Battery substitute (CHEAP)

[cabinfourus]

The C rating is the most critical with flight batteries. Lithium Polymer batteries are used over the other lithium types only because of the high discharge current they can provide. They are extra dangerous because of this, but it's the only reason they are used. A Typhoon H draws 10 to 20 Amps in flight; more than an electric bar heater. Li-ion batteries can't provide this.

You would be correct. The C rating is basically how fast a battery can deliver it's power to the motor(s). I have ran some tests on the battery I posted about here and the results are actually favorable to the drone. My concerns are the cell amounts. With a Yuneec battery having only 4 and this battery having 8 it does change the delivery dynamics a bit. I still have a few things to test before I put this thing in a drone but I will post my results when I finish.

I have gotten side tracked with my 'honey do list' lately and haven't had time to get back to this project. (c:

 

[cabinfourus]

Have you actually performed load testing to confirm that statement? I have, and have done so repeatedly. The correct value is in excess of 40 amps but less than 50 with normal and aggressive flight profiles.

Locate and review my thread about alternative batteries for the data.

I have ran amp, draw, and load tests on the TH and my results differ from yours also. My amps reached a max of 26 on an H and only 44 on an H Plus.

There are way too many variables here to compare my results to someone else. Things like wind, flight speed, climb rate, weather, and pilot will change the results. Also, the H and H Plus both have different setups and hardware, so their results are extremely different when it comes to measuring the batteries numbers. Where the H only pulls around 18-28 amps (depending on many variables) the H Plus pulls up to 50. I am guessing this is where you and the other member's numbers differ. He may be talking about the H and you the H Plus.

The battery for the H Plus is rated at 50 amps. The battery for the H is rated at 20.

With all this said, I should be a bit more clear on this laptop battery. I am testing it more for the H and not the H Plus. I am sure if someone wanted to research this more, they may find a type of laptop battery that could handle the H Plus's amperage draw.

I only replied to this because of the "foolish" comments. So everyone would understand that both sets of numbers are correct if you look deeper into the specifications.

 

[cabinfourus]

Based on that information, the 8S would be two 4S batteries in parallel to provide a 14.8v output. I suspect you will find the max C value to be way too low to be usable for either aircraft. Typically Li-ion batts are used in low power applications.

Exactly. This is the area I was working on. The laptop this battery fits is huge and pulls some serious loads. The actual specs list it at 14 amps. A laptop battery is designed to give steady and consistent power over longer periods of time than a drone. Drones require quick amps for things like take-off, wind, turns, etc. This being 8 cells it would be smoother amperage but slower and is the problem I am working on. I want to keep the cost under 30 bucks.

If I were to guess at a C rating for this laptop battery I would say around 4-6. The Yuneec H battery is a 8C battery, so it is close. If for nothing else, this laptop battery could be used for 'normal' flying. What I mean by normal is a slow take-off, not much wind, and a lot of hovering. I really hope this battery surprises me when I test it. The biggest reason I stated this project was due to the Watt Hours being so close on both batteries.

 

[PatR]

Cabin,

I’ve never owned an H Plus. All my load tests have been performed on H-480 and 920 Plus models. All testing was intended to capture loads at peak values using the most stressful, max thrust flight commands. Typical weather conditions were ideal for general flying.

 

[Steve Carr]

If for nothing else, this laptop battery could be used for 'normal' flying.

You are working on an interesting project and many of us will be curious regarding your results.
When you are prepared to do a test flight it might be best to leave the camera in the car in the event something doesn't go right.

 

[PatR]

Agree with all of Steve’s post.

 

[thoneter]

You are working on an interesting project and many of us will be curious regarding your results.
When you are prepared to do a test flight it might be best to leave the camera in the car in the event something doesn't go right.

I'd say do a test flight with the drone bolted down so when it fails it only has 0 feet to fall!

 

[PatR]

Funny thing you mention that as it is how I test out new builds to assure they are fit to fly.

 

[thoneter]

Funny thing you mention that as it is how I test out new builds to assure they are fit to fly.

It's how I test my wax wings in the Arizona summers!

 

[Whisperit]

I really should watch these threads more often...

PatR - no, I have never actually measured the loading on my H520! Quite an awkward thing to try to do I imagine....

But considering that a flight might only last 20mins if flown aggressively and that would use up about 5000mAh of battery capacity, then that means the mean draw was around (5Ah/0.333hrs=) 15A.

Of course, peak loads can be much higher, but most good quality LiPo's can cope with very brief discharges well about their C rating. But 15A is well above what a Li-ion battery can safely supply for 20mins. Still, the results will be interesting.

 

[PatR]

I’ve measured over 44A with a Typhoon H-480, which I found surprising. The start up and camera loads are very small, averaging a little over an amp each. As you say, the flight loads are the big power drain, with hover and full throttle being the worst. One has nothing to assist lift while the other feeds motors always wanting more.

 

[PatR]

Oneter,

There are some pretty tall mountains in Arizona. Find the highest one on a summer day to see what happens[emoji6]

 

[Sureshot]

It was during a hand catch at the end of a flight.
The voltage was low (14.6) and I accidentally bumped the flight mode to "smart".
The result was a full power surge.
Since the voltage dipped lower, the current went way high to make power.
I don't know the max amps, but it was enough to burnout all 4 power FET's.

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[Whisperit]

PatR: Was that 44 Amps a brief surge? Do you know how long it lasted?

 

[h-elsner]

Here is a chart from Typhoon H Plus flown in Sports mode:

It's going up to 50A peak. I think for the H480 it is nearly the same. It has the same weight thus needs the same energy.

There are 18650 LiIon cells up to 30A peak. For 4S2P you must plan some more money.
I found a cell 15A nominal, 20A peak for 7 Euro. I don't know how good it is (noname).

br HE

 

[PatR]

PatR: Was that 44 Amps a brief surge? Do you know how long it lasted?

I do not know the duration of max power draw. The inline device used measures and displays the load as it occurs but only records the low and the high. For weight and simplicity I did not employ a full recorded broadcast telemetry system.

Reason for that was knowing that additional weight added to the aircraft would induce higher power consumption, which would have had more impact on data generated.

A reasonable assumption would have peak power consumption occurring during any period the aircraft accelerates at full power from a take off or hover using full throttle. Although not proven at this time it is possible it also occurs during periods of full power extreme maneuvering flight with GPS turned off. Multiple flights were performed using “normal” GPS “on” with mild maneuvering and max performance mode with GPS turned off.

You could locate and review my alternative battery thread and review the numbers posted. They were reasonably consistent across numerous flights. The break downs also included aircraft and battery weights.

 

[Whisperit]

h-elsner: That's a great graph! Saved to my "useful info" folder. What logging system did you use?
PatR: I did find your Alternative Battery Thread, read a bit then saw it is now 11 pages long....!

 

[h-elsner]

The graph is from Sensor_*.txt file in the ST16S which is a part of the Flight2Log file collection. The sensor file has misleading file extension. It is a binary file containing MAV link messages.
Unfortunately the Typhoon H did not record values for current, the H Plus did in the sensor file.

br HE

 

[PatR]

If anyone wants to expend the expense and effort, Eagle Tree offers a fairly comprehensive selection of telemetry recording and/or live broadcast system, along with numerous different sensors. They aren’t cheap but I’ve had one for close to 15 years and it still functions just fine. They are quite accurate and download telemetry to an Excel graph. They also make a very good and easy to set up flight controller. The instruction manual is stellar.

 

[cabinfourus]

I’ve measured over 44A with a Typhoon H-480, which I found surprising.

As do I. The C rating of a Typhoon H battery is 8. If you do the math, this will tells us that the H battery has no more than 43.2 amps at any time.

I did find something VERY interesting that I will share with you all. The 3DR Solo drone uses the same exact battery specs as the TH. I repair drones for people and a guy brought me his 3DR Solo that he thought was a submarine and had flown it into a lake. He said that he had put the drone in his basement for two years and lost interest in it. He had 4 batteries with the drone and I tested them. All 4 batteries still had a nearly full charge. He let me keep one of them to open it up and see what cells were in it. The 3DR has flat cells but the numbers came back to a company in the US. I tested this battery with my TH and it held up way better than the OEM Yuneec battery. Out of 9 flights, the average fly time was 24 minutes. Now, this was w/o the real sense module. I did run the CGO3+ camera during all flights.

If you choose to open one of these batteries up yourself, be very careful!