dirtybird

My Feedback: (5)

I just received a new RCXEL ignition. Its marked 6 to 7.4V. Apparently it has been modified to work with A123's

karolh

Good news for those who feel the need to run more than 5.0 volts (a fully charged 4.8 volt pack) on their ignitions.

Karol

dirtybird

My Feedback: (5)

I don't think the extra voltage will help. The windings are probably modified to produce the same high voltage it did on 4.8 v. You dan't want too much voltage, it will break down the insulation
Its just that the NI-CD's are PTA to charge and they lose that charge if they sit for a month or more

kerwin50

there may be lots of changes inside the unit inculding some sort of regulator

pe reivers

Eneloop NiMH cells do not lose their charge very quickly. 90% retention after one year! I would rather like to see the operating voltage drop to one single A123 or LiPo cell than the high 7.4V

dirtybird

My Feedback: (5)

I have an ignition system that works just great on my replica Super Cyclone with a single A123 cell. That system was developed back in the thirties. What go's around comes around.

earlwb

I would bet that they simply added a voltage regulator to the ignition module so it can handle 6.0v to 7.4 volts OK.
With them stating to use  6.0v to 7.4v, sure does imply they are using a voltage regulator to drop the voltage down to 5.0v for the electronics inside.

dirtybird

My Feedback: (5)

I doubt it. A regulator is a notorious problem unit when used with an intermittent load.
A simple change in the turns ratio of the coil will lower the output voltage and require no extra parts.

bcchi

I would bet you are wrong.I have seen the new circuit that XU Liang is useing.Not a voltage reg.
Adrian will not be useing the new RCEXL circuit on the C&H Ignitions,but he can build the new Ignitions to work from 3.7 to 12 volts.
BCCHI

captinjohn

BCCHI, Is the guy that knows this stuff !

MTK

Insulation breakdown? Which insulation are you referring to? Insulations currently used on RCExl CDIs utilize appropriate material and thickness for the voltages encountered.

Ni-Cds are old technology. Why not use 21st century batteries? Current state of art battery chemistries and battery characteristics are superior in every practical way........

earlwb

Well people have been using external regulators with the ignition units for years now where they wanted to use LiPo's or LiFe packs or larger Nicad or NMH packs.
So it isn't a big stretch to put in a small single IC switching regulator inside the unit. The switching regulators handle current demand changes really well.

flycatch

My Feedback: (26)

Think twice before you install this unit. I removed mine due to interference problems and I'm not alone.

captinjohn

YA.....Where is some proof !

BadAzzMaxx

?????

Are you talking about the higher voltage ignition or the RCexl ignition in general.

The only time I have seen a interference problem is when the plug cap was not installed properly.

What ignition did you use in place of it.

Milton

dirtybird

My Feedback: (5)

Correct.
But when you increase the input voltage this no longer is the case.
I am talking about the insulation between the wires in the coil and in the spark plug lead.

earlwb

How about http://www.tech-aero.net/ultra-ibec
or
http://www3.towerhobbies.com/cgi-bin...&I=LXSWL3&P=ML
or
if those aren't strong enough then http://www3.towerhobbies.com/cgi-bin...&I=LXYCA6&P=ML
budget versions of the UBECs from Hobby King http://www.hobbyking.com/hobbycity/s...R_2F_UBEC.html
for big planes
http://www.chiefaircraft.com/smt-reg04.html
or
http://www.chiefaircraft.com/catalog...ce&q=Smart-Fly

ref http://www.rcgroups.com/forums/showthread.php?t=1560085

MTK

Silicone rubber insulation on both of those items. Silicone rubber has one of the highest dielectric strengths of all plastics/rubbers per unit thickness.

dirtybird

My Feedback: (5)

OK but everything has its limits.
RCXEL warned not to use more than 6V or eventually the unit would fail.
Why else would a higher voltage ruin a unit?
If the unit produces 40000v with an input of 5v, a 1v increase in the input would increase the output 8000V

Truckracer

My Feedback: (19)

I seriously doubt there would be silicone insulation on the HV coil windings. Coil breakdown could be a real possibility but I would think Rcexl would factor higher primary voltages into any redesign of the coil.

bcchi

If you have a RFI problem with rcexl ignition system you probably do not have the plug cap all the way down over the hex of the spark plug.We had very few cpmplaints fo RFI with the RCEXL ignitions and nearly all of them were because the spark plug cap was not all the way on. If you do not use the RCEXL ignition which one are you going to use.
BCCHI

telejojo

I've bought a lot of eneloop bats. and made 4.8 packs and run in my gasser's from 20cc to 100cc and fly all day and never had a problem.............

earlwb

They use magnet wire inside the ignition coils. Granted the varnish insulation is a higher quality varnish coating, but the same stuff. What happens if if you increase the air gap on the spark plug, the extremely high voltage spike will start to punch holes in the winding insulation causing it to short out. A similar effect happens if the driving voltage on the primary windings is too high causing a higher than normal voltage level on the secondary high voltage windings. The higher input voltage also causes a higher current flow to occur where parts get more hot too,

But I think the problem is with the electronic components inside of the CDI unit. The micro-processor and or transistors being used are 5.0v devices and have a max rating of 6.0v. Plus some of the capacitors inside as well may be limited to 6.0v. So I think one of these components would fail before the ignition coil shorted out.

Those new RCexl CDI units that can handle 6.0 to 7.4v battery packs are very interesting. I'll have to get one later myself. But right now all of my CDI's work really well off of 4.8v battery packs. So there is no need to put one of the new ones in yet.

captinjohn

The eneloop is the best cell I have used.....love em ! Capt,n

MTK

Often the primary insulation material of choice for windings is polyimide lacquer. Polyimide also has extremely high dielectric strength, about as high as silicone.

The secondary insulation or cladding is often silicone or polyamide (nylon), depending on maximum temperature reached. Years ago I worked at a company that produced this type of wire. Our applications were aerospace related, so the materials may have been more top shelf....... Point is there are only a couple chemistries that can withstand the voltage potentials involved and still stay flexible enough to wind tightly with no damage. Anything else will short practically immediately.

In other words, as is true with so many things the average person takes for granted, there is quite a bit of technology that goes into producing "simple" wire for windings power coils