Help me choose an ESC please

[kink]

Ok after some debate I pulled the trigger on a brushed 19T motor. I will reveal what model later on in my build thread. But it looks very cool, I have secured tons of long lasting brushes for it, plus I plan on customising it with different anodising to suit my RC10 build.

So I need to decide what ESC to get for this 19T brushed motor. I guess it hinges on whether I go for Lipo or NIMS, due to input voltage restrictions. So give me your opinions on batteries please. I know zero about Lipo!

Anyway I found these ESC, what do you think?...


LRP
http://www.ebay.co.uk/itm/330889857053?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

LRP (similar - no idea why it costs more)
http://www.ebay.co.uk/itm/390459295098?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

LRP (tiny, which may be handy)
http://www.ebay.co.uk/itm/380522811334?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Tekin 1
http://www.ebay.co.uk/itm/230780665601?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Tekin 2
http://www.ebay.co.uk/itm/350561848484?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649


^
What are the reasons to choose one over another?

[Stumpy]

When choosing an ESC, the first thing I look at the motor rating of the ESC, to ensure that the ESC will run the motor I want to run.. The ESC motor rating (in turns) MUST be lower than the turns rating of the motor you want to use... eg. A 12 turn ESC should easily run a 20 turn motor, but a 20 turn ESC will most likely overheat if running a 12 turn motor.. Understand??

Cost, or value for money is what I look at next.. Some other factors I look at when considering the Cost or value of an ESC are...

Forward/Reverse... Do you require reverse..??

BEC voltage and current rating.. The BEC (or Battery Eliminator Circuit) is the part of the ESC that provides power to the receiver and servos.. Most radio systems are designed to run on 4.8 Volts to 6 Volts.. Thus an ESC with a 6 Volt, 3 Amp BEC will be able to provide more power to the receiver and servos (meaning that the servo will be faster) than an ESC with a 5 Volt 1.2 Amp BEC will.. (If you are planning on using a high torque/speed digital servo, then getting an ESC with the highest BEC rating will become more important, so you will get the best performance from your servo..)

LiPo Cutoff... Having an inbuilt LiPo cutoff is becoming more important these days, with more and more people moving to LiPo batteries.. If the ESC does not have an internal LiPo cutoff, then you will need to factor in the additional cost of an external low voltage cutoff, or alarm...

Size is the next thing I consider.. A smaller ESC simply will be easier to mount in your car due to its smaller size..

Imput Voltage is something I look at, but is not a big issue these days.. There is no reason why an ESC that is designed to work with 6+ NiMh or NiCd cells will not work with a 7.4V 2S LiPo.. Just be aware that there are some (brushless) ESC's out there that are designed to work with 1S..

Personally, I would choose the Tekin FXR although, either of the first two LRP ESC's you posted should run your motor with no problems..

Mark

[Stumpy]

I personally would not bother with NiMh/Nicd batteries for a runner.. LiPo is the way to go..

The main factors to consider when moving to LiPo are..

LiPo batteries do not like to be discharged below 3 Volts per cell (6 volts for a 2S pack).. You will need some type of low voltage cutoff or alarm to tell you when your pack has reached this level.. Allowing a LiPo to fall below this voltage level will mean that your charger probably wont charge it, but if the charger does try to charge it, it could puff and burst into flames..

Each LiPo cell has a nominal voltage of 3.7 Volts, and a fully charged voltage of 4.2 Volts..

Charging... Buy a charger that is capeable of BALANCE charging LiPo batteries.. There are plenty of inexpensive units out there that will do the job, the IMAX range (or one of the clones/copies) seem to be a popular choice..

Capacity... Capacity is directly proportional to runtime.. The graeter the capacity, the longer the runtime.. Capacity is measuerd in AMP HOURS.. Basically a battery with a 5000mAh capacity (5 Amp/hour) can deliver 5000mA (or 5Amps) for one hour.. The relationship between current and time is inversely proportional, meaning a 5Ah battery will deliver 10 Amps for 0.5 hours or 2.5 Amps for two hours..

The "C" Rating... The "C" rating is reported to be the MAXIMUM output current rating of the battery pack, and this rating should NOT be exceeded.. The "C" rating will typically be printed on the battery label near the capacity.. An example is 20C, 40C, 65C etc.. The maximum output current is calculated by multiplying the "C" rating by the batteries capacity.. eg. A 20C 5000mAh (or 5 Amp hour) capacity multiplied by 20C equals 100Amps...

Weight.... LiPo's are much lighter than NiMh or NiCd batteries..

Safety Summary...

* Use a quality charger, on the LiPo setting...
* Balance Charge whenever possible to keep the cells balanced..
* Use a LiPo charging sack when charging. Dont charge with the battery in your car.. (The LiPo sack will contain a LiPo fire.. If the battery catches fire in your car, you will loose your car as well)
* Dont exceed the manufacturers maximum charge rate..
* Dont exceed the C rating of the battery..
* Use a Low Voltage Cutoff when running the battery..
* Store the batteries as per the manufacturers instruction, typically 60% charged.
* Use only HARD CASSED packs..
* Do not puncture a LiPo cell... (A punctuerd cell usually means FIRE..)

Hopefully I havent scared you away from LiPo batteries, but if treated with respect, they are as safe, if not safer than NiCd or NiMh..

Mark..

[Bormac]

Those Tekin's are far better in my opinion than the LRP models you have selected. I used to run with the LRP v7.1, Quantum Competition, QC2 and QC3. I then moved on to the Tekin FX series of brushed esc's and I really like them.
I'm no expert but it would seem the cheaper more hobby grade units often have 4 wires leading from the ESC unit while the more serious units have only 3. Also heat can be the enemy and the higher the spec of esc the less it will overheat (in most cases).
I used to find that the LRP QC3 had a lipo cut off point that didn't work as well as I'd like.
Now days all of my brushed ESC's are the TEKIN FX PRO. The cut off works exactly as it should for Lipo use and the pragramming is simple enough to get right.

My opinion is to go with the TEKIN FX/R if that's what you have to choose from in this lot.

[kink]

THANKS Mark - what an extremely detailed reply! Much appreciated

One question - If I do not use mycar for a month, would the Lipo batteries drain back to zero volts if left to themselves? Would this cause damaged? If so how is this avoided?

Does anyone here still use Nims or Nicad? Obviously the performance and life will be shorter, I get that. Just wondering.



Re: ESC

Ok I will buy Tekin. Any reason to buy the Pro over the FXR?

[Stumpy]

LiPo batterires do not suffer from "self discharge" in the same way that NiMh cells do.. The do still self discharge, just no where near as much or as fast..

When I was racing, I worked out that after my race I had used about 2000mAh out of my 5000mAh batteries, so I figured that was close enough to the manufacturers 60% storage capacity, and I would store them at that level until I raced again the following month.. Sometimes, due to bad weather we would miss one or two months in a row, with no ill effects to the batteries.. (The LiPo's I used were Reedy 5000's, Gens Ace 5000's and IP5000's)

I still have some older GP3300 NiMh packs that see occasional use, mainly in cars for my niece and nephew where performance is not required..

The "PRO" version of the Tekin FX/FX-R ESC's has no motor limit.. More information can be found on Tekins website.. http://www.teamtekin.com/fx.html

EDIT.. One more thing... LiPo's do not suffer from the "memory effect" that NiCd and NiMh cells do, so there is no need to discharge them before recharging like you do for Nicd/NiMh, you just take them out of storage, place them on charge, and when they are fully charged, run them in your car..

If you do find that you havent used them (or aren't going to use them) for some time, then you can always put them back on the charger for a "top up" to get them back to that storage level..

[teman]

I like the 1st gen Castle Sidewinder since it will do brushed or brushless and is fully programable. They're quite reasonably priced as well. Just my 2 cents of course.

[kink]

Ok thanks a lot.

Any thoughts on decent brand chargers to use for Lipo? Not for racing or anything serious. Just well made, reliable, very EASY to operate or program...?

[Coelacanth]

I like the 1st gen Castle Sidewinder since it will do brushed or brushless and is fully programable. They're quite reasonably priced as well. Just my 2 cents of course.

I second that vote, a Sidewinder is a great choice for a vintage runner. I'm using a Sidewinder in CYANide. The current version of the Sidewinder is the Sidewinder 3, but it's not much different from the previous models. You'll find several of the older units all over eBay for $50 or less.

http://www.castlecreations.com/products/sidewinder.html

Wasn't Castle blowing those out at cheap prices not too long ago? Unfortunately it seems they must've sold out, probably was a clearance sale of older stock.

[slapshot1979]

As for a charger I always direct people to hobby kings Accucel 6. (product code ACC6) inexpensive and Ive had mine 4-5 years without problem.

I was a little nervous about Lipo at first also, I think everyone was but once you get used to it, you will never go back.

The guys above layed it out very well, some good advice there. I vote for the castle sidewinder also.

[teman]

There's just 1 catch with the Castles, you need the Castle link/ field programming card IMO, it should come with the ESC however that's not the case

[Coelacanth]

There's just 1 catch with the Castles, you need the Castle link/ field programming card IMO, it should come with the ESC however that's not the case

I think I read somewhere that you don't need the programming card, it's optional, but gives you more flexible adjustment options.

[teman]

Correct, basic programming can be done with the menu beeps but is rather annoying to say the least, much more hassle free with the card. The bad news is with the original Sidewinder a firmware upgrade to the newest version is suggested which can only be done by the Castle link. When I get home I'll check what that is, I want to say "1.32" but let me check. Both of mine were cogging until I did the firmware upgrade. The coolest feature is the power curve tweek with Castle link, well worth the $ to enable this feature. It would be far better if you could store more than one curve "tweek" setting on the esc itself, but you can only store one besides the basic settings like throttle-brake-punch etc.