By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by CML

Puffing packs - edf jet

Options

All Topics | Latest Posts

Search for:  in Thread Title in  
TonyS11/08/2020 23:49:37
avatar
1185 forum posts
325 photos

I’ve a problem. I have a Hobbyking Phazer. It’s a small foamy edf that I use for a bit of fun and flying practice. It was built for a 3s battery or so the sales spiel goes.

the last two times I’ve flown it with a 3s 30C 1800 pack, the packs have puffed up and been red hot on landing.

ive bought a slightly larger 3s pack that is rated at 60c which I hope will last a bit longer. Would a 4s pack be better at handling the loads or would that simply fry the ESC and motor?

MattyB12/08/2020 00:05:45
avatar
2203 forum posts
32 photos

No, 4S will do the opposite of what you want; current and watts will go up, and you may fry your ESC and/or motor if they exceed their ratings. You’ve done the right thing to increase the C rating of the battery, but before you fly it put it on the wattmeter and see what figures you are getting so you know if you need to do any throttle management.

Simon Chaddock12/08/2020 00:33:17
avatar
5774 forum posts
3055 photos

TonyS

It really will pay to find out how many amps the motor is taking at full power on a fully charged new battery.

A 'good' 1800 mAh 30C pack should be able to deliver 54A but only for 2 minutes! Also once it has got really hot its capability is compromised so the next time it will get just as hot yet delivering fewer amps.

A 60 C rated pack should easily handle the amps that damaged the 30C battery but if it is significantly heavier the extra weight will require the EDF to work that bit harder for the same performance.

EDFs are inefficient copared to a prop so they work batteries hard. wink 2

Richard Clark 212/08/2020 04:49:40
426 forum posts
Posted by TonyS on 11/08/2020 23:49:37:

I’ve a problem. I have a Hobbyking Phazer. It’s a small foamy edf that I use for a bit of fun and flying practice. It was built for a 3s battery or so the sales spiel goes.

the last two times I’ve flown it with a 3s 30C 1800 pack, the packs have puffed up and been red hot on landing.

ive bought a slightly larger 3s pack that is rated at 60c which I hope will last a bit longer. Would a 4s pack be better at handling the loads or would that simply fry the ESC and motor?

 

As MattyB says 4S will make it worse. The current will go up, not down.

So you have done the right thing in buying a higher C rated battery.

But even then, do NOT believe the C rating, as Simon appears to do. It is nonsense, just pure marketing hype. Though a 60C rated battery is likely to deliver the same or a little more current as a 30C rated one of the same capacity due to a lower voltage drop than the 30C one. This may marginally improve the performance even with the battery probably being slightly heavier, and the battery should not get so hot.

Edited By David Ashby - Moderator on 12/08/2020 10:27:28

TonyS12/08/2020 07:20:02
avatar
1185 forum posts
325 photos

Thanks everyone.
it’s frustrating that almost anything I’ve put in this plane is getting wrecked.
I do manage throttle and only have it running ‘flat out’ on WOT for a few seconds at a time. Proving to be expensive flying. I’m wondering whether cheap ESCs or motors are more likely to damage batteries 🤔

Frank Skilbeck12/08/2020 08:26:31
avatar
4811 forum posts
107 photos

The fact that they are red hot on landing is the problem it is the heat that damages the batteries, which is down to two things, the internal resistance of the battery (higher C rating should be a lower resistance) or very poor cooling. Cheap ESCs or motors might reduce the efficiency a bit so the battery has to put out a bit more for the same motor output but they will not intrinsically damage a battery.

Not all battery makes ore the same, and unfortunately price isn't a good measure of quality either.

Keith Miles 212/08/2020 08:48:35
464 forum posts
6 photos
Posted by TonyS on 12/08/2020 07:20:02:

Thanks everyone.
it’s frustrating that almost anything I’ve put in this plane is getting wrecked.
I do manage throttle and only have it running ‘flat out’ on WOT for a few seconds at a time. Proving to be expensive flying. I’m wondering whether cheap ESCs or motors are more likely to damage batteries 🤔

I know next to nothing about EDFs but an experienced colleague has one, bought new, that has eaten two or three motors and a fan in fairly quick succession and for no immediately obvious reason. Not sure about the batteries, though.

He, too, is not a happy chappie!

It does make one wonder if a few designs are inherently flawed and/or not properly tested before they enter the market.

Good luck with the battery upgrade. Certainly worth trying. Don’t buy too many just yet, though!

ken anderson.12/08/2020 09:21:32
avatar
8747 forum posts
810 photos

tony,i would have a go with a watt meter,sounds like too much is getting pulled out of the battery's...you mention they are Hot...I would treat them with caution in case they Pop...don't waste any more batts until you've determined whats going on...kulou

ken anderson...ne..1..watt meter dept.

Engine Doctor12/08/2020 10:16:01
avatar
2584 forum posts
40 photos

Agree with all above , need higher C rated battery. A lot of these ready to go models seem to quote battery sizes and C ratings that make the model look more attractive to the purchaser knowing full well that you stand no chance of a refund if it ruins a battery or burns out. The watt meter is the way to go.

Simon Chaddock12/08/2020 10:48:54
avatar
5774 forum posts
3055 photos

TonyS

If you can tell us what EDF it is and ideally the specification of the fan and motor we might be able to determine what is supposed to be happening which should help once you have measured what is actually happening.

It is also possible some else may have bought the same plane so would be able to confirm or not if there is a particular problem with yours.

TonyS12/08/2020 10:59:47
avatar
1185 forum posts
325 photos

Looking at the set-up I suspect a big part of the problem is the lack of any airflow in the battery compartment. Worse than that it's a very snug fit in a foam cavity - like a hot water cylinder jacket!!

Might be time to start punching holes!!

MattyB12/08/2020 11:27:07
avatar
2203 forum posts
32 photos
Posted by TonyS on 12/08/2020 10:59:47:

Looking at the set-up I suspect a big part of the problem is the lack of any airflow in the battery compartment. Worse than that it's a very snug fit in a foam cavity - like a hot water cylinder jacket!!

Might be time to start punching holes!!

There is a long thread over on RCGroups about this model - might be worth a trawl to see if others have had these issues and if so how they addressed them...

PS - I see what you mean about the layout, there can't be much airflow getting to the pack in it's foam tomb...

Edited By MattyB on 12/08/2020 11:30:07

Richard Clark 212/08/2020 11:33:53
426 forum posts
Posted by MattyB on 12/08/2020 11:27:07:
Posted by TonyS on 12/08/2020 10:59:47:

Looking at the set-up I suspect a big part of the problem is the lack of any airflow in the battery compartment. Worse than that it's a very snug fit in a foam cavity - like a hot water cylinder jacket!!

Might be time to start punching holes!!

There is a long thread over on RCGroups about this model - might be worth a trawl to see if others have had these issues and if so how they addressed them...

PS - I see what you mean about the layout, there can't be much airflow getting to the pack in it's foam tomb...

Edited By MattyB on 12/08/2020 11:30:07

It seems to fly very well.

perttime12/08/2020 11:40:48
avatar
184 forum posts
11 photos

Wouldn't Voltage sag, if you are drawing more Amps than the battery can handle, end the ESC intervene?

The lack of airflow past the pack cannot be good.

Frank Skilbeck12/08/2020 12:10:46
avatar
4811 forum posts
107 photos
Posted by perttime on 12/08/2020 11:40:48:

Wouldn't Voltage sag, if you are drawing more Amps than the battery can handle, end the ESC intervene?

Not necessarily, if the 3s pack had a resistance of 0.01 ohms per cell, then at 30 amps this is a 0.9v voltage drop across the battery pack, which in turn is 27 watts dissipated as heat. If the cell resistance was 0.005 ohms then this drops to 14 watts.

Keith Miles 212/08/2020 12:21:07
464 forum posts
6 photos
Posted by Richard Clark 2 on 12/08/2020 11:33:53

It seems to fly very well.

Sounds like it might fry very well, too!

smiley

Bob Cotsford12/08/2020 12:45:19
avatar
8744 forum posts
487 photos

Could you cut some grooves in the foam tomb to encourage a bit more flow around the battery in combination with a hole in the front of the hatch? They wouldn't need to be deep but width counts, just leave enough foam in contact with the battery to locate it properly.

J D 812/08/2020 12:54:44
avatar
1578 forum posts
85 photos

My Phase 3 EF 16 is quite hard on battery's One problem with EDF types I find is that to get the most fun flying one tends to fly flat out a lot of the time.

The EF16 has a hole at the front of the canopy that sends some cooling air over the batt which I later enlarged to increase the flow. ESC is in the duct roof and has plenty of cooling.aeroplanes

Keith Miles 212/08/2020 13:18:28
464 forum posts
6 photos

TonyS,

Referring back to your original post, would I be correct to assume that the model was originally okay or has this always been an issue?

You also said that “everything” you put in is being wrecked. Do you mean just different batteries or have you replaced other components?

Even my very limited knowledge of electric models suggests that it is, primarily, the ESC that needs adequate airflow rather than the battery.

On reflection, I agree with those who suggest a power check (both watts and current) to begin with to see if the figures are what they should be or are excessive. You can then determine whether or not you are using a battery of too low a C rating or whether you have a problem elsewhere.

No point in buying and fitting a higher C rating battery if it is merely masking a fault!

Edited By Keith Miles 2 on 12/08/2020 13:53:41

Lima Hotel Foxtrot12/08/2020 13:29:23
avatar
397 forum posts
Posted by Richard Clark 2 on 12/08/2020 04:49:40:
Posted by TonyS on 11/08/2020 23:49:37:

I’ve a problem. I have a Hobbyking Phazer. It’s a small foamy edf that I use for a bit of fun and flying practice. It was built for a 3s battery or so the sales spiel goes.

the last two times I’ve flown it with a 3s 30C 1800 pack, the packs have puffed up and been red hot on landing.

ive bought a slightly larger 3s pack that is rated at 60c which I hope will last a bit longer. Would a 4s pack be better at handling the loads or would that simply fry the ESC and motor?

As MattyB says 4S will make it worse. The current will go up, not down.

So you have done the right thing in buying a higher C rated battery.

But even then, do NOT believe the C rating, as Simon appears to do. It is nonsense, just pure marketing hype. Though a 60C rated battery is likely to deliver the same or a little more current as a 30C rated one of the same capacity due to a lower voltage drop than the 30C one. This may marginally improve the performance even with the battery probably being slightly heavier, and the battery should not get so hot.

Edited By David Ashby - Moderator on 12/08/2020 10:27:28

Also don't take as gospel what people write on here when they state it as a fact and slam other users, take your research from a multiplicity of sources.

It is clear that your packs have puffing due to heat and stressful current draw, in my opinion (based on my personal experience) you would be better off leaving packs aimed at fixed wing alone and go for the higher rated multirotor race packs which can deliver very high C ratings for short durations without damage.

All Topics | Latest Posts

Please login to post a reply.

Latest Forum Posts
Support Our Partners
Sussex Model Centre
CML
Slec
electricwingman 2017
Sarik
Advertise With Us
Latest "For Sale" Ads
NEW POLL - has the pandemic altered your event safety perceptions?
Q: Has the covid pandemic deterred you from attending shows and events in 2021?

 No, I'll be attending just as many as I usually do
 No, but I'll choose my event with greater care
 Yes, I'll attend fewer events going forward
 Yes, I wont attend any where previously I have

Latest Reviews
Digital Back Issues

RCM&E Digital Back Issues

Contact us

Contact us

Magazine Locator

Want the latest issue of RCM&E? Use our magazine locator link to find your nearest stockist!

Find RCM&E!