I measured it at 138 g. but let's call it 140. I use Tattu 850 mAh LiPo 95C batteries and with them the total weight comes in between 241 and 245. Sadly tthe individual battery weight varies up to 5 grams and I have the feeling newer revisions of the same battery are much heavier.

These batteries can provide up to 6-7 minutes flight time (possibly even a bit more if floating or keeping static altitude), if pushed to their limit normal flight time is up to 4 minutes. I am still new to the hobby and still do avoid dangerous tricks and flying through obstacles. I have also recently changed the standard antennas of my v2 DJI goggles and am testing/not risking range. As small as the Babyhawk II HD may look, it can go quite far away (I've chosen it with TBS crossfire) so the limitation is mostly with the goggles' range. And I need GPS as I already almost lost the drone behind a relatively nearby forest. The Nebula Pro camera is also very good so doesn't need any extra ones on the top (it took me quite a lot of efforts to get it instead of the basic Nano or similar low quality cameras this drone is generally provided with).

So, since this is the only drone I currently have and the investment so far including radio controller with extra CF module, the drone itself, charger with various adapters, the goggles, field battery testers, batteries, has been quite big, I want to stick to it as-is and use it for everything (at least for now, it is also a great all-rounder no matter how you look at it). Funnily the new DJI 03 system doesn't seem to be a revolutionary upgrade over the Vista - especially with horrible to average results in low light, much worse than the previous generation which is another reason to not push myself into spending more for marginal gains.

To return to the M100 Mini connections, did the photos provided shed more light compared to the Betaflight Ports information? They show what is available and how existing connectons are made. I can see Babyhawk videos on YouTube with GPS modules connected to existing FC that work very well, there is however no information of the connections made, just OSD and failsafe tests.

Hi d@wn,

Let's assume that one wants to maximize fly time even at the expense of performance
and stay below the 250 gram weight limit. To maximize Fly Time  the highest energy to
weight  ( Wh/grams ) for any given weight allowance. For example a battery with an
Energy ratio .175 Wh/g has more energy than a battery with one at .133 Wh/g.

So, starting with a craft having a dry weight of 140 grams leaves 109 grams Maximum
battery weight to stay below the 250 gram mark.  These numbers are actually pretty
good. I have one 4-inch that comes in about 130 grams dry, but most of my 4-inch rigs
are between 140-160 grams. I also tend to leave about 100 gram battery allowance.

From what I can tell, the Tattu 4S 850 mAh battery weighs about 104 (+/-) grams and 
has an Energy ratio of about .130 Wh/g. So there is 144 grams. So, this is about 6-7 
minutes of Fly Time, correct? . Now, if this quad is fitted with a GNB 3S 1550 mAh battery 
that weighs about 100 grams and has an Energy ratio of.177 Wh/g. The Fly Time should 
be increased; maybe by a couple of minutes. Only flight test will show any differences.

GNB also makes a 4S 850 mAh 60C battery that weighs about 73 grams. This battery 
does have an average C rating, but that doesn't matter for a cruiser.

Later, iFly 

Hi d@wn,

It all depends on what you want the quad to do and what you expect.

Oh yeah, switching to bi-blade props should improve the efficiency a bit.

When you get larger than a 3-inch quad, it becomes more challenging to
get a lot of fly time while staying below the 250-gram limit. In fact, we 
had a Challenge just to see what folks could do with it. Yes, it can be
done, however, none of these quads are hi-performance builds. 

I am working a sub-250 gram build methodology <-- click
Although it is still a work in progress, it should provide some insight
into building (or buying for that matter) this type of craft. The quad's
purpose determines whether endurance and fly time is more important
or is it gut ripping hi-performance.

A 4-inch is my favorite size for high altitude cruising, but this size (and up) 
needs a pretty large space. For the most part, I get around 10-15 minutes
of fly time with my 4-inchers. 

My pet size for a quad to just play around with is the 2.5-inch. Interestingly, 
I get around 17 minutes of fly time from my 2.5-inch all stock GEPRC Phantom 
(analog) when fitted with a GNB 3S 1100 mAh 68 gram battery. 

Yes, all are of my drones that are less than 7-inch weigh less than 250 grams. 

More, Later, iFly  

I am unsure if I understand correctly - can 3S batteries with higher capacity be used on drones with recommended 4S ones? I use the recommended by Emax 4S 850 mAh, although a higher end, battery for this drone. Can you use different cell batteries, you know motors are designed for certain voltages so I never experimented as I don't want surprises.

The Babyhawk can probably fly 10+ minutes, there was a guy on YouTube who did 20 minutes however he reached some unsafe battery levels. I try to avoid unnecessary cycles so only charge my batteries to 4.16V and discharge them (on the drone) to 3.80V, always using less than 1c when charging. I know I can go much higher safely but I won't do. The Babyhawk can float for I guess at least 10 minutes with a 850 mAh and can be also used for long range too but I won't go into either 700 mW, not to mention 1W or more, millimeters above my brain and into the eyes. This is extreme radiation, especially if you fly a lot of batteries (not to mention how legal it is almost anywhere in the world).

Your sub-250 gram build methodology is absolutely a must-read but I will do so tomorrow as I only have a very limited time at the moment.

I am also still waiting for my soldering iron (not sure why it is taking so long) and I will come back again when I need to solder the GPS module. In the end I didn't get true idea what is possible with my current mainboard. If the guy with the connections close to RGB did it, it is definitely possible. I may also go directly to HGLRC and ask for help/second opinion.

Hi d@wn,

First, electric motors can, and do handle a range of voltages. Keeping the voltage at or below
the maximum value is fine. The lowest voltage would be that where the motor just doesn't
spin or not fast enough to fly, however, it certainly will not harm the motor.

That said the EMAX ECO Series 1404 3700kv motors are fitted to the BabbyHawk II HD 
which, according to the tech specs are rated for 2S-4S. Although, the EMAX product page
for the quad does not list what battery to use, you could use any 2S, 3S, or 4S battery and
be ok. Now, on 2S, the thing might not fly very well if it flies at.

OK, now we play the game. I will use the Flywoo Explorer LR4 as an example because they 
tout this as a sub-250, Long Range craft. We yes, sort of, but not at the same time. From Flywoo's
AD, they show the Explorer LR4 as weighing 238.4 grams with a 4S 750 mAh battery strapped
onto it. Yep, sub-250 grams, BUT won't do high fly times and long range with THAT battery.
Both Flywoo and the guy in the video use a 4S 18650 3000 mAh battery that weighs about
200 grams (+/-) to achieve the 20-30 minute fly times, BUT that is NOT a sub-250 gram
craft; more like 330-350 grams and can not be flown legitimately under the Recreational
Exemption. According to the FAA, sub-250 grams is the Maximum Gross Takeoff Weight
including the battery and any payloads. The dry weight of the craft is irrelevant. Technically,
these quads are NOT sub-250 grams when fitted with a large battery or any payload that
pushes the weight beyond that limit. This is the game they play. It leads folks to believe
that it is a sub-250 gram quad, however, they don't say that this is only with batteries 
that weight at or below a certain weight. 

A bit about batteries. The nominal voltage for a standard 1S cell is 3.7 volts with an actual
voltage range of about 3.0 (+/-) volts to 4.20 volts. The 3.8 HV ones are generally charged
to 4.35 volts with the same lower voltage. Now, these are LiPo batteries. The Li-Ion batteries
are 3.7 volt nominal so they charge to a maximum of 4.20 volts, BUT, they can be safely 
discharged below 3V. 

In the OSD, I generally show the per cell voltage, but not the total voltage. That way, I don't
have to calculate a bunch of stuff for batteries having different cell counts. It all works out
the same, but the average per cell voltage is easier to keep track of (at least for me). I do
tend to "push" the batteries a bit, but it works for me so I will keep doing what I do. 

I am assuming that the 700 mW and 1W is the VTX output wattage. I generally run my VTXs 
at 200 mW to 400 mW. Yeah, I am running analog. 

Since it violates the FAA regulations to fly beyond visual line of sight, there simply is no such
thing as a legitimate long range flight. There just isn't. Consequently, I don't do long range so
I have no need to push a bunch of energy from my VTX. I do still go for endurance, just in a
much smaller space. Time in the Air that is what matters to me. 

Later, My Friend, iFly  

The Crux35 is a similar 3.5" drone like the BabyhawkII, just a little lighter. I fly it on both 3S and 4S batteries, and it does fly on 2S but lacks power. Depending on your flying style, but if you like cruising and not after top speed then try a lighter 3S HV pack. I most often fly it with a 3S 550mah HV 48g pack and easily get 8 minutes or more of flight time. A heavier 4S 550 HV pack has more punch/power/speed but I get shorter flight times more like 6-7 min.

Motors operate at a higher efficiency on the low end compared to the high end. And depending on your weight/throttle difference it could be quite significant.

That's very good to know. I already have 4 850 mAh R-line 4S Tattu batteries and I now regret a bit since they are heavy and I always wanted the drone to be as light as possible.

@mstc, @iFly4rotors, which is the best 3S battery option for the Babyhawk in terms of capacity/flight time but also discharge level (like the best of all worlds)? iFly4rotors, pleasure to see truth told right about staying under 250 g. with the right set on the top; something that manufacturers and Youtubers skip/hide when they claim flight time on a sub-250g drone.

Two of my 850 mAh batteries are as far as I remember at 92-93 g., the other two are 97-98 g. They are the same model, just different revisions (or markets). If I can get a lower weight with acceptable discharge level and better flight time this will be gorgeous. I may sell my heavier batteries (almost new) and just keep the 3S.


Also, can I ask, what voltage do you stop your drone at and switch batteries?

I think everyone has their own preference on batteries and there is no best option. I tend to have a misassortment of different batteries, and will try them on different drones.

HV batteries are lighter in weight so I think they are more suitable for micros, but they do wear down faster than non-HV. My Crux was around 110g, since Babyhawk is heavier maybe you want to try a 3S 650 HV for cruising. Unfortunately C-ratings are more a marketing number, but probably don't want to go below 70C.
For HV I have some CNHL which perform nicely and are a great deal when they go on sale. I also have GNB which are even lighter in weight, but find these degrade much faster (seems their c-rating is quite a bit overrated). But again so many choices out there, others will have different experience/preference.

Hi d@wn,

As mstc mentioned, each of us has our own priorities and preferences. The endurance
pilot has different battery needs than the hi-performance stunt pilot, even for the same
quad. The endurance pilot needs extended fly time while the hi-performance pilot needs
raw power, fast acceleration, and fast battery rebound after a hard punch. I am an
endurance pilot and strive for the most fly time at the expense of hi-performance. 

We also have different views about battery characteristics and handling. Some count the
number of charges on each battery and strive to make the battery last as long as possible.
On the other hand, I am sort of lazy about all that since those things are not that important
to me. I don't keep track of my batteries, I don't storage charge them, I often have one or
more charged up and sitting on the bench, and I will often drain the battery until the quad
will not longer stay in the air. To me, batteries are to a quad what gasoline is to a car; 
consumable. Use it unit it is gone; then get more. 

Most of my fleet will handle batteries from 2S to 4S regardless of the actual quad size from
my 2-inch whoop build to my 5-inch builds. Consequently, a 3S battery will work in pretty
much any of my quads except the 1S tiny whoops. The GNB 3S 1100 mAh 60C 68 gram
battery is my standard, default, "Pet" battery because it will work in just about everything.
The weight is light enough that it works in 2 and 2.5inch craft. My GEPRC Phantom gets
between 15-17 minutes consistently using this battery. My larger quads get about 10-12
minutes of fly time with it.

Since my focus is on the sub-250 gram category, I have a maximum battery weight allowance 
of 100 grams which works with quads having a dry weight of 149 grams or less. If I am want
to run a heavier battery, the build would need to be parred down to a dry weight of, say, 130
grams; less if possible. These 10 grams or so can then be added to the battery allowance and
bring it up to 110 grams maximum. 

Now, d@wn, your quad has a dry weight of about 140 grams so you could conceivably go
right up to 100 grams. With this in mind, the largest 4S battery that I could find within that
weight limit is the GNB 4S 1100 mAh 60C 97gram battery is rated at 16.72 Watt hours and
has an energy ratio rating of .172 << this battery should provide more fly time than your 
4S 850 mAh battery for about the same weight. A GNB 3S 1550 mAh 60C 100gram battery
is rated at 17.67 Watt hours and has an energy ratio rating of .177 which is a slight bit
higher and should, in theory, give just a bit more fly time. The only way to know for sure
is to test them especially since batteries are not consistent and often vary from one to another.
Personally, I would go for the 4S 1100 mAh battery first because it will still provide decent 
acceleration. 

If you have any size 3S battery, I would give it a try and observe the performance on 3S.
If you have a bunch of 1S batteries, you could make an adapter, run them in series and 
essentially make a 3S "pack". It does work and I have done this many times. 

Look around, see if you can find a battery that weighs 100 grams or less AND has a Watt 
Hour value that is higher than 17.67 Watt Hours. GNB consistently has the best Energy
for the weight of the battery which makes them good for endurance.

By the way, a 2 cell Li-Ion battery weighs about 100 (+/-) grams so that will likely take out
Li-Ion batteries as an option. I am not even sure that a 2S battery is viable for powering your 
quad. Hmm. 


I think my first choice would be the GNB 4S 1100 mAh 60C 16.72 Watt Hour 97g battery.
Then, I might also try the GNB 3S 1550 mAh 60C 17.67 Watt Hour 100g battery. 

In theory, both of these batteries should be pretty close for Fly Time.

If you haven't yet, you might want to download and take a look at my Parts Guide <-- Click

Besides being a convenient place to do a quick comparison of components especially things like
motors, frames, and batteries; there is also a Build Guide with calculators, and assorted other
information. 

Later, iFly 

Hi guys,

Sorry for reviving a relatively old thread however after updating and configuring the flight controller's firmware to work with the M10 GPS chip and making sure the drone flies OK afterwards, I have finally decided to solder the GPS module. Here is an image of my flight controller:



I was thinking, by the way as suggested by HGLRC too, to use the bottom right ports (where it says RGB, GND, 5V, VTX, TX1 & RTX1. The problem is only the Gnd, 5V and VTX ports are unsoldered/available to use, the TX1 & RX1 are used by the Vista system. The same relates to the bottom left ones - all soldered apart from the Sbus one (from what I can see). The top left ports are all available but there is no Tx and Rx there (BZ-, 3.3V, Gnd, 5V, Camera).

I can use the Gnd and 5V at the right bottom as planned, how about the Tx and Rx?

This is the suggested connection by the manufacturer:



Any advice on the Tx and Rx connections will be highly appreciated. Thank you.

Hi D@wn,

Check your PM. Since the Vista uses TX1-RX1, you will have to use the reconfigured pads
A14 and RGB as per the RC Group thread.

You will also need to use a SoftSerial port as per the instructions in the RC Group thread. 
The SoftSerial port should come up as UART11.

As for the power, Red = +5V, Black = GND. It looks like there are 3 sets of power pads on 
that FC board. If all of these have something connected, then you will have to piggy back 
onto one of the sets. Pick one, it doesn't matter which set. This is ok.

Later, iFly