Hmm. Unfortunately SMC seem to be sold out of both the ESC/motor combo, and the batteries I'd be after...

Those are the same tracks I run at. For Outlawrc stock motors work great, but at CamRC everything is mod and a stock motor is going to feel like you are going around the track at a slow crawl compared to everyone else. So I would not recommend the justock. Hobbywing does make good esc's but you're better off getting an esc that will work at both tracks. I would recommend the following hobby shops amainlandhobbies.ca owned by a friend of mine and racer at the track he has very good rates. GripworksRC.com another racer at the track usually brings his wares to the track. gogohobbies.com in Coquitlam. You can talk to Chris the outlawrc club president owns hi-performance.ca but they are a distributorship and deal strictly with LHS. You have to be wary about importing batteries because they are outrageous to ship unless you have a P.O. box in the states. OutlawRC has rules against using a higher voltage battery. You can use them but you are limited to the same voltage of a regular lipo. Tekin ESC's are good but you won't notice a difference between them and the Hobbywing which is cheaper.

There is that too. That's the one downside to ordering his stuff. I don't know if he is just picky about quality and it takes longer for the factory to fulfill his orders, or if he makes an annual bulk order that will arrive this spring? If you email him, he'll tell you when he is expecting new stock.


You might also consider Gens Ace if you need one right away. I've had good luck in the past. My oldest pack is a gens ace, and it still performs good..but it doesn't get used much now that I mostly stopped running 1/10 scale.

Thanks for the local input! Looks like Gripworks and Amainland are out of stock of a lot of stuff, but gogohobbies is round the corner from my office, and since I'm just about the only one at work today I know what I'm doing on my lunch break...

I was going to come out to Outlaw last night but life got in the way. I'll try and come out for the next Wednesday race.

I'll wait and see when SMC expect to have some stock, but right now I'm just trawling through the classifieds on here trying to put a build together. Since I'm trying to keep cost down by going used as much as possible, I already have a US mailbox setup that I will collect from in a couple of weeks.

OK, another question I suspect gets asked a lot but I couldn't find any info by searching:

C-rating. I understand this is the maximum current that can be drawn from the battery during use, or supplied to the battery during charge, as a fraction of its capacity. Taking the SMC battery as an example, it is rated at 4600mAh, 90C. So it can support a current of ~ 415 A. SMC give a solid explanation on their site as to why the C-rating should be treated with caution, and give their measurement and methodology of currents that their batteries support. For this battery it is 85A. Quite a discrepancy!

Now, if we acknowledge that I have no interest in charging this battery in anything under 30 minutes, clearly, I don't need anything more than a 2C rated battery based on charging alone.

Now consider output. Take, for example, a typical ESC that is rated for 120 A continuous current. Based on the C-rating, this battery is massively overkill since it will never be asked to provide anything like 415 A continuous current. If the 85 A value is the value to use, is this a bad combination? Presumably if the ESC tries to draw more current than the battery is rated for one risks voltage drops and brown-outs?

Just to prevent potential (costly) mistakes:

Charging limit for any LiPo I know, is a 1-digit rating, usually something between 1 and 5 - I've never seen the need to charge at more than 2C.

Any 2(or 3)-digit C-rating (usually 25 or above) is for discharging only. And those have to be taken with a ton (rather than just a grain) of salt indeed. As you said: I wouldn't want to see what happens, if you really pulled 415A from that battery for any prolonged period of time. 85A however sounds kinda conservative again, given that this would equal less than 20C (LiPos were rated higher than that even before the numbers quickly grew ridiculously high). But on the other hand, we're dealing with peak currents on the one hand and continuous currents on the other... so the truth probably lies somewhere in between.

Same is true for ESCs by the way - and the manufacturers aren't all that clear about what exactly is rated for the stated current - just the internal components? The whole ESC? Including wires and connectors? So also these 120A have to be taken with a grain (not a ton this times) of salt as well.

Given all that... any modern LiPo from a proven source (not some 5$ no brand) with a rating of 90C should be capable of handling any of today's 540 sized rc car motor on the market. Maybe not 5 times over, but not under either.

In general some esc's I have seen are more willing to draw hard on the battery than others. If the battery can keep up, I have seen a performance boost just by switching ESCs. But, you do risk brownouts if the battery can't keep up (in that case, in general lowering the punch usually fixes that).

As you stated you are looking into the 13.5 4wd blinky class. Personally from what I am seeing, getting a motor that has a more torque basis seems to work better. So when looking for a motor, I personally would keep that mind. Personally I have been quite happy with the performance of the Motiv MC2 motors. Its like they included what other companies ultra torque rotor out of the box. I run my vehicle as a 13.5 blinky in a full mod class and can usually make the amain with the power delivery not being a concern. I actually think it helps my driving as I can't compensate for bad driving with trying to power through everything like I could with a mod motor.

As for batteries, I ended up standardizing on Promatch's new 6000mah HV batteries. These have been working excellent for the money. I also like there customer support.

For radio, definitely go with something that at least has EPA adjustments, exponential for steering is also a plus. I use the Futaba 3PV and the R204GFE receivers since they don't need an antenna. The radio has all the features I need, and is relatively cheap (about $100). Futaba receivers are also relatively cheap too.

Looking forward to hearing how things go for you and welcome back!

Dirk is spot on. Many ratings are tweaked and picked for advertisement purposes. The C rating used on many packs can be a "theoretical limit" based strictly on the chemistry of the cell, not on the complete construction. It doesn't hold up to real world testing.

Here's an example:
I have a B64 just like you, but I have a Tekin RSX and 6.5 turn motor paired with a 4600mah 90C pack. I can typically run for 12 minutes at race pace before the low voltage cutoff hits. In 12 minutes, I consume the whole 4600mah and my charger confirms this amount. This means I averaged 23 amps. If I bought a speed control rated for 30 amps continuous, it would overheat after a few laps.

Most people have found that you need speed controls rated around 40 to 60 amps for spec style classes (13.5 and 17.5) to avoid overheating. For mod, ratings of 100-150 are more typical. Best thing to do is look for someone else's experience with a specific product rather than trusting the numbers on the box.

This whole "C" rating thing is a giant, big, hairy, stupid lie, to be technical about it!

Everyone on the internet believes it, but it is total BS. It means nothing. That's why I'm a fan of what SMC is trying to do, which is to provide meaningful battery info.


On a 1/8 truggy with the high KV ROAR motor (Tekin 2250kv), max peak current I have seen is just under 110A, running on pavement. We're talking instant backflip torque, BTW. This peak amperage is short duration.

Average amp draw, again on 1/8 scale, is going to be 15-20A, assuming constant running on a track.

From what I recall from briefly running 1/10 oval with a 13.5T motor on clay track, my peak amperage was 35A.


Take for example the SMC 4S 14.8v 4,500mAh "True Spec Premium" 85A (90C).

Obviously 85 amps /=90C. 90C = 405amps! A true 90C pack would be capable of a complete and safe discharge in less than 1 second! That is a capacitor, not a battery!

In reality, we're looking at a real ~19C rating, which is good for 85 amps. This is the performance that modern LiPo cells are capable of, and there isn't anything we can buy that is going to discharge significantly faster. But that is okay, because this is plenty!

This is perfectly adequate for everything up to and including a 1/8 scale 4x4 truggy (w/ high KV motor) racing on any surface that isn't blacktop. If you're running on blacktop, you might want that "extreme" battery. But in most situations there are a lot of limitations in the system that will prevent you from maxing out a battery. A more reasonable KV motor draws less current, for example. Other limitations are wire diameter, battery connectors, solder joints, etc.

And don't forget, a 2wd 1/10 on clay track maxed out at 35A! So any pack will be fine. Buying a known brand helps ensure no bad cells that lead to premature failure.

(To answer the ESC question directly, the Amp draw is determined 100% by the motor. A bigger ESC is great, maybe more reliable, as long as it fits in the car and doesn't add too much weight.)

I agree 100%, but just want to clarify that 90C equals discharging any capacity battery in 40 seconds. Still a ludicrous number.

Thanks all for clarifying, and for this:

for making me laugh!

Danny from SMC has answered my questions directly via email also. Super fast and helpful. Two of the 4600mAh/90C/85A shorty packs are now on their way to me from Bego racing. They had stock, and they're in Canada, so no headaches re: international shipping of LiPos.

Also have a Motiv MC2 13.5 on it's way courtesy of the classifieds, so I'm well on my way. Still to go: ESC, charger, servo, radio...

for charger I have been enjoying my icharger setup. If I want to do high amp charging / discharging (with a bank) I can, or, just do regular stuff. nice flexibility.

As for ESC, been using the maclan gear and I have been liking it. For a more cost sensitive selection, Hobbywing can have you covered no sweat.

For servo, multiple options out there, I am liking the Protek 160Ts in my EB410s and YZ2s.

if this is a 13.5 blinky class you can not adjust punch.. and i don't think you can use a High voltage lipo.must be 8.4 max in voltage..but those rules are at tacks i run at..and 13.5 blinky class.

I saw a Savox 1258tg on amazon for $40 the other day. Best deal and an excellent servo. The venom dual charger is cheap and AC/DC it will do everything you need it to mainland has access to them only about a 1/3 of his stuff is actually on his website you have to ask him. Radio do yourself a favor and don't go cheap. You can say definitely feel the difference and you can keep it for a very long time.