Demon Power Products RC Blog

Our DL5000 packs are now back in stock. Sorry for the delay.
Click here to go straight to DL5000

Nick

Some of you have asked for the option of the Demon LiPo to be fitted with Corally style tube connectors built into the pack.
We aticipate delivery any day if this is more to your liking.
Same extreme high quality, high C rating with ultra low resistance like all of our LiPos.
Also with the same low prices and sorry, but no fancy packaging.
For those that do require fancy packaging and wish to throw it in the dustbin 10 seconds later, then this can be purchased for an additional £8 .

Mardave Stock has arrived.

We can also ship the famous british Mardave brand abroad now.

Team V-Dezign is releasing new 1-piece top decks for TRF 416 and Serpent S400 touring cars.

The V-Dezign TRF416 deck fits the car perfectly and gives more flex to the car in rear. Also less tweak issues as there are no separated topdeck parts like in standard 416 has. Made from 2mm graphite.

Tamiya TRF416 1 Piece Top Deck

The Serpent S400 top deck is a long waited option for S400 users.
Team Serpent fatory team drivers are using these decks also! Compared to standard topdeck, the V-Dezign long 1-piece deck gives more general traction and more on-power steering. Made from 2mm graphite. Also allows use of LiPo packs like the like Team Drivers!

Serpent S400 1 Piece Top Deck

We have been doing a lot of testing since LiPo battery packs have been released for RC cars.

Comparing different packs, different C rated packs and other attributes, We have rejected a number of cells from different manufactures due to inconsistent balanced cells within the packs and and also by internal resistance.

The C rating is all well and good but how do you know if a high rated (e.g. 30C) rated pack is actually what is says on the packet.

We have tested LiPo of various C rating from different manufacturers and the differences really are amazing. Both on the track and by measuring internal resistance.

Normal NiCd and NiMh cells are very different to LiPo packs but one thing that remains a very good measure of a good battery is the internal resistance.
The lower the resistance the better the pack in terms of performance. The lower the resistance is the best indication of the C rating also.
The lower the rating,  the higher the C rating.
The Demon DL4000 packs for example are rated at 30C(120 amp continuous) have an internal resistance of 3mOhm typical.
The Demon DL5000 which are rated at 20C (100 amp continuous) have 3 to 4mOhm
The Demon DL3600 which are rated at 25 C (90 amps continuous) have 4 mOhm.
We recently tested some 3800 packs from another manufacturer rated at 25C+ and they only gave 9mOhm internal. i.e. more than double the resistance.
Other manufacturers packs have shown figures of 12 mOhms or more.
Replacing these with a new low internal resistance LiPo pack of cells will transform a car in terms of speed and punch.

Note also that the power and capacity and long life of a LiPo is directly proportional to the weight, so there is no way a lightweight LiPo will deliver very high power for the full duration without fading and losing performance after fewer charges.
A high quality heavy LiPo will remain consistent and we have charged a DL5000 300 times without any loss of power.

Note that good quality LiPo cells also do not lose duration at different rates like NiMh cells. Therefore a quality LiPo will retain balance within the cells in the pack even after 100s of charges.

The balance connector is a means of testing a LiPo occasionally to give peace of mind and just to make sure all is ok. It is not necessary to charge with the balance lead every time, and we have charged Lipo packs 100s of times without the balance lead without any problem. Also that the pack will charge faster without the balance lead as the charger does not have to keep checking each cell.

No Cells or Animals where blown up in this testing. Thanks for listening.

Thanks

Nick

Demon soon to stock the ever popular Mardave brand of kits and parts. We already stock some of the best 4 cell packs of cells for these cars so we thought it was about time we acknowledged what a great brand this is.

Mardave produced the first R/C Model car kit made in Europe, and won at the first U.K. R/C Car, race meeting held at Berk Hampstead in 1971. Mardave also built the first permanent radio controlled model car race circuit in 1972 at New bridge in Leicester.

Here are the Kits that Mardave produce…

V12BNG     V12 Banger Kit 2007 Spec With V10 mounts & V7Mod
V12Club    V12 Kit inc speed Controller BodyMounts and Shell
V12Race    V12 Kit No speed Controller but inc Batt holder
V12Racer   V12 Kit inc ViperOvalECO & Batt Holder
V12Worlds V12 Kit Worlds Edition
V12VRX      V12 VRX Edition
V12RSMini  V12RS Mini ex Speedo but with Kimb/Bearings/Shell
RebelRacer  All NEW Rebal Racer
MiniRacer    All NEW Mini Racer Kit
V12CAT      V12 Caterham inc Sticker Set by Nittel Graffix
COB COBRA Off Road KIT
V10Kit         V10 Touring Car

Please let us know if there are any particular Mardave parts you would like to see on our site.

Oh well, another one of those weekends and off to Bashley for some boat racing. I mean Car racing if it is dry!. This time the Gazebo is water proof…. We think

New Cyclone car, New Nosram 10.5 motor, New Futabe Servo, New 2.4ghz KO Esprit III system. What else can I change? Maybe the the driver if it all goes wrong.

We were not going to use our blog as a advertising point but thought I would for this, as loads of you have been asking when the Serpent S400 gear diffs would be back in stock. Guess what, they are. Finally. Thanks.

So decided to take a trip up to the Cotswold last Sunday. Woke up at 5 and headed off about 5:30. Got to the track and guess what, raining. However, we where proud of ourselves as we had got a nice new waterproof gazebo. Let’s see the British weather stop us now. So got it all setup in case the rain decided to stop and unpacked all our gear ready for (maybe) some racing. Anyway decided to take a stroll around, stopping at each tent and gazebo on the way around to minimize getting soaked. We had to laugh as we entered a gazebo which was leaking as it was not waterproof. What made it even funnier was the site of about 4 people inside with large umbrellas (which could barley fit) trying to hold back the rain. How proud we where that ours was water proof, chuckle chuckle……

The laughter was short lived. Decided to get back to our area, walked inside and.. WET WET WET. Leaking, waterproof my backside. Upon investigating further we discovered that it was water resistant. Oops not waterproof. Not even splash proof, as after about 10 minutes later we could have got the shampoo out.

So at around 9:30 the meeting gets called off as the heavens opened. Never mind, and we decided to pack up quick and see if we can get booked into Aldershot for the rest of the day as it was said to be dry. So 1 hour 30 minutes later, we almost arrive and the weather looks good. 5 minutes later and guess what, yep we brought the weather with us and the heavens opened again. Bl**dy typical!. At this point we decide that the British weather has beaten us and decide to get back for the Grand Prix, ultimately thinking that it would also be called off too. Not this time…

Unfortunately the day had Beaton me and I nodded off about 10 minutes into it

Bugger.

Some racers are not sure whether to suck or blow.

One day they will find out if they are lucky which is best for them.

However regarding fans , blowing is the only effective way. The reason is that the impellor collects air from a 180 degree sphere and blast it as a jet onto the hot target. If you fit a skirt around the fan body the blast is even more effective.

Now if you were to try and suck the hot air from the target it would have to occupy the 180 degree sphere or cold air would also be pulled in, say from the sides which would have no cooling effect. But if the fan had skirts enclosing the hot target then the air flow would remove the heat .

Also the cooling effect is directly proportional to the surface area that the moving air passes over, so fitting a multi finned heatsink should help the cooling. But beware that sometimes the heatsinks are a poor fit with air gaps between the motor and heatsink and also the airflow can be turbulent and less effective.

I recommend the biggest fan possible as the air moved by the fan blades increases greatly for just a small diameter increase. So use at least a 30mm and up to 50mm square is possible.

Note that fans vary considerably and the airflow of the cheap ones is almost useless

Get a high rpm fan say 5 to 6 volt and run at the 7.2 volt. Also the deeper they are the more effective the blades, so look for a 8 to 10mm deep case, which will also be stronger.

Expect to pay up to £15 for a real high performance fan.

The one I use is 50mm square, 10mm deep, weighs 20gm, 5volt. Airfow rated at 10.2 cu ft/min (or 17.34 cu m /min) Anyone want to work out the litres per sec? I think it is about 4.75.

Anyway that is a good airflow, and keeps my LRP 10.5 brushless from meltdown.

So suck or blow, you decide.

Nick

Now, we are trying to scare people about brushless motors but please try not to get them too hot. We have seen a number of brushless motors burnt out from way too much heat due to over gearing or adjusting the timing ring without knowing the implications.

Remember you cannot abuse these motors like you can with brushed motors. Brushed motors, when they over heat will generally cause the brushes to burnout, com to blacken or even magnets to go off. All of these can be fixed by new brushes, a skim and the can also be re-magnetized. Brushed motors very rarely will have the windings melt as the brushes will generally go off before this has happened.

When most makes of Brushless motors and too hot, it will cause the windings in the can to melt along with other components inside. The can on a brushless motor is the expensive part! Sorry their is noooo repair service for this abuse.

Bottom line:
1)    Do NOT over gear them.
2)    Monitor the temperature as per the manufacturer’s recommendations.
3)    Keep them cool with a couple of fans and a heat sink especially in the summer. If you are using LiPos then you have no excuse for the additional weight of fans. 2 fans will not slow the brushless motor down as they take minimal wattage.

Just because your mates motor has not burnt out on the same gearing does not mean yours will not. We all have different driving styles. Some are smooth and some just hammer the throttle and brakes.

Another note is that when using brakes on brushless motors, the power is taken far more from your cells. Brushed motors have stronger magnetic field and will slow down quicker. Brushless motors need to have their pulse reversed to get them to slow down quickly. This equals more heat and more power taken from your cells.

We all want our cars to go faster that the next person. Just be careful.
I will try to get a picture up of some burnt out windings to show you the damage.

Testing down Aldershot track today, trying to go faster.

I used to be quite good , but am off the pace now, probably due to lack of testing, but more likely just getting worse with age.

So , took the 3rd hand Cyclone , Moorespeed down to see if I could tweek my lap times. Hoped to find 0.5sec a lap with clever adjustments.

Car felt good at start but already o.5 sec slower than Nigel who has the new TC. Also was slowest of the 4 of us testing. Looked at their setups which are a lot different from mine. I was trying the new XRay black springs, 2.6 rear and 2.8 front, which I’m told are the new in thing. Nigel however still uses the HPI silver springs front and rear. I also use the 1.4mm roll bars front and 1.5mm rear, while all others use a soft copper 1.2 mm rear.

I try the 1.2 mm rear bar and find the car perhaps has more rear grip, but i push harder making the back hang out sideways exiting corners. I go back to the heavy rear bar.

I try Jons cyclone which looks good, only to find it has no steering, I understeer straight off the track on the sweeper. He says to take a high line into the curve, sweeping in, but I usually enter low and hug the wall, which will not work. I understeer at every corner and give it back.

It seems I drive with extreme steering and cannot drive with any understeer. I guess that is why the back of my car often jumps from side to side. However I persevere. I reduce rear toe block from 3 to 2.5. On the Cyclone you never know what you will get with the rear toe, as they seem to have random angles from 4 degree to zero depending on your luck. Mine seems reasonable for a clockwisde oval so I carry on. Car appears the same so I leave it on.

After a few other adjustments, nothing makes much difference. So finally put on some almost new tyres (Sorex 32). Car immediately responsive, hanging on and plenty of steering.  Times are best I have achieved all day.

So, all I learnt after all, was that new tyres are better than anything else if you want to go faster. But we knew that already. I think my memory is going as well as my driving.

Nick