Emax 250, 1200 / 1800 or 2200 mah?

[NorcoT]

Hey everyone, just finished building my 250 emax. Waiting for some weather to get its maiden flight done. Currently I only have one small pack (3s 2200) so that';s going to be the first flight.

Any experience with this kit on 3s 1200 or 1800 or 2200 lipo? quad will only be carrying fpv camera and tx, no gopro or mobius so it should be fairly light. Just planning some gentle fpv flying too so not hungry for performance.

If I remember correctly I think it was about 700g or just over with the 2200mah on board.

I also have a 4000mah multistar low c pack which only weighs 260g, might give that a whirl for a laugh [emoji14]

[kilby]

Personally I would say somewhere between 1300 and 1800 is where 250s are happiest.

I have seen them with 2200s but it';s a bit too heavy for anything bother than proving it flies

[NorcoT]

Ok noted.  Might look at 1600 then, right in the middle.

[Paul01]

Look at the higher C rated batteries too, as you tend to find you get better flight times from them even when you';re not pushing the quad.

[NorcoT]

Noticeable extra time? I found some 25c 1800 zippy for fairly cheap. At £14 I was just going to order a pair and give them a whirl.. I see some higher c ones for £20 but if I buy 2 of them it';s not far off buying 3 of the lower c.

[Paul01]

All depends on how you fly, I wouldn';t buy less than 35c zippy compacts for my 250. I like zippy compacts but do find there c ratings are quite optimistic

[NorcoT]

Ok thanks,  I';ll give the cheap pack a shot, maybe get a high c pack down the line and compare. My 250 build was only meant to be a budget rig second to my 450...

How much flight time do you get roughly for your packs? I';m hoping for 6 or 7 mins gentle flight. . Maybe a bit optimistic.

[Friskle]

Practically speaking a higher C rating does not guarantee that you will see longer flight times. but,, you will find better overall performance from a Higher rated battery.

[Paul01]

I';m getting about 7 mins with zc 1500 35c

[Nige]

I use 1500 Zpiiy compacts and 1600 nanotechs both are great and give me around 7 mins gentle flight or 5 mins screaming flight..

Nige

[robocog]

Is it just me then?
How are people getting seemingly better runtimes?

Mines Nighthawk carbon frame, Emax 1806-2280kv motors, gemfan 5030 props, CC3D FC, orangeRX, Boscam 200mw VTX and a sony superhad cam and a HK low voltage beeper, nothing extra bolted to it (no LEDS';s...not even using a PDB - to conserve weight)

Using Zippy compact 1300 (3s) cells within a few seconds of hover if I punch the throttle I get the low volt beep
I can (and do) fly till its really complaining about all cells hitting 3.7, otherwise I would not get anywhere close to 4 mins flight

I have set the TX to tell me my 4 mins are up and when the cells are measured they are claiming about 3.8ish with no load and when I charge them back up I am putting less than 80% back in
They are balanced when they come off charge and have the full 12.6v in them

The Zippy Compacts 1300';s I have claim to be 25C series - is it because they are low C rated that makes my low volt beeper trigger so soon?
(thinking of ditching the beeper as it is quite annoying and fairly useless TBH)

I have 4X Turnigy nano-tech 1300mAh 3S 45~90C';s about to plop through the letterbox - hoping they will be better

maybe I should go bigger MAH? was hoping to get closer to 6-7 mins out of a pack
It';s not as if I am consistently heavy on the throttle as I';m still wearing L plates

Regards
Rob

[NorcoT]

Is it just me then?
How are people getting seemingly better runtimes?

Mines Nighthawk carbon frame, Emax 1806-2280kv motors, gemfan 5030 props, CC3D FC, orangeRX, Boscam 200mw VTX and a sony superhad cam and a HK low voltage beeper, nothing extra bolted to it (no LEDS';s...not even using a PDB - to conserve weight)

Using Zippy compact 1300 (3s) cells within a few seconds of hover if I punch the throttle I get the low volt beep
I can (and do) fly till its really complaining about all cells hitting 3.7, otherwise I would not get anywhere close to 4 mins flight

I have set the TX to tell me my 4 mins are up and when the cells are measured they are claiming about 3.8ish with no load and when I charge them back up I am putting less than 80% back in
They are balanced when they come off charge and have the full 12.6v in them

The Zippy Compacts 1300';s I have claim to be 25C series - is it because they are low C rated that makes my low volt beeper trigger so soon?
(thinking of ditching the beeper as it is quite annoying and fairly useless TBH)

I have 4X Turnigy nano-tech 1300mAh 3S 45~90C';s about to plop through the letterbox - hoping they will be better

maybe I should go bigger MAH? was hoping to get closer to 6-7 mins out of a pack
It';s not as if I am consistently heavy on the throttle as I';m still wearing L plates

Regards
Rob

How old is your zippy? how many mah';s are you putting back into it when charging?

[Paul01]

Yes they are too low a C rating, I have some Zippys rated at 35c and they still show signs of voltage sag but my 25c Gens Ace performs so much better

[annikk.exe]

I wouldn';t use anything less than 40C to be honest.

2200 seems WAY too big to me, I have a Zippy 3s 1500mAh 40C/50 burst, and that seems slow in comparison to my Multistar 3S 1400mAh 40C/80burst.
In future I hope to buy 45C 1300 packs.

The low C rating of your battery is what causes it to sag so badly.  Low voltage alarm is actually quite useful when you have a battery that is up to the job. :>  I use Taranis/Naze32/D4R-II built in telemetry and check for low voltage using a Global Variable.  The variable becomes true if the voltage dips below the specified level for at least 6 seconds - this is to stop it nagging me unnecessarily when it';s sags a bit after I';ve just gone full throttle.

To increase flight time, reduce weight. :>

[flybywire]

I started out using ZC 1800';s for my 250, and was getting a 10 minute flight.  TBH, I think that';s actually too long for a 250, as the better you get, the faster you fly, and I think 5 minutes of intense concentration is enough for my ageing brain to handle!  I now have a mottley collection of ZC';s from 1000 to 1800, with 1300 & I think 1500 in between, so I would recommend 1300 or 1500 for optimum performance.

I don';t bother with telemetry myself, just use a timer, works fine for me.   

Oh yeah, I just bought twp 1300 Nanotech';s (60-90) so I';ll be checking them out at the weekend with any luck.  I hope the farmer has mown the grass for me!

[Paul01]

Oh yeah, I just bought twp 1300 Nanotech';s (60-90) so I';ll be checking them out at the weekend with any luck.  I hope the farmer has mown the grass for me!

As a fellow zippy user, it';ll be interesting to hear what you think of the nanotech

[xxpitt]

If you going to be flying hard. I';d say 1800, no smaller than 1600 anyway

[NorcoT]

Thanks, I thought it would be a bit of personal preference. I just ordered 2x 1800 25c zippy compacts for £30. They';ll do to start with, if I get 7 min a pack I';ll be chuffed. This is my first 250 so maybe when it start thrashing it i will get better lipos

[robocog]

My zippys are new (no more than 5 or 6 charges each)
I have been very gentle on them - and charged at less than 1c and brought it down before going beyond 3.7
This can be as short as 3 mins

Managed to test one of the nano-techs and instantly noticable that the extra c rating in them makes all the difference
Unfortunately I had an incident that bought me down before I could test how far into the pack I got before the 3.7v beeps - but it was waaaay past the 2 mins hover and punchout of the zippy compacts
Will retire them to goggle power bricks only- simply not man enough C rating wise
Glad I didn';t buy a lot of them
Interestingly the Nano techs are the same size as my zippys bar a few mm fatness wise, thought they would be physically a fair bit longer and wider for the extra rating

Regards
Rob

[flybywire]

It is odd that folk have such different experiences with ZC';s!  I have loads of them, and although they do get a bit hot and soft if used hard, they';re not really that bad.  Still, always on the lookout for better gear!

[robocog]

well...my results

I got an extra 3 mins flight (hovering and throttle punchouts) before I got a beep for 3.7v for one cell during a hard throttle up (beeping did not go on and on like the Zippys do), it just let me know that a cell went under my set volt...but then recovered
I managed some hovering and softer throttle ups before it became more frequent beeps to let me know it was time to land (I was ignoring my TX letting me know my 4 mins was well and truly up)

3 whole mins extra flight time! that';s nearly double!
it /felt/ more punchy throughout (may be in my head, maybe not)

The Nano-Tech was not as warm as the ZC';s get

both 1300 mah and both the same price, but vastly different

/IF/ it';s purely down to the C rating, (20C V 45- 90C claimed) then its a night and day difference and is THE thing that needs to be high priority when choosing cells

If they are still behaving like this after a few cycles I';ll be a very happy camper and be back for more, no longer looking at bigger cells

7 mins is more than acceptable for me and happy I have discovered why people are seemingly getting much better flight times than I was - not just internet boasting after all!...LOL

Regards
Rob

[Dino]

As a fellow zippy user, it';ll be interesting to hear what you think of the nanotech

I went from using ZC 1500 35c to the Nano Tech 1300 45-90cs and the difference in performance is pretty obvious.  As already stated, I found that I';d get the low voltage beep from the ZCs if I gave it the tiniest bit of welly, however the Nanos don';t care if I strangle them!

[NorcoT]

As robocog has mentioned worst case scenario is that I end up using these zippys to run my monitor and receiver.  always a use :)

Some very mixed reviews here though, will have to just wait and see how I get on.

[annikk.exe]

/IF/ it';s purely down to the C rating, (20C V 45- 90C claimed) then its a night and day difference and is THE thing that needs to be high priority when choosing cells

This is my view, C rating is everything. :>

I am tempted by these:
http://www.hobbyrc.co.uk/3s-65c-1300mah-lipo-battery-pack

Anyone tried Kypom batteries?  65C/130burst is impressive stats.

[Nige]

since setting up telemetry on my 250';s properly i';ve ditched the lipo alarms.. but I have had to compensate for the voltage reading the naze sends to the frsky.. I have my TX speak the flight battery voltage every 15 seconds and this changes with load.. for example if im punching it the reading might be 11.2 volts go back to a hover and it goes back up to say 11.6 volts.. I would let the batts go down to a constant 11 volts in the hover before landing.. however, when i put them on the charger they all still had 11.8 volts..

After some experimentation I have discovered that if I wait till the naze is say 10.6 volts in hover the flight battery is actually down to 11.0 volts when i come to charge.. so thats what I do.. I also set up a flight battery low warning now at 10.6 volts..

this is now giving me a good 6-7 mins of gentle flight and 4-5 mins of more aggressive flight. in other words im getting the most out of my flight batteries

[annikk.exe]

After some experimentation I have discovered that if I wait till the naze is say 10.6 volts in hover the flight battery is actually down to 11.0 volts when i come to charge.. so thats what I do.. I also set up a flight battery low warning now at 10.6 volts..

I find that too... I have "low voltage" set to 10.6volts, and "critical" at 10.4volts.  After landing the battery usually bounces back up to 11.1v or thereabouts.

Interesting how you';ve set this up with voltage alerts every 15 seconds, I did mine slightly differently; it stays silent normally, but it says "voltage low" and "voltage critical" when certain thresholds are reached, and pulling SH reads out the voltage at that instant.

For the low/critical voltage alarms, I set up a "global variable" which becomes TRUE if the voltage drops below a certain threshold.
Then I have a special function that triggers the "low voltage" sound bite whenever that Global Variable is TRUE.  The sound bite is set to repeat every few seconds.
However I found that the voltage drops below that threshold quite early on, due to voltage sag from full throttle.  So I was getting "low voltage" just a few seconds into the flight.  That was rather annoying.

My solution was to add a "delay" to the global variable.  As I recall, it';s the field on the far right of the "Global Variables" page.  Adding a delay of 6 seconds means that the voltage must stay below the threshold for a full 6 seconds before the Global Variable becomes True.

That way, the Taranis doesn';t start nagging me until the battery really is getting low. :>

[NorcoT]

After some experimentation I have discovered that if I wait till the naze is say 10.6 volts in hover the flight battery is actually down to 11.0 volts when i come to charge.. so thats what I do.. I also set up a flight battery low warning now at 10.6 volts..

This is like the Naza Line Voltage Loss parameter. There is a drop in measured voltage when you draw power. DJI';s method is to set an alarm, fly until alarm is activated, land and measure battery voltage. The difference if what you set the alarm to and the measured amount is then the line loss. This parameter is then used to ';calibrate'; (reduce) the actual alarm. So when the Naza is in flight it will look for a voltage of lets say 10.6v instead of 11v as it looses 0.4v when the motors are running, when you land and shut down, the lipo is in fact at resting voltage of 11v.

Unfortunately my 250 doesnt have these gadgets, so instead I have an inline battery monitor with a live readout, I hook up, note the voltage when stationary, and then note the voltage when in hover, calculate the drop in voltage when flying compared to when stationary. And now I set my LiPo alarm that amount lower than my desired minimum.