power requirements with secraft retracts

K

ksrimoungchanh

Member
Hello All:

I am running:
S800 (OEM props)
Zenmuse Next5 (but have Nex7 on it)
(gopro also for Pilot)
(2) 5.8 VTX (1 300mw, 1 600mw)
(2 parallel) APLUS 6000mah 65C

I fly about 7-10 mins average before landing. Still have juice to go up and hover around.

I added the Secraft retracts and added the CC BEC.

I now get 3mins or around there. Today, I was testing, and took the bird up to about 80ft, did the retracts.. hovered for another 15 secs.. and it started losing altitude fast.. I had the stick all the way up and it was still heading down. I extended the retracts just in time for a little bump. but then the bird gain strength again and started positive climb again.. since I had the stick way up, I had to bring it back to center again.. and did... had some weird time holding altitude.. kept doing the same the whole flight. I finally brought it back.. exchange fresh battery set.. recalibrated but it still had same symptoms.

I did not want to extend the risk, so called it quit for the day and trying to get input.

Would the Secraft pull that much?

Thanks again,

KS
 

heli001

heli001

Triple Tree Aerodrome
How is your "New" CC BEC wired into the system? I would not think the Secraft retracts would pull that much from your system unless something is seriously wrong. Can you put a Watt meter on the retract circuit and see what it is pulling...? We are actually running ours off of a Powersafe receiver with a Y harness.........
 

FerdinandK

FerdinandK

Member
Was it cold outside? If the AUW is on the limit for the given batteries, such a behavior can occur.

The secraft retracts take around 1A each. A standard Hobbyking 3A BEC is doing the job, if the voltage of the BEC is adjustable you should set it to 5.0V (the higher output voltage , the more amps it will take). If the secraft would take too much, the BEC would burn, but not bring the whole bird down.

Another option would be that you have some sort of mixer on your RC-TX set for this switch, that causes some trouble.

best regards

Ferdinand
 

K

ksrimoungchanh

Member
After taking some time to get fresh eyes, I notice, my Y power cable was using the wrong sized cable. I had a Y cable with XT60 to split the power from the battery to the retracts power and the S800 top-plate power. The 10Gauge cable was from the battery to the retracts power, then the 14-16G one was to the S800.. I have not tested it, but am thinking my 14-16gauge will not support the S800. It was cold so I had gloves and did not even think about testing temperature on the cables.

BTW: my BEC is currently tested at 5~6V,

Thanks for everyones input.. will test and report..

KS
 

K

ksrimoungchanh

Member
NO go!! this is something else.. not related to the retracts..

any help would be appreciated.:
S800 stock props
Zen15 with NEX7
5.8mhz VTX 600mw.
2x 6000mah APLUS 65C 22.2

Have secraft landing but don't have it connected, thinking it was the issue. Also checked batteries, battery cable size and connectors. Did this on 2 batteries out on the same day. This was the second fresh pack.

It flies fine for first minute or so.. then as you can hear... I end up full throttle and it will still descend till it lands.. then a few seconds later, it will have power again.


out of ideas.

KS
 
Last edited by a moderator:

FerdinandK

FerdinandK

Member
To me this looks like the batteries are dead or it is too cold for them, or both, do you have telemetry to see the in-flight voltage?

best regards

Ferdinand
 
Last edited by a moderator:

K

ksrimoungchanh

Member
FerdinandK,

I currently don't have telemetry, but will be picking one up. so, I tested the batteries before and after, still power left.. I thought there were people flying in even colder environment.

Thanks for your input... I order new batteries a few weeks ago.. so expecting several new packs.. will try that too.

KS
 

FerdinandK

FerdinandK

Member
I also do fly in cold environment, which I love, since the "air is do dense" :), but here I do preheat the cells (in some sort of car-refrigerator which can also heat) and I cover the cells by some foam, to avoid the outer cells getting cold. If the cells are healthy it would also work without, but it gives you access to the last 10%.

That you flew without voltage monitor indicates, that you do not "see" the voltage under load an from time to time you drain too much from the cells (which damages them). I a cold environment you just notice that damage first. So I would assume with new and fresh cells you are ok again. You should also be prepared, that the cells will not work forever. With the current cells I achieve one season of flying, maybe a bit more, maybe a bit less.

best regards

Ferdinand
 

K

ksrimoungchanh

Member
Thank you for your input.. makes sense. This is my first full season of flying so cold weather flying is first on for me. I am now looking for iosd now. :)

Thanks again,

KS
 


K

ksrimoungchanh

Member
Thanks Chris,

That was a very informative video.. I do have FMA PL8 and check the resistance each time I charge the battery inside the house... If I cool down my charging container to simulate the cold weather out there, I should expect to see different Ohm resistance reading, correct? Since my charger is station inside "warmer" it always shows 1.2-1.5 ohms for all 6 cells. There are a couple of packs that have a larger difference like 1.2-2.2 between the highest and lowest cell. Again, that is all measured in my warmer work bench.

what is the best way to wrap the batteries..someone suggested foam? I went to my local battery shop and got some free battery shrink wrap. I was thinking of putting foam and shrink wrapping them for the winter/cold flying season.

Any suggestion?

KS
 

FerdinandK

FerdinandK

Member
If you get the lipos (from the store), they are typically covered with that "bubble"-plastic (or something similar), that is an option (in addition to preheat them before start). It is just to keep them at temperature until start, to isolate the outer cells and to hold the heat they produce on their own during the flight.

IMGP2580.JPG


IMGP2581.JPG


best regards

Ferdinand
 

K

ksrimoungchanh

Member
@ FerdinandK,

Notice you have the bullets that are not molded to each other, do you plug the ground/Neg/Black wire first are do you do the POS? I alway replace my ends with XT60 and thinking of going XT90 to standardize one up.. since I also have a Skyjib heavy lift too.

But if I can get away with just using what the battery vendor supply, then maybe I just stick to that.. but I do have parrellell batteries that might have to end up XT90 parrellel cable anyway.

Just wondering..

KS

FerdinandK said:
If you get the lipos (from the store), they are typically covered with that "bubble"-plastic (or something similar), that is an option (in addition to preheat them before start). It is just to keep them at temperature until start, to isolate the outer cells and to hold the heat they produce on their own during the flight.

IMGP2580.JPG


IMGP2581.JPG


best regards

Ferdinand
Click to expand...
 

FerdinandK

FerdinandK

Member
I have "standardized" to 4mm gold long ago. If I run batteries in parallel I connect all black (-) first and then I plug all red. Works fine for me, If I have higher power requirements I run more connectors in parallel (on my X16 I run four batteries in parallel).

best regards

Ferdinand
 

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