Decent lipo packs in oz?

[MegaDoomer]

Well i my align lipo died after 5 flights (yes we looked after it and were in specs had awesome ventalation etc etc ) My LHS said they just die sometimes for no reason.

So im trying to find some 2000mah+ 18c+ lipo packs that are decent kokam or thunder power ? or maybe someone else has a recommendations ? They need to be able to handle at least 25A discharge

All i need is place in oz that sells them too :)
Thanks :0

[osmium_192]

I would look at www.modelfight.com.au

They have the flight power 20C and 30C burst batteries. i use the 1800 mA battery for my t-rex and its great. so far on 10 flights its going strong. those battereis arnt the cheapest, but they have a good following and a good brand. flight power is like the equiv of kokam in the US. Theres also dual sky batteries that are cheaper, but im not sure about 25A for a 2A battery.

Proof of the performance is that the batteries are not even warm after a heli flight.

Owen

[Idefix_APAC]

Hi there,

have a look at www.rc-warbirds.com (http://www.rc-warbirds.com).
The packs are pretty good value for money. I'm using the 2000mAh 3S pack with my Trex (450th brushless - 26A :D ).

8 minutes of full 3D flight and the packs are only slightly warm. Compared with the polyquest 1800XP I was using before they are much more powerful at less heat.

Hope this helps.

[RussellK]

Being a bit dark on Aussie shops at the moment, I'd suggest you have a look at
http://aircraft-world.com/shopdisplaycategories.asp?id=87&cat=batteries
they have a pretty consistent 4-day delivery to Oz and the postage is damn cheap.

[osmium_192]

4 day delivery..... I just ordered form them and nothing has arrived for 10 days. And i only ordered 85g of items.. (i think)

Im definately not all to happy with LHS, they all look pretty scary and mean when you ask too many questions, and correct them when they say that using 3S in stead of 2S will increase the RPM and reduce the APM draw slightly... (WHAT THE??)

Definately alot of options here. Modelflight offers express postage for $12 and when they say express, they mean express. Ive have orders from perth arrive in 2 days,and to melb arrive the next day.

Owen

[RussellK]

Owen,

Did you get an email saying it has been sent? I've done about 8 or so orders over the last few years and the delivery time has been pretty consistent - perhaps it's different to WA, but that wouldn't explain 10 days...

[osmium_192]

Tracking Message for order
Date: 1/16/2006
Time: 1/1/1900 12:13:04 AM
From: Brian

Message:
Hello Owen,

Your package was sent today via PARCEL POST, as requested in your order.

As found on our Shipping Policies page:
http://www.aircraft-world.com/default.asp?id=10
Please note the following:

(Residents of USA and Australia)
Most orders to USA and Australia arrive in 4-8 days but occasionally one takes a few days more. There is no guaranteed delivery time for Parcel post packages to USA and Australia. Allow four weeks. Insurance to USA and Australia for Parcel Post packages is limited, and is only in the form of store credit. Please always select "EMS Express" for high-value orders.

(Residents of all other countries)
The "Small Packet" Parcel Post service (from $2.50) is reliable and usually quick, but there is the POTENTIAL that you will have to wait 6 weeks or more due to slow customs clearance. Virtually all packages eventually arrive, but yours could take months in the worst case. THERE IS NOTHING WE CAN DO IF YOUR PARCEL POST PACKAGE IS LATE! THERE IS NO INSURANCE FOR PARCEL POST SHIPPING METHOD OUTSIDE USA and AUSTRALIA.

You can review and print your orders via our webpage:
Go to 'My Details', (right side of the webpage) click on 'Login' and fill in your last name and email address.
After logging in, click on 'Review Previous Orders'.


Best Regards,

Brian
International Sales Manager, Air Craft
http://aircraft-world.com

For future inquires, please direct email to:

Order-related questions: shop@aircraft-world.com
Technical questions: tech@aircraft-world.com


Order Details - Tracking Message

Order amount: US$20.98

Owen Chin
12 Alsop Place
Kardinya, Western Australia 6162
AU

Products Ordered:


QRP-60521
QRP Narrow HINGE TAPE for Micro to S400 models 12mmx35M (~.5 x 113
Quantity : 1
Price : US$1.90

GW-LFW-508-21
GWS Light Hub Wheels 51mm (2g ea) (2PCS-SET)
Quantity : 1
Price : US$2.40

HP-WR-010
LIGHT EXTENSION CABLE 300mm (12") length
Quantity : 4
Price : US$2.85

NHP-217
BULB APPLICATOR - FINE for Medium to Thin CA
Quantity : 1
Price : US$0.50

AC-WIRE1M-18
18 AWG (1.219mm)
Quantity : 1
Price : US$2.50


Heres the email. Still dont really have anything against AC yet. Ill be patient.

Owen

[pldaniels]

Not to plug my own store but ... I've got a few 2S2200's left at http://nqrc.com

Then I'll be getting more different sizes in after this.

As for your experience with Align, I know what you mean, had the same thing happen to me. 5 flights or so and then BLAM, wouldn't hold voltage under any meaningful sort of load.

Paul.

[pldaniels]

4 day delivery..... I just ordered form them and nothing has arrived for 10 days. And i only ordered 85g of items.. (i think)


I've ordered from AW many times over the last 2~3 years and found them to be highly reputable. Sometimes however things just go wrong with shipping and your 1 week shipping becomes 1 month, it's fairly rare, I'd say that only one package that I can recall took that long, the rest have almost always been exactly 1 week.

Hope your package arrives soon!

Paul.

[RussellK]

Damn. I put an order in on Wednesday and it was sent off by the same guy - I hope it doesn't take that long too :(

[pldaniels]

You guys might be running into the Chinese new-year holiday period (Japan isn't quite China, I realise, but the effects could be rather widespread)... always bad news for speedy shipping.

Paul.

[osmium_192]

I doubt chinese new year attacked my package, but i think it wouldn affect it anyway. LOL

I think its more a customs thing or similar. I ordered a pack of 18awg wire which could have been used for WMDs....

Owen

(All comments above are of a non serious nature and thus does not carry any meaning whatsoever)

[pldaniels]

Owen,

One shouldn't laugh too hard... I had a difficult time getting my 20 lipos in via most couriers "What? Lithium? NO WAY" *sigh*

Paul.

[rredbeak]

Im new,whats a lipo pack ??? Rod :)

[pldaniels]

lipo, short for lithium-polymer. It's a battery chemical system which has one of the highest energy densities per weight/volume, typically twice the energy of a similar mass/sized NiMH pack.

Down side of lipo is that they require slightly different handling and require different chargers.

Paul.

[osmium_192]

It revolutionsied the model plane industry. Allowing the weight of the plane to be reduced SIGNIFICANTLY. The smaller the plane, the more significant the weight of the battery, so halving that weight has massive effects on performance and freedom of design.

My micro indoor plane of 35cm span using a normal NiCd battery has the battery take up 80% of the total weight. If i used LiPos i could almost halve the weight and this nearly halve the flying speed, or mean i can load it up with more equipment, like controlling devices for an elevator control.

LiPos also have a more rectangular shape rather than the round cylinder shape so fit in planes far more efficiently too.

LiPos are the way to go, no doubt. The cost though might be an issue, but that problem is being solved all the time with more and more manufacturers/resellers competing in the market.

Owen

[bobert13581]

are there any problems getting lipos through the postal system?
e.g. posties scared that the packs will get too warm in their vans and then explode?

[rredbeak]

Are they worth the money if theyre handled and charged properly ???

I make my own packs with batteries that have solder tabs etc etc. Can this be done with LiPo's ???

I always thought that Nimh was the ants pants but if these guys are better then im going to change over..
I assume you can buy LiPo chargers locally. Or can a custom made charger suffice?if so what is the charging rates per cell ??
TIA.. Rod :)

[pldaniels]

Bobert,

I've had no problems with posties thus far. Clearly one should still wrap/pack lipos with preventing damage in mind.

Rod,

Lipos out and out beat NiMH hands down for pretty much every task. The only NiMH's I still use are the 4 x 2/3AAA packs I use for my DLG's --- and that's because I need the added weight.

Yes, everything regarding lipos is available locally. For a good reliable charger, I suggest the "Swallow Advance", for $99 AUD it's one of the best value computer chargers (it'll do NiCD, NiMH, LiIon, LiPoly, Pb).

Paul.

[osmium_192]

Ive got one. Its a brilliant charger, except dont use the cycle function. It doesnt seem to let you program the discharge cutoff.... so cycle your batts manually.

This charger ive seen under 6 names already (or more) but its all the same. Aircraft world sells it under the hyperion name. Eflypower sells it under the megapower name, ive seen it under the multiplex name in the US, X-Power, and a few others.

Id be careful with custom chargers. You need a CCCV charger setup with the ABSOLUTE top at 4.2v per cell. at 4.3v per cell the cell goes explosive, not just a pop, but a hissssss BOOM and flames. And charge at <1C. Lithiums also might need cell balancing since the CCCV setup means that theres no significant increase in resistance when fully charged, so theres no natural balancing of the cells. So eventually you neec a cell balancer that will charge each cell individually. I have a align 4 cell balancer and that was 69 dollars from eflypower. mine is an active balancer, it charges each cell to 4.2v, while some cheaper (not always, you can get rip offs) types include a little circuit that shunts the charging energy from being put into the cell, to a resistor that gets hot.

LiPos all the way now, its a far superior power source for power per gram.

Owen

[rredbeak]

TY guys for the assistance,yes i will buy a charger as it sounds far too complex for me LOL...

Ill checkout Lipos on the net now that i know what they are ... Good Flying.. Happy Landings.. Rod :)

[pldaniels]

Rod,

Go do some research. Best that you arm yourself with real facts and take the time to learn how to use the new computer chargers. You'll discover a lot of alarming lipo incidents, of which most are attributable to people making a series of bad mistakes. Just like petrol or any other energy dense material, it's important to know what you're handling. Used correctly, lipos are safe.

Paul.

[rredbeak]

TY Paul. Yes i thoroughly agree. Cheers.. Rod :)

[rredbeak]

Paul,

A few questions regarding the Swallow Advance...

As well as Cycle Nicads,will it condition Nicads as well ?

On the input of the advance its got alligator clips but on the output it only appears to have Banana sockets... I ASSUME the LIPOS come with plugs designed for receivers or so. Will i have to make up a adjustment cable from Banana Plugs to RX female ??? OR is there a female socket elsewhere on the charger that i cant see ?? The only pics i can get of the Swallow Advance is face only...

Without extra external wiring how does one charge individual batteries as in 4 nicad / Nimh batteries ?

Dick Smith used to sell plastic battery snaps that holds 4 to 10 batteries [different holders] with a 216 [9volt] input plug. Is this the way to charge 4 batteries Nimh or Nicad ??

It looks like a great thing with an overly large array of protection circuits,makes one feel safe using it....

Reading some of the warnings and some of the horror stories it clearly Demands safety and no "she'll be right" Attitudes.

I assume the charger is self sensing as to the number of batteries / cells attached. Its only the output plug [charging end] that i find confusing at the moment.

Im not ready to buy at this point as im still getting into the hobby after a few years break and ive bought a bunch of Nimh batteries thinking they were the latest technology and have a dedicated Nimh charger with it...

I DO AGREE that technology MUST continue and Lipo's appear to be the way of the future,although the warninge are a little worrying even using the CORRECT battery charger the warnings are strict.

One wonders where technology will swing from here LOL. I ASSUME Lipos are relatively new technology,and i think in future you will be able to buy direct replacement batteries [lipo] for TX's right down to RX's in all common plug designs.

Im thinking now of modifying my TX to take a lipo THEN externally charge it for safety. i see they come in various voltages...

Cheers.. Rod :)

[pldaniels]

Rod,

With the Swallow [Advance], you're right, there's only the two banana sockets, with these you run a lead to your battery which typically will either have a Deans Ultra or Deans Micro connector on it (the two defacto type battery/ESC connectors for anything over 5A of current).

What I have at home here is a set of leads with each type of battery connector on it and banana plugs on the other end.

You can also still use those battery pack holders that DSE sells (*sigh* memories, I used to work at DSE) and just connect up a 9V type connector with banana plugs on the other end.

For NiMH/NiCd cells, the Swallow charger will auto-sense the peak charge point, you only have to tell it what current rate to charge at.

For LiIon/LiPoly, you have to tell the Swallow what voltage to charge to, ie, 3.7V, 7.4V, 11.1V etc. I don't know if the "Advanced" version auto-detects, however it's still always very very good to check what the charger thinks it's doing to what you want it to do.

Lipos can be a little bit scarey but so long as you realise that there are dangers you'll generally be safe, it's up to you to be aware.

Paul.

[RussellK]

As far as I can tell, the golen rule with Lipos is not to bring them anywhere near luxury vehicles:
http://www.rcgroups.com/forums/showthread.php?s=&threadid=140641

[rredbeak]

Thats an amazing thread Russellk...Definatley proving the volatility of these new Lipo's...
The important thing is that the manufacturers pick up on accidents like this and use what was a horrible accident to better manufacture a safer Lipo.
They manufacture / test Lipos under perfect conditions i imagine. i DONT think they realise the severe impacts the batteries get in our hobby. I DONT think they have tested them in heavy impact situations...

So, as sad as the burnt car is ,we should make something positive come of it by refering the circumstances to the manufacturers and let them devise a better safer product.

On one website i read the DO NOT section first,it went on to say NEVER leave a lipo unnattended ANYTIME whilst under charge / discharge. Do NOT charge in a vehicle . Do NOT charge under the bonnet of a vehicle..

It just goes on and on. The warnings made it sound more like a secret weapon rather than a battery. BUT as the pics of the burnt car shows,the website was totally correct even tho the circumstances were slightly different [not charging but storing it]

The Club i used to belong to before i had several years break used to say " Never waste a good crash" meaning learn from it. In this instance we should do the same. Notify the manufacturers ,all of them but be sure to include all the circumstances..

It wiil make a better safer product for us long term.

In the meantime im sticking with my Nimh batteries LOL. no ive never damaged any but if i do ill treat all batteries with the same respect as Lipo's..

Cheers Rod :)

[RussellK]

Meh, as far as I'm concerned electrics in general are simply dangerous - considerably moreso than glow - it's pretty hard to get methanol fuel to do anything bad (unless you light it or drink it) and glow engines make so much noise, you kind of know they're gonna hurt unless you're careful. When they're quiet you know they're safe.

Batteries, NiMH or NiCad can cause an instantaneous world of grief just by an inadvertent short circuit - the wire immediately welds making it impossible to disconnect, and suddenly there's a bunch of acrid poisionous smoke and most likely fire. Lipos take this a step further by the actual battery pack joining the party and swelling up and exploding too.

Similarly, electric motors can fire up to full torque and power in an instant with no warning whatsoever.

All that said, I use both glow and electric, but I'm a lot more cautious with electric. I'll charge my lipos in the F150, but never in the SAAB or any other vehicle with leather seats - that's just asking for trouble.

[pldaniels]

Russel,

Is it the leather that causes the explosions? Something in the tanning process? ;)

I fly gliders and e-flight, I find gliders more relaxing for many reasons, not least of which is not worrying about the amazing amount of destruction that can be the end result of a crashed e-flight plane.

... of course, I still use lipos :D


Paul.

[RussellK]

Leather? Tanning? No, it just means the car's expensive - lipos can sense that Paul. They know :|

I tried gliders once, but it hurts my neck all that gazing straight up, only to realise you've been tracking a goddamn eagle for the last 5 minutes (which explains your rather impressive thermalling) and christ knows where your plane's got to.

I actually haven't had any nasty accidents with electrics, yet, but they've scared me once or twice, whereas glow engines have mainly just hurt my ears - especially a ducted fan spinning at 28k while trying to tweak the mix.

[pldaniels]

Russell,

Sounds like pylon racing too (glow, with rossi motors).... waaaaaaaaaiiillllllll "Nah, needs to go another octave" waaaaaaaaaaaaaaaaaaaaaaaaaa*silence* "Yep, that's it" (so high pitch it actually starts sounding quieter)

You should try Discus-launch-gliders, they never get away too far and you spend a good amount of time throwing them up again (about 1 throw for 60 seconds without lift, or 5~10 minutes with lift).

Paul

[MegaDoomer]

Can you PM me when you get higher rating lipos in :) at least 18-20c :)




Not to plug my own store but ... I've got a few 2S2200's left at http://nqrc.com

Then I'll be getting more different sizes in after this.

As for your experience with Align, I know what you mean, had the same thing happen to me. 5 flights or so and then BLAM, wouldn't hold voltage under any meaningful sort of load.

Paul.

[pldaniels]

Mega,

What sizes specifically are you after? I can get up to 20~24C atm, with the factory testing their 30C ones over the last couple of weeks. I personally tend to be happy enough with 12~15C primarily because I like to fly for at least 10 minutes so that's a 6C draw with perhaps a 10~12C burst here and there.

Paul

[RussellK]

Actually Paul, I'm also poking around for some new lipos - 3S 1700-2200mAh, 15-20C - anything on the horizon?

[pldaniels]

Russell,

well, the next batch was going to be a lot of 3S2200's, 2S2200's, 3S1350, 2S1350 and ... and... I was thinking of something small like 700~800mA ? too many choices.

Paul

[osmium_192]

The swallow advance doenst have auto lipo detection, just a warning if you put the wrong one.

The output is pretty simple. All you need is just a set of banana connectors (4mm which are available at DSE) and connect that to your batteries.

I have a Deans Ultra connector on my charger lead because thats the standard i have for all my battery packs. So to charge my LiPos i just hook it up.

For Nimh Packs i also have Deans Ultra connectors so its the same as for my LiPos. BUT i dont just use my charger for RC stuff. I use it for my camera batteries (AA cell) and yes, i do use a battery holder and i simply use aligator clips to hook it up to the charger banana plugs.

If i dont have a battery holder, i would normally resort to magnets. (the strong NdFeB (rare earth) magnets), I put magnets on the batteries and it hold all the batteries in a line. I use this for my C cell batteries for my torch when i dont have a C cell holder.

The charger does have an auto cutoff detection when charging NiXX cells, so you dont need to worry about that. Just make sure you dont let it over charge, with a low cell count and a low charge current it does sometimes not detect a full charge and contine charging untill you turn it off, so just remember to time it and after the time you would normally let it charge for, check on the charger to see if its finished.

When chargin NiXX, refrain from touching the wires. Doing this might cause the resistance of the wires to change. This isnt a problem if you used VERY positive connectors and soldered the connectors, such as the deans ultra connector. If the resistance changes, the the voltage will shift up or down and might falsely trigger the charger to end charge. If this happens though, just set it to charge again.

When you say condition a battery, that just means cycling a NiXX battery. Id reccomend manually doing this on the charger.. i.e. charge it, then when its done you program it to discharge to about 1.05v per cell. Once done you reprogram it to charge again... and so on. i wouldnt use the inbuilt cycling program since it doesnt ask for a discharge cutoff, so might damage your batteries if over discharged which happend to my battery when i tried it (luckily it was someting that was already almost worth nothing).


Anyways, have fun

Owen

[RussellK]

well, the next batch was going to be a lot of 3S2200's, 2S2200's, 3S1350, 2S1350 and ... and... I was thinking of something small like 700~800mA ? too many choices.


When are these likely to make an appearance? Any idea of price on the 3S 2200's?

[pldaniels]

RussellK,

Right now, I'm recovering from a rather outlandish expenditure burst, which has left me in a situation where I'm banned from making new orders until perhaps another 4 weeks. After that a given order would take about 2 weeks to be processed and arrive. However, it's a big tussle... more batteries, or more GWS BL gear... choices choices (it's one or the other at the moment because both factories have minimum-order sizes).

If you need lipos "right now" or "very soon", then honestly I suggest you check out Aircraft-world or similar as I will only dissapoint in terms of delivery time at this stage (don't you hate being honest? :D )

Price wise, the 3S2200 @ 15C would be about $49 ~ $59 AUD, depends on what customs do. If customs decides to hold the package then instantly the price jumps at least 10% simply because of the costs involved in going through customs, it's cruel, I know but that's the nature of the importing game, sometimes you're fine and stuff comes through without a hitch, other times you get slapped with a bucketload of fees.

Paul.

[RussellK]

I'm after some sooner rather than later. Pity though - your price is very good. I'm trying to decide whether it's worth giving this bunch a go:
http://www.himodel.com/en/rc_catalog/electric_98p1.php

Their prices are pretty good, but it seems you have use EMS which adds about US$20 to the price. If I get 2, their 1700 20C packs work out at AU$65 each and their 2200 20C packs AU$79 each.

I don't really need 20C - I'm only looking to push about 16 amps or so, but the cheapest from Aircraft World is the Hyperion 1800 20C at AU$87.

That said, I dunno if the HiModel packs are any good, but then again, I've heard nothing about the Hyperion packs either. Sigh.

[rredbeak]

Osmium,Ty for your input..

Cheers.. Rod :)

[rredbeak]

Osmium... Are Deans connectors high current rated ??? Rod :)

[RussellK]

Yup, Deans Ultra are pretty much the standard for high current packs - I'm not sure of the max rated current, but I've seen claims of 80+ amps.

[osmium_192]

The maximum current rating is really just controlled by the resistance of the wire and the temperature you are prepared to have the wire get to.

The higher the resistance of the wire, the greater the amount of power that gets converted into heat, following the rule,

power loss = I^2 x R
or
Power lost in watts = current^2 x resistance

and the voltage drop as a result of the resistance - V = I x R
(this voltage drop is exactly why the voltage sags under loading, batteries have an internal resistance and that controls that voltage drop under load. Thats why High C battereis give more power than low C discharge rated batteries)

anyways, from the first formula you can see that the more current that you put into a wire, the greater the amount of heat is produced. So ideally the material with the lowest resistance is prefered, so we could all use 10cm diameter gold wires and have almost no loss into the wires, but weight becomes an issue. (and $$)

But using thinner wires that have a higher resistance means more losses into heat. Hot wire cutters exploit this and by using high resistance wire, the heat loss wil heat up the wire to hundreds of degrees.

So for your use its really a trade off between weight and efficiency. I think ive read somewhere that the deans connector including the sodler joint is equivalent to about 12 gauge wire. 12 gauge wire is huge and id say will safely handle the 60+ amp range, with accpetable voltage drop.
(And also the shorter the wire the lower the losses.)

I have normal hook-up wire with me, and i also have a 12G hook-up wire (i know its funny). I use the 12G only to minimise voltage drops over 2m of wire because with the normal 20G hook up wire i was getting about 2v drop at 5A which really throws off the values displayed on the powersupply readouts.

For the pucture - The hook up wire i think is 20 gauge, and that gets very warm at 10A, losing about 20% of the power :o when i use that to test my esc motor setups. The dualsky battery has 16gauge wire, the evo 20 battery has i think 14 gauge wire and the hook up wire on the right has 12 gauge wire.

Owen

[pldaniels]

I should add one small item here, just to fill in the theories...

One way to get lower resistance with lighter wire is to use a great number of small wires. The reason why this works can be explained in two ways.

1) Electricity/electrons flow on the surface of the wire, so the greater the surface area the less resistance, so, in theory, you can use an infinate number of infinately small wires and have zero resistance (don't you love theories).

2) Putting resistors/resistance in parallel reduces the net effective resistance (seems counter intuitive at first, until you view a resistor as a water pipe of a given diameter - the more pipes you have in parallel the more water you can get across).

So, if you have a choice, get wire with a high conductor/strand count, rather than a few thick ones (go check the ultra-heavy-duty wire at DickSmith - has about 512 strands, very flexible but high current rating for its diameter). High end speaker wire is similar too (for similar reasons, low voltage drop requirements, long runs).


Another thing - since we're on this topic....

- Voltage refers to the energy level of a single electron (as such)
- Current refers to the number of electrons flowing

If you think like that a lot of concepts start to make sense when it comes to power/resistance/BEC issues/etc.

... hope that helps some people.

[rredbeak]

Turning the Deans Ultra towards to so that the terminals resemble a letter "T"
which is the commonly used positive terminal ? The Top [horizontal] or the down terminal [vertical] ???

yes i like your cable setup Osmium...

Cheers.. Rod :)

[pldaniels]

The top.

[osmium_192]

The fat part = the bigger part, which is the positive part.

Its the convention i and the manufacturers follow.

(btw, whos inflex-lap in the chat room)

[RussellK]

1) Electricity/electrons flow on the surface of the wire, so the greater the surface area the less resistance, so, in theory, you can use an infinate number of infinately small wires and have zero resistance (don't you love theories).


What you describe here is called the "skin effect" and only applies to AC current - it's not applicable the DC current we use in our aircraft power systems (except maybe between the BSC and BL motor).

Thus a stranded wire and a solid wire of the same cross-sectional area will have virtually the same resistance (not exactly the same as there's little air gaps between the strands).

[pldaniels]

Russell,

You sure about that, I thought it was for any electrical/electron charge --- time to bring out those physics books again, it's only 1400 pages thick, big green and ugly... but it was my University text.

Osim,

Yes yes, I'm inflex / inflex-lap :)

[osmium_192]

Ive known the skin effect to be applicable in high freq AC currents also, but never really thought about DC. Well multi strand is good anyway, it allows for more flexibility and prevents "fractures" when bending the wire sharply, or after multiple bending on the same spot, (like what happens when you plug, unplug battery packs and the recoil bends the wires over and over agian)

Owen

[rredbeak]

I didnt realise that there was a thick and a thin contact.. but its the Top so now i know TY Guys.

Yes the Skin Effect is for AC oscillation only,mostly dominant in HF oscillation.

Cheers Rod :)

[osmium_192]

The contacts are the same size, but the plastic body does vary in shape, its somewhat pear shaped, with the wider part on the top of the "T" being the positive.

And when soldering, remember to insert the Heatshrink BEFORE you solder the wires. Its still not uncommon for me to solder the wires and then... "WHERES THE HEATSHRINK!?!?!?". So ill unsolder, and then resolder the contacts and end up with an uglier joint...


Owen

[pldaniels]

Owen,

No fun that "resoldering" bit :( Agreed though, I do it plenty of times myself.

Even more fun is when you do remember, but the heatshrink slips back towards the join a bit as you're soldering it - the heat from the wire then causes the heatshrink to start shrinking before it's meant to *ARUGH*

[RussellK]

Russell,
You sure about that, I thought it was for any electrical/electron charge --- time to bring out those physics books again, it's only 1400 pages thick, big green and ugly... but it was my University text.


Yeah, the skin effect is only AC, and the depth of the effect varies with frequency. I found a good entry in the WikiPedia:
http://en.wikipedia.org/wiki/Skin_effect

That physics text isn't Halliday and Resnick "Fundamentals of Senior Physics" by any chance (shiver)?

[osmium_192]

Yep, thats happened many times as well. Sometimes i try to use the residual heat of soldering to heat the heatshrink, by pushing the heatshrink up just after soldering. I know that its risky, but i still do it.... and quite often the heatshrink gets caught half way and shrinks there.

But thats all completely my fault....

Owen

[pldaniels]

Owen, $19.95 for a heat gun is WELL worth it. For years I didn't have one - I bought one from DickSmith about 5 months ago... wondered how on earth I survived without.

Paul.

[osmium_192]

Well i use a room heater normally, which is the same as a heat gun except designed for heating a room. Or if im lazy ill just use my soldering iron (have it really close to it) and when im really lazy ill move the heatshrink over the connector.

The last method works really well when it works, but every now and again it gets stuck half way.....

Owen