it's visible from 5 feet away.
Start and run the motor up to the expected headspeed/throttle.

I would not consider that a safe thing to do, especially with a 600 machine, you would be putting yourself in line for a darwin award or at least wrecking your machine.
If you do insist on doing it, try throttle up to mid stick (0 degree pitch), click it into idle up 1 or 2 and then give it minus collective - pushing the heli back on to the ground instead of up.

The eagle tree system is very acurate, it even has a temp sensor for lipo and motor and is well worth the hour setup, 5 min flight and 5 min download of graph. The only disadvantage to it is the extra cost, but if your serious into to electrics then it does give good info.

workaccount

coolwings wrote: »

Tether the heli to the ground. Put a wattmeter on the side where it's visible from 5 feet away.
Start and run the motor up to the expected headspeed/throttle.
Now just look at the wattmeter and read the screen.Wait 45 seconds to see if there is battery voltage brownout/fade on this load which might lower the rpm. If there is, read the new power consumption.
You see all you need to know. Running on the ground increases your power demand, so you see a maximum reading, that should not be exceeded while in flight at the same throttle level.

Of course you can get a data logger with sensors, fly the model, land, hook the log up to your computer and download the nice little graph.
I might do that if I had a spare lifetime to waste and believed the reviews for such things. But my wattmeter is effective and simple and does everything I need.

syl77 wrote: »

I would not consider that a safe thing to do, especially with a 600 machine, you would be putting yourself in line for a darwin award or at least wrecking your machine.

The eagle tree system is very acurate, it even has a temp sensor for lipo and motor and is well worth the hour setup, 5 min flight and 5 min download of graph. The only disadvantage to it is the extra cost, but if your serious into to electrics then it does give good info.

If I got a watt meter that just records the max amperage in a session wouldn't that do the trick. ie. If someone was doing an advanced maneuver on the chopper then when it lands I could look and see the max. used was 22c and know in the future that the battery can take it.

I'm thinking "Watts up" at the moment but haven't confirmed it can do what I want. What I have listed above is the only solution I want/need at the moment.

coolwings

syl77 wrote: »

I would not consider that a safe thing to do, especially with a 600 machine, you would be putting yourself in line for a darwin award or at least wrecking your machine.....

Errrr - I've done it with helis up to .60 size, a lot bigger and a lot more powerful, nothing broke and I'm still here.
When I said tether, I meant that. Not a tiddly little bit of string.
I use 6 feet of clothes line through the UC bows and 4 x foot long screwdrivers tent pegged into the ground.
Before I developed this better method I used to use tyre levers and concrete blocks. It ain't going nowhere!
But of course Syl your way would also work just fine too.

workaccount wrote: »

If I got a watt meter that just records the max amperage in a session wouldn't that do the trick..

Not sure what you mean there. Are you sure we are talking about the same piece of kit here?
A watt meter shows you live, every moment, what is being consumed right then. You rev up, see the effect, rev down see the effect, go to max throttle and it's there on the screen looking at you. Not a total figure you look at when it's all over, you're monitoring battery voltage, amps current, power (watts) and cumulative watts, live, every second.

Look at this to see the setup:


Now look at this:
Top is after plugging in, throttle off, power zero.
Lower is 30-60 seconds later on full throttle with twin jets blowing over 350 litres of air per second.
The battery is under very heavy load now. The model has consumed 691 milliamp hours so far

At 65 amps (full throttle with it's "small pack") my A-10 had serious brownout on those cells, 17V down to 11.5Volts! That's a hard test for many batteries to pass.
Now, if I told you that a 17V pack was going to draw 65Amps in my model you might think that I had 17.1 x 65.1 = 1.11 kilowatts. Right?
WRONG!
Under such a heavy load see how the voltage of the pack sags 6 volts down to 11.5V.
So the power I actually get is 11.5 V x 65 A = 750 Watts of power.

The wattmeter is showing the falloff well, but the realtime view shows the tiny time lag in power calculation as the brownout occurs.

By the way at 3/4 throttle I get the same power, by matching my throttle to the max battery's ability.

And if you ACTUALLY HOLD the pack while draining it so fast it is the strangest sensation. The heat magically appears inside the cells from inside, like their heart is going on fire and you can feel it. It is an odd feeling, knowing energy from electrons is flowing inside, then seconds later the heat wells up and out.

Hope this explains how we use these tools.

workaccount

coolwings wrote: »

Not sure what you mean there. Are you sure we are talking about the same piece of kit here?
A watt meter shows you live, every moment, what is being consumed right then. You rev up, see the effect, rev down see the effect, go to max throttle and it's there on the screen looking at you. Not a total figure you look at when it's all over, you're monitoring battery voltage, amps current, power (watts) and cumulative watts, live, every second.

Well I think at the beginning my requirements are much less than you use. If my battery is able to cope with 25c for a full session without going over 65 degrees then I want to use the wattmeter to measure if my chopper is pulling more than 25c.

So I want to hook the watt meter up and take my chopper for a spin...then check the max amps drawn during that session and if they are too high reduce the head speed. That's all I want it to do now but I'm sure I'll discover more uses in the future. So the only problem I am trying to to solve for myself by buying the watt meter is to to minimize resistance buildup from drawing too much current hence maximizing battery life!



I would also like to have a device that I could use to discharge my batteries at 25c ie. 125amps. and monitor temperature to make sure no cells are going over 65 degrees.

If they were going over 65 I could assume resistance has risen and the batteries are no longer in good enough condition to be ran constantly at 25c. Although more testing could dictate that they are still in good enough condtion to be ran at 22c for example constantly. I could be completely wrong with the above non-educated theory?

coolwings

How about this:
Example
My model weighs 2 kgs ready to fly.
To hover it will require 180Watts per kilo, to 200 W/Kg.
Therefore it needs 2kgs x 200W = 400watts
This model has a 4S 3200mah lipo pack with a labelled voltage of 3.5 x 4 = 14V
Under load it will be 3volts per cell that makes the real voltage 3 x 4 = 12V.

Power (watts) = volts x amps.
So my model's 400 watts = 12V x the amps

400 / 12 = amps = 33.3A

And with my 3.2 amp cells that is just over 10C, which is what most 20C labelled lipos are just about able to do continuously.

No wattmeter. Good maths!
Assumes good components. Add maybe 20% extra capacity (maybe 30%) for money saved at the equipment buying stage if things are not to melt/emit smoke!

Do that for yours plugging in your own equipment's power and weight.