Mini Titan - Power usage with stock motor + Esc

[comeflywithme]

Hi

I finally got myself an onboard data logger so I thought I'd share some of my findings I got from using it on the Mini Titan E325.

Setup:

Stock Motor + esc
Radix 325 CF blades
FP Evo 20 (25C) 2170mah
GY401, 9650 (Tail)
HS65 (Cyclic)
+/- 10deg
Governor mode at 80%

Flying was 6min of Aerobatics and mild 3d (flips, tic tocs etc), fairly aggresive on throttle.

Righty so here's a the interessting stuff,

Peak amp - 36.96A at 9.63V (3.21V/cell). In Watts, thats a whopping 355.9!! Not bad for a stock setup

Average taken over 5min (following 1 min into flight and all during 3d in Idle up 2) showed the following:

Average amps: 18.02
Average Volts: 10.40
Average Watts: 186.26
Average cumlative maH usage: 300/min

Motor temp after all this was 60-65deg C and Battery + esc at about 45 deg C so all within safe margins.

So what does this all mean?...

Well for starters, 355 Watts is far from bad so we get plenty of power (although you dont really need a monitor to find that).

Put into context with data collected from my twister 3d a zoom type 400 size heli - I only got peak discharges of 12amp max!! (less than a third of what I got with the Mini titan). Considering that the mini titan only weights about 200g more, this means we have nearly twice the power to weight ratio!.

Some other important findings are:

-37Amp peak is frighteningly close to the 40A limit specified on the stock esc so I'd be careful experimenting with other more powerful options. The stock setup should be safe though.

-Voltage doesnt drop below 9.6V which is ok for a 3 cell lipo (Remember - Low voltage is what kills LIPO's so this is an important factor).

-The peak 37A discharge was achieved about 5 mins into flight which shows good retention of performance throughout flight when this setup is used.

Anyway thats as far as I got so far, if there's anything you'd like to add, comment or ask then please feel free to do so.

The next thing I'm planning to do it to compare the stock woodies to the radix blades and at some later stage perhaps to compare some different motors aswell.

Sorry if all this Geeky waffling on bored anyone! :-)

[EricW]

No not boring!, love this stuff, thanks for letting us now.
I'm pretty new to this but the figures show that the stock setup is engineered instead of guessed, and we have Lot's of power :)
I still fly with my first set of woodies so I'm curious about the results compared to the Radix blades.

[usherwdp]

Hi,

I've got a very similar setup (401, 9650, stock ESC and motor) so the information is great. thanks for sharing it!!!

I'm finding that I get about 6 mins on a similar battery before the tail starts to wag and the head speed drops. When I charge it I'm only putting about 1450 back in!

Don't really understand why the performance is effected when I'm only putting 1450 back in. Still I am new to this :oops:

Cheers,

Peter

[kgfly]

I've got a very similar setup (401, 9650, stock ESC and motor) so the information is great. thanks for sharing it!!!

I'm finding that I get about 6 mins on a similar battery before the tail starts to wag and the head speed drops. When I charge it I'm only putting about 1450 back in!

Don't really understand why the performance is effected when I'm only putting 1450 back in.

What are your temperatures like ? What is your LVC set at ? After 6min of hard flying it is possible the batteries or ESC are overheating or that the voltage has dropped enough under load for the LVC to kick in.

[comeflywithme]

Hmmm that does sound a bit strange.

Usherwdp, what type of LIPO are you using?. From my own experience and also many reviews of the MT, I've found that the quality of LIPO used has a big effect and can lead to lower power as well as earlier voltage decay. I initially used an older 2000mAH Airpower LIPO and found the difference between this and the better Flightpower LIPO was huuuuge!!

I dont normally run my lipo to the point where the esc LIPO protection kicks in but I accidentally did on the most recent flight (Couldnt hear timer over nitro birds whizzing around infront of me :arggg: ).

I've attached the voltage and mAH data which should show that using a good LIPO you get a slow/steady decrease of Voltage over the first 5-6mins of flight. After this you'll notice a very rapid reduction of voltage which causes your head speed to decay and your esc's lipo saver to kick in and oscillate your head speed or stop the motor completely. This didnt happen untill I'd gone through just over 1800mAH though.

Its quite interesting how nicely this fits in with the 80% discharge rule people always talk about (although I dont intend on running my LIPO down to 90% again to prove it). :)

[EricW]

I got the same with a 15C lipo.
Got some tailwag and dropping headspeed even in the beginning of flight.
Once I fly it's OK but it's not ideal.
My FPevo 25 2170 has more than enough power and performs throughout the flight.
Looks like you need at least 20C to get reasonable performance?

[usherwdp]

Hi,

comeflywithme, I'm using a Thunder Power 2070. Would you recommend a different battery? I'm thinking of having another, so I don't have to wait around for that one to charge :(

kgfly, I'm just doing basic hovering. I haven't got the tool to check the temp, but the battery and motor are warm but not hot.

I have to say that I have disabled the voltage cut off, I just keep an eye on the time and how much I'm putting back in :oops:

Do you think the battery might need balancing?

Cheers,

Peter

[comeflywithme]

ThunderPower LIPO's as far as I'm aware are pretty much as good as the FP's. Having said that, in the long term LIPO's are only as good as you treat them so depending on how much cycles you've put through them, how many times you overdischarged them and how unballanced they are your LIPO might be in a bad stateby now.

A few cycles without ballancing are probably fine but after that some cells will start to get unballanced and this results in individual cells being overly discharged (e.g. 2 cells are at 3.4V & 1 is at 3.0V - any further discharge from here will reduce the unballanced cell to below 3V and damage it)

My Airpower 2000mah Lipo for example had great performance initially but after running 30-40 cycles through it without ballancing (didnt have suitable ballance connector), the performance drop was eeeeenoooormous!

My advice is - buy a ballancer - they cost less than a single lipo and will prolong your LIPO life for up to 3-4 times compared to running it unballanced. YOu can always have a go at balancing your old FP pack but I wouldnt get my hopes too high.

As far as choice of LIPO is concerned, either FlightPower or ThunderPower are great but I'd recommend sticking to one type of LIPO they often have different types of Ballance leads.

Temperatures - if your LIPO and esc are around body temperature or just above - theire fine, if your motor can be touched for 5+ secs without any discomfort - it should be fine too.

Damn I have to learn to keep these messages shorter! :D

[usherwdp]

comeflywithme,

Thank you for the great info. Can you recomend a balencer or what to look out for. I currently have a pro peak prodigy II charger.

Cheers,

Peter

[comeflywithme]

Glad to be of help!,

Ballancers should work with any type of charger including your pro peak prodigy II.

The only thing to look out for is that the ballancers ballance leads match the ones on your LIPO. Easiest way to be sure is to buy a Thunder Power's 2-5 Cell smart balancer for TP Cells or Flight Power's V-Ballance for FP Cells.

There might be some universal ballancers out there too (i.e. you just buy the appropriate lead for your cells) but I'm not sure.

[usherwdp]

Thank you

Good advice I feel. Realraptors has them for £36 + PP :D

I've had a look at the online manual... Sorry silly question :oops: but do you use it after charging or before.

Thanks for your help.

Peter

[comeflywithme]

£36 Sounds reasonable - I always check at least 2 or 3 shops to get the best price though. :)

Dont ballance before charging - I believe ballancers work by dicharging the cells with the highest voltage to match the one with the lowest. On a low unballanced LIPO the ballancer will use its safety cut-off to stop you from balancing as the lowest cell is most likely below the safe limit.

You normally have two options:

1. Ballance a full pack (after charging) by only connecting it to the ballancer and not the charger

2. Ballance a pack whilst charging. The FP V-Balance uses a set of though charger leads to connect to the LIPO's charging leads in addition to the ballancing connection. I presume the TP one has a simillar system.

Either option is ok. I normally ballance whilst charging which ensures that all cells are balanced throughout the charge as opposed to being leveled off at the end. I'm not sure if either way of doing it has any big advantage in terms of LIPO performance and life though. Maybe someone else here knows.

Hope this helps

[usherwdp]

Thanks for all the info and help.

Looks like another purchase on the way

Cheers,

Peter

[EricW]

I always balance my lipo's during a charge.
And once the battery is 100% and my charger starts beeping i leave the pack connected until the balancer leds are all off (source: finless video, in my case there off when all cells are equal).
Then it's fully charged and balanced.
AFAIK, when you only balance after charging you just topp off the higher cellvoltages to equal with the voltage off the lowest one.
So you lose a little juice, not much though.
And i'm sure it's better to balance during a charge because you will never overcharge a single cell in a pack.

[usherwdp]

Hi EricW,

Hope all is well with you. Thanks for the info.

What balancer do you use?

Cheers,

Peter

[stevehonn]

If you have a pack that has one or two cells higher than the rest then charging without the balancer could lead to overcharging these cells. The V Balancer is best used during charge as it not only balances but can also shut the charger off if any cells or the pack itself become overcharged. If the pack isn't balanced at the end of the charge using the V Balancer, push the button to take the V Balancer out of link mode, it will then shut itself down when the pack is balanced.

One thing to be careful of when buying a V Balancer in the UK is to make sure it is the later version with a heatsink, early models without can melt the base of the balancer (both of mine have done this).

[EricW]

Hi Peter,

I'm doing fine thanks, to much wind here so i didn't get a chance to train some more :(, hope to fly this evening though.
Did some SIM flying instead :)
I use a prodigy pro peak charger on a 12V pc powersupplymod and a Robbe 5 cell balancer.

Eric

[usherwdp]

Thanks guys,

As Eric mentioned there is a great finless video on the TP balancer. I watched it last night and it all makes perfect sense now. :lol:


Think I will go with the TP balancer, not just because of the video but my batteries are TP and its only £36 :D

Haven't been able to fly the titan for the same reason as Eric, the wind has been gusting really strong in the south of England over the last few days. Probably a good thing, with an unbalanced battery :D

Cheers,

Peter

[comeflywithme]

Hopefully it should calm down a bit for the weekend :) - I'm starting to go cold turkey!

[usherwdp]

I know how you feel...

According to the Met office it is going to be windy through the weekend :arggg:

http://www.metoffice.gov.uk/weather/uk/se/tunbridge_wells_forecast_weather.html

Cheers,

Peter

[comeflywithme]

Well seeing that they never seem to get it right when good weather is predicted, lets hope they got this one wrong too! :D